Plastids are membrane-bound organelles found in plant cells and some protists that are involved in photosynthesis and storing food. There are three main types - chloroplasts contain chlorophyll and carry out photosynthesis, chromoplasts are colored and contain pigments like carotenoids, and leucoplasts are colorless and store food like starch. Chloroplasts have an inner and outer membrane, and contain stacks of thylakoid membranes where photosynthesis takes place. Chlorophyll and accessory pigments like carotenoids are embedded in the thylakoids and absorb light energy for photosynthesis.
This document summarizes several key organelles and structures found in plant cells, including dictyosomes (Golgi apparatus), lysosomes, microbodies, vacuoles, the nucleus, chloroplasts, and cell walls. It also compares plant and animal cells, noting that while they share some similar organelles, plant cells are generally larger, have cell walls, chloroplasts, central vacuoles, and can synthesize all amino acids. The main functions of plant cell organelles are described, such as protein modification in dictyosomes and waste degradation in lysosomes.
The document summarizes the ultrastructure of plant cells by describing several key organelles and their functions. It discusses the cell wall, cell membrane, endoplasmic reticulum, plastids, mitochondria, and ribosomes. The endoplasmic reticulum is divided into rough and smooth types, with rough ER involved in protein synthesis and smooth ER producing lipids. Plastids include leucoplasts, chloroplasts, and chromoplasts. Chloroplasts perform photosynthesis while chromoplasts produce pigments. Mitochondria generate ATP through cellular respiration. Ribosomes assemble amino acids to form proteins.
The plant cell wall is a rigid structure composed of cellulose microfibrils embedded in a matrix of hemicellulose, pectin, and structural proteins. It provides shape and protection to plant cells and differs significantly from the membranes of other eukaryotic cells. The primary cell wall is thin and allows for cell expansion. Secondary cell walls are thicker and do not expand. They are strengthened through the addition of lignin. The orientation of cellulose microfibrils determines the shape of the cell and is controlled by cortical microtubules in the cell.
The document summarizes the different types of plastids found in plant cells. It discusses chloroplasts, which perform photosynthesis; chromoplasts, which synthesize and store pigments; leucoplasts, a non-pigmented category including amyloplasts for starch storage, elaioplasts for lipid storage, and proteinoplasts containing protein crystals. Chloroplasts have a double membrane structure with internal thylakoids and perform the two stages of photosynthesis using chlorophyll. Chromoplasts give fruits and flowers their colors and develop from chloroplasts during ripening.
Plastids are double membrane organelles found in plant and algae cells. They are responsible for manufacturing and storing food and often contain pigments used in photosynthesis. There are several types of plastids that serve different functions: chloroplasts contain chlorophyll and are found in plant leaves to perform photosynthesis; chromoplasts contain colored pigments and are found in flowers and fruits; leucoplasts are non-pigmented and act as storage units for starches, lipids, and proteins in plant roots and other non-photosynthetic tissues.
Chloroplasts are organelles found in plant cells and algae that conduct photosynthesis. They have a complex structure with double and triple membrane systems that divide the chloroplast into compartments. Chloroplasts contain pigments like chlorophyll that capture light energy during photosynthesis to convert carbon dioxide and water into oxygen and energy-rich organic compounds like sugars. This process occurs through light-dependent and light-independent reactions. In addition to their primary role in photosynthesis, chloroplasts also synthesize other biomolecules like proteins, lipids, and fatty acids.
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.
This document summarizes several key organelles and structures found in plant cells, including dictyosomes (Golgi apparatus), lysosomes, microbodies, vacuoles, the nucleus, chloroplasts, and cell walls. It also compares plant and animal cells, noting that while they share some similar organelles, plant cells are generally larger, have cell walls, chloroplasts, central vacuoles, and can synthesize all amino acids. The main functions of plant cell organelles are described, such as protein modification in dictyosomes and waste degradation in lysosomes.
The document summarizes the ultrastructure of plant cells by describing several key organelles and their functions. It discusses the cell wall, cell membrane, endoplasmic reticulum, plastids, mitochondria, and ribosomes. The endoplasmic reticulum is divided into rough and smooth types, with rough ER involved in protein synthesis and smooth ER producing lipids. Plastids include leucoplasts, chloroplasts, and chromoplasts. Chloroplasts perform photosynthesis while chromoplasts produce pigments. Mitochondria generate ATP through cellular respiration. Ribosomes assemble amino acids to form proteins.
The plant cell wall is a rigid structure composed of cellulose microfibrils embedded in a matrix of hemicellulose, pectin, and structural proteins. It provides shape and protection to plant cells and differs significantly from the membranes of other eukaryotic cells. The primary cell wall is thin and allows for cell expansion. Secondary cell walls are thicker and do not expand. They are strengthened through the addition of lignin. The orientation of cellulose microfibrils determines the shape of the cell and is controlled by cortical microtubules in the cell.
The document summarizes the different types of plastids found in plant cells. It discusses chloroplasts, which perform photosynthesis; chromoplasts, which synthesize and store pigments; leucoplasts, a non-pigmented category including amyloplasts for starch storage, elaioplasts for lipid storage, and proteinoplasts containing protein crystals. Chloroplasts have a double membrane structure with internal thylakoids and perform the two stages of photosynthesis using chlorophyll. Chromoplasts give fruits and flowers their colors and develop from chloroplasts during ripening.
Plastids are double membrane organelles found in plant and algae cells. They are responsible for manufacturing and storing food and often contain pigments used in photosynthesis. There are several types of plastids that serve different functions: chloroplasts contain chlorophyll and are found in plant leaves to perform photosynthesis; chromoplasts contain colored pigments and are found in flowers and fruits; leucoplasts are non-pigmented and act as storage units for starches, lipids, and proteins in plant roots and other non-photosynthetic tissues.
Chloroplasts are organelles found in plant cells and algae that conduct photosynthesis. They have a complex structure with double and triple membrane systems that divide the chloroplast into compartments. Chloroplasts contain pigments like chlorophyll that capture light energy during photosynthesis to convert carbon dioxide and water into oxygen and energy-rich organic compounds like sugars. This process occurs through light-dependent and light-independent reactions. In addition to their primary role in photosynthesis, chloroplasts also synthesize other biomolecules like proteins, lipids, and fatty acids.
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 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 plants and algae that carry out photosynthesis. They have an inner and outer membrane, with an intermembrane space between them. Inside is the stroma, which contains thylakoids that are arranged in stacks called grana. Chloroplasts contain their own genome and divide independently. According to the endosymbiotic theory, chloroplasts originated from cyanobacteria that were engulfed by other cells but not destroyed. Chloroplasts import most proteins from the cytosol through translocation complexes in the inner and outer membranes. They perform photosynthesis through light and dark reactions, using solar energy to fix carbon dioxide and produce oxygen and carbohydrates.
Cytoplasm is a gel like fluid present between the plasma membrane and the nucleus
Cytoplasm is the semi-fluid substance of a cell that is present within the cellular membrane and surrounds the nuclear membrane
It is sometimes described as the nonnuclear content of the protoplasm
Motor molecules also carry vesicles or organelles to various destinations along “monorails’ provided by the cytoskeleton.
Interactions of motor proteins and the cytoskeleton circulates materials within a cell via streaming.
Recently, evidence is accumulating that the cytoskeleton may transmit mechanical signals that re-arrange the nucleoli and other structures.
Chloroplasts are organelles found in plant cells that contain chlorophyll, which allows them to carry out photosynthesis. Chloroplasts have an inner and outer membrane, as well as internal structures called thylakoids that are stacked to form grana. Within the chloroplast is the stroma, which contains enzymes and DNA, allowing the chloroplast to divide itself. Chloroplasts are able to convert sunlight into chemical energy through photosynthesis.
This document summarizes key information about plant cell walls. It begins by introducing the topic and providing background on the discovery of cell walls. It then describes the main components of plant cell walls, including the three layers (middle lamella, primary cell wall, and secondary cell wall). The structural organization and chemical composition of cell walls is also summarized. Finally, the main functions of the cell wall in providing structure, protection, and facilitating transport are outlined.
Prokaryotes have relatively simple structures compared to eukaryotes. They lack membrane-bound organelles and have a plasma membrane, cell wall, and genetic material not enclosed within a nucleus. Bacteria come in various shapes including cocci, bacilli, and spirilla. Their cell walls differ between gram-positive and gram-negative bacteria. Prokaryotes also possess external structures like flagella, pili, and capsules. They reproduce through binary fission and some form resistant endospores.
The document summarizes key aspects of prokaryotic cell structure. Prokaryotic cells are typically small, have a large surface area to volume ratio, and come in a variety of shapes. They are bounded by a cell wall and membrane. The cell wall is thick and made of specialized molecules. Unlike eukaryotic cells, prokaryotes lack internal membrane-bound organelles and have a circular DNA genome not enclosed in a nucleus. Ribosomes are smaller than in eukaryotes and structures like flagella, pili, and inclusion bodies are used for motility, attachment and storage.
This presentation summarizes key information about peroxisomes. Peroxisomes are membrane-bound organelles found in the cytoplasm of eukaryotic cells that contain oxidase enzymes and help breakdown hydrogen peroxide. They have a dense matrix and participate in important functions like fatty acid breakdown, alcohol detoxification, and bile acid/cholesterol synthesis. Disorders can arise if single peroxisomal enzymes are abnormal, affecting the nervous system, liver, and other organs. Two examples given are adrenoleukodystrophy, which involves VLCFA metabolism, and Zellweger's syndrome, caused by a lack of functional peroxisomes due to mutations affecting transport of enzymes.
Chloroplasts are organelles found in plant and algal cells that conduct photosynthesis. They contain their own DNA and can replicate independently. Chloroplasts have a double membrane structure and a thylakoid membrane system within a protein-rich stroma. They vary in shape and number per cell depending on the plant species. Chloroplasts capture sunlight using chlorophyll and convert it to chemical energy through photosynthesis, and also perform other functions like amino acid synthesis.
The document summarizes the structure and functions of the Golgi apparatus. It notes that the Golgi apparatus was discovered in 1898 by Camillo Golgi and is present in all eukaryotic cells. It has a central stack of flattened, interconnecting sacs called cisternae. The Golgi apparatus modifies proteins and lipids from the ER, carrying out functions like secretion, synthesis, sulfation, phosphorylation, and apoptosis. It packages molecules into vesicles which are transported within the cell.
Plant cells are typically rectangular in shape with a large, permanent vacuole and cell wall made of cellulose. They contain plastids like chloroplasts and have fewer mitochondria than animal cells. Plant cells divide using a cell plate, while animal cells are spherical, have a small temporary vacuole, lack plastids and a cell wall, and divide using a furrow with centrosomes aiding the process.
This document provides information about the archaea domain. It begins with an introduction to the six kingdoms of life and explains how archaea were recognized as a distinct domain separate from bacteria and eukaryotes based on rRNA studies. It then discusses the characteristics of archaea including their cell structure, unusual lipids, ability to thrive in extreme environments, and classification into five phyla. Examples are provided of notable archaea genera from each phylum like Sulfolobus, Halobacterium, Methanococcus, and Methanopyrus.
This document provides a taxonomic classification for the genus Volvox, breaking it down from the broadest category of Kingdom Plantae to the specific genus. It lists Volvox in the kingdom Plantae, phylum Chlorophyta, class Chlorophyceae, order Volvocales, and family Volvocaceae.
The document discusses plant cell walls and membranes. It provides details on:
- The structure and layers of plant cell walls, including the primary and secondary cell walls.
- The major components and functions of plant cell walls, which provide shape, protection and support to cells.
- How cell walls are permeable and limit the passage of large molecules.
- The structure and components of plasma membranes, including the phospholipid bilayer and integral membrane proteins that perform important functions like transport and signaling.
The document discusses the endosymbiont theory of the origin of eukaryotic cells. It proposes that eukaryotic cells evolved from prokaryotic cells through endosymbiosis. Specifically, it suggests that mitochondria originated from alpha proteobacteria and chloroplasts from cyanobacteria that were engulfed but not destroyed by other prokaryotic cells and eventually developed a mutualistic relationship living inside the host cell. Evidence for this includes mitochondria and chloroplasts having their own DNA similar to these bacteria, as well as inner membranes like those found in some bacteria.
Plants absorb water through their roots and transport it throughout the plant. There are two main mechanisms of water absorption: active absorption which requires metabolic energy and occurs in slowly transpiring plants, and passive absorption driven by transpiration from the leaves. Most water is absorbed in the root hairs and younger root regions through osmosis as water moves from higher to lower water potential down a gradient. The water then travels upward through the xylem vessels via bulk flow and diffusion processes to reach the leaves where it is lost to transpiration.
The pigment chlorophyll is found inside the chloroplasts, each leaf contains millions of chloroplasts. Inside each one, there are stacks of membranes that hold the chlorophyll molecules.
Plastids are membrane-bound organelles found in plant and algal cells that often contain pigments used in photosynthesis. There are several types of plastids that serve different functions: chloroplasts contain chlorophyll and are the site of photosynthesis; chromoplasts contain carotenoids and synthesize and store pigments; gerontoplasts are involved in chloroplast degradation during senescence; and leucoplasts like amyloplasts, elaioplasts, and proteinoplasts store starches, lipids, and proteins respectively. It is believed that plastids evolved from endosymbiotic cyanobacteria that were engulfed by plant cells and eventually became specialized organelles.
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 plants and algae that carry out photosynthesis. They have an inner and outer membrane, with an intermembrane space between them. Inside is the stroma, which contains thylakoids that are arranged in stacks called grana. Chloroplasts contain their own genome and divide independently. According to the endosymbiotic theory, chloroplasts originated from cyanobacteria that were engulfed by other cells but not destroyed. Chloroplasts import most proteins from the cytosol through translocation complexes in the inner and outer membranes. They perform photosynthesis through light and dark reactions, using solar energy to fix carbon dioxide and produce oxygen and carbohydrates.
Cytoplasm is a gel like fluid present between the plasma membrane and the nucleus
Cytoplasm is the semi-fluid substance of a cell that is present within the cellular membrane and surrounds the nuclear membrane
It is sometimes described as the nonnuclear content of the protoplasm
Motor molecules also carry vesicles or organelles to various destinations along “monorails’ provided by the cytoskeleton.
Interactions of motor proteins and the cytoskeleton circulates materials within a cell via streaming.
Recently, evidence is accumulating that the cytoskeleton may transmit mechanical signals that re-arrange the nucleoli and other structures.
Chloroplasts are organelles found in plant cells that contain chlorophyll, which allows them to carry out photosynthesis. Chloroplasts have an inner and outer membrane, as well as internal structures called thylakoids that are stacked to form grana. Within the chloroplast is the stroma, which contains enzymes and DNA, allowing the chloroplast to divide itself. Chloroplasts are able to convert sunlight into chemical energy through photosynthesis.
This document summarizes key information about plant cell walls. It begins by introducing the topic and providing background on the discovery of cell walls. It then describes the main components of plant cell walls, including the three layers (middle lamella, primary cell wall, and secondary cell wall). The structural organization and chemical composition of cell walls is also summarized. Finally, the main functions of the cell wall in providing structure, protection, and facilitating transport are outlined.
Prokaryotes have relatively simple structures compared to eukaryotes. They lack membrane-bound organelles and have a plasma membrane, cell wall, and genetic material not enclosed within a nucleus. Bacteria come in various shapes including cocci, bacilli, and spirilla. Their cell walls differ between gram-positive and gram-negative bacteria. Prokaryotes also possess external structures like flagella, pili, and capsules. They reproduce through binary fission and some form resistant endospores.
The document summarizes key aspects of prokaryotic cell structure. Prokaryotic cells are typically small, have a large surface area to volume ratio, and come in a variety of shapes. They are bounded by a cell wall and membrane. The cell wall is thick and made of specialized molecules. Unlike eukaryotic cells, prokaryotes lack internal membrane-bound organelles and have a circular DNA genome not enclosed in a nucleus. Ribosomes are smaller than in eukaryotes and structures like flagella, pili, and inclusion bodies are used for motility, attachment and storage.
This presentation summarizes key information about peroxisomes. Peroxisomes are membrane-bound organelles found in the cytoplasm of eukaryotic cells that contain oxidase enzymes and help breakdown hydrogen peroxide. They have a dense matrix and participate in important functions like fatty acid breakdown, alcohol detoxification, and bile acid/cholesterol synthesis. Disorders can arise if single peroxisomal enzymes are abnormal, affecting the nervous system, liver, and other organs. Two examples given are adrenoleukodystrophy, which involves VLCFA metabolism, and Zellweger's syndrome, caused by a lack of functional peroxisomes due to mutations affecting transport of enzymes.
Chloroplasts are organelles found in plant and algal cells that conduct photosynthesis. They contain their own DNA and can replicate independently. Chloroplasts have a double membrane structure and a thylakoid membrane system within a protein-rich stroma. They vary in shape and number per cell depending on the plant species. Chloroplasts capture sunlight using chlorophyll and convert it to chemical energy through photosynthesis, and also perform other functions like amino acid synthesis.
The document summarizes the structure and functions of the Golgi apparatus. It notes that the Golgi apparatus was discovered in 1898 by Camillo Golgi and is present in all eukaryotic cells. It has a central stack of flattened, interconnecting sacs called cisternae. The Golgi apparatus modifies proteins and lipids from the ER, carrying out functions like secretion, synthesis, sulfation, phosphorylation, and apoptosis. It packages molecules into vesicles which are transported within the cell.
Plant cells are typically rectangular in shape with a large, permanent vacuole and cell wall made of cellulose. They contain plastids like chloroplasts and have fewer mitochondria than animal cells. Plant cells divide using a cell plate, while animal cells are spherical, have a small temporary vacuole, lack plastids and a cell wall, and divide using a furrow with centrosomes aiding the process.
This document provides information about the archaea domain. It begins with an introduction to the six kingdoms of life and explains how archaea were recognized as a distinct domain separate from bacteria and eukaryotes based on rRNA studies. It then discusses the characteristics of archaea including their cell structure, unusual lipids, ability to thrive in extreme environments, and classification into five phyla. Examples are provided of notable archaea genera from each phylum like Sulfolobus, Halobacterium, Methanococcus, and Methanopyrus.
This document provides a taxonomic classification for the genus Volvox, breaking it down from the broadest category of Kingdom Plantae to the specific genus. It lists Volvox in the kingdom Plantae, phylum Chlorophyta, class Chlorophyceae, order Volvocales, and family Volvocaceae.
The document discusses plant cell walls and membranes. It provides details on:
- The structure and layers of plant cell walls, including the primary and secondary cell walls.
- The major components and functions of plant cell walls, which provide shape, protection and support to cells.
- How cell walls are permeable and limit the passage of large molecules.
- The structure and components of plasma membranes, including the phospholipid bilayer and integral membrane proteins that perform important functions like transport and signaling.
The document discusses the endosymbiont theory of the origin of eukaryotic cells. It proposes that eukaryotic cells evolved from prokaryotic cells through endosymbiosis. Specifically, it suggests that mitochondria originated from alpha proteobacteria and chloroplasts from cyanobacteria that were engulfed but not destroyed by other prokaryotic cells and eventually developed a mutualistic relationship living inside the host cell. Evidence for this includes mitochondria and chloroplasts having their own DNA similar to these bacteria, as well as inner membranes like those found in some bacteria.
Plants absorb water through their roots and transport it throughout the plant. There are two main mechanisms of water absorption: active absorption which requires metabolic energy and occurs in slowly transpiring plants, and passive absorption driven by transpiration from the leaves. Most water is absorbed in the root hairs and younger root regions through osmosis as water moves from higher to lower water potential down a gradient. The water then travels upward through the xylem vessels via bulk flow and diffusion processes to reach the leaves where it is lost to transpiration.
The pigment chlorophyll is found inside the chloroplasts, each leaf contains millions of chloroplasts. Inside each one, there are stacks of membranes that hold the chlorophyll molecules.
Plastids are membrane-bound organelles found in plant and algal cells that often contain pigments used in photosynthesis. There are several types of plastids that serve different functions: chloroplasts contain chlorophyll and are the site of photosynthesis; chromoplasts contain carotenoids and synthesize and store pigments; gerontoplasts are involved in chloroplast degradation during senescence; and leucoplasts like amyloplasts, elaioplasts, and proteinoplasts store starches, lipids, and proteins respectively. It is believed that plastids evolved from endosymbiotic cyanobacteria that were engulfed by plant cells and eventually became specialized organelles.
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.
Chloroplasts contain accessory pigments like chlorophyll b and carotenoids that help broaden the range of wavelengths of light absorbed during photosynthesis beyond just the wavelengths absorbed by chlorophyll a. These accessory pigments absorb different wavelengths of light and transfer the absorbed energy to chlorophyll a, the primary photosynthetic pigment, improving the efficiency of light absorption and energy production through photosynthesis.
Plants produce a variety of pigments that serve important physiological functions and attract pollinators and seed dispersers. There are three main types of pigments in plant leaves: chlorophylls, which are responsible for photosynthesis; carotenoids, which provide yellow and orange colors; and anthocyanins, which make leaves appear red in autumn. These pigments absorb different wavelengths of light and contribute to the diverse colors seen in plants.
Chloroplasts are double-membrane organelles found in plant cells and algae that contain chlorophyll and are the sites of photosynthesis. They capture energy from sunlight through chlorophyll and convert it into chemical energy in the form of ATP and NADPH through the light-dependent reactions. The chemical energy is then used to fix carbon dioxide from the air and produce sugars in the Calvin cycle. Chloroplasts have an inner membrane, intermembrane space, and outer membrane and contain stacked structures called thylakoids where photosynthesis takes place and the stroma where the Calvin cycle occurs.
Chloroplasts are double-membrane organelles found in plant cells that contain chlorophyll and carry out photosynthesis. They have an inner membrane, intermembrane space, and outer membrane, and contain stacked structures called grana that are made of disc-shaped thylakoids where chlorophyll is located. Chloroplasts are able to convert sunlight into chemical energy through photosynthesis, producing oxygen and synthesizing sugars from carbon dioxide and water.
Dr. Vikas Meashi summarized Fritsch's 1945 book that classified algae into 11 classes based on pigments, food storage, reproduction type, motility, and flagella. The classes included Chlorophyceae, Xanthophyceae, Chrysophyceae, Bacillariophyceae, Cryptophyceae, Dinophyceae, Chloromonadineae, Euglenineae, Phaeophyceae, Rhodophyceae, and Myxophyceae. Examples were provided for each class.
This document discusses plant pigments and their role in photosynthesis. It explains that chlorophyll is the main green pigment found in plants and is responsible for their green color. Chlorophyll is located within chloroplasts in plant cells and absorbs light energy which is used to synthesize glucose and oxygen from carbon dioxide and water. In addition to chlorophyll, plants also contain accessory pigments like carotenoids and xanthophylls that absorb other wavelengths of light and provide colors like red, orange and yellow. As temperatures drop in fall, chlorophyll breaks down revealing the underlying accessory pigments, changing the leaves' colors.
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 double-membrane organelles found in plant cells and algae that are the site of photosynthesis. They have a complex structure consisting of an outer and inner membrane, grana stacks, stroma lamellae, and thylakoids. Chloroplasts perform critical functions like absorbing light energy to produce chemical energy through photosynthesis. Malfunctions can occur due to nutrient deficiencies, mutations, virus infections, or physical damage. Chloroplasts communicate with the cell through signaling pathways involving reactive oxygen species, calcium ions, phytohormones, and retrograde signaling. They have applications in bioenergy production, biopharmaceuticals, genetic engineering, and environmental monitoring.
This document discusses various plant pigments including chlorophyll, carotenoids, flavonoids, anthocyanins, and tannins. It provides details on their chemical structures, occurrence in plants, roles in photosynthesis and coloring foods. Chlorophyll a and b are the main light harvesting pigments in plants, while carotenoids like lycopene and lutein contribute to flower and fruit colors. Flavonoids include subgroups like anthoxanthins and anthocyanins which produce yellow or red/blue pigmentation in flowers. Anthocyanins are water soluble pigments that appear red, purple or blue depending on pH. Tannins are polyphenolic compounds that occur widely in plant tissues.
Carotenoids are fat-soluble plant pigments that range in color from yellow to purple. There are two main types: carotenes and xanthophylls. Carotenes are pure hydrocarbons found in plants and some animals. They are responsible for colors like orange. Xanthophylls contain oxygen and are found in plant leaves and tissues to modulate light absorption during photosynthesis. Both types serve protective and energy transfer functions in plants and determine colors in fruits, vegetables, and some animals.
Unicellular green algae like Chlamydomonas reproduce through binary fission and flagellated zoospores. Algae are classified based on their photosynthetic pigments. Green algae contain chlorophyll a, chlorophyll b, and carotenoids. Spirogyra is a filamentous green alga with cylindrical cells arranged in helical filaments. It reproduces asexually through fragmentation and sexually through scalariform and lateral conjugation. Volvox is a colonial green alga. Red algae exhibit varied multicellular forms and contain the red pigment phycoerythrin.
This document discusses the different types of plastids found in plant cells. It begins by describing plastids as double membrane-bound organelles that can vary in shape and contain DNA and ribosomes, allowing them to replicate. Their main functions are food synthesis, carbohydrate and lipid storage. There are three main types of plastids: chloroplasts, which contain chlorophyll and carry out photosynthesis; chromoplasts, which contain carotenoids and give color to flowers and fruits; and leucoplasts, which are colorless and store carbohydrates, proteins or lipids in different plant tissues. The document focuses on describing the structure, components and functions of chloroplasts in detail.
Plastids are major organelles found in plant and algae cells. They are classified as either chromoplasts or leucoplasts. Chromoplasts contain pigments like carotenoids and are found in colored tissues like flower petals. Leucoplasts are colorless and store foods like starch or lipids. Chloroplasts, containing chlorophyll, are the site of photosynthesis and are found mainly in green plant tissues. Chloroplasts have an inner membrane system with thylakoids and grana where the light reactions of photosynthesis occur.
The document discusses pigments found in algae. There are three main types of pigments - chlorophyll, carotenoids, and phycobilins. Chlorophyll is the primary photosynthetic pigment and comes in various forms, with chlorophyll a present universally. Carotenoids include carotenes like beta-carotene and xanthophylls like fucoxanthin. Phycobilins include phycocyanin which is blue and absorbs green/red, and phycoerythrin which is red. Different algal groups contain predominant combinations of these pigments, which contribute to their distinctive colors.
This document explains leaf chromatography and the pigments found in leaves. It provides instructions for performing leaf chromatography to separate and view the different pigments. During leaf chromatography, alcohol is used to extract pigments from crushed leaves on a coffee filter. Different pigment bands appear on the filter over time, including orange carotenoids, yellow xanthophylls, blue-green chlorophyll A, and greenish-yellow chlorophyll B. Chromatography separates mixtures and is used in scientific research, food processing, forensics, and quality control.
Plastids are double-membrane organelles found in plant and algae cells that are responsible for important biochemical functions. There are three main types of plastids: chloroplasts, which facilitate photosynthesis; chromoplasts, which produce and store pigments; and leucoplasts, which synthesize compounds like proteins and starches. Chloroplasts have an additional internal membrane system called thylakoids that form stacks and contain chlorophyll. Chromoplasts and leucoplasts come in various subtypes depending on their contents and shape. All plastids contain a double membrane, stroma, DNA, ribosomes and other components that allow them to perform vital roles in plant cells.
The document provides a detailed overview of the history and evolution of chemical use in agriculture. It discusses how the earliest recorded uses of chemicals in agriculture date back to ancient Egypt and the Roman Empire when sulphur was used to control pests in grain stores. It then outlines several important milestones and discoveries that expanded the use of chemicals in agriculture throughout history, such as the Haber-Bosch process in the early 1900s and the rise of the agrochemical industry between 1940-1960. The document also examines the environmental and health implications of modern chemical farming practices.
1. Soil fertility refers to a soil's ability to support plant growth through favorable chemical, physical, and biological conditions, including providing essential nutrients. Regular soil testing can help farmers understand their soil's nutrient levels and needs.
2. Factors that affect soil fertility include organic matter content, soil texture, pH, moisture, aeration, temperature, and biota activity. Management practices like crop rotation, cover cropping, organic fertilization, reduced tillage, and intercropping can improve soil fertility over time.
3. Earthworms, microbes, fungi, and other soil biota play an important role in soil fertility by breaking down organic matter, improving soil structure, and making nutrients available to
This document discusses solid waste pollution and its management. It defines different types of solid waste such as municipal waste, hazardous waste, and biomedical waste. It describes the sources and impacts of solid waste pollution including various diseases. The major causes of increased solid waste are identified as population growth, urbanization, and increased affluence. Common methods for municipal solid waste disposal include landfilling, recycling, incineration, composting, while hazardous waste requires specialized disposal methods. Proper waste management can reduce pollution and health impacts.
1. Soil fertility refers to a soil's ability to support plant growth through favorable chemical, physical, and biological conditions, including providing essential nutrients. Regular soil testing can help farmers understand their soil's nutrient levels and needs.
2. Factors that affect soil fertility include organic matter content, soil texture, pH, moisture, aeration, temperature, and biota activity. Management practices like crop rotation, cover cropping, no-till farming, and fertilization can help preserve and improve soil fertility over time.
3. Earthworms, green manures, and organic matter additions increase soil fertility by loosening the soil, adding nutrients, and promoting beneficial microbial activity. Mixed cropping and mulching also help
Organic farming is a method that aims to protect the environment and ecology by using natural resources and avoiding synthetic inputs. It focuses on crop rotations, composting, and biological pest control to nourish soils and crops without chemicals. The principles of organic farming are health, ecology, fairness, and care - seeking to sustainably produce nutritious food while safeguarding farmer, consumer, and environmental well-being for current and future generations. Practicing organic techniques like composting and crop rotations can help improve soil health, reduce costs, and strengthen food security in an environmentally-friendly way.
Ecological balance refers to a stable state of dynamic equilibrium within an ecosystem where species and genetic diversity remain stable despite natural disturbances. It ensures the continuous existence of organisms and signifies a sustainable habitat where animals, plants, and microorganisms depend on each other. Maintaining ecological balance is important as it creates stable environments and enhances thriving of organisms.
Climate conditions such as temperature, rainfall, sunlight, soil quality, and growing season length influence the nutritional production of crops. Different crops thrive in different climates. Crop rotation, the practice of planting different crops in sequences, provides benefits like nutrient management, pest and disease control, and soil structure improvement, leading to more nutritionally valuable food. Factors like crop selection, sequence, cover crops, and local conditions should be considered when planning crop rotations.
Foliose, fruticose, and crustose lichens are the three main growth forms of lichens. Foliose lichens have broad, leaf-like structures, fruticose lichens have branching, shrub-like structures, and crustose lichens form crusts that tightly adhere to the substrate on which they grow. These three categories describe the different morphological forms that lichens can take on rocks, trees, and other surfaces.
The document summarizes key information about the endoplasmic reticulum (ER):
- ER is a network of membrane-bound tubules, vesicles and sacs found in most cell types that is involved in protein and lipid synthesis.
- It has two forms - rough ER with attached ribosomes that synthesizes proteins, and smooth ER without ribosomes that synthesizes lipids.
- ER was first observed under electron microscopes in the 1940s and was termed the endoplasmic reticulum in 1952. It plays an important role in protein processing and transport within cells.
Golgi bodies are membrane-bound organelles found in eukaryotic cells that serve as the centers of cellular secretion and processing. They modify, package, and transport proteins and lipids and are made up of stacks of flattened sacs called cisternae. Golgi bodies were first discovered and described in 1898 by Camillo Golgi, who observed them in neurons and termed them the "internal reticular apparatus." They play an important role in synthesizing and packaging molecules for export from the cell.
The electron transport chain (ETC) transports electrons from electron donors like NADH to molecular oxygen. It consists of protein complexes embedded in the inner mitochondrial membrane. Complexes I, III, and IV pump protons out of the matrix, building up an electrochemical gradient used for ATP synthesis. Electrons flow from complex to complex via mobile carriers like coenzyme Q and cytochrome c. This transfers energy from electrons to protons, conserving energy as ATP. Mitochondria contain many copies of the ETC to generate sufficient ATP through oxidative phosphorylation.
Mitochondria are double-membraned organelles found in eukaryotic cells that generate most of the cell's supply of adenosine triphosphate (ATP). They contain their own DNA and ribosomes. The inner membrane forms folds called cristae that increase its surface area and house protein complexes involved in oxidative phosphorylation. This process uses energy released from oxidation of nutrients to produce ATP. Mitochondria were first observed in the 1880s and their role in cellular respiration was established in the mid-20th century through studies of their structure and biochemical properties.
The document discusses three proposed mechanisms for the formation of mitochondria: self-duplication of existing mitochondria, de novo origin from cytoplasmic vesicles, and transformation from non-mitochondrial systems like the plasma membrane or ER. It states that the self-duplication hypothesis through fission of existing mitochondria is now most widely accepted. The endosymbiont hypothesis that mitochondria evolved from prokaryotes engulfed by early eukaryotic cells over a billion years ago is also described. Mitochondria's key functions like ATP production through oxidative phosphorylation are summarized.
Anacardiaceae is a family of trees and shrubs commonly known as the mango or cashew family. Key characteristics include alternate, simple or pinnately compound leaves; pentamerous flowers with 10 stamens inserted on a disc and 1-2 carpels forming a drupe fruit. Many plants in this family produce edible fruits like mango and cashew nut. Resins from some species are used for varnishes while others provide gums or cause skin irritation. The family includes about 80 genera and 600 species mostly found in tropical regions.
Coffee is a crop cultivated primarily in southern India. There are two main species - Arabica and Robusta. Arabica grows at higher elevations between 900-1200 meters and produces higher quality coffee, while Robusta grows at lower elevations and is more resilient. The document provides detailed information on the morphology, varieties, and management of coffee plants. It describes the plant structure including leaves, flowers, fruits, and berries and lists commercially important Arabica and Robusta varieties. It also includes a monthly management time table outlining operations such as harvesting, pruning, pest control, and nursery activities.
Capsicum annuum, commonly known as chilli pepper, is an important crop cultivated worldwide for use as a spice, vegetable, and ornamental. It is rich in vitamins C and A. Chilli peppers show variation in shape, color, size, and pungency depending on variety and region. India is the largest producer of chillies, with the states of Andhra Pradesh, Maharashtra, Karnataka, Odisha, and Tamil Nadu accounting for over 70% of national acreage. Chillies have various economic uses as food flavoring, medicine, and natural colorants.
Production of synthetic seed involves encapsulating somatic embryos, shoot buds, or cell aggregates using tissue culture techniques. This allows for the large-scale, low-cost propagation of plants while maintaining genetic uniformity. Synthetic seeds can be stored longer than traditional seeds and planted directly in fields without the need for transplanting. While synthetic seeds have advantages over traditional micropropagation methods, their production and germination rates can still be limited for some plant species.
Shoot tip culture is a plant tissue culture technique used to produce virus-free plants by culturing the meristematic tissue at the tip of a plant shoot. This allows production of new plants that are genetically identical to the donor plant but free of viruses, as viruses are unable to move between cells in the meristem. The protocol involves surface sterilizing and culturing shoot tip explants less than 1mm on agar media, with stages of culture establishment, shoot proliferation, and root regeneration using cytokinins and auxins. Shoot tip culture has applications in micropropagation, storage of plant genetic resources, quarantining imported plant materials, and eliminating viruses from infected plants.
Somatic embryogenesis is the process where embryos form from somatic (non-reproductive) plant cells in vitro. It is an important biotechnological tool that allows for clonal propagation, genetic transformation, and other applications. The first observation of somatic embryogenesis was in carrot cells in 1958. Somatic embryogenesis occurs through direct or indirect pathways and involves induction, development, and maturation stages. It has advantages over zygotic embryogenesis like a higher propagation rate and applications in synthetic seed production and genetic engineering.
Tissue culture is a method of biological research where plant tissues are grown under sterile conditions. There are several methods of plant tissue culture including seed culture, embryo culture, callus culture, cell culture, bud culture, meristem culture, and protoplast culture. Each method involves explants from various plant tissues being placed on nutrient media to induce cell growth and differentiation. Tissue culture has many applications including rapid clonal propagation, inducing genetic variation, producing transgenic plants, and conserving plant genetic resources.
More from Kottakkal farook arts and science college (20)
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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Find out more about ISO training and certification services
Training: ISO/IEC 27001 Information Security Management System - EN | PECB
ISO/IEC 42001 Artificial Intelligence Management System - EN | PECB
General Data Protection Regulation (GDPR) - Training Courses - EN | PECB
Webinars: https://pecb.com/webinars
Article: https://pecb.com/article
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For more information about PECB:
Website: https://pecb.com/
LinkedIn: https://www.linkedin.com/company/pecb/
Facebook: https://www.facebook.com/PECBInternational/
Slideshare: http://www.slideshare.net/PECBCERTIFICATION
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
2. •Plastids (Schimper - 1883) are self-duplicating
membrane-bound cell organelles, concerned with the
synthesis and storage of food.
•They are present in algae, plants and some protists.
•There are three kinds of plastids, namely leucoplasts,
chromoplasts and chloroplasts.
•They can change from one type to another, and are
derived from proplastids.
•Leucoplasts are colourless, and the others coloured.Most
plastids are coloured due to the presence of pigments.
•Some important pigments and their respective colours
are given below
3. Colour Pigment
•1. Chlorophylls Green
•2. Carotenes Yellow or red
•3. Xanthophylls Yellow, orange or brown
•4. Phycoerythrin Red
•5. Phycocyanin Blue-green
•6. Haematochrome Red
•7. Fucoxanthin Brown
•8. Bacteriorhodopsin Purple
4. •Most pigments are usually seen in plastids.
•However, certain other pigments, such as anthocyanins,
are found dissolved in the cytoplasmic matrix.
•The blue, red, pink and violet colours of some flowers,
fruits, stems and leaves are due to the presence of
anthocyanins.
•Plastids are mainly concerned with the synthesis and
storage of food.
•Also, they serve asthe centres of several biosynthetic
reactions, such as the synthesis of purines, pyrimidines,
fatty acids and amino acids.
5. LEUCOPLASTS
•Leucoplasts (leukoplasts) are colourless plastids,
without colouring pigments, thylacoids and
ribosomes.
•Usually, they are found in germ cells, embryonic
cells, meristematic cells and fully differentiated
tissues, which are not normally exposed to sunlight.
•Plastids, found in cotyledons are initially colourless,
but later on they transform to chloroplasts.
6.
7. •Leucoplasts are specialised for the synthesis
and storage of reserve food.
•Leucoplasts which synthesise and store starch
are called amyloplasts, those which synthesise
and store proteins are called proteoplasts or
aleuroplasts, and those which synthesise and
store lipids are called elaioplasts (lipidoplasts,
oleoplasts, or oleosomes).
•Amyloplasts are found in endosperm,
cotyledons and storage tubers.
8. •Often, leucoplasts get transformed to chloroplasts and
chromoplasts under certain circumstances.
•The appearance of green colour on stored tubers of
potato is due to the conversion of leucoplasts to
chloroplasts.
•Amyloplasts are found in cotyledons, endosperm and in
storage organs, such as potato tubers.
•Elaioplasts are commonly found in the tissues of
liverworts and monocotyledons.
•Aleuroplasts are found in many seeds.
•Structurally, leucoplasts are similar to chloroplasts with
double layered limiting membrane, but with fewer
lamellae.
9. CHROMOPLASTS
•Plastids, coloured other than green, are called chromoplasts.
They occur in the petals, fruits and roots of some higher
plants.
•Chromoplasts develop either from chloroplasts (as in petals),
or rarely from leucoplasts (as in carrot roots).
•During the transformation of chloroplast to chromoplast,
chlorophylls and starch gradually decrease in quantity, large
globuli are formed and arranged along the plastid membrane,
lamellar structures break down and stroma gets disorganised.
•These changes result in the empty appearance of the plastid
centre.
10.
11. •During the transformation of leucoplasts to
chromoplasts, certain fibrils appear which later on give
rise to crystals, filling up the whole plastid.
•The crystals are in the form of sheet - like structures,
containing large quantities of carotenoids.
•Chromoplasts may be red, orange, or yellow.
•The red colour of ripening tomatoes is due to the
presence of chromoplasts which contain the carotenoid
pigment leucopene.
•Chromoplasts, containing phycocyanin and
phycoerythrin, are found in algae.
•In green plants, they contain carotenoid pigments
(carotenes and xanthophylls).
12. •They show great variety of shape, but are mainly
irregular. Granular, angular and forked types also occur.
•The irregular and sharply pointed shapes are partly due
to the presence of coloured substances in a crystalline
form (e.g. roots of carrot).
•The chromoplasts of brown algae, dinoflagellates and
diatoms, which contain fucoxanthin, are called
phaeoplasts.
•Those of red algae, which contain phycoerythrin, are
called rhodoplasts.
•The chromoplasts of blue-green algae (Cyanobacteria)
are blue-green in colour and they contain chlorophyll-a,
carotenoids and phycobilins.
13. CHLOROPLASTS
•Chloroplasts are green, chlorophyll-containing,
photosynthetically active plastids.
•They are the active energy-transducing centres
where light energy is trapped, converted to
chemical energy and conserved in organic
molecules with simultaneous synthesis of ATP.
•Chloroplasts are found in green bacteria, green
algae, green plants and green protists.
14.
15. Morphology
•Chloroplasts are among the largest cytoplasmic
organelles, clearly observable under the low power of
compound microscopes.
•Their size, shape and distribution vary with different
cells and species.
•Their average size varies from 4 to 6 u in diameter and
1 to 3 μ in thickness.
•The chloroplasts of polyploid cells may be larger than
those of diploid cells.
•In general, the chloroplasts of sciophytes (shade-plants)
may be larger than those of heliophytes (sun-plants).
16.
17. •In some algae, such as Spirogyra, Chlorella and
Chlamydomonas, only a single chloroplast is present in
each cell.
•On the other hand, a cell in the spongy tissue of a grass
leaf may have 30 to 50 chloroplasts.
•Their average number in land plants is 20 - 40 per cell.
•Their division, which occurs in the proplastid stage
(immature stage), is not correlated with cell division.
•Blue-green algae lack definite chloroplasts; instead they
possess loosely arranged cytoplasmic membranes,
which contain photosynthetic pigments.
18. •Chloroplasts are mostly spherical, ovoid, discoid,
vesicular or cup-shaped.
•In some algae, they may be reticulate (e.g.,
Oedogonium), stellate (e.g., Zygnema), band-
shaped (e.g., Ulothrix), spiral (e.g., Spirogyra), or
cup-shaped (e.g., Volvox).
•Chloroplasts are uniformly distributed within the
cytoplasm.
•Their distribution depends mainly on external
conditions, such as light intensity.
19. Chemical composition
•Chloroplasts are formed of water, proteins, lipids,
DNA, RNAs, mineral ions, chlorophylls and other
pigments, and the enzymes and biochemical factors
required for DNA replication, RNA synthesis,
protein synthesis and photosynthesis.
•Proteins serve as enzymes and intrinsic and
extrinsic membrane proteins.
•The lipid contents include phospholipids,
triglycerides, sterols and waxes.
20.
21. •The photosynthetic pigments are of two
groups, namely principal pigments and
accessory pigments.
•The principal pigment in green plants is
chlorophyll-a and those of bacteria include
bacteriochlorophyll, chlorobium chlorophyll,
bacteriorhodopsin, etc.
•The accessory pigments of green plants
include chlorophyll-b and carotenoids
(carotene and xanthophyll).
22. •The accessory pigments of marine algae
include chlorophylls-c and d phycoerythrin
and phycocyanin.
•Accessory pigments expand the light
spectrum from which energy can be
captured.
•The energy absorbed by them is transferred
to chlorophyll-a in the early stages of
photosynthesis.
•Photochemical reaction takes place only in
chlorophyll-a.
23. Chlorophylls
•Chlorophylls are asymmetrical, green, Mg-containing
photosynthetic pigments.
•They can absorb blue-violet (435-438 nm) and red (670-680
nm) light and transmit or reflect green light (so they appear
green).
•Their photosynthetic activity will be maximal in red light.
•There are different kinds of chlorophylls, such as chlorophylls
a, b, c and d, bacteriochlorophyll and chlorobium chlorophyll.
•Of these, chlorophylls a and b are found in green plants, and
c and d are found in cyanobacteria, some protists and some
algae.
24. •A chlorophyll molecule is a magnesium-porphyrin
derivative. It consists of a pyrole head or nucleus, a
phytol tail and a side group.
•Head is hydrophilic, and the tail hydrophobic and
lipophilic.
•Head is a ring of four pyrole molecules, often called
tetrapyrole ring or porphyrin ring, with a Mg atom in the
centre.
•Tail is a long hydrocarbon chain, attached to the
porphyrin ring.
25. •Linked to the porphyrin ring is a side group,
different in different kinds of chlorophylls.
•It is the chemical nature of the side group that
determines the properties of chlorophyll.
•The side group of chlorophyll-a is a methyl group
(CH3), and that of chlorophyll-b is an aldehyde
group (-CHO).
•Chlorophyll a is bluish-green and chlorophyll b is
yellowish-green.
26.
27.
28. •The empirical formula of chlorophyll-a is C55
H72 O5 N4 Mg, and that of chlorophyll-b is
C55 H70 O6 N4 Mg.
•Several varieties of chlorophyll - a may be
recognized, such as chl.a 673 ,chl.a 683,
P680, P700 etc.
29. Carotenoids
• These are yellow, orange, brown, or red pigments, found in all
photosynthetic plants.
• Together with anthocyanins, carotenoids impart autumn colours to
leaves (when chlorophyll breaks down).
• They are found in some flowers and fruits also (e.g., carrot, tomato,
pumpkin).
• Carotenoids absorb the blue and green light of the visible spectrum
and transfer the light energy to chlorophyll to be used in
photosynthesis.
• They also protect chlorophyll molecules from photo-oxidation (by
molecular oxygen in high-intesity light).
• Carotenoids are of two groups, namely carotenes (C40H56) and
xanthophylls (C40H56O₂).
30. • Carotenes are red or orange-coloured hydrocarbons (terpenes).
• Xanthophylls are brown or yellow and oxygenated hydrocarbons.
• The common carotenes include a, ß, y and d carotenes, phytotene,
lycopene, neurosporene, etc.
• During digestion in vertebrates, B-carotene gets hydrolysed to two
identical portions, which yield vitamin A.
• Xanthophylls are more abundant than carotenes.
• They differ from carotenes in having oxygen.
• The major xanthophylls of higher plants include lutein,
violaxanthin, zeaxanthin and neoxanthin.
• The commonest xanthophyll of diatoms and brown algae is
fucoxanthin.
• Lutein gives yellow colour to autumn leaves.
31. Phycobilins
• Phycobilins are red or blue accessory photosynthetic pigments, found in
cyanobacteria and red algae.
• They differ from chlorophylls and carotenoids in being water-soluble.
• They are similar to the porphyrin part of chlorophylls, except that Mg is
absent and the tetrapyrroles are linear rather than cyclic.
• There are two major groups of phycobilins, namely phycoerythrins and
phycocyanins.
• Phycoerythrins are red-coloured.
• They absorb dim and blue-green light, which can reach ocean depths.
• So, phycobilins enable algae to live in deep waters.
• Phycocyanins are bluecoloured.
• They absorb extra orange and red light.
32. Bacteriorhodopsin
• In Halobacteria, there is a light-absorbing proteinous pigment in the
plasma membrane, called bacteriorhodopsin.
• It is formed of a single polypeptide of 247 amino acids.
• It resembles the visual pigment rhodopsin, found in the retinal rods of
vertebrate eye.
• It exists in two interconvertible forms, namely "purple" and "bleached".
• The former absorbs light at a wavelength of 570 nm, and the latter at 412
nm.
• As the pigment transforms from the purple to the bleached form, it loses
H+ ion, and in the reverse transformation it picks up and H+ ion (Racker
and Stoeckenius 1974).
• Thus, bacteriorhodopsin functions as a proton pump, that is driven by
light.
33. Structure of chloroplast
• Chloroplast is a double-walled and fluid-filled bag.
• It has a gelatinous core, called matrix or stroma, covered by two
concentric membranes.
• Across these membranes, molecular exchange takes place between
stroma and cytosol.
• The outer membrane is highly permeable, and the inner one is less
permeable.
• In between these membrane is the intermembrane space or
periplastidial space.
• The membranes have lipoprotein composition, lamellar structure
and fluid-mosaic organization.
• They consist of two separate layers of 40-60 Å thickness.
34.
35. • Stroma is a metabolic centre where CO₂ fixation and the synthesis
of nucleic acids, sugars, starch, fatty acids and some chloroplast
proteins take place.
• It contains a lamellar membrane system, ribosomes, circular DNA,
messenger and transfer RNAs, starch grains, lipid globules (called
plastoglobuli), and the enzymes for DNA duplication, genetic
transcription, genetic translation and the dark reactions of
photosynthesis.
• Stroma contains nearly 50% of the chloroplast proteins most of
which are of the soluble type.
• Most algal chloroplasts contain pyrenoids, in association with
starch grains.
• Pyrenoids contain the active enzyme ribulose biphosphate
carboxylase.
• Hence, they are believed to be involved in carbohydrate synthesis.
36. •In lower organisms, chloroplasts are primitive.
•They are bounded by a two-layered membrane and
contain pigment-coated plates in the matrix. Such
chloroplasts are called lamellate chloroplasts.
•The extensive stromal membrane system is called
thylacoid system or lamellar system.
•Chlorophyll molecules and light-absorbing accessory
pigments are embedded in it. It mainly consists of
several cylindrical discs, called grana.
•Each granum is a parallel stack or pile of 5 to 50 or
more flattened, closed and pigmented sacs, called
granal thylacoids or granal lamellae.
37.
38.
39. •Adjacent grana are connected together by a system of tubular
membranes, called intergranal thylacoids or fret membranes.
•In addition to these, a few unstacked thylacoids may also be
present in the stroma.
•They are called stromal thylacoids or stromal lamellae.
•They form a system of anastomosing tubules that are joined
to the grana thylacoids
•The number of thylacoids in a granum is different in different
groups.
•There is only a single thylacoid in each granum in
Rhodophyceae, two in Cryptophyceae, three in
Phaeophyceae and Bacillariophyceae, and many in others.
40. •In the bundle sheath cells of C4 plants, a specialised type of
chloroplasts are found.
•In them, lamellae are uniformly dispersed in the stroma,
without forming grana. So, they are called agranal chloroplasts.
•The leaves of C4 plants have the peculiar kranz anatomy and
hence their agranal chloroplasts are also called kranz type
of chloroplasts.
•Different views have been expressed to explain the relation
between granal and intergranal thylacoids.
•Steinmann and Sjostrand hold that stromal and intergranal
lamellae develop from granal discs. Hedge and others are of
opinion that granal discs are locally swollen thylacoids.
41. •Thylacoids have lipoprotein composition and laminar
organization.
•They are formed of thin molecular sheets or layers,
called laminae or lamellae.
•These are the store houses of photosynthetic pigments
and the enzymes of the light reactions of photosynthesis.
•The membranes also contain photochemically inactive
light-harvesting complex proteins (LHCP) and the
electron carriers cytochrome-b, cytochrome-f,
plastoquinone and plastocyanin.
42. Photosystems or pigment systems
•The light-absorbing photosynthetic pigments in the
thylacoid membrane are arranged in two complex
pigment systems, namely photosystem I(PSI) and
photosystem II (PSII).
•PSI is present mainly in unstacked membranes, and PSII
mainly in stacked membranes.
•These two systems are structurally distinct, but
functionally related. They are linked together by mobile
electron carriers.
43. •Each photosystem has many thousand
functional photosynthetic units, called
quantasomes.
•Each unit, in turn, consists of nearly 200-400
chlorophyll molecules and many accessory
pigment molecules.
•The pigment systems can absorb all
wavelengths of the visible spectrum, especially
those between 400 and 500 nm, and those
between 600 and 700 nm.
44. •Each functional unit has a photochemical reaction
centre, often called photocentre.
•It serves as an energy trap for the collection and
conversion of light energy; it brings about the conversion
of light energy to chemical energy.
•It is formed of chlorophyll-a molecules, bound to a
protein complex.
•The reaction centre of PSI is termed P700 and that of PSII
is termed P680.
•The former has an absorption maximum at 700 nm, and
the latter has it at 680 nm.
45. •The reaction centre is surrounded by a cluster of light-
absorbing pigment molecules.
•They form a light-gathering antenna system to absorb
photons.
•Hence, they are often called light-harvesting antenna
molecules.
•They include chlorophyll-a, chlorophyll-b, ß-carotenes
and other accessory pigments.
46. • Antenna molecules remain complexed with a few polypeptides,
forming the light-harvesting complex (LHC).
• This complex is more prominent in PSII than in PSI.
• It is mainly localized in stacked thylacoids. Its main function is to
capture solar energy and it has no photochemical activity at all.
• PSI and PSII differ from each other with regard to their LHC; in the
LHC of PSII, the amount of chlorophyll-a is much lesser than those of
chlorophyll-b and ß-carotene, while in the LHC of PSI it is much
higher than those of chlorophyll-b and ßcarotene.
• In the photosystems, the pigment molecules are very closely and
orderly arranged.
• This enables each molecule to absorb photon energy and pass it on
to the next molecule and finally to the reaction centre by a chain-
transfer mechanism.
47. Quantasomes
• Quantasomes are closely packed arrays of spherical or oblate granular
particles, regularly arranged on or in chloroplast thylacoids.
• They are considered to be the smallest light harvesting photosynthetic units,
capable of carrying out photochemical reactions.
• In green plants, each of them contains nearly 200-400 chlorophyll-a molecules,
some accessory pigments, electron carriers and the enzymes of light reactions.
• [Quantasomes were first noticed by Moor, Weier and Benson, and were first
isolated by Park and Biggins-1964]
• Evidences suggest that at least two distinct classes of quantasomes are present,
namely the smaller ones on the membrane surface and the larger ones inside the
membrane.
• Functionally, the smaller and larger quantasomes are believed to represent
pigment systems (photosystems) I and II respectively.
48. Semigenetic autonomy of chloroplasts
•Cytological studies have revealed the presence of
circular DNA, RNAs and ribosomes in chloroplasts.
•Nucleic acids are of the bacterial type.
•The DNA content of a chloroplast is about ten times
greater than that of a mitochondrion.
•The presence of DNA, RNAs and ribosomes gives
chloroplasts the ability to synthesise proteins.
•This makes them genetically semiautonomous.
49. Functions of chloroplasts
•(i) Energy fixation and the synthesis of organic molecules:
• Chloroplasts are the centres of photosynthesis.
• By photosynthesis, they manufacture organic molecules and bring about
energy fixation.
• Energy fixation is the overall process by which solar energy is trapped,
converted to chemical energy and conserved in the energy-bonds of organic
molecules.
• Energy fixation is significant in that it brings about the transduction of light
energy to chemical energy and thereby initiates the dynamics of the
ecosystem.
• Thus, the functional state of the ecosystem seems to be largely dependent
on the energy fixation by chloroplasts.
50. (ii) Synthesis of nucleic acids and proteins:
• Just as mitochondria, chloroplasts are also semiautomous organelles.
• With some autonomy they too can synthesise nucleic acids and
protein and thus bring about gene expression through the
replication, transcription and translation of the genetic code.
• Chloroplasts contain the complete molecular machinery for the
synthesis of nucleic acids and proteins.
• Chloroplast DNA can underego enzymatic replication and produce
multiple copies of it.
• Similarly, it can undergo transcription and synthesise RNAs.
• Making use of their DNA, RNAs, ribosomes and enzymes chloroplasts
can carry out genetic translation and synthesise some chloroplast
proteins also.
51. (iii) Extra-chromosomal (cytoplasmic) inheritance:
•Chloroplast DNA contains extra-chromosomal
genes, called plastogenes or plasma genes.
•They can govern non-Mendelian inheritance
and control plastid characters, generally in co-
operation with chromosomal genes.
•Plastogenes are believed to control the
inheritance of leaf colour in some plants.
52. (iv) Provide energy and carbon for
all heterotrophs:
•Chloroplasts carry out photosynthesis and
produce organic molecules, which form
the basic source of energy and carbon for
all heterotrophic organisms.
•So, most organisms directly or indirectly
depend on chloroplasts for their energetic
and nutritional requirements.
53. v) Enrich atmospheric O, and maintain the
stratospheric ozone layer:
•Oxygenic photosynthesis in chloroplasts removes CO₂
from the atmosphere and releases O₂ to the
atmosphere.
•This enriches the atmospheric oxygen store.
•Virtually, the entire atmospheric oxygen build up is the
product of oxygenic photosynthesis over the past 3300
million years.
•A portion of this oxygen treasure is converted to
stratospheric O, by the action of UV radiation.
54. •This ozone layer screens out harmful solar and
cosmic radiations and thereby protects the life on
earth.
•Thus, it becomes clear that without chloroplasts
and green plants there would be no oxygen in the
atmosphere, and life on earth would be almost
impossible.
55. (vi) Reduction of nitrite to ammonia :
•The reducing power of energised (light-
activated) electrons in chloroplasts drives
the reduction of NO₂ to NH3.
•The ammonia thus formed provides nitrogen
for the synthesis of nitrogenous compounds,
such as amino acids, nucleotides, etc.
56. Origin of plastids
• Many theories have been put forward to explain the origin and development of
plastids. Some of them are the following:
(a) Monotropic development
• This theory holds that plastids are autonomous organelles and they can change
from one form to another either reversibly or irreversibly.
• So, according to it, plastids are not formed de novo, but are always formed by
interconversion.
• It also holds that chromoplast is a degenerated form of chloroplast, formed by
the irreversible transformation of chloroplast.
• This transformation involves an irrecoverable loss of chlorophyll.
57. b) Development from proplastids
• Several workers hold that plastids develop from tiny cytoplasmic bodies, called
proplastids or plastid precursors.
• Proplastids are simple self-duplicating structures with a clear matrix, bounded by
a double-layered membrane.
• The matrix contains DNA and RNAs.Proplastids develop first in the cytoplasm of
meristematic cells.
• On exposure to light, they elongate and develop 'blebs' from the inner side of
their double-layered envelope.
• These blebs become lamellae, which in turn, multiply through linear splitting.
• Simple lamellae undergo growth and differentiation and give rise to granal,
intergranal and stromal lamellae. This results in the transformation of proplastids
to mature chloroplasts.
58. (c) Division and budding
•In lower plants, new plastids originate by the
division and budding of the existing ones.
•During division, ring-like constrictions appear,
which gradually deepen and finally divide the
plastid into fragments.
•These fragments then differentiate into mature
plastids.
•Budding of plastids also takes place under certain
special circumstances.
59. (d) Nuclear origin
•Proplastid-like structures have been observed
near the nucleus in some cases.
•This has led some workers to think that
proplastids originate from nucleus by the
evagination of nuclear envelope.
•Then, proplastids develop to mature plastids.