it gives information about the nucleus which is the major cell component and its various parts like nuclear pores,nucleolus etc. it helps in the replication of DNA which contain genetic material.
The document defines the cell nucleus and describes its structure. The nucleus is a membrane-bound organelle found in eukaryotic cells that controls the cell and contains most of its DNA. It has an outer and inner membrane that envelop the nucleoplasm, which contains chromatin, nucleoli, and nuclear pores. The nucleolus is in the center and produces ribosomes, while chromatin contains DNA instructions for the cell.
1. The nuclear envelope possesses nuclear pores that allow for transport of materials between the nucleus and cytoplasm.
2. The nuclear pores contain annuli, which are circular structures that the inner and outer membranes of the nuclear envelope fuse through.
3. The nuclear envelope separates the nucleus from the cytoplasm and regulates transport while protecting the DNA.
The nucleus is a membrane-bound organelle that contains the genetic material (DNA) of eukaryotic cells. It takes up about 10% of the cell volume and facilitates transcription and replication processes to maintain cell integrity. The nucleus contains nucleoplasm, nucleolus, chromosomes, and a phospholipid bilayer nuclear membrane with pores. It serves as the control center of the cell by synthesizing proteins and controlling traits and metabolism. Chromatin is the complex of DNA and proteins within the nucleus that allows for compaction of DNA.
The document discusses research using cryo-electron microscopes to study the nuclear pores in cell nuclei. Key findings include:
1) Researchers discovered a previously unknown "molecular gate" structure inside the nuclear pores that only allows certain molecules to pass through.
2) Nuclear pores are among the largest and most complex structures in the cell, comprising over 200 individual proteins arranged in a ring-like architecture.
3) The molecular gate structure's discovery may lead to new insights into disease treatment and discovery by better understanding how molecules pass through the nuclear pores.
The nucleus is the control center of the cell that contains the cell's genetic material. It is surrounded by a double membrane called the nuclear envelope that separates the genetic material from the cytoplasm. The nucleus maintains the integrity of genes and controls cell activities through regulating gene expression. It also contains the nucleolus, which is not surrounded by a membrane and is the site of ribosomal RNA synthesis and ribosome assembly.
The document provides information about the nucleus and its components. It discusses that the nucleus is a prominent organelle found in eukaryotic cells that controls cellular activity. It describes the various structures of the nucleus including the nuclear envelope, nucleolus, chromatin, and nuclear pores. The nuclear envelope forms the boundary of the nucleus and contains nuclear pores that regulate transport between the nucleus and cytoplasm. Chromatin and the nucleolus are also described along with their roles in packaging DNA and synthesizing RNA, respectively.
The nucleus is an organelle found in eukaryotic cells that houses the cell's genetic material. It was first observed by Anton van Leeuwenhoek in the 17th century and further described by Robert Brown in the 19th century. The nucleus is surrounded by a double membrane called the nuclear envelope and contains chromatin fibers, nucleoplasm, and one or more nucleoli. It controls cell functions and stores the cell's genetic information in the form of DNA.
The document defines the cell nucleus and describes its structure. The nucleus is a membrane-bound organelle found in eukaryotic cells that controls the cell and contains most of its DNA. It has an outer and inner membrane that envelop the nucleoplasm, which contains chromatin, nucleoli, and nuclear pores. The nucleolus is in the center and produces ribosomes, while chromatin contains DNA instructions for the cell.
1. The nuclear envelope possesses nuclear pores that allow for transport of materials between the nucleus and cytoplasm.
2. The nuclear pores contain annuli, which are circular structures that the inner and outer membranes of the nuclear envelope fuse through.
3. The nuclear envelope separates the nucleus from the cytoplasm and regulates transport while protecting the DNA.
The nucleus is a membrane-bound organelle that contains the genetic material (DNA) of eukaryotic cells. It takes up about 10% of the cell volume and facilitates transcription and replication processes to maintain cell integrity. The nucleus contains nucleoplasm, nucleolus, chromosomes, and a phospholipid bilayer nuclear membrane with pores. It serves as the control center of the cell by synthesizing proteins and controlling traits and metabolism. Chromatin is the complex of DNA and proteins within the nucleus that allows for compaction of DNA.
The document discusses research using cryo-electron microscopes to study the nuclear pores in cell nuclei. Key findings include:
1) Researchers discovered a previously unknown "molecular gate" structure inside the nuclear pores that only allows certain molecules to pass through.
2) Nuclear pores are among the largest and most complex structures in the cell, comprising over 200 individual proteins arranged in a ring-like architecture.
3) The molecular gate structure's discovery may lead to new insights into disease treatment and discovery by better understanding how molecules pass through the nuclear pores.
The nucleus is the control center of the cell that contains the cell's genetic material. It is surrounded by a double membrane called the nuclear envelope that separates the genetic material from the cytoplasm. The nucleus maintains the integrity of genes and controls cell activities through regulating gene expression. It also contains the nucleolus, which is not surrounded by a membrane and is the site of ribosomal RNA synthesis and ribosome assembly.
The document provides information about the nucleus and its components. It discusses that the nucleus is a prominent organelle found in eukaryotic cells that controls cellular activity. It describes the various structures of the nucleus including the nuclear envelope, nucleolus, chromatin, and nuclear pores. The nuclear envelope forms the boundary of the nucleus and contains nuclear pores that regulate transport between the nucleus and cytoplasm. Chromatin and the nucleolus are also described along with their roles in packaging DNA and synthesizing RNA, respectively.
The nucleus is an organelle found in eukaryotic cells that houses the cell's genetic material. It was first observed by Anton van Leeuwenhoek in the 17th century and further described by Robert Brown in the 19th century. The nucleus is surrounded by a double membrane called the nuclear envelope and contains chromatin fibers, nucleoplasm, and one or more nucleoli. It controls cell functions and stores the cell's genetic information in the form of DNA.
The document discusses the key parts of a cell's nucleus. It describes the nucleus as the cell's "CPU" that stores DNA and coordinates the cell's activities. The nucleus contains chromosomes that hold the cell's genetic information. Within the nucleus are the nucleolus, which manufactures ribosomes, and the nuclear envelope and pores, which regulate passage between the nucleus and cytoplasm. The nucleus controls critical cell functions like growth, metabolism, and reproduction.
The nucleus is a membrane-bound organelle found in eukaryotic cells that contains the cell's genetic material (DNA). It controls cellular metabolism and protein synthesis, regulates cell division and differentiation, and maintains the integrity of genes. The nucleus contains nucleoplasm, nuclear envelopes, nucleoli, and chromosomes. It is usually located in the center of animal cells and near the periphery of plant cells. The number and structure of chromosomes provide heredity information and vary between species.
The nucleus is a membrane-bound organelle that houses the cell's chromosomes and controls cell growth and reproduction. It contains the cell's hereditary material and is usually located in the center of the cell. The nucleus is surrounded by a double membrane called the nuclear envelope that separates the nucleus from the cytoplasm. Within the nucleus are chromosomes containing DNA, the nucleolus which produces ribosomes, and nucleoplasm similar to cytoplasm.
The nucleus is an organelle found in eukaryotic cells that contains the cell's genetic material. It is enclosed by a double membrane and contains chromosomes, chromatin, and the nucleolus. The nuclear membrane acts as a barrier between the cell's cytoplasm and the materials inside the nucleus. Nuclear pores allow selective transport of molecules through the nuclear membrane. The nucleolus produces ribosomal RNA and is involved in protein synthesis. Chromatin contains DNA and proteins that condense to form chromosomes during cell division. The document provides details on the structure and functions of the nucleus and its components.
The plasma membrane controls what enters and leaves the cell. There are three main ways drugs pass through:
1) Passive diffusion - Lipid-soluble drugs pass directly through the membrane.
2) Facilitated diffusion - Carrier proteins transport specific molecules like glucose.
3) Active transport - Energy-dependent pumps move molecules against a concentration gradient.
The nucleus is a spherical organelle found in eukaryotic cells that was first discovered by Leeuwenhoek and described in more detail by Robert Brown. It accounts for about 10% of the cell's volume and ranges from 2-5 micrometers in diameter. The nucleus contains genetic material, is surrounded by a double membrane with nuclear pores, and acts as the control center of the cell by storing hereditary material and producing ribosomes and RNA.
The nuclear pore complex regulates the passage of molecules between the nucleus and cytoplasm. It is comprised of several subunits that form a channel with a central pore. Surrounding the pore is a nonmembranous annulus with spoke-like structures. The pore wall contains columnar and lumenal subunits anchored by transmembrane proteins. Tiny fibrils extend from both sides in basket-like configurations, with different protein compositions on each side. Nuclear pores allow entry and exit of proteins and molecules to perform functions inside and outside the nucleus.
The nuclear envelope encloses the DNA and defines the nuclear compartment. It is composed of an inner and outer nuclear membrane with nuclear pores that regulate transport between the nucleus and cytoplasm. The nuclear pores have a diameter between 10-100nm and their number, or pore density, correlates with a cell's transcriptional activity. Transport through the pores is regulated by signal proteins that open the pores to precisely the right extent to allow passage of molecules and particles between the nuclear and cytoplasmic compartments.
The nucleus and nucleolus are organelles found within eukaryotic cells. The nucleus contains most of the cell's genetic material and is surrounded by a double nuclear membrane. It functions as the control center of the cell. The nucleolus is located within the nucleus and is the site of ribosomal RNA transcription. It has three main components - fibrillar center, dense fibrillar component, and granular component. The nucleolus is made up of proteins and RNA and its main function is to produce ribosomal RNA.
The nucleus is surrounded by a double membrane called the nuclear envelope. Underlying the inner nuclear membrane is the nuclear lamina, a fibrous network composed of lamin proteins that provides structural support. Nuclear pores embedded in the nuclear envelope selectively regulate the transport of molecules in and out of the nucleus. The nucleolus within the nucleus is the site of ribosome biogenesis and contains genes for ribosomal RNA. Mutations in lamin genes can cause premature aging diseases like Hutchinson-Gilford progeria syndrome.
The nuclear membrane, also known as the nuclear envelope, is a double lipid bilayer that surrounds the genetic material and nucleolus in eukaryotic cells. It consists of an inner and outer nuclear membrane, with the space between called the perinuclear space. The nuclear membrane functions to compartmentalize the nuclear material, maintain the shape and stability of the nucleus, regulate the transport of substances into and out of the nucleus through nuclear pores, and facilitate communication between the nucleus and the cell.
Discovery of nucleus
Evolution of nucleus
Structure of nucleus
Function of nucleus
Diseases related with nucleus
The nucleus was the first organelle to be discovered.
The probably oldest preserved drawing dates back to the early microscopist Antonie van Leeuwenhoek (1632 – 1723). He observed a "Lumen", the nucleus, in the red blood cells of salmon.
The nucleus was also described in 1831 by Scottish botanist Robert Brown.
Brown was studying orchids under microscope when he observed an opaque area, which he called the areola or nucleus, in the cells of the flower's outer layer. He did not suggest a potential function.
The cell nucleus is a membrane bound structure that:-
Contains the cell's hereditary information
Controls the cell's growth and reproduction
Direct the other components of cell through protein regulation
Make Proteins through central dogma of cell
DNA mRNA Protein
Emery-Dreifuss muscular dystrophy
Mutations in nuclear lamins associated with Emery-Dreifuss muscular dystrophy.
Emery-Dreifuss muscular dystrophy (EDMD) is a neuromuscular degenerative condition with an associated dilated cardiomyopathy and cardiac conduction defect.
It can be inherited in either an X-linked or autosomal manner by mutations in the nuclear proteins emerin and lamin A/C, respectively.
Traditionally muscular dystrophies were associated with defects in sarcolemma-associated proteins and, therefore, a nuclear connection suggested the existence of novel signalling pathways associated with this group of diseases.
Subsequently, other mutations in the lamin A/C gene were attributed to a range of tissue-specific degenerative conditions, collectively known as the 'laminopathies’.
The nucleus contains the DNA blueprint for the cell and machinery to replicate DNA and synthesize RNA. It regulates transport between the nuclear and cytoplasmic compartments, and contains heterochromatin and euchromatin. The nuclear envelope is a double membrane with nuclear pores that regulate transport. It surrounds the nucleolus, which synthesizes ribosomal components, and the chromatin, which condenses during cell division.
The document discusses two recent studies on nuclear transport and its implications for medical research. The first study used high-speed atomic force microscopy to visualize the dynamics of nuclear pores in colon cancer cells at nanoscale resolution. It found that nuclear pore deformation may be involved in cancer cell death. The second study identified a potential way to prevent mRNA with disease-causing mutations from leaving the nucleus in motor neuron disease. Advances in understanding nuclear transport could lead to new treatment approaches for diseases like cancer and amyotrophic lateral sclerosis.
The nucleus has several key functions and structures that allow it to control the cell. The nuclear membrane separates the nuclear material from the cytoplasm and regulates what passes in and out through nuclear pores. Within the nucleus are nucleoli, which produce ribosomes, and chromosomes, which contain DNA and genes that control cell activities and inheritance.
The nucleus was discovered in 1831 by Robert Brown. It is the largest organelle in eukaryotic cells, typically measuring 11-22 micrometers in diameter. The nucleus contains the cell's chromosomes, which are composed of DNA and protein. DNA contains the genetic information needed to build and organize cells.
Cells are the fundamental units of life, and all organisms are made up of one or more cells. The document discusses two important cellular components - the nucleus and ribosomes. The nucleus houses most of the cell's DNA and directs protein synthesis. It is enclosed by a double membrane and contains chromosomes. The ribosomes use information from DNA to synthesize proteins according to instructions provided by messenger RNA. They assemble in the nucleolus and exit into the cytoplasm to perform protein synthesis.
11 chap 4 (the cell) f.sc 1st year biology helping notes the college studyMary Smith
This document provides a summary of key concepts about cells from a biology textbook chapter. It begins with short question and answer explanations of chloroplasts, their components, grana interconnectivity, nucleus shape and contents. It then discusses other organelles like thylakoids, when the nucleus is visible, cell wall composition, diseases like Tay-Sachs, peroxisome enzymes, glyoxisomes, and more. The document aims to help students understand the basic structures and functions of organelles and other cellular components.
The nucleus contains an internal structure that organizes genetic material and localizes functions. A key part is the nucleolus, where rRNA genes are transcribed and ribosomal subunits assembled. Chromatin is organized into heterochromatin and euchromatin, and each chromosome occupies its own territory within the nucleus. The nucleolus forms around rRNA gene clusters and contains regions for transcription, processing, and ribosome assembly. Ribosomal proteins assemble with pre-rRNA to form subunits that are exported from the nucleus.
Robert Hooke discovered cells in 1665 using an early microscope. He observed the structures of cork cells. The development of electron microscopes in the 1930s allowed scientists to view cells and organelles at much higher magnifications. Key discoveries included the nucleus by Brown in 1831, living cells by Van Leeuwenhoek in 1674, and the proposal of the cell theory by Schleiden, Schwann, and Virchow from 1838-1858 stating that cells are the fundamental unit of life. Plant cells have additional structures like a cell wall and chloroplasts. The main components of plant cells are the cell membrane, cytoplasm, and nucleus. The nucleus contains DNA and controls the cell.
The nucleus is a membrane-bound organelle found in eukaryotic cells that contains most of the cell's genetic material. It is surrounded by a double membrane called the nuclear envelope, which contains nuclear pores that regulate the transport of molecules into and out of the nucleus. The nucleus contains DNA organized into chromosomes, and functions to control gene expression and maintain the integrity of genetic material. Other structures in the nucleus include the nucleolus, which is involved in ribosome assembly, and various subnuclear bodies that perform different functions.
The document discusses the key parts of a cell's nucleus. It describes the nucleus as the cell's "CPU" that stores DNA and coordinates the cell's activities. The nucleus contains chromosomes that hold the cell's genetic information. Within the nucleus are the nucleolus, which manufactures ribosomes, and the nuclear envelope and pores, which regulate passage between the nucleus and cytoplasm. The nucleus controls critical cell functions like growth, metabolism, and reproduction.
The nucleus is a membrane-bound organelle found in eukaryotic cells that contains the cell's genetic material (DNA). It controls cellular metabolism and protein synthesis, regulates cell division and differentiation, and maintains the integrity of genes. The nucleus contains nucleoplasm, nuclear envelopes, nucleoli, and chromosomes. It is usually located in the center of animal cells and near the periphery of plant cells. The number and structure of chromosomes provide heredity information and vary between species.
The nucleus is a membrane-bound organelle that houses the cell's chromosomes and controls cell growth and reproduction. It contains the cell's hereditary material and is usually located in the center of the cell. The nucleus is surrounded by a double membrane called the nuclear envelope that separates the nucleus from the cytoplasm. Within the nucleus are chromosomes containing DNA, the nucleolus which produces ribosomes, and nucleoplasm similar to cytoplasm.
The nucleus is an organelle found in eukaryotic cells that contains the cell's genetic material. It is enclosed by a double membrane and contains chromosomes, chromatin, and the nucleolus. The nuclear membrane acts as a barrier between the cell's cytoplasm and the materials inside the nucleus. Nuclear pores allow selective transport of molecules through the nuclear membrane. The nucleolus produces ribosomal RNA and is involved in protein synthesis. Chromatin contains DNA and proteins that condense to form chromosomes during cell division. The document provides details on the structure and functions of the nucleus and its components.
The plasma membrane controls what enters and leaves the cell. There are three main ways drugs pass through:
1) Passive diffusion - Lipid-soluble drugs pass directly through the membrane.
2) Facilitated diffusion - Carrier proteins transport specific molecules like glucose.
3) Active transport - Energy-dependent pumps move molecules against a concentration gradient.
The nucleus is a spherical organelle found in eukaryotic cells that was first discovered by Leeuwenhoek and described in more detail by Robert Brown. It accounts for about 10% of the cell's volume and ranges from 2-5 micrometers in diameter. The nucleus contains genetic material, is surrounded by a double membrane with nuclear pores, and acts as the control center of the cell by storing hereditary material and producing ribosomes and RNA.
The nuclear pore complex regulates the passage of molecules between the nucleus and cytoplasm. It is comprised of several subunits that form a channel with a central pore. Surrounding the pore is a nonmembranous annulus with spoke-like structures. The pore wall contains columnar and lumenal subunits anchored by transmembrane proteins. Tiny fibrils extend from both sides in basket-like configurations, with different protein compositions on each side. Nuclear pores allow entry and exit of proteins and molecules to perform functions inside and outside the nucleus.
The nuclear envelope encloses the DNA and defines the nuclear compartment. It is composed of an inner and outer nuclear membrane with nuclear pores that regulate transport between the nucleus and cytoplasm. The nuclear pores have a diameter between 10-100nm and their number, or pore density, correlates with a cell's transcriptional activity. Transport through the pores is regulated by signal proteins that open the pores to precisely the right extent to allow passage of molecules and particles between the nuclear and cytoplasmic compartments.
The nucleus and nucleolus are organelles found within eukaryotic cells. The nucleus contains most of the cell's genetic material and is surrounded by a double nuclear membrane. It functions as the control center of the cell. The nucleolus is located within the nucleus and is the site of ribosomal RNA transcription. It has three main components - fibrillar center, dense fibrillar component, and granular component. The nucleolus is made up of proteins and RNA and its main function is to produce ribosomal RNA.
The nucleus is surrounded by a double membrane called the nuclear envelope. Underlying the inner nuclear membrane is the nuclear lamina, a fibrous network composed of lamin proteins that provides structural support. Nuclear pores embedded in the nuclear envelope selectively regulate the transport of molecules in and out of the nucleus. The nucleolus within the nucleus is the site of ribosome biogenesis and contains genes for ribosomal RNA. Mutations in lamin genes can cause premature aging diseases like Hutchinson-Gilford progeria syndrome.
The nuclear membrane, also known as the nuclear envelope, is a double lipid bilayer that surrounds the genetic material and nucleolus in eukaryotic cells. It consists of an inner and outer nuclear membrane, with the space between called the perinuclear space. The nuclear membrane functions to compartmentalize the nuclear material, maintain the shape and stability of the nucleus, regulate the transport of substances into and out of the nucleus through nuclear pores, and facilitate communication between the nucleus and the cell.
Discovery of nucleus
Evolution of nucleus
Structure of nucleus
Function of nucleus
Diseases related with nucleus
The nucleus was the first organelle to be discovered.
The probably oldest preserved drawing dates back to the early microscopist Antonie van Leeuwenhoek (1632 – 1723). He observed a "Lumen", the nucleus, in the red blood cells of salmon.
The nucleus was also described in 1831 by Scottish botanist Robert Brown.
Brown was studying orchids under microscope when he observed an opaque area, which he called the areola or nucleus, in the cells of the flower's outer layer. He did not suggest a potential function.
The cell nucleus is a membrane bound structure that:-
Contains the cell's hereditary information
Controls the cell's growth and reproduction
Direct the other components of cell through protein regulation
Make Proteins through central dogma of cell
DNA mRNA Protein
Emery-Dreifuss muscular dystrophy
Mutations in nuclear lamins associated with Emery-Dreifuss muscular dystrophy.
Emery-Dreifuss muscular dystrophy (EDMD) is a neuromuscular degenerative condition with an associated dilated cardiomyopathy and cardiac conduction defect.
It can be inherited in either an X-linked or autosomal manner by mutations in the nuclear proteins emerin and lamin A/C, respectively.
Traditionally muscular dystrophies were associated with defects in sarcolemma-associated proteins and, therefore, a nuclear connection suggested the existence of novel signalling pathways associated with this group of diseases.
Subsequently, other mutations in the lamin A/C gene were attributed to a range of tissue-specific degenerative conditions, collectively known as the 'laminopathies’.
The nucleus contains the DNA blueprint for the cell and machinery to replicate DNA and synthesize RNA. It regulates transport between the nuclear and cytoplasmic compartments, and contains heterochromatin and euchromatin. The nuclear envelope is a double membrane with nuclear pores that regulate transport. It surrounds the nucleolus, which synthesizes ribosomal components, and the chromatin, which condenses during cell division.
The document discusses two recent studies on nuclear transport and its implications for medical research. The first study used high-speed atomic force microscopy to visualize the dynamics of nuclear pores in colon cancer cells at nanoscale resolution. It found that nuclear pore deformation may be involved in cancer cell death. The second study identified a potential way to prevent mRNA with disease-causing mutations from leaving the nucleus in motor neuron disease. Advances in understanding nuclear transport could lead to new treatment approaches for diseases like cancer and amyotrophic lateral sclerosis.
The nucleus has several key functions and structures that allow it to control the cell. The nuclear membrane separates the nuclear material from the cytoplasm and regulates what passes in and out through nuclear pores. Within the nucleus are nucleoli, which produce ribosomes, and chromosomes, which contain DNA and genes that control cell activities and inheritance.
The nucleus was discovered in 1831 by Robert Brown. It is the largest organelle in eukaryotic cells, typically measuring 11-22 micrometers in diameter. The nucleus contains the cell's chromosomes, which are composed of DNA and protein. DNA contains the genetic information needed to build and organize cells.
Cells are the fundamental units of life, and all organisms are made up of one or more cells. The document discusses two important cellular components - the nucleus and ribosomes. The nucleus houses most of the cell's DNA and directs protein synthesis. It is enclosed by a double membrane and contains chromosomes. The ribosomes use information from DNA to synthesize proteins according to instructions provided by messenger RNA. They assemble in the nucleolus and exit into the cytoplasm to perform protein synthesis.
11 chap 4 (the cell) f.sc 1st year biology helping notes the college studyMary Smith
This document provides a summary of key concepts about cells from a biology textbook chapter. It begins with short question and answer explanations of chloroplasts, their components, grana interconnectivity, nucleus shape and contents. It then discusses other organelles like thylakoids, when the nucleus is visible, cell wall composition, diseases like Tay-Sachs, peroxisome enzymes, glyoxisomes, and more. The document aims to help students understand the basic structures and functions of organelles and other cellular components.
The nucleus contains an internal structure that organizes genetic material and localizes functions. A key part is the nucleolus, where rRNA genes are transcribed and ribosomal subunits assembled. Chromatin is organized into heterochromatin and euchromatin, and each chromosome occupies its own territory within the nucleus. The nucleolus forms around rRNA gene clusters and contains regions for transcription, processing, and ribosome assembly. Ribosomal proteins assemble with pre-rRNA to form subunits that are exported from the nucleus.
Robert Hooke discovered cells in 1665 using an early microscope. He observed the structures of cork cells. The development of electron microscopes in the 1930s allowed scientists to view cells and organelles at much higher magnifications. Key discoveries included the nucleus by Brown in 1831, living cells by Van Leeuwenhoek in 1674, and the proposal of the cell theory by Schleiden, Schwann, and Virchow from 1838-1858 stating that cells are the fundamental unit of life. Plant cells have additional structures like a cell wall and chloroplasts. The main components of plant cells are the cell membrane, cytoplasm, and nucleus. The nucleus contains DNA and controls the cell.
The nucleus is a membrane-bound organelle found in eukaryotic cells that contains most of the cell's genetic material. It is surrounded by a double membrane called the nuclear envelope, which contains nuclear pores that regulate the transport of molecules into and out of the nucleus. The nucleus contains DNA organized into chromosomes, and functions to control gene expression and maintain the integrity of genetic material. Other structures in the nucleus include the nucleolus, which is involved in ribosome assembly, and various subnuclear bodies that perform different functions.
The document discusses cellular organelles, focusing on the nucleus and mitochondria. It provides detailed information on the structure and functions of the nucleus, including that it is bounded by a double membrane and contains genetic material. It also describes the inner structures of the nucleus like the nucleolus and nuclear pores. Additionally, it discusses how the nucleus changes during cell division. For mitochondria, it notes that they are the powerhouses of the cell, generating energy through cellular respiration and having an inner membrane with folds called cristae to enhance this process.
STRUCTURE AND FUNCTIONS OF NUCLEUS OF A CELL.pptxRASHMI M G
The nucleus is the part of a cell that contains DNA organized into chromosomes and is located in the middle of the cell. It is surrounded by the nuclear envelope, which is a double membrane that separates the nucleus from the cytoplasm. The nuclear envelope contains nuclear pores, which are gateways that allow molecules to move into and out of the nucleus.
The Cell: The Histology Guide
Nucleus - The Cell: The Histology Guide - University of Leeds
The nucleus is found in the middle of the cells, and it contains DNA arranged in chromosomes. It is surrounded by the nuclear envelope, a double nuclear membrane (outer and inner), which separates the nucleus from the cytoplasm. The outer membrane is continuous with the rough endoplasmic reticulum.
open.baypath.edu
Nucleus – BIO109 Biology I Introduction to Biology
The boundary of the nucleus, called the nuclear envelope, is a double membrane that contains small openings called nuclear pores. These pores are gateways that allow molecules to move into and out of the nucleus, enabling it to communicate with the rest of the cell.
The nucleus has three main parts:
Nuclear membrane: A protective barrier of the nucleus
Nucleoplasm: The cytoplasm of the nucleus, which is a semifluid matrix that contains chromatin, the less condensed form of DNA that organizes into chromosomes during mitosis or cell division
Nucleolus: A spherical structure that produces and assembles the cell's ribosomes
The nucleus controls and regulates the activities of the cell, such as growth and metabolism.
What are the 4 types of nucleus?
What are the 3 parts of a nucleus?
How many nuclei are in a cell?
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The nucleus is the largest organelle in eukaryotic cells, taking up about 10% of the cell volume. It houses most of the cell's DNA and controls its metabolic and hereditary activities. The nucleus is enclosed by a double membrane with nuclear pores that regulate transport between the nucleus and cytoplasm. Inside the nucleus are nucleoplasm, nucleolus, and chromatin containing the cell's chromosomes. The nuclear envelope, nuclear lamina, and nuclear pores play important roles in controlling nuclear structure and transport.
DNA
its Discovery
Who Discovered DNA?
Credit for who first identified DNA is often mistakenly given to James Watson and Francis Crick, who just furthered Miescher’s discovery with their own groundbreaking research nearly 100 years later. Watson and Crick contributed largely to our understanding of DNA in terms of genetic inheritance, but much like Miescher, long before their work, others also made great advancements in and contributions to the field.
In 1866, before many significant discoveries and findings, Gregor Mendel was the first to suggest that characteristics are passed down from generation to generation. Mendel coined the terms as recessive and dominant.
In 1869, Friedrich Miescher identified the “nuclein” by isolating a molecule from a cell nucleus that would later become known as DNA.
In 1881, Nobel Prize winner and German biochemist Albrecht Kossel, who is credited with naming DNA, identified nuclein as a nucleic acid. He also isolated those five nitrogen bases that are now considered to be the basic building blocks of DNA and RNA: adenine (A), cytosine (C), guanine (G), thymine (T) and uracil (U) in case of RNA).
In 1882, Walther Fleming devoted research and time to cytology, which is the study of chromosomes. He discovered mitosis in 1882 when he was the first biologist to execute a wholly systematic study of the division of chromosomes. His observations that chromosomes double is significant to the later discovered theory of inheritance.
In Early 1900s, Theodor Boveri and Walter Sutton were independently working on what’s now known as the Boveri-Sutton chromosome theory, or the chromosomal theory of inheritance. Their findings are fundamental in our understanding of how chromosomes carry genetic material and pass it down from one generation to the next.
In 1902, Mendel’s theories were finally associated with a human disease by Sir Archibald Edward Garrod, who published the first findings from a study on recessive inheritance in human beings in 1902. Garrod opened the door for our understanding of genetic disorders resulting from errors in chemical pathways in the body.
In 1944, Oswald Avery first outlined DNA as the transforming principle, which essentially means that DNA transform cell properties.
The nucleus is a double-membrane organelle found in eukaryotic cells that contains most of the cell's genetic material. It has a spherical shape but can be other shapes depending on the cell. The nucleus contains chromatin with DNA, nucleolus, and is surrounded by a nuclear envelope. It acts as the control center of the cell by transmitting genetic information for protein synthesis, cell division, growth and differentiation.
The nucleus is a membrane-bound organelle found in eukaryotic cells that contains the cell's genetic material. It maintains the integrity of genes and controls cell activities through regulating gene expression. The nucleus is surrounded by a double membrane with nuclear pores that allow transport between the nucleus and cytoplasm. Chromatin fibers containing DNA and histones are organized into chromosomes inside the nucleus. The nucleolus is a dense structure where ribosomal RNA is synthesized.
The document discusses the key components and structure of the nucleus. It notes that the nucleus was discovered in 1831 and is the controlling center of the cell, usually located in the center. The nucleus contains the cell's hereditary information and controls growth and reproduction. It is surrounded by a nuclear envelope membrane and houses chromosomes, which contain DNA. The nucleus also contains a nucleolus that produces ribosomal RNA, chromosomes that carry DNA, and nucleoplasm similar to cytoplasm.
The document discusses the key components and structure of the nucleus. It notes that the nucleus was discovered in 1831 and is located at the center of most cells, where it controls cell activities and houses genetic material. The nucleus contains a double-layered nuclear envelope that encloses chromosomes, nucleolus, and nucleoplasm. Chromosomes contain DNA that provides genetic instructions, while the nucleolus produces ribosomes and the nucleoplasm is a liquid found within the nuclear envelope.
The document is a presentation on the nucleus and endoplasmic reticulum. It begins with background on the discovery of the nucleus by Leeuwenhoek and others. It then defines the nucleus as the control center of the cell that contains most of the cell's genetic material. It describes the main characteristics, size, shape, and ultrastructure of the nucleus, including the nuclear envelope, pores, lamina, chromosomes, nucleolus, and other components. It also summarizes the functions of the nucleus and endoplasmic reticulum, who discovered the ER, its definition, structure including cisternae, tubules and vesicles, types (rough and smooth ER), and functions in protein transport and synthesis.
The nucleus is a spherical organelle found in eukaryotic cells that controls cell functions and contains DNA. It is surrounded by a double membrane and contains chromatin, nucleoplasm, and one or more nucleoli. The nucleus controls gene expression and protein synthesis, regulates cell growth and division, and maintains hereditary material. It allows for the exchange of molecules with the cytoplasm through nuclear pores in its membrane. The nucleus contains the cell's genetic material and plays a key role in controlling cell activities and functions.
The nucleus is a membrane-bound organelle that houses the cell's DNA. It contains several sub-compartments including the nucleolus, which is the site of ribosome biogenesis. The nuclear envelope, composed of two lipid bilayers separated by perinuclear space, encloses the nucleus and regulates transport between the nucleus and cytoplasm through nuclear pore complexes. Within the nucleus, DNA is organized into either loosely packed euchromatin or tightly packed heterochromatin. The nucleolus forms around clusters of rRNA genes and is the site of rRNA transcription and ribosome subunit assembly.
Nucleus-the heart of the cell-cellular organellesbiOlOgyBINGE
In cell biology, the nucleus is a membrane-bound organelle found in eukaryotic cells.
The nucleus is found in all the eukaryotic cells of the plants and animals.
here u will find every detail of nucleus.
for more details ,visit @biOlOgy BINGE-insight learning (youtube channel)
The nucleus houses a cell's genome and controls cellular activities. It is enclosed by a double membrane nuclear envelope punctuated by nuclear pores that regulate transport between the nucleus and cytoplasm. Within the nucleus, DNA is organized into chromatin and various sub-compartments carry out functions like transcription and RNA processing. Chromosomes occupy distinct territories and nuclear pores facilitate macromolecular transport through the nuclear envelope.
The document provides an overview of cell organelles. It begins by defining a cell and its basic components. It then distinguishes between prokaryotic and eukaryotic cells, noting that eukaryotic cells are more complex with internal organelles. The three major parts of the cell - plasma membrane, nucleus, and cytoplasm - are introduced. Further details are given about the nucleus, its structures, and its role. The cytoplasm and its components of cytosol and inclusions are defined. Finally, the key organelles found in eukaryotic cells are described, including their structures and functions.
The nucleus is a spherical organelle found in eukaryotic cells that is surrounded by a double membrane nuclear envelope. It contains the cell's genetic material and coordinates various cellular activities such as protein synthesis, cell growth, and DNA replication and transcription. The nucleus contains chromatin, which packages the DNA, as well as nucleoli that produce ribosomes for protein synthesis.
The document summarizes key information about the cell nucleus:
1. The nucleus was the first organelle discovered and contains most of the cell's genetic material. It maintains the integrity of genes and controls the cell.
2. The nuclear envelope separates the nucleoplasm from the cytoplasm. Nuclear pores allow transport between the two compartments.
3. Chromatin within the nucleus organizes the DNA into chromosomes. The nucleolus synthesizes rRNA to assemble ribosomes.
The document discusses the discovery and components of the cell nucleus. It describes how Robert Brown first observed nuclei in plant cells and how others later established that cells only come from pre-existing cells. The main components of the nucleus are then outlined, including the nuclear envelope, nucleoplasm, nuclear pores, nuclear lamina, chromosomes, and nucleolus. The nuclear envelope forms a double membrane barrier with nuclear pores that regulate transport. The nuclear lamina provides structural support and anchors other structures. The nucleolus is responsible for producing ribosomes.
The nucleus is a large membrane-bound organelle found at the center of eukaryotic cells that contains the cell's genetic material in the form of chromosomes. It directs the cell's activities and is involved in cellular reproduction. Key features include being visible under a light microscope due to its acidic nature, containing DNA, RNA, and the nucleolus which produces ribosomes. The nuclear envelope encloses the nucleus and contains pores that regulate material passing in and out.
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natural resistance of body against infectionzainabsarfraz4
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4. NUCLEUS
The nucleus ( nuclei from Latin nucleus or
nuculeus, meaning kernel) is a membrane
enclosed organelle found in eukaryotic cells.
It contains most of the cell's genetic material
(DNA), organized as multiple long linear DNA
molecules in complex with a large variety of
proteins, such as histones, to form
chromosomes.
The genes within these chromosomes are the
cell's nuclear genome.
5. HISTORY
The nucleus was the first
organelle to be discovered.
Antonie van Leeuwenhoek (1632 –
1723). He observed a "Lumen",
the nucleus, in the red blood cells
of salmon.
The nucleus was also described
by Franz Bauer in 1804
6. ROBERT BROWN
And in 1831 by
Scottish
botanist Robert
Brown in a talk at
the Linnean Society
of London.
Brown was
studying orchids
under microscope
when he observed
an opaque area,
which he called the
areola or nucleus,
in the cells of the
flower's outer layer
7. MATTHIAS SCHLEIDEN
In 1838, Matthias
Schleiden proposed
that the nucleus
plays a role in
generating cells
thus he introduced
the
name "Cytoplast" (
cell builder).
He believed that he
had observed new
cells assembling
around "cytoplasts
8. FRANZ AND ROBERT
REMAK
Franz Meyen was a
strong opponent of
this view, having
already described
cells multiplying by
division and
believing that many
cells would have no
nuclei
Robert Remak (1852)
and Rudolf Virchow
(1855) who
decisively
propagated the new
paradigm that cells
are generated solely
by cells ("Omnis
cellula e cellula").
9. DISCOVERY OF
NUCLEUS
The function of
the nucleus
remained unclear.
Between 1876 and
1878
Oscar Hertwig
published several
studies on the
fertilization of sea
urchin eggs
showing that the
nucleus of the
sperm enters the
oocyte and fuses
with its nucleus.
10. NUCLEATED CELL
This was the first time it was suggested that an
individual develops from a (single) nucleated cell.
Hertwig confirmed his observation in other animal
groups, e.g., amphibians and molluscs.
Eduard Strasburger produced the same results for
plants (1884).
12. STRUCTURE OF
NUCLEUS
The nucleus is
the largest
organelle of the
cell.
The nucleus
appears to be
dense, spherical
organelle.
It occupies about
10% of the total
volume of the
cell.
The shape of the
nucleus is mostly
round, it may be
oval, disc shaped
depending on the
type of cell.
13. COMPONENTS OF
NUCLEUS STRUCTURE
The structure of nucleus contains following
components:
• Nuclear envelope
• Nuclear pore
• Nucleoplasm
• Nucleolus
• Chromosomes
https://www.shutterstock.com/search/nuclear+pore
15. NUCLEAR
ENVELOPE
A nuclear membrane, also known as the nuclear envelope is
the lipid bilayer membrane which surrounds the genetic
material and nucleolus in eukaryotic cells.
,It seprates the nuclear contents from the cytoplasm.It is
continuous with the ER at number of points.
During prophase in mitosis ,the chromatids condense to form
chromosomes and nuclear envelope disintegrate.During
metaphase, the nuclear envelope is completely disintegrated.
http://www.gettyimages.com/photos/nuclear-pores
16. NUCLEAR ENVELOPE
The nuclear membrane consists of two lipid
bilayers the inner nuclear membrane, and the
outer nuclear membrane. The space between
the membranes is called the “perinuclear
space”, a region continuous with the lumen
(inside) of the endoplasmic reticulum. It is
usually about 20–40 nm wide.
http://www.gettyimages.com/photos/nuclear-pores
17. OUTER MEMBRANE OF
NUCLEAR ENVELOPE
The outer nuclear membrane also shares a common border
with the endoplasmic reticulum.While it is physically linked,
the outer nuclear membrane contains proteins found in far
higher concentrations than the endoplasmic reticulum.
Nesprin proteins present in mammals are
expressed in the outer nuclear membrane.
Nesprin proteins connect cytoskeletal
filaments to the nucleoskeleton.
http://bscb.org/learning-
resources/softcell-e-
learning/nuclear-pore/
18. INNER MEMBRANE OF
NUCLEAR ENVELOPE
• The inner nuclear membrane encloses the nucleoplasm, and is
covered by the nuclear lamina, a mesh of intermediate
filament.
• It is connected to the outer membrane by nuclear pores which
penetrate the membranes.
http://bscb.org/learning-resources/softcell-e-learning/nuclear-pore/
19. NUCLEAR LAMINA
A layer of protein is
present closely
associated with nuclear
side of inner membrane.It
is called nuclear lamina.
Nuclear lamina is a
network of intermediate
filaments and it helps to
maintain the shape of the
nucleus and maintain the
organization of genetic
material.
It also plays role
in mitosis and
meosis.The
lamina acts as
site of
attachment for
chromosomes.
It is lined with a
fiber network
called as nuclear
lamina which is
10-40 nm thick
and provide
strength.
20.
21.
22. NUCLEAR PORES
https://www.shutterstock.com/search/nuclear+pore
The nuclear envelope is perforated by pores. The whole complex has
diameter of about 150nm and the diameter of the opening is about 50nm.
There are about 3,000-4,000 nuclear pore complexes in the nuclear
envelope of animal cells.
The nuclear membrane is punctured by thousands of nuclear pore
complexes large hollow proteins about 100 nm across, with an inner
channel about 40 nm wide. They link the inner and outer nuclear
membrane.
23. FUNCTIONS OF
NUCLEAR PORE
The pore
complex
regulates the
movement of
macromolecules
and particles.
This pore gives
the nucleus
direct contact
with the ER.
The size of
pores prevent
the DNA from
leaving but It
allows RNA and
proteins to
move out.
25. STRUCTURE OF NUCLEAR
PORE COMPLEX
It is cylindrical in structure.It has 8 fold symmetry.
It is composed of large proteins.These proeins
contain an alpha solenoid or a beta propeller fold.
In some cases, both are present.Eight protein
molecules are called annular subunits.
The annular subunits form the spoke assembly ring.It
surrounds the actual pore called outer ring
26. STRUCTURE OF NUCLEAR
PORE COMPLEX
The center of pore contains a plug like structure.The 8 annular units are
attached to the membrane by luminar subunits.
two rings are attached to each luminar subunits.
One faces the nucleus and other faces the cytoplasm.The nucleoplasmic
side of NPC has fibrils.
A cage like assembly is attached on the nucleaoplasmic side. The
nucleoplasmic side and cytoplasmic side of the NPC are very differenrt.
This causes the differences in the selective transport in the two directions.
29. NUCLEOLUS
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1225182/
The most visible structure within non dividing nucleus is nucleolus. The
nucleolus is a non- membranous bound structure. The nucleolus (plural
nucleoli) is a dense, spherical-shaped structure present inside the nucleus.
Some of the eukaryotic organisms have nucleus that contains up to four
nucleoli.Their number depends on the species and cell reproductive cycle.
The nucleus of many eukaryotic cells contains a structure called a nucleolus.
As the nucleus is the "brain" of the cell, the nucleolus could loosely be
thought of as the brain of the nucleus. The nucleolus takes up around 25% of
the volume of the nucleus.
30. FUNCTIONS OF NUCLEOLUS
The function of
nucleolus is to
synthesize
ribosomes. An
actively growing cell
can produce 10,000
ribosomes per
minute.
The nucleolus plays an
indirect role in protein
synthesis by producing
ribosomes. These ribosomes
are cell organelles made up
of RNA and proteins; they
are transported to the
cytoplasm, which are then
attached to the endoplasmic
reticulum.
Nucleolus
synthesizes
and stores
rRNA.Thus
nucleolus is
composed of
two regions:
Peripheral
granular
region: It is
composed of
precursors of
ribosomal
subunits.
31.
32. NUCLEAR CHROMOSOME
The microscopic threadlike part of the cell that
carries hereditary information in the form of genes.
46 chromosomes found in human cells have a length of 200 nm .
if the chromosomes were to be unraveled roughly 2 meters (about
6.5 feet) in length.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1225182/
33. CHROMOSOMES
A defining feature
of any
chromosome is its
compactness
The compactness of
chromosomes help to
organize genetic
material during cell
division and enabling
it to fit inside nucleus
of a cell
34. PROKARYOTES
CHROMOSOMES
The prokaryotes –
bacteria and archaea – typically have
a single circular chromosome.
The chromosomes of most bacteria can
range in size from only 130,000 base
pairs in the endo symbiotic bacteria.
14,000,000 base pairs in the soil-
dwelling bacterium
35.
36. STRUCTURE IN SEQUENCE
Prokaryotic chromosomes have less sequence-
based structure than eukaryotes.
Bacteria typically have a one-point (the origin of
replication) from which replication starts.
some archaea contain multiple replication origins.
The genes in prokaryotes are organized
in operons, and do not usually contain introns.
37. DNA PACKAGING
They do not possess nuclei.
their DNA is organized into a
structure called the nucleoid
The nucleoid is a distinct structure and
occupies a defined region of the bacterial
cell.
In archaea, the DNA in chromosomes is even
more organized, with the DNA packaged.
Prokaryotic chromosomes and plasmid are
generally supercoiled.
38.
39. EUKARYOTES CHROMOSOMES
In eukaryotes, nuclear
chromosomes are
packaged by proteins
into a condensed
structure
called chromatin.
Existence of
chromosome in
cell
Chromosomes may
exist as either
duplicated or
unduplicated.
Unduplicated
chromosomes are
single double heliex.
duplicated
chromosomes contain
two identical copies
(called chromatids or
sister chromatids)
joined by
a centromere
40.
41. Chromosomes
• Contain the genetic
material: DNA, RNA
Chromatin
• Is the chromosomal
material in its
decondensed, threadlike
state.
44. STRUCTURE OF EUKARYOTIC
CHROMOSOME
Each chromosome is made up of two
chromatids (chromosomal arms)
Chromatids are joined to each other at a small
constricted region called the centromere..
The centromere helps the chromatids attach to
the spindle fibers during cell division
45. COMPOSITION OF CHROMATINS
The two
chromatid
s are made
up of :
very thin
chromatin
fibers which
are made up
of 40% DNA
and 60%
histone
proteins.
Each chromatin
fiber consists of
one DNA helix
coiled around
eight histone
molecules like a
loop; such a
complex is
called
nucleosome.
46.
47. NUCLEAR LAMINA
The nuclear lamina is a structure
near the inner nuclear membrane
and the peripheral chromatin.
Nuclear lamina is a dense (30
to100 nm thick) fibrillar network
inside the nucleus of most cells.
48. COMPOSITION
It is composed of intermediate
filaments and membrane associated
proteins
The increasing number of proteins that
interact with lamina and interactions
between these proteins and chromatin-
associated proteins make the nuclear
lamina a highly complex .
The nuclear lamina is an essential
component of metazoan cells.
49. FUNCTION OF
NUCLEAR LAMINA
The nuclear
lamina
regulates DN
A replication
and cell
division.
It
participates
in chromatin
organization.
it anchors
the nuclear
pore
complexes e
mbedded in
the nuclear
envelope.
50. The nuclear lamina is associated with
the inner face of the
double bilayer nuclear envelope,
whereas the outer face is continuous
with the endoplasmic reticulum.
51. SYNTHESIS OF LAMINA
lamina are synthesized in the cytoplasm and
later transported to the nucleus interior, where
they are assembled before incorporated into
existing nuclear lamina.
Lamina found on the cytosolic face of the
membrane, bind to the cytoskeleton to provide
structural support. Lamina are also found inside
the nucleoplasm.
52.
53. NUCLEAR MATRIX
Nuclear matrix is
the network
of fibers found
throughout the
inside of a cell
nucleus and is
somewhat similar
to the
cell cytoskeleton.
The nuclear matrix,
along with
the nuclear
lamina aid in
organizing the
genetic information
within the cell.
56. 1. STORAGE OF DNA IN
NUCLEUS
DNA Hereditary
material store
genetic
information
And for
Eukaryotic
cell activities
DNA is
responsible
for protein
synthesis
57. 2. PRODUCTION OF PROTEINS
FROM NUCLEUS
Nucleus is known as “protein Factories” which
synthesize proteins from amino acids.
59. 3. PRODUCTION OF RIBOSOMES
FROM NUCLEUS
• proteins and RNA (ribonucleic acid) are stored in the
nucleolus.
The nucleolus makes
ribosomal subunits from
proteins and ribosomal
RNA, also known as
rRNA.
It then sends the
subunits out to the
rest of the cell
where they combine
into complete
ribosomes
62. 4. HELP IN TRANSPORT
OF MATERIALS
• Nucleus means” Kernel or Nut”. Nucleus is covered by a
membrane it allow the movement of materials across the
membrane.
• Exchange of
hereditary material
(DNA and RNA) occurs
between the nucleus
and the rest of the cell..
Selective
transportation of
regulatory factors
and energy
molecules through
nuclear pores
66. THREE STEPS IN TRANSCRIPTION
PROCESS
RNA polymerase is the main transcription enzyme
Transcription begins when RNA polymerase binds
to a promoter sequence near the beginning of a
gene (directly or through helper proteins).
RNA polymerase uses one of the DNA strands (the
template strand) as a template to make a new,
complementary RNA molecule.
70. GENETIC INFORMATION
Nucleus take
part in
transmission of
genetic
Information
from parent
cells to its
daughter
cells
From one
generation to
next
generation
75. CELL GROW IN SIZE
Newly formed
cells grow in size
become mature
with the help of
structural protein
and other
substances
formed on
instruction from
gene contained in
chromatin
79. ANIMAL CELL NUCLEUS
Animal cell nucleus is
a membrane bound
organelle.
It is surrounded by
double membrane.
The nucleus
communicates with
the surrounding cell
cytoplasm through the
nuclear pores.
80. FUNCTIONS OF ANIMAL CELL
NUCLEUS
The DNA in the
nucleus is responsible
for the hereditary
characteristics and
protein synthesis.
Nucleolus is a prominent
structure in the nucleus.
This aids in ribosome's
production and protein
synthesis.
81.
82. PLANT CELL NUCLEUS
Plant cell
nucleus is a
double-
membrane
bound
organelle.
It controls the
activities of
the cell and is
known as the
master mind
or the control
center of the
cell.
The plant cell
wall has two
layers - the
outer
membrane
and the inner
membrane
which
encloses a
tiny space
known as
perinuclear
space.
83. FUNCTIONS OF PLANT CELL
NUCLEUS
The nucleus communicates
to the cell cytoplasm through
the nuclear pores present in
the nuclear membrane.
The nuclear membrane is
continuous with the
endoplasmic reticulum.
The DNA is responsible for
cell division, growth and
protein synthesis.
84.
85. BACTERIAL CELL NUCLEUS
The bacterial
cell does not
contain any
nucleus.
The bacterial
chromosome
is not enclosed
in a membrane
bound
nucleus.
The bacterial
chromosome
is circular and
located in the
cytoplasm.
86.
87. RNA MODIFICATION:
tRNA molecules are synthesized by
cleaving a single strand of precursor
RNA.
These rRNA are produced through post-
transcriptional cleavage of it.This is also
called trimming.
88.
89. RNase is an enzyme involved in trimming.In
this enzyme containing RNA,rather than the
protein, is responsible for its activity.
90. BASE MODIFICATION OF RRNA
AND TRNA
Methylation of rRNA is subj
ected. In
this process, a methyl
group is transferred.
Addition of the terminal
CCA residues
and tRNAs were
aminoacylated.
91. 3′ terminal of pre-mRNA and after enzymatic cleavage at a site
approximately 20 bases downstream from this location ,more
than 1000 A’s (adenylic acid) are added by poly (A) polymerase.
An additional nucleotide, a 7-methylguanosine is added to the 5'-
end to form a cap-structure. This process is called capping
92.
93. PROCESSING IN MRNA
Exons code for
amino acids and
collectively
determine the
amino acid
sequence of the
protein product. It is
these portions of
the gene that are
represented in final
mature mRNA
molecule.
Introns are
portions of the
gene that do not
code for amino
acids, and are
removed
(spliced) from the
mRNA molecule
before
translation.
94.
95. NUCLEAR TRANSPORT
• a
These signals are referred to
as nuclear localization signals
(NLSs) or nuclear export
signals (NES), respectively. In
proteins, they are
specific amino acid sequences.
Bound
by soluble import or
export receptors that
shuttle between
nucleus and
cytoplasm.