Chloroplasts are double-membrane organelles found in plant cells that contain chlorophyll and are the site of photosynthesis. Chloroplast DNA is circular and ranges in size from 120,000 to 170,000 base pairs. It contains approximately 120 genes, including genes that encode proteins involved in photosynthesis and the transcription and translation machinery. Chloroplast DNA replication is semi-conservative and there are typically multiple copies of the chloroplast genome within each chloroplast.
Chloroplasts are organelles found in plant cells and algae that conduct photosynthesis. They contain their own DNA known as the chloroplast genome, which is typically 100-200kb in size and encodes genes for photosynthesis. The chloroplast genome is highly conserved and maternally inherited. It has been used for phylogenetic studies and shows potential for genetic engineering due to high transgene expression and maternal inheritance that prevents gene flow to other species.
Mitochondria contain their own circular genome that is 16.5kb in size and located in the mitochondrial matrix. The mitochondrial genome contains 37 genes that encode 13 proteins, 22 tRNAs, and 2 rRNAs. These genes help produce enzymes and proteins that are crucial for oxidative phosphorylation and energy production in mitochondria. The control region of mitochondrial DNA contains signals that regulate mitochondrial DNA and RNA synthesis.
This document discusses chloroplast DNA (cpDNA). Chloroplasts contain their own circular genome of double-stranded DNA ranging from 140-200kb. The cpDNA contains genes that code for proteins involved in photosynthesis as well as rRNA and tRNA. It has a quadripartite structure containing single copy and inverted repeat regions. Tobacco and liverwort were two of the first chloroplast genomes to be sequenced. Molecular studies of cpDNA regions have been useful for plant systematics. Replication of cpDNA is independent of nuclear DNA and involves enzymes like DNA polymerase and helicase.
The document discusses totipotency in plant cells. Totipotency refers to the ability of single plant cells to regenerate into a whole plant through cell differentiation and tissue culture techniques. The document outlines various tissue culture systems used to study totipotency, including callus culture, suspension culture, single cell culture, and protoplast culture. Factors that influence a cell's ability to express totipotency, such as the explant source and culture conditions, are also discussed.
The mitochondrion is a membrane-bound organelle found in eukaryotic cells. It has an outer membrane, intermembrane space, inner membrane, cristae (folds in the inner membrane), and matrix. The inner membrane contains proteins involved in oxidative phosphorylation and ATP synthesis. Mitochondria contain their own circular DNA separate from the cell's nuclear DNA. Chloroplasts are similar organelles found in plant cells that conduct photosynthesis, and also contain their own DNA.
Single cell culture involves isolating single cells from plant tissue and culturing them on a nutrient medium. There are mechanical and chemical methods for isolation. Cells can be cultured using various techniques like microchamber, microdroplet, or nurse culture techniques. The paper raft nurse culture places isolated cells on nutrient-soaked paper placed on actively growing callus tissue. Single cell culture is important for fundamental studies, mutation analysis, and industrial applications like crop improvement and production of medicinal compounds.
Mitochondria contain their own DNA and play an essential role in cellular respiration by generating ATP. While small, the mitochondrial genome encodes components of the electron transport chain. Manipulation of the mitochondrial genome holds promise for crop improvement due to maternal inheritance and absence of position effects. However, transforming the mitochondrial genome remains challenging due to difficulties incorporating foreign DNA and a lack of selectable markers. Successful manipulation could generate cytoplasmic male sterility for hybrid seed production.
The document discusses organogenesis, which is the development of adventitious organs or primordial from undifferentiated plant cell mass through differentiation. It describes the process, including dedifferentiation and redifferentiation stages. There are two types of organogenesis - direct organogenesis which does not involve callus formation, and indirect organogenesis which involves callus formation. Organogenesis is used in plant tissue culture to regenerate plants through shoot or root cultures and is influenced by factors like explant source and size, plant growth regulators, and culture conditions. It has commercial applications in micropropagation of plants.
Chloroplasts are organelles found in plant cells and algae that conduct photosynthesis. They contain their own DNA known as the chloroplast genome, which is typically 100-200kb in size and encodes genes for photosynthesis. The chloroplast genome is highly conserved and maternally inherited. It has been used for phylogenetic studies and shows potential for genetic engineering due to high transgene expression and maternal inheritance that prevents gene flow to other species.
Mitochondria contain their own circular genome that is 16.5kb in size and located in the mitochondrial matrix. The mitochondrial genome contains 37 genes that encode 13 proteins, 22 tRNAs, and 2 rRNAs. These genes help produce enzymes and proteins that are crucial for oxidative phosphorylation and energy production in mitochondria. The control region of mitochondrial DNA contains signals that regulate mitochondrial DNA and RNA synthesis.
This document discusses chloroplast DNA (cpDNA). Chloroplasts contain their own circular genome of double-stranded DNA ranging from 140-200kb. The cpDNA contains genes that code for proteins involved in photosynthesis as well as rRNA and tRNA. It has a quadripartite structure containing single copy and inverted repeat regions. Tobacco and liverwort were two of the first chloroplast genomes to be sequenced. Molecular studies of cpDNA regions have been useful for plant systematics. Replication of cpDNA is independent of nuclear DNA and involves enzymes like DNA polymerase and helicase.
The document discusses totipotency in plant cells. Totipotency refers to the ability of single plant cells to regenerate into a whole plant through cell differentiation and tissue culture techniques. The document outlines various tissue culture systems used to study totipotency, including callus culture, suspension culture, single cell culture, and protoplast culture. Factors that influence a cell's ability to express totipotency, such as the explant source and culture conditions, are also discussed.
The mitochondrion is a membrane-bound organelle found in eukaryotic cells. It has an outer membrane, intermembrane space, inner membrane, cristae (folds in the inner membrane), and matrix. The inner membrane contains proteins involved in oxidative phosphorylation and ATP synthesis. Mitochondria contain their own circular DNA separate from the cell's nuclear DNA. Chloroplasts are similar organelles found in plant cells that conduct photosynthesis, and also contain their own DNA.
Single cell culture involves isolating single cells from plant tissue and culturing them on a nutrient medium. There are mechanical and chemical methods for isolation. Cells can be cultured using various techniques like microchamber, microdroplet, or nurse culture techniques. The paper raft nurse culture places isolated cells on nutrient-soaked paper placed on actively growing callus tissue. Single cell culture is important for fundamental studies, mutation analysis, and industrial applications like crop improvement and production of medicinal compounds.
Mitochondria contain their own DNA and play an essential role in cellular respiration by generating ATP. While small, the mitochondrial genome encodes components of the electron transport chain. Manipulation of the mitochondrial genome holds promise for crop improvement due to maternal inheritance and absence of position effects. However, transforming the mitochondrial genome remains challenging due to difficulties incorporating foreign DNA and a lack of selectable markers. Successful manipulation could generate cytoplasmic male sterility for hybrid seed production.
The document discusses organogenesis, which is the development of adventitious organs or primordial from undifferentiated plant cell mass through differentiation. It describes the process, including dedifferentiation and redifferentiation stages. There are two types of organogenesis - direct organogenesis which does not involve callus formation, and indirect organogenesis which involves callus formation. Organogenesis is used in plant tissue culture to regenerate plants through shoot or root cultures and is influenced by factors like explant source and size, plant growth regulators, and culture conditions. It has commercial applications in micropropagation of plants.
The document summarizes the mechanism of T-DNA transfer during Agrobacterium tumefaciens infection. It explains that T-DNA is a fragment of DNA transferred from the tumor-inducing (Ti) plasmid of A. tumefaciens into the host plant genome. The T-DNA is bordered by repeats and encodes genes that cause tumors in the plant. Virulence genes are expressed in response to plant signals and produce single-stranded T-DNA, which forms a complex with other proteins and is transported into the plant cell and integrated into the plant nuclear DNA, causing uncontrolled cell growth and tumor formation. The mechanism involves multiple virulence protein complexes and integration of T-DNA is directed by the
This document discusses cytoplasmic male sterility (CMS), a maternally inherited trait in plants where the plant is unable to produce functional pollen. CMS is caused by mitochondrial mutations or rearrangements that interfere with pollen development. Nuclear restorer genes can suppress CMS by interacting with the mitochondrial genes. CMS is used in hybrid seed production systems in many crops.
This document discusses the C-Value Paradox, which is the observation that there is no correlation between the complexity of an organism and the amount of DNA (C-value) in its genome. The document provides examples showing that C-values, or the amount of DNA per haploid cell, can vary widely both within and across species, from 105 base pairs in mycoplasma to over 109 base pairs in mammals. While complexity tends to increase with higher C-values, exceptions exist, demonstrating there is no direct linear relationship between genome size and organism complexity. The term "C-value" refers to the haploid DNA content of a species.
RFLP and RAPD are PCR-based techniques used to analyze genetic variations between individuals. RFLP involves restricting genomic DNA with enzymes, separating fragments via electrophoresis, and comparing patterns. Variations in fragment lengths indicate polymorphisms. RAPD uses short, arbitrary primers to randomly amplify genomic DNA and compare patterns between individuals. Both techniques are useful for constructing genetic maps, identifying genes, distinguishing individuals, and studying genetic diversity and relationships between organisms.
Chromosomes are organized structures that package DNA and proteins in eukaryotic cells. Bacterial genetic material is concentrated in the nucleoid as a single circular DNA chromosome. Eukaryotic cells contain linear chromosomes housed within the nucleus. Chromosomes are made up of DNA, histone proteins, and non-histone proteins. They contain genes and regulatory elements and vary in structure between species.
Restriction enzymes cut DNA molecules at specific recognition sites. Restriction mapping involves digesting an unknown DNA segment with restriction enzymes and analyzing the fragment sizes to determine the locations of restriction sites. One method involves single and double digestions with two enzymes followed by gel electrophoresis to separate the fragments by size. By comparing the fragment patterns between single and double digestions, the positions of each restriction site can be mapped, generating a restriction map of the DNA segment. Restriction mapping was previously important for characterizing cloned DNA but is now easier using DNA sequencing, though analysis of restriction sites remains useful for comparing chromosomal organization between strains.
Cybrids are produced through the fusion of protoplasts from two different plant species, combining the cytoplasm of both but the nucleus of only one species. This technique allows for the transfer of cytoplasmic traits like male sterility between incompatible species. Protoplast isolation, fusion, selection, and regeneration of hybrid cells into whole plants are required to produce cybrids. Cybrids can be used to study cytoplasmic genes and transfer desirable agricultural traits, overcoming sexual incompatibility barriers in plant breeding.
1. There are four main models of DNA replication: rolling circle replication, theta replication, bidirectional replication of linear DNA, and telomere replication.
2. Rolling circle replication involves nicking circular DNA and using one strand as a template to produce multiple copies of the original circular DNA.
3. Theta replication occurs in prokaryotes and involves unwinding circular DNA at an origin of replication and replicating bi-directionally to form a theta-shaped structure.
4. Bidirectional replication of linear DNA involves unwinding DNA at origins of replication and using leading and lagging strand synthesis to replicate in both directions until the ends of the linear genome are reached.
This document provides information on various methods of gene transfer in plants, including Agrobacterium-mediated gene transfer and direct gene transfer methods. Direct methods rely on delivering large amounts of DNA to plant cells through techniques like particle bombardment, electroporation, and microinjection. Agrobacterium-mediated gene transfer utilizes the bacterium Agrobacterium, which transfers genes into plant genomes. The document discusses several direct and Agrobacterium-mediated methods in detail and provides advantages and limitations of each approach.
This document describes the process of protoplast isolation, culture, and fusion from Ankita Singh and Vinars Dawane of the Government Holkar Science College in Indore. It provides an overview of protoplast isolation methods including mechanical, sequential enzymatic, and mixed enzymatic. Sources of protoplasts include leaves, callus cultures, and cell suspension cultures. The viability of isolated protoplasts can be tested through microscopy, tetrazolium reduction, fluorescein diacetate staining, and Evan's blue staining. Protoplasts are cultured through regeneration of cell walls, cell division, and development of callus/whole plants. Protoplast fusion can be spontaneous, mechanical, or
One of the first plausible models to account for the preceding observations was
formulated by Robin Holliday.
The key features of the Holliday model are the formation of heteroduplex DNA; the
creation of a cross bridge; its migration along the two heteroduplex strands,
termed branch migration; the occurrence of mismatch repair; and the
subsequent resolution, or splicing, of the intermediate structure to yield different
typesof recombinant molecules.
The human mitochondrial genome is much smaller than the nuclear genome, consisting of 16,569 base pairs. It contains 37 genes, 13 of which code for proteins involved in cellular respiration. Mitochondrial DNA is inherited solely from the mother and encodes for transfer RNA, ribosomal RNA and proteins that are critical subunits of the oxidative phosphorylation complexes. The human mitochondrial genome has a highly condensed structure with minimal non-coding regions and some overlapping genes. It also differs slightly from the standard genetic code.
Mitochondrial biogenesis is the process by which cells increase mitochondrial numbers. It was first described by John Holloszy in the 1960s, when it was discovered that physical endurance training induced higher mitochondrial content levels, leading to greater glucose uptake by muscles. Mitochondrial biogenesis is activated by numerous different signals during times of cellular stress or in response to environmental stimuli, such as aerobic exercise.
This document discusses different concepts of genes including:
1. Classical concepts viewed genes as units of heredity, transmission of characters, and mutation.
2. Molecular concepts define genes as the entire nucleic acid sequence required for protein synthesis, including coding and regulatory regions.
3. Genes have a fine structure and can be divided into functional units called cistrons based on complementation testing of mutants.
The document discusses the nucleosome model of chromosome structure. It describes how DNA wraps around histone proteins to form nucleosomes, which are the basic units of chromatin. Specifically:
- Nucleosomes consist of 146-166 base pairs of DNA wrapped around an octamer of core histone proteins H2A, H2B, H3, and H4.
- Linker histone H1 binds to the DNA as it enters and exits each nucleosome, forming a structure known as a chromatosome.
- Adjacent nucleosomes are joined by 10-80 base pairs of linker DNA. The histone proteins and DNA interact via ionic bonds between negatively charged DNA and positively charged residues on
Chloroplast DNA (cpDNA) is circular, double-stranded DNA found in chloroplasts. cpDNA ranges in size from 120-2000kb depending on the species. It contains genes that encode components of the chloroplast protein synthesis machinery like rRNA, tRNA, and ribosomal proteins. It also contains genes for photosynthesis proteins. While cpDNA was originally derived from cyanobacteria, chloroplasts have become dependent on the plant cell nucleus for many genes as cpDNA has lost much of its original genetic information over evolutionary time. Comparisons of cpDNA sequences between species has provided insights into chloroplast and plant evolutionary relationships.
This document discusses transposable elements (TEs), which are segments of DNA that can move within genomes. It covers their discovery by Barbara McClintock in corn in the 1940s. TEs are classified into different types based on their structure and mechanism of movement. The document also examines the mechanisms of transposition, mutagenic effects, regulation, and presence of TEs across bacteria, fungi, and eukaryotes like humans. TEs make up a large fraction of genomes and contribute to genetic variation and disease.
This document discusses methods for producing haploid plants through gynogenesis, or haploid production from female gametes. It describes two main methods - ovary culture and ovule culture - for inducing gynogenesis in vitro. Key steps include excising ovaries from plants and culturing them on nutrient media supplemented with hormones to induce parthenogenesis. Successful gynogenesis has been achieved in several plant families, with the frequency of responsive ovules typically being low, around 1-5%. Producing haploid plants provides benefits for genetic studies.
Chloroplasts are organelles found in plant cells and algae that conduct photosynthesis. They have their own DNA and can synthesize some of their own proteins, making them semi-autonomous. Chloroplasts contain chlorophyll and carotenoids which capture light energy. Their internal structure includes an envelope, stroma, and thylakoids where the light reactions take place. It is believed that chloroplasts originated through endosymbiosis between cyanobacteria and eukaryotic cells. The two main stages of photosynthesis are the light reactions on the thylakoid membranes which produce ATP and NADPH, and the dark reactions in the stroma that use these products to fix carbon into sugars.
Chloroplasts are organelles found in plant cells and algae that are responsible for photosynthesis. They have a double membrane and internal thylakoid membranes that form stacks called grana. The thylakoids contain chlorophyll and protein complexes that absorb light energy and convert it chemically during photosynthesis. Chloroplasts have their own DNA and encode approximately 30 proteins involved in photosynthesis, including the important RuBisCO protein. They are similar to mitochondria in that they both generate energy and contain their own genetic material.
The document summarizes the mechanism of T-DNA transfer during Agrobacterium tumefaciens infection. It explains that T-DNA is a fragment of DNA transferred from the tumor-inducing (Ti) plasmid of A. tumefaciens into the host plant genome. The T-DNA is bordered by repeats and encodes genes that cause tumors in the plant. Virulence genes are expressed in response to plant signals and produce single-stranded T-DNA, which forms a complex with other proteins and is transported into the plant cell and integrated into the plant nuclear DNA, causing uncontrolled cell growth and tumor formation. The mechanism involves multiple virulence protein complexes and integration of T-DNA is directed by the
This document discusses cytoplasmic male sterility (CMS), a maternally inherited trait in plants where the plant is unable to produce functional pollen. CMS is caused by mitochondrial mutations or rearrangements that interfere with pollen development. Nuclear restorer genes can suppress CMS by interacting with the mitochondrial genes. CMS is used in hybrid seed production systems in many crops.
This document discusses the C-Value Paradox, which is the observation that there is no correlation between the complexity of an organism and the amount of DNA (C-value) in its genome. The document provides examples showing that C-values, or the amount of DNA per haploid cell, can vary widely both within and across species, from 105 base pairs in mycoplasma to over 109 base pairs in mammals. While complexity tends to increase with higher C-values, exceptions exist, demonstrating there is no direct linear relationship between genome size and organism complexity. The term "C-value" refers to the haploid DNA content of a species.
RFLP and RAPD are PCR-based techniques used to analyze genetic variations between individuals. RFLP involves restricting genomic DNA with enzymes, separating fragments via electrophoresis, and comparing patterns. Variations in fragment lengths indicate polymorphisms. RAPD uses short, arbitrary primers to randomly amplify genomic DNA and compare patterns between individuals. Both techniques are useful for constructing genetic maps, identifying genes, distinguishing individuals, and studying genetic diversity and relationships between organisms.
Chromosomes are organized structures that package DNA and proteins in eukaryotic cells. Bacterial genetic material is concentrated in the nucleoid as a single circular DNA chromosome. Eukaryotic cells contain linear chromosomes housed within the nucleus. Chromosomes are made up of DNA, histone proteins, and non-histone proteins. They contain genes and regulatory elements and vary in structure between species.
Restriction enzymes cut DNA molecules at specific recognition sites. Restriction mapping involves digesting an unknown DNA segment with restriction enzymes and analyzing the fragment sizes to determine the locations of restriction sites. One method involves single and double digestions with two enzymes followed by gel electrophoresis to separate the fragments by size. By comparing the fragment patterns between single and double digestions, the positions of each restriction site can be mapped, generating a restriction map of the DNA segment. Restriction mapping was previously important for characterizing cloned DNA but is now easier using DNA sequencing, though analysis of restriction sites remains useful for comparing chromosomal organization between strains.
Cybrids are produced through the fusion of protoplasts from two different plant species, combining the cytoplasm of both but the nucleus of only one species. This technique allows for the transfer of cytoplasmic traits like male sterility between incompatible species. Protoplast isolation, fusion, selection, and regeneration of hybrid cells into whole plants are required to produce cybrids. Cybrids can be used to study cytoplasmic genes and transfer desirable agricultural traits, overcoming sexual incompatibility barriers in plant breeding.
1. There are four main models of DNA replication: rolling circle replication, theta replication, bidirectional replication of linear DNA, and telomere replication.
2. Rolling circle replication involves nicking circular DNA and using one strand as a template to produce multiple copies of the original circular DNA.
3. Theta replication occurs in prokaryotes and involves unwinding circular DNA at an origin of replication and replicating bi-directionally to form a theta-shaped structure.
4. Bidirectional replication of linear DNA involves unwinding DNA at origins of replication and using leading and lagging strand synthesis to replicate in both directions until the ends of the linear genome are reached.
This document provides information on various methods of gene transfer in plants, including Agrobacterium-mediated gene transfer and direct gene transfer methods. Direct methods rely on delivering large amounts of DNA to plant cells through techniques like particle bombardment, electroporation, and microinjection. Agrobacterium-mediated gene transfer utilizes the bacterium Agrobacterium, which transfers genes into plant genomes. The document discusses several direct and Agrobacterium-mediated methods in detail and provides advantages and limitations of each approach.
This document describes the process of protoplast isolation, culture, and fusion from Ankita Singh and Vinars Dawane of the Government Holkar Science College in Indore. It provides an overview of protoplast isolation methods including mechanical, sequential enzymatic, and mixed enzymatic. Sources of protoplasts include leaves, callus cultures, and cell suspension cultures. The viability of isolated protoplasts can be tested through microscopy, tetrazolium reduction, fluorescein diacetate staining, and Evan's blue staining. Protoplasts are cultured through regeneration of cell walls, cell division, and development of callus/whole plants. Protoplast fusion can be spontaneous, mechanical, or
One of the first plausible models to account for the preceding observations was
formulated by Robin Holliday.
The key features of the Holliday model are the formation of heteroduplex DNA; the
creation of a cross bridge; its migration along the two heteroduplex strands,
termed branch migration; the occurrence of mismatch repair; and the
subsequent resolution, or splicing, of the intermediate structure to yield different
typesof recombinant molecules.
The human mitochondrial genome is much smaller than the nuclear genome, consisting of 16,569 base pairs. It contains 37 genes, 13 of which code for proteins involved in cellular respiration. Mitochondrial DNA is inherited solely from the mother and encodes for transfer RNA, ribosomal RNA and proteins that are critical subunits of the oxidative phosphorylation complexes. The human mitochondrial genome has a highly condensed structure with minimal non-coding regions and some overlapping genes. It also differs slightly from the standard genetic code.
Mitochondrial biogenesis is the process by which cells increase mitochondrial numbers. It was first described by John Holloszy in the 1960s, when it was discovered that physical endurance training induced higher mitochondrial content levels, leading to greater glucose uptake by muscles. Mitochondrial biogenesis is activated by numerous different signals during times of cellular stress or in response to environmental stimuli, such as aerobic exercise.
This document discusses different concepts of genes including:
1. Classical concepts viewed genes as units of heredity, transmission of characters, and mutation.
2. Molecular concepts define genes as the entire nucleic acid sequence required for protein synthesis, including coding and regulatory regions.
3. Genes have a fine structure and can be divided into functional units called cistrons based on complementation testing of mutants.
The document discusses the nucleosome model of chromosome structure. It describes how DNA wraps around histone proteins to form nucleosomes, which are the basic units of chromatin. Specifically:
- Nucleosomes consist of 146-166 base pairs of DNA wrapped around an octamer of core histone proteins H2A, H2B, H3, and H4.
- Linker histone H1 binds to the DNA as it enters and exits each nucleosome, forming a structure known as a chromatosome.
- Adjacent nucleosomes are joined by 10-80 base pairs of linker DNA. The histone proteins and DNA interact via ionic bonds between negatively charged DNA and positively charged residues on
Chloroplast DNA (cpDNA) is circular, double-stranded DNA found in chloroplasts. cpDNA ranges in size from 120-2000kb depending on the species. It contains genes that encode components of the chloroplast protein synthesis machinery like rRNA, tRNA, and ribosomal proteins. It also contains genes for photosynthesis proteins. While cpDNA was originally derived from cyanobacteria, chloroplasts have become dependent on the plant cell nucleus for many genes as cpDNA has lost much of its original genetic information over evolutionary time. Comparisons of cpDNA sequences between species has provided insights into chloroplast and plant evolutionary relationships.
This document discusses transposable elements (TEs), which are segments of DNA that can move within genomes. It covers their discovery by Barbara McClintock in corn in the 1940s. TEs are classified into different types based on their structure and mechanism of movement. The document also examines the mechanisms of transposition, mutagenic effects, regulation, and presence of TEs across bacteria, fungi, and eukaryotes like humans. TEs make up a large fraction of genomes and contribute to genetic variation and disease.
This document discusses methods for producing haploid plants through gynogenesis, or haploid production from female gametes. It describes two main methods - ovary culture and ovule culture - for inducing gynogenesis in vitro. Key steps include excising ovaries from plants and culturing them on nutrient media supplemented with hormones to induce parthenogenesis. Successful gynogenesis has been achieved in several plant families, with the frequency of responsive ovules typically being low, around 1-5%. Producing haploid plants provides benefits for genetic studies.
Chloroplasts are organelles found in plant cells and algae that conduct photosynthesis. They have their own DNA and can synthesize some of their own proteins, making them semi-autonomous. Chloroplasts contain chlorophyll and carotenoids which capture light energy. Their internal structure includes an envelope, stroma, and thylakoids where the light reactions take place. It is believed that chloroplasts originated through endosymbiosis between cyanobacteria and eukaryotic cells. The two main stages of photosynthesis are the light reactions on the thylakoid membranes which produce ATP and NADPH, and the dark reactions in the stroma that use these products to fix carbon into sugars.
Chloroplasts are organelles found in plant cells and algae that are responsible for photosynthesis. They have a double membrane and internal thylakoid membranes that form stacks called grana. The thylakoids contain chlorophyll and protein complexes that absorb light energy and convert it chemically during photosynthesis. Chloroplasts have their own DNA and encode approximately 30 proteins involved in photosynthesis, including the important RuBisCO protein. They are similar to mitochondria in that they both generate energy and contain their own genetic material.
- Chloroplasts are organelles found in plant cells and algae that conduct photosynthesis. They contain chlorophyll and have a double membrane structure.
- The inner membranes of chloroplasts form sac-like structures called thylakoids, which contain the pigments and proteins involved in the light-dependent reactions of photosynthesis. These reactions trap light energy from the sun and use it to convert water to oxygen and produce ATP and NADPH.
- The products of the light reactions, ATP and NADPH, are used in the light-independent Calvin cycle which occurs in the chloroplast stroma. The Calvin cycle converts carbon dioxide into glucose using the energy from ATP and NADPH.
ORGANELLAR GENOME AND ORGANELLAR INHERITENCERanjan Kumar
This document summarizes organellar genomes and inheritance. It discusses the history of discovering DNA in chloroplasts and mitochondria in the 1960s. Key points:
- Chloroplast and mitochondrial DNA are found in plant and animal cells and are inherited separately from nuclear genes.
- Endosymbiotic theory proposes that chloroplasts and mitochondria originated from engulfed photosynthetic and aerobic bacteria, respectively.
- Organellar DNA replication and gene expression occur within the organelles. Uniparental, non-Mendelian inheritance is observed.
- Differences exist between organellar and nuclear DNA as well as between chloroplast and mitochondrial genomes.
Dr.S.KARTHIKUMAR
Associate Professor
Department of Biotechnology
Kamaraj College of Engineering and Technology, K.Vellakulam-625701, TN, India
Email: skarthikumar@gmail.com
Chloroplasts are organelles found in plant cells and eukaryotic photosynthetic organisms that conduct photosynthesis. They have a double-layered envelope and contain a granular stroma matrix and lamellar thylakoid membranes that are the site of the light reactions of photosynthesis. Chloroplasts also contain DNA and ribosomes and perform key functions like carbon fixation and photorespiration. Their main pigment, chlorophyll, absorbs light energy and drives the photosynthetic process within the chloroplast.
Chloroplasts are organelles found in plant cells and algal cells that conduct photosynthesis. They have an outer and inner membrane and contain stacks of thylakoids that harbor chlorophyll. During photosynthesis, chloroplasts absorb sunlight and use it to convert carbon dioxide and water into oxygen and energy-rich glucose to fuel the plant's growth. Chloroplasts vary in shape, size, and number between plant species and cell types. They play a vital role in producing food and oxygen for ecosystems.
The document discusses mitochondria and chloroplasts. It provides definitions and descriptions of their structures, functions, and genomes. Mitochondria are organelles that convert food into ATP and are involved in cell death and growth. They have outer and inner membranes that create compartments. Chloroplasts contain chlorophyll and are the sites of photosynthesis. They are bound by outer and inner membranes that create a fluid-filled interior with thylakoid membranes where light reactions occur. Both organelles have semi-autonomous genomes that interact with the cell's nuclear genome.
1. Chloroplast DNA (cpDNA) is circular DNA located in chloroplasts that contains genes essential for photosynthesis. These genes are inherited extra-nuclearly and do not follow Mendelian patterns of inheritance.
2. In 1909, Correns discovered that four o'clock plant leaf color was inherited maternally through the chloroplast rather than through nuclear genes. This was an early example of non-Mendelian cytoplasmic inheritance.
3. Chloroplast genes code for proteins involved in photosynthesis, though nuclear genes are also required. Mutations in chloroplast genes often result in white or yellow leaves due to disrupted chlorophyll production.
chloroplast being the second semi-autonomous organelle of the plant cell also harbours its genome. the presentation includes various characteristic features of this organelle genome along with its functional pecularities and significance
Extra nuclear genome.power point presentationharitha shankar
This document discusses extra nuclear genomes, specifically chloroplast DNA and mitochondrial DNA. It provides details on:
1) Chloroplast DNA is circular DNA ranging from 120-155kb that encodes around 120 genes and is present in multiple copies within chloroplasts.
2) Mitochondrial DNA also exists as circular DNA that varies in size and encodes RNA and some proteins. In mammals it is 16.5kb while in plants it can be over 100kb.
3) Both organelle genomes are transcribed and translated within their respective organelles but rely on nuclear genes for some functions like replication machinery. They have their own genetic codes that differ slightly from nuclear codes.
Mitochondrial and chloroplast DNA are circular and much smaller than nuclear DNA. They contain genes that code for proteins involved in cellular processes like energy production. Mitochondrial DNA is maternally inherited, while chloroplast DNA can be biparentally or maternally inherited depending on the species. Mutations in mitochondrial DNA can cause diseases by disrupting cellular functions carried out by mitochondria.
Chloroplasts are double-membraned organelles found in plant cells and algae that conduct photosynthesis. They contain chlorophyll and have a circular DNA. Chloroplasts were first observed in 1837 and were given their current name in 1884. It is believed they evolved from cyanobacteria through endosymbiosis. Chloroplasts have an inner and outer membrane, stroma, thylakoids, grana, and lumen. Photosynthesis takes place in two stages - the light reaction uses chloroplast pigments to convert sunlight to chemical energy, while the dark reaction fixes carbon using products of the light reaction.
Chloroplasts are organelles found in plant cells that perform photosynthesis. They have an outer and inner membrane that enclose the stroma. Within the stroma are thylakoids which are membranous sacs that contain chlorophyll. Thylakoids are stacked into grana where the light reactions of photosynthesis take place, producing ATP and NADPH. The light-independent reactions then use these products in the stroma to fix carbon and produce sugars through the Calvin cycle. Other structures include the intermembrane space, peripheral reticulum, plastoglobuli, chloroplast ribosomes, and starch granules for short-term storage of sugars.
Structure And Types Of Nucleic Acids by SandeepSandeep Chede
This document discusses the structure and types of nucleic acids DNA and RNA. It provides details on:
1) The chemical components and structure of DNA, including that it is a double-stranded helix with complementary base pairing between strands.
2) The three main types of DNA structures - A-DNA, B-DNA, and Z-DNA - and their distinguishing characteristics such as helical shape, groove size, and environmental conditions under which each form is favored.
3) The structure and function of mitochondrial DNA, including that it is maternally inherited and encodes 37 essential genes in humans.
4) The types and functions of RNA, including ribosomal RNA, messenger RNA, and
Chloroplasts are membrane-bound organelles found in plant cells and algae that contain chlorophyll and are the site of photosynthesis. They have an outer and inner membrane, with an intermembrane space between. Inside is the stroma, which contains chloroplast DNA, ribosomes, and the thylakoid system of membranes where photosynthesis occurs. Chloroplasts contain chlorophyll and other pigments like carotenoids and absorb light to drive the light-dependent reactions of photosynthesis, producing ATP and NADPH for the Calvin cycle to fix carbon and produce sugars. Their primary function is photosynthesis to produce food for plants.
The term Chloroplast was first described by Nehemiah Grew and Antonie Van Leeuwenhoek.
“Chloro” means green while“ Plast” means living.
Chlorophyll pigments present in the chloroplast imparts the green colour to plants.
Chloroplasts are present in plants and other eukaryotic organisms that conducts photosynthesis
Responsible for photosynthesis, are in many respects similar to mitochondria.
Chloroplasts are larger and more complex than mitochondria, and they perform several critical tasks in addition to the generation of ATP.
Chloroplasts synthesize amino acids, fatty acids, and the lipid components of their own membranes.
The reduction of nitrite (NO2-) to ammonia (NH3), an essential step in the incorporation of nitrogen into organic compounds, also occurs in chloroplasts.
Mitochondria are membrane-bound organelles found in eukaryotic cells that produce energy through respiration. They were first observed by Richard Altmann and named by Benda. Mitochondria have an outer and inner membrane, with cristae extending inward from the inner membrane. They contain their own DNA and ribosomes. Mitochondria play key roles in cellular metabolism and energy production.
Polytene chromosome with respect to historical basis, occurrence, structural organisation, bands and inter bands, puff are briefly stated for basic idea.
You may find this interesting understand the reason behind the gaint structure of these chromosomes.
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Chloroplasts are organelles found in plant cells and eukaryotic photosynthetic organisms that conduct photosynthesis. They have a double membrane envelope and contain a stroma, thylakoids, and chloroplast DNA. Thylakoids contain light-absorbing pigments and perform the light reactions of photosynthesis, while the stroma is the site of the dark reactions where CO2 is fixed into sugars. Chloroplasts are essential for photosynthesis as they trap solar energy to produce ATP and NADPH via light reactions, and use these products to fix CO2 into carbohydrates via dark reactions, providing energy for plant growth.
Garlic is a cultivated plant that grows from a bulb and is known for its strong odor and flavor. It is grown worldwide for both culinary and medicinal purposes. There are over 300 varieties of garlic cultivated globally, with the main varieties being hardneck and softneck garlic. In India, garlic is mainly produced in states like Rajasthan, Uttar Pradesh, and Gujarat. It is cultivated through planting individual cloves in the ground and providing irrigation and fertilizers to support growth. Garlic bulbs are harvested after around 3-6 months of growth when the leaves begin to dry up.
Penicillin was the first antibiotic to be discovered in 1928 from the fungus Penicillium notatum. It was purified in the 1940s and used widely during World War 2. Industrial production involves growing the fungus Penicillium chrysogenum in large fermenters, extracting and purifying the penicillin. The fermentation process yields about 50 grams of penicillin per cubic meter now compared to 1 milligram previously. Purification involves filtration, extraction into organic solvents like butyl acetate, and crystallization to produce the final product.
The document discusses absorption and action spectra. It defines absorption spectra as showing the wavelengths of light absorbed by a pigment, while action spectra show the rate of photosynthesis at different wavelengths. Both chlorophyll absorption and photosynthetic action spectra have peaks in the blue and red parts of the visible spectrum, with a trough in the green, indicating these wavelengths are most and least effective for photosynthesis respectively. There is generally strong correlation between absorption and action spectra since pigment absorption provides the energy for photosynthesis.
This document summarizes a study that collected and identified microalgae from various freshwater bodies in India. Samples were taken from 8 sites in November and December 2018 and isolated through serial dilution. A total of 70 microalgal species were observed, with 50 identified. The most abundant phylum was Chlorophyceae, making up 46% of identified species. Water parameters like pH and temperature were also measured. The aim was to document the diversity of microalgae and understand how they vary across sites and contribute to ecosystems as primary producers.
Healing gardens can enhance the hospital healing process by providing a stress-relieving environment. A proposed pyramidal healing garden would not only benefit patients but also accelerate plant growth. Studies found that placing patients under the pyramid reduced pain and healed burns faster. Growing pets like puppies and kittens in hospitals could also help patients heal from hospital stress. Medicinal and fragrant plants could purify the air. The pyramidal garden aims to relieve patient stress and create an energizing environment that benefits both plants and patients through its amplified signals.
This document provides information on several species of barb fish that are popular aquarium fish. It discusses their natural habitats, behaviors, tank requirements, compatibility with other fish, appearance, and care needs. Key details include that barbs are social schooling fish that do best in groups of 5 or more in aerated, acidic-neutral water. They are active swimmers and should be kept with tankmates that can tolerate boisterous behavior. Information is given on the black ruby barb, denison barb, gold barb, rosy barb, tiger barb, tinfoil barb, zebra barb, and their scientific names, sizes, temperatures, pH and hardness requirements.
Plants that lived millions of years ago and became embedded in stratified rock provide the most accurate links in plant evolution and genetics. Fossils are preserved in many ways such as compressions, impressions, incrustations, casts, petrification, and inclusion in amber, with each method preserving different details of the plant. Paleobotany is important for reconstructing ancient ecosystems, climate, and the development and evolution of plants by studying plant fossils preserved in various forms and using techniques like radiocarbon dating to determine the age of fossils.
Janaki Ammal was an Indian botanist who made significant contributions to the understanding of polyploidy in sugarcane. She conducted extensive research at the Sugarcane Breeding Institute in Coimbatore, analyzing chromosome numbers and varieties to select the best for cross-breeding sweeter hybrids. Her work played a vital role in improving sugarcane yields in India. Ammal had a distinguished career as a scientist and held several leadership roles, including as Director-General of the Botanical Survey of India. She was honored with the Padma Shri for her pioneering research in cytogenetics and service to Indian botany and agriculture.
Yoga has origins dating back over 5,000 years to ancient India. Its early teachings were orally transmitted and written on fragile materials, resulting in uncertainty around its earliest history. Yoga developed through four main periods: pre-classical yoga saw its inclusion in Vedic texts; classical yoga was systematized by Patanjali's Yoga Sutras; post-classical yoga incorporated Tantra and a focus on the physical body; and in modern times, Hatha yoga has spread globally with pioneers popularizing its various styles and schools.
- "Ozymandias" is a 14-line sonnet written by Percy Bysshe Shelley in 1817 about a traveler's encounter with the ruined statue of the once-mighty Egyptian pharaoh Rameses II.
- The traveler tells the speaker of coming upon two vast stone legs without a body and a crumbling stone head half buried in the desert sand, which were all that remained of a statue with an inscription claiming "My name is Ozymandias, king of kings."
- Around the decaying remains, nothing else survives except the "lone and level sands" stretching as far as the eye can see, vividly portraying how the vanity and
Marchantia is a genus of liverworts that reproduces both sexually and asexually. The plant body is a flattened thallus with dorsal midribs that bear gemmae cups for asexual reproduction. Male and female gametophytes develop on separate plants. During sexual reproduction, sperm from the male antheridia fertilize eggs in the female archegonia to form zygotes. These zygotes develop into sporophytes that produce spores through meiosis. The spores disperse and can germinate to form new gametophyte generations.
This document discusses different types of cell division including mitosis, meiosis, and amitosis. It provides detailed descriptions of the stages and processes involved in mitosis, including interphase, prophase, metaphase, anaphase, telophase, and cytokinesis. It notes that mitosis is important for the growth and multiplication of cells in both unicellular and multicellular organisms. It also discusses the significance of mitosis and its role in cancer development and cloning.
1) Gastrulation in frog embryos involves the inward migration of cells through the blastopore, converting the blastula into a gastrula with three germ layers.
2) Specifically, endodermal and mesodermal cells involute inward, with mesoderm occupying the region between endoderm and ectoderm. The blastopore gradually closes.
3) This process transforms the spherical blastula into a bilaterally symmetrical gastrula, which then undergoes neurulation to form the neural tube and become a neurula.
Evidence of Jet Activity from the Secondary Black Hole in the OJ 287 Binary S...Sérgio Sacani
Wereport the study of a huge optical intraday flare on 2021 November 12 at 2 a.m. UT in the blazar OJ287. In the binary black hole model, it is associated with an impact of the secondary black hole on the accretion disk of the primary. Our multifrequency observing campaign was set up to search for such a signature of the impact based on a prediction made 8 yr earlier. The first I-band results of the flare have already been reported by Kishore et al. (2024). Here we combine these data with our monitoring in the R-band. There is a big change in the R–I spectral index by 1.0 ±0.1 between the normal background and the flare, suggesting a new component of radiation. The polarization variation during the rise of the flare suggests the same. The limits on the source size place it most reasonably in the jet of the secondary BH. We then ask why we have not seen this phenomenon before. We show that OJ287 was never before observed with sufficient sensitivity on the night when the flare should have happened according to the binary model. We also study the probability that this flare is just an oversized example of intraday variability using the Krakow data set of intense monitoring between 2015 and 2023. We find that the occurrence of a flare of this size and rapidity is unlikely. In machine-readable Tables 1 and 2, we give the full orbit-linked historical light curve of OJ287 as well as the dense monitoring sample of Krakow.
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...Scintica Instrumentation
Targeting Hsp90 and its pathogen Orthologs with Tethered Inhibitors as a Diagnostic and Therapeutic Strategy for cancer and infectious diseases with Dr. Timothy Haystead.
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdfSelcen Ozturkcan
Ozturkcan, S., Berndt, A., & Angelakis, A. (2024). Mending clothing to support sustainable fashion. Presented at the 31st Annual Conference by the Consortium for International Marketing Research (CIMaR), 10-13 Jun 2024, University of Gävle, Sweden.
TOPIC OF DISCUSSION: CENTRIFUGATION SLIDESHARE.pptxshubhijain836
Centrifugation is a powerful technique used in laboratories to separate components of a heterogeneous mixture based on their density. This process utilizes centrifugal force to rapidly spin samples, causing denser particles to migrate outward more quickly than lighter ones. As a result, distinct layers form within the sample tube, allowing for easy isolation and purification of target substances.
SDSS1335+0728: The awakening of a ∼ 106M⊙ black hole⋆Sérgio Sacani
Context. The early-type galaxy SDSS J133519.91+072807.4 (hereafter SDSS1335+0728), which had exhibited no prior optical variations during the preceding two decades, began showing significant nuclear variability in the Zwicky Transient Facility (ZTF) alert stream from December 2019 (as ZTF19acnskyy). This variability behaviour, coupled with the host-galaxy properties, suggests that SDSS1335+0728 hosts a ∼ 106M⊙ black hole (BH) that is currently in the process of ‘turning on’. Aims. We present a multi-wavelength photometric analysis and spectroscopic follow-up performed with the aim of better understanding the origin of the nuclear variations detected in SDSS1335+0728. Methods. We used archival photometry (from WISE, 2MASS, SDSS, GALEX, eROSITA) and spectroscopic data (from SDSS and LAMOST) to study the state of SDSS1335+0728 prior to December 2019, and new observations from Swift, SOAR/Goodman, VLT/X-shooter, and Keck/LRIS taken after its turn-on to characterise its current state. We analysed the variability of SDSS1335+0728 in the X-ray/UV/optical/mid-infrared range, modelled its spectral energy distribution prior to and after December 2019, and studied the evolution of its UV/optical spectra. Results. From our multi-wavelength photometric analysis, we find that: (a) since 2021, the UV flux (from Swift/UVOT observations) is four times brighter than the flux reported by GALEX in 2004; (b) since June 2022, the mid-infrared flux has risen more than two times, and the W1−W2 WISE colour has become redder; and (c) since February 2024, the source has begun showing X-ray emission. From our spectroscopic follow-up, we see that (i) the narrow emission line ratios are now consistent with a more energetic ionising continuum; (ii) broad emission lines are not detected; and (iii) the [OIII] line increased its flux ∼ 3.6 years after the first ZTF alert, which implies a relatively compact narrow-line-emitting region. Conclusions. We conclude that the variations observed in SDSS1335+0728 could be either explained by a ∼ 106M⊙ AGN that is just turning on or by an exotic tidal disruption event (TDE). If the former is true, SDSS1335+0728 is one of the strongest cases of an AGNobserved in the process of activating. If the latter were found to be the case, it would correspond to the longest and faintest TDE ever observed (or another class of still unknown nuclear transient). Future observations of SDSS1335+0728 are crucial to further understand its behaviour. Key words. galaxies: active– accretion, accretion discs– galaxies: individual: SDSS J133519.91+072807.4
Anti-Universe And Emergent Gravity and the Dark UniverseSérgio Sacani
Recent theoretical progress indicates that spacetime and gravity emerge together from the entanglement structure of an underlying microscopic theory. These ideas are best understood in Anti-de Sitter space, where they rely on the area law for entanglement entropy. The extension to de Sitter space requires taking into account the entropy and temperature associated with the cosmological horizon. Using insights from string theory, black hole physics and quantum information theory we argue that the positive dark energy leads to a thermal volume law contribution to the entropy that overtakes the area law precisely at the cosmological horizon. Due to the competition between area and volume law entanglement the microscopic de Sitter states do not thermalise at sub-Hubble scales: they exhibit memory effects in the form of an entropy displacement caused by matter. The emergent laws of gravity contain an additional ‘dark’ gravitational force describing the ‘elastic’ response due to the entropy displacement. We derive an estimate of the strength of this extra force in terms of the baryonic mass, Newton’s constant and the Hubble acceleration scale a0 = cH0, and provide evidence for the fact that this additional ‘dark gravity force’ explains the observed phenomena in galaxies and clusters currently attributed to dark matter.
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDSSérgio Sacani
The pathway(s) to seeding the massive black holes (MBHs) that exist at the heart of galaxies in the present and distant Universe remains an unsolved problem. Here we categorise, describe and quantitatively discuss the formation pathways of both light and heavy seeds. We emphasise that the most recent computational models suggest that rather than a bimodal-like mass spectrum between light and heavy seeds with light at one end and heavy at the other that instead a continuum exists. Light seeds being more ubiquitous and the heavier seeds becoming less and less abundant due the rarer environmental conditions required for their formation. We therefore examine the different mechanisms that give rise to different seed mass spectrums. We show how and why the mechanisms that produce the heaviest seeds are also among the rarest events in the Universe and are hence extremely unlikely to be the seeds for the vast majority of the MBH population. We quantify, within the limits of the current large uncertainties in the seeding processes, the expected number densities of the seed mass spectrum. We argue that light seeds must be at least 103 to 105 times more numerous than heavy seeds to explain the MBH population as a whole. Based on our current understanding of the seed population this makes heavy seeds (Mseed > 103 M⊙) a significantly more likely pathway given that heavy seeds have an abundance pattern than is close to and likely in excess of 10−4 compared to light seeds. Finally, we examine the current state-of-the-art in numerical calculations and recent observations and plot a path forward for near-future advances in both domains.
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...Sérgio Sacani
We present the JWST discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS
+
53.13485
−
27.82088
with a host spectroscopic redshift of
2.903
±
0.007
. The transient was identified in deep James Webb Space Telescope (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic followup with NIRCam and NIRSpec, respectively, confirm the redshift and yield UV-NIR light-curve, NIR color, and spectroscopic information all consistent with a Type Ia classification. Despite its classification as a likely SN Ia, SN 2023adsy is both fairly red (
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∼
0.9
) despite a host galaxy with low-extinction and has a high Ca II velocity (
19
,
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km/s) compared to the general population of SNe Ia. While these characteristics are consistent with some Ca-rich SNe Ia, particularly SN 2016hnk, SN 2023adsy is intrinsically brighter than the low-
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Ca-rich population. Although such an object is too red for any low-
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cosmological sample, we apply a fiducial standardization approach to SN 2023adsy and find that the SN 2023adsy luminosity distance measurement is in excellent agreement (
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1
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) with
Λ
CDM. Therefore unlike low-
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Ca-rich SNe Ia, SN 2023adsy is standardizable and gives no indication that SN Ia standardized luminosities change significantly with redshift. A larger sample of distant SNe Ia is required to determine if SN Ia population characteristics at high-
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truly diverge from their low-
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counterparts, and to confirm that standardized luminosities nevertheless remain constant with redshift.
3. Chloroplast Definition
“Chloroplast is an organelle that contains the photosynthetic pigment chlorophyll that captures sunlight and converts it into
useful energy, thereby, releasing oxygen from water. “
Chloroplasts are found in all higher plants. It is oval or biconvex, found within the mesophyll of the plant cell. The size of
the chloroplast usually varies between 4-6 µm in diameter and 1-3 µm in thickness. They are double-membrane organelle
with the presence of outer, inner and intermembrane space. There are two distinct regions present inside a chloroplast known
as the grana and stroma.
Grana are made up of stacks of disc-shaped structures known as thylakoids. The grana of the chloroplast consists of
chlorophyll pigments and are the functional units of chloroplasts.
Stroma is the homogenous matrix which contains grana and is similar to the cytoplasm in cells in which all the organelles are
embedded. Stroma also contains various enzymes, DNA, ribosomes, and other substances. Stroma lamellae function by
connecting the stacks of thylakoid sacs.
4. Functions of Chloroplast
The most important function of the chloroplast is to synthesize food by the process of photosynthesis.
Absorbs light energy and converts it into chemical energy.
Chloroplast has a structure called chlorophyll which functions by trapping the solar energy and used for the synthesis
of food in all green plants.
Produces NADPH and molecular oxygen (O2) by photolysis of water.
Produces ATP – Adenosine triphosphate by the process of photosynthesis.
The carbon dioxide (CO2) obtained from the air is used to generate carbon and sugar during the Calvin Cycle or dark
reaction of photosynthesis.
5. Organization of Chloroplast
Structural organization of chloroplast is signified by the presence of double membrane envelope and soluble phase, the
stroma, and an internal membrane system, the thylakoids. Both thylakoid and stromal systems are committed for light
reaction and carbon dioxide fixation respectively.
Chloroplast attains diversified shapes. Higher plants exhibit lens shaped chloroplasts in their cytosol. The size
measures anywhere between 5 and 10 pm long.
Stroma contains soluble enzymes known as rubisco (ribulose bisphosphate carboxylase-oxygenase), accountable for
upto 50% of the total leaf proteins. Its molecular weight of 500,000 consists of eight large subunits and eight small
subunits and it is credited with one of the most abundant available protein in nature. It executes photosynthesis by
accepting carbon dioxide as its substrate and reduces this to carbohydrate status.
6. Several members of monocots show marginal deviation in their CO2 fixation process, generally known as C4 plants. The
maize, for example, is a C4 plant in which initial carbon dioxide fixation occurs in leaf mesophyll cells containing
chloroplasts, which lack rubisco and ultimately devoid of starch.
The enzyme PEP carboxylase (phospho enol pyruvate carboxylase) acts as a major enzyme, catalyses first half of the
reaction by forming four carbon oxaloacetate, which is then converted into aspartic acid and malic acid which are exported
to bundle sheath cells, where they are decarboxylated and CO2 is refixed by bundle sheath due to the rubisco and operate
the Calvin cycle.
In addition to their role in performing photosynthesis and carbon metabolism, chloroplasts are involved in other vital
functions such as the synthesis of amino acids and nucleotides, protein synthesis, pigments and hormones.
7. Chloroplast DNA
Chloroplast DNA is comparatively large, circular in nature, commonly denoted
as ctDNA. The presence of DNA in chloroplast was first identified in 1962.
The size of chloroplast DNA is usually 140 kb in higher plants and less than
190 kb in lower eukaryotic plants. However, the size of the ctDNA is generally
between 120 and 155 kb.
8. History of cpDNA
The presence of DNA in chloroplasts was first suggested during the early 1950s . Subsequent studies supported the
existence of extranuclear DNA in the chloroplasts of other plant species came about in the late 1950s and early 1960s.
In 1963, Masahiro R. Ishida, together with Ruth Sager, was acknowledged for being the first to extract the chloroplast
DNA. They were able to isolate chloroplasts from the alga, Chlamydomonas, and found an enriched satellite DNA that
has a buoyant density of 1,702 gm/cm3 and GC content of 39.3%.2 Soon, more DNA molecules were obtained from the
chloroplasts of higher plant species by other independent research teams.
The demonstration of a unique DNA species in chloroplasts has led to intensive studies of both the structure of
chloroplast DNA and its expression. These studies have been accelerated by gene cloning and DNA sequencing
techniques developed in the mid-1970s.
9. The first physical map of chloroplast DNA was constructed for maize in 1976 and the first chloroplast
gene was cloned in 1977. These studies and others established a new field, 'chloroplast molecular
biology,' and the organization and expression of chloroplast genomes were among the most extensively
studied fields in plant molecular biology.
After 10 years the entire sequence of the chloroplast DNA was determined in tobacco, liverwort and
then in rice. Sequences for defined regions of many other chloroplast DNAs have also been completed,
but the identification and expression analysis of many chloroplast genes have mostly been done with
several representative higher plants and green algae.
10.
11.
12. Size of Chloroplast genomes
Almost all chloroplast DNAs fall into the size range of 120 to 160 kb.
Among chloroplast genomes for which an accurate size estimate exists, the siphonous green alga Codium fragile has the
smallest chloroplast DNA known (85 kb) while the green alga Chlamydomonas moewusii has the largest (292 kb).
The chloroplast genome of the giant green alga Acetabularia is more complex than those of other plants and its genome
size appears to be 2000 kb.
The population of chloroplast DNA in a plant species is generally homogeneous. However, the chloroplast genome of
the brown alga Pylaiella littoralis has been shown to be composed of two different circular DNA molecules of 133 kb
and 58 kb in size
One of the outstanding features of the chloroplast DNAs found in most plants is the presence of a large inverted repeat
(IR) which ranges from 6 to 76 kb in length. Most of the size variation among land plant chloroplast DNAs can be
accounted for by changes in the length of the IR. The segments of the IR are separated by one large and one small
single-copy region (LSC and SSC, respectively).
Pea, broad bean, alfalfa and pine chloroplast DNAs are exceptions to this pattern and lack IRs
13. Structure and Characteristics
cpDNA is typically circular, and consists of base pairs ranging from 120,000 to 170,000 long. It has about 120
genes. Several copies of cpDNA molecules are present in each chloroplast. A chloroplast is one of the plastids, the
others are chromoplasts and leucoplasts. The chloroplasts are the photosynthetic type of plastid containing high
amounts of chlorophyll (the green pigment). The chloroplast has at least three membrane systems: outer membrane,
inner membrane, and thylakoid system (the site of photosynthesis). The stroma, which is the matrix of the
chloroplast, in between the grana contains cpDNA, enzymes, molecules, and ions. It is where the dark reactions of
photosynthesis occur. Most cpDNAs contain inverted repeats of about 4,000 to 25,000 base pairs long, with the
exceptions of pea plants and certain red algae that do not have inverted repeats in their cpDNAs.
14. By employing DNA-binding flourescent dye several copies of the plastid genome have been visualized. The size of the chloroplast
genome can be comparable to bacteriophage T4 (165 kb). There are many copies of circular DNA in chloroplast, i.e., between 20
and 100 copies per chloroplast in higher plants.
In higher plants, chloroplast DNA exists as double-stranded circular molecule. Unlike nuclear DNA, it does not contain 5-methyl
cytosine and is not associated with histones. Its buoyant density is around 1.690 gmL-1, which is corresponding to G + C ratio to
approximately 37 per cent.
Measurement is based on DNA-DNA association through light on the potential coding capacity of the plastome. The molecular
weight of the plastid DNA is between 80 and 100 million, which corresponds between 12,000 and 150,000 base pairs
15.
16. Chloroplast contains one type of chromosome and assumes polyploid status. In young leaves, number of chloroplast attains 200 or
more. DNA replication in plastid is semi conservative. In chloroplasts of maize and pea, DNA replication begins at two sites about
7000 base pairs apart and proceeds in both the directions.
Chloroplasts contain introns. They fall into two classes. One of the intron classes is located in tRNA genes and another class in
protein coding region. Several photosynthetic related genes that encode proteins are located in thylakoid membrane.
Several evidences confirmed that chloroplast DNA contains 45 genes coding for RNA and 27 genes coding for proteins. These
proteins are mainly involved in chloroplast gene expression. The genes coding for proteins of the thylakoid membrane and another 10
gene products are committed for electron transport process.
A restriction map for maize chloroplast DNA (139 kb) reveals that plastome contains unique 22,000 base pair inverted repeated
sequence, containing the rRNA genes (Fig.). Some other plastome with similar repeats contains two copies of rRNA genes.
17.
18. The Characteristics of Chloroplast Gene
Expression
The chloroplast gene-expression system is evolutionarily derived from photosynthetic bacteria that were endocytosed by
ancestral eukaryotic plant cells more than 1.5 billion years ago . During evolution, chloroplasts have retained core components
of the gene-expression apparatus from their prokaryotic progenitors. In addition, they obtained many eukaryotic properties, such
as RNA editing, the prevalence of introns, and complex processing patterns from polycistronic RNA precursors . Here, we
briefly describe the processes of chloroplast gene expression in plants .
19.
20. Overview of chloroplast gene expression. In plants, most chloroplast genes are organized as operons and
are controlled by single promoters (bent arrow). These genes are transcribed by two distinct types of RNA
polymerase: Nucleus-encoded RNA polymerase (NEP) and plastid-encoded RNA polymerase (PEP). The
resulting primary transcripts require several processing steps to form mature mRNA, including 50 and 30
trimming, intercistronic cleavage, RNA splicing, and RNA editing. In order for these events to take place,
numerous nucleus-encoded proteins are translated in the cytosol and imported into the chloroplast, where
they control and/or regulate chloroplast gene expression. Chloroplast gene translation is conducted by
bacterial-type 70S ribosomes, which occurs cotranscriptionally. Since the mRNA turnover rate within
chloroplasts is slow, most ribosomes function in posttranscriptional steps. Moreover, chloroplast gene
expression is involved in responses to environmental cues
21. Chloroplast ribosomes
Chloroplast ribosomes contain about 50 ribosomal proteins, distributed between the two subunits. The 23 S, 5 S, 4.5 S
rRNA are present in the 50 S subunit and the 16 S rRNA is in the 30 S subunit. Plastid contains tRNA synthetase
enzymes. The presence of plastid tRNA is able to charge all of the 20 protein amino acids. Synthesis of protein in
chloroplast utilizes normal genetic code.
The sequences of the maize and tobacco 16 S rRNA genes are 1491 and 1486 nucleotides in length, respectively. They
show 96% sequence homology with each other. Similarly, DNA sequence of 23 S rRNA genes from maize and tobacco
is 2898 and 2804 nucleotides respectively.
The distance between 16 S (end) and the 23 S (start) of rRNA gene is 2408 base pairs in maize and 2080 in tobacco .
On the contrary, the distance among prokaryotic organisms is very less, for example, in E. coli distance is 440 base
pairs. Longer distance among higher plants is due to the presence of introns upto 950 base pairs.
22. During transcription the 16 S, 23 S, 4.5 S rRNA sequence in chloroplast together with the tRNA in the spacer region
between 16 S and 23 S genes are transcribed as a polycistronic RNA, which is a precursor RNA undergoes modification to
produce mature tRNA and rRNA. Transcription of the rRNA genes takes place at promoter site by chloroplast RNA
polymerase upstream from the mature 16 S rRNA sequence and continues till end of the 4.5 S sequences.
Post-transcriptional processing of rRNA such as intron splicing, generation of a number of RNA fragments, the ligation of
RNA sequence takes place. Information on the synthesis and processing of chloroplast mRNA is meagre. They seem to be
devoid of 5′ cap and do not contain long region of polyadenylic acid at the 3′ end. Some reports suggested that chloroplast
mRNA may contain short runs of oligo A
23.
24. Plastid Regulatory Sequence
Sequencing of plastid genes such as rbcL, rRNA, tRNA, CF polypeptides and photogene 32 have been
accomplished, of which rubisco large subunit gene from maize was the first to be sequenced (Mcintosh et al.,
1980). There are two putative promoter regulatory sequences (TTGATA and TATGA) present in this region.
The putative regulatory sequence rbcL of other species shows deviation .
25. Expression of rbcL Gene in Chloroplast:
Rubisco gene contains eight subunits of which four are smaller subunits and other four are larger subunits. The
genes for larger (L) sububits are coded in chloroplast DNA, and genes for smaller (S) subunits are coded in nuclear
DNA. In nuclear code genes have mRNA with 5′ cap and poly-A sequence as evidenced in rubisco gene.
They are translated on cytosol ribosomes. The transit peptide, which varies from 40 to 60 amino acids in different
plants, is transported into chloroplast. After entry of eight smaller subunits inside the chloroplast, signal peptides
are cleaved and association between larger subunits and smaller subunits takes place to become functional
holoenzyme.
26.
27. There is a considerable imbalance between the number of nuclear-encoded genes for plastid function and number
of plastid-coded genes in photosynthetic cells of higher plants.
Several hundreds of gene copies will be produced in chloroplast due to their high copy number; on the other
hand, nuclear DNA contains only few copies of the genes for photosynthetic functions.
Inspite of this imbalance, some well coordination of gene expression could be seen in the chloroplast of higher
plants.
28. Biological function
It is presumed that in due course some parts of the chloroplast genome were transferred to the nuclear
genome. The process is called endosymbiotic gene transfers. Because of this transfer, the chloroplast genome
is greatly reduced compared with that of cyanobacteria, which are conjectured as the ancestral origin of
chloroplasts.
29.
30.
31.
32.
33. Case studies
Five Complete Chloroplast Genome Sequences from Diospyros: Genome Organization and
Comparative Analysis- journals.plos.org
Jianmin Fu et al[2016], https://doi.org/10.1371/journal.pone.0159566
Diospyros is the largest genus in Ebenaceae, comprising more than 500 species with remarkable economic value, especially Diospyros kaki Thunb., which has
traditionally been an important food resource in China, Korea, and Japan. Complete chloroplast (cp) genomes from D. kaki, D. lotus L., D. oleifera Cheng., D.
glaucifolia Metc., and Diospyros ‘Jinzaoshi’ were sequenced using Illumina sequencing technology. This is the first cp genome reported in Ebenaceae. The cp genome
sequences of Diospyros ranged from 157,300 to 157,784 bp in length, presenting a typical quadripartite structure with two inverted repeats each separated by one large
and one small single-copy region. For each cp genome, 134 genes were annotated, including 80 protein-coding, 31 tRNA, and 4 rRNA unique genes. In all, 179 repeats
and 283 single sequence repeats were identified. Four hypervariable regions, namely, intergenic region of trnQ_rps16, trnV_ndhC, and psbD_trnT, and intron of ndhA,
were identified in the Diospyros genomes. Phylogenetic analyses based on the whole cp genome, protein-coding, and intergenic and intron sequences indicated that D.
oleifera is closely related to D. kaki and could be used as a model plant for future research on D. kaki; to our knowledge, this is proposed for the first time. Further,
these analyses together with two large deletions (301 and 140 bp) in the cp genome of D. ‘Jinzaoshi’, support its placement as a new species in Diospyros. Both
maximum parsimony and likelihood analyses for 19 taxa indicated the basal position of Ericales in asterids and suggested that Ebenaceae is monophyletic in Ericales.
34. The complete nucleotide sequence of the
tobacco chloroplast genome: its gene
organization and expression-embopress.org
K. Shinozaki et al[1986] https://doi.org/10.1002/j.1460-2075.1986.tb04464.x
The complete nucleotide sequence (155 844 bp) of tobacco (Nicotiana tabacum var. Bright Yellow 4) chloroplast DNA has been determined. It
contains two copies of an identical 25 339 bp inverted repeat, which are separated by a 86 684 bp and a 18 482 bp single‐copy region. The genes
for 4 different rRNAs, 30 different tRNAs, 39 different proteins and 11 other predicted protein coding genes have been located. Among them, 15
genes contain introns. Blot hybridization revealed that all rRNA and tRNA genes and 27 protein genes so far analysed are transcribed in the
chloroplast and that primary transcripts of the split genes hitherto examined are spliced. Five sequences coding for proteins homologous to
components of the respiratory‐chain NADH dehydrogenase from human mitochondria have been found. The 30 tRNAs predicted from their genes
are sufficient to read all codons if the ‘two out of three’ and ‘U:N wobble’ mechanisms operate in the chloroplast. Two sequences which
autonomously replicate in yeast have also been mapped. The sequence and expression analyses indicate both prokaryotic and eukaryotic features of
the chloroplast genes.
35. Conservation of chloroplast genome
structure among vascular plants-Springer
Jeffrey D. Palmer & Diana B. Stein (1986)
The first physical map of a gymnosperm chloroplast genome and compared its organization with those of a fern and several angiosperms by
heterologous filter hybridization. The chloroplast genome of the gymnosperm Ginkgo biloba consists of a 158 kb circular chromosome that
contains a ribosomal RNA-encoding inverted repeat approximately 17 kb in size. Gene mapping experiments demonstrate a remarkable similarity
in the linear order and absolute positions of the ribosomal RNA genes and of 17 protein genes in the cpDNAs of Ginkgo biloba, the fern Osmunda
cinnamomea and the angiosperm Spinacia oleracea. Moreover, filter hybridizations using as probes cloned fragments that cover the entirety of the
angiosperm chloroplast genome reveal a virtually colinear arrangement of homologous sequence elements in these genomes representing three
divisions of vascular plants that diverged some 200–400 million years ago. The only major difference in chloroplast genome structure among these
vascular plants involves the size of the rRNA-encoding inverted repeat, which is only 10 kb in Osmunda, 17 kb in Ginkgo, and about 25 kb in most
angiosperms. This size variation appears to be the result of spreading of the repeat through previously single copy sequences, or the reverse process
of shrinkage, unaccompanied by any overall change in genome complexity.
36. An update on chloroplast genomes-
Springer
V. Ravi, J. P. Khurana, A. K. Tyagi & P. Khurana Published: 28 November 2007
Plant cells possess two more genomes besides the central nuclear genome: the mitochondrial genome and the chloroplast genome (or
plastome). Compared to the gigantic nuclear genome, these organelle genomes are tiny and are present in high copy number. These genomes
are less prone to recombination and, therefore, retain signatures of their age to a much better extent than their nuclear counterparts. Thus, they
are valuable phylogenetic tools, giving useful information about the relative age and relatedness of the organisms possessing them. Unlike
animal cells, mitochondrial genomes of plant cells are characterized by large size, extensive intra-molecular recombination and low
nucleotide substitution rates and are of limited phylogenetic utility. Chloroplast genomes, on the other hand, show resemblance to animal
mitochondrial genomes in terms of phylogenetic utility and are more relevant and useful in case of plants. Conservation in gene order, content
and lack of recombination make the plastome an attractive tool for plant phylogenetic studies. Their importance is reflected in the rapid
increase in the availability of complete chloroplast genomes in the public databases. This review aims to summarize the progress in
chloroplast genome research since its inception and tries to encompass all related aspects. Starting with a brief historical account, it gives a
detailed account of the current status of chloroplast genome sequencing and touches upon RNA editing, ycfs, molecular phylogeny, DNA
barcoding as well as gene transfer to the nucleus.
37. Methods for Obtaining and Analyzing
Whole Chloroplast Genome Sequences
(science direct)
Robert K.Jansen et al.(2005)
During the past decade, there has been a rapid increase in our understanding of plastid genome organization and evolution due to the
availability of many new completely sequenced genomes. There are 45 complete genomes published and ongoing projects are likely to
increase this sampling to nearly 200 genomes during the next 5 years. Several groups of researchers including ours have been developing
new techniques for gathering and analyzing entire plastid genome sequences and details of these developments are summarized in this
chapter. The most important developments that enhance our ability to generate whole chloroplast genome sequences involve the generation
of pure fractions of chloroplast genomes by whole genome amplification using rolling circle amplification, cloning
genomes into Fosmid or bacterial artificial chromosome (BAC) vectors, and the development of an organellar annotation program (Dual
Organellar GenoMe Annotator [DOGMA]). In addition to providing details of these methods, we provide an overview of methods for
analyzing complete plastid genome sequences for repeats and gene content, as well as approaches for using gene order and sequence data
for phylogeny reconstruction. This explosive increase in the number of sequenced plastid genomes and improved computational tools will
provide many insights into the evolution of these genomes and much new data for assessing relationships at deep nodes in plants and other
photosynthetic organisms.