The nucleus is a membrane-enclosed organelle found in eukaryotic cells that contains the cell's genetic material. It is surrounded by a double nuclear envelope that separates the nucleus from the cytoplasm and contains nuclear pores to regulate the transport of molecules. Within the nucleus are chromosomes made of DNA and proteins that control gene expression and cellular activities.
Nucleus” is a Latin word meaning Kernel
It is the “CONTROL CENTER” of the cell
Average diameter of nucleus is 6um, which occupies around 10% of cell volume
Nuclear Envelope
Nuclear Pores and complex
Nuclear lamina
Chromosomes & Chromatin
Nucleolus
Nucleoplasm
Nucleus” is a Latin word meaning Kernel
It is the “CONTROL CENTER” of the cell
Average diameter of nucleus is 6um, which occupies around 10% of cell volume
Nuclear Envelope
Nuclear Pores and complex
Nuclear lamina
Chromosomes & Chromatin
Nucleolus
Nucleoplasm
Discovered by an English biologist Robert Brown in 1831.
It is also know as the, “Brain of the cell” or “Control centre of the cell”
On the basis of absence and presence of nucleus cell may be divided into Prokaryotes and Eukaryotes respectively.
NUMBER- Mostly uninucleate
Binucleate – Hepatocytes,Chondryocytes, fungi
Polynucleate- Tapetal cell, myocytes
Anucleated Cell- Red Blood cell
Sieve tube element
Component of Nucleus Nuclear membrane
Nuclear pore
Nucleoplasm
Nucleolus
Chromatin
Nuclear Membrane :Also called the nuclear envelope, is a double membrane layer that separates the contents of the nucleus from the rest of the cell.
The nuclear membrane is a lipid bilayer, meaning that it consists of two layers of lipid molecules.
Outer Layer: The outer layer of lipids has ribosomes, structures that make proteins, on its surface. It is connected to the endoplasmic reticulum.
Inner Membrane: Network of fibers and proteins attached to the inner membrane is called the nuclear lamina. It structurally supports the nucleus, plays a role in repairing DNA, and regulates events in the cell cycle such as cell division and the replication of DNA.
cell wall means rigid layer of polysaccharides lying outside the plasma membrane of the cells of plants, fungi, and bacteria. In the algae and higher plants it consists mainly of cellulose.
Meiosis is a double division which occurs in the diploid cells and give rise to four haploid cells ,each having half the number of chromosomes as compared to the parent cell.
Meiosis is the process in which a single cell divides twice to form four haploid daughter cells.
These cells are the gametes – sperms in males and egg in females.
For more details, visit @biOlOgy BINGE-insight learning
Discovered by an English biologist Robert Brown in 1831.
It is also know as the, “Brain of the cell” or “Control centre of the cell”
On the basis of absence and presence of nucleus cell may be divided into Prokaryotes and Eukaryotes respectively.
NUMBER- Mostly uninucleate
Binucleate – Hepatocytes,Chondryocytes, fungi
Polynucleate- Tapetal cell, myocytes
Anucleated Cell- Red Blood cell
Sieve tube element
Component of Nucleus Nuclear membrane
Nuclear pore
Nucleoplasm
Nucleolus
Chromatin
Nuclear Membrane :Also called the nuclear envelope, is a double membrane layer that separates the contents of the nucleus from the rest of the cell.
The nuclear membrane is a lipid bilayer, meaning that it consists of two layers of lipid molecules.
Outer Layer: The outer layer of lipids has ribosomes, structures that make proteins, on its surface. It is connected to the endoplasmic reticulum.
Inner Membrane: Network of fibers and proteins attached to the inner membrane is called the nuclear lamina. It structurally supports the nucleus, plays a role in repairing DNA, and regulates events in the cell cycle such as cell division and the replication of DNA.
cell wall means rigid layer of polysaccharides lying outside the plasma membrane of the cells of plants, fungi, and bacteria. In the algae and higher plants it consists mainly of cellulose.
Meiosis is a double division which occurs in the diploid cells and give rise to four haploid cells ,each having half the number of chromosomes as compared to the parent cell.
Meiosis is the process in which a single cell divides twice to form four haploid daughter cells.
These cells are the gametes – sperms in males and egg in females.
For more details, visit @biOlOgy BINGE-insight learning
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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)
There are different components in the nucleus. A thin but distinct covering called the nuclear envelop, also known as the karyotheca, defines its perimeter. The solutes of the nucleus are dissolved in a clear fluid substance inside the envelope known as nucleoplasm, nuclear sap, or karyolymph.
The nuclear matrix, a network of protein-containing fibrils, the chromatin, which is made up of finely entwined nucleoprotein filaments, and one or more spherical structures known as nucleoli are all suspended in the nucleoplasm (singular, nucleolus). The nucleus is devoid of microtubules and membranes.
However, the nuclei of protozoans that form a mitotic spindle within the nuclear envelop contain microtubules. The nucleus is made up of 9–12% DNA, 5% RNA, 3% lipids, 15% simple basic proteins like histone or protamines, and 65% complex acid or neutral proteins. It also contains organic phosphates, inorganic salts or ions like Mg++, Ca++, and Fe++, as well as polymerases for the synthesis of DNA and RNA.
Functions
The nucleus serves as the cell's administrative hub. It performs the following primary purposes: By controlling the production of structural proteins, it keeps the cell alive. By directing the synthesis of enzymatic proteins, it controls cell metabolism. In addition to information about structure and metabolism, it also contains genetic material for the organism's behaviour, development, and reproduction. When necessary, it causes cell replication. It is where ribosome subunit formation takes place. By keeping only a select few genes active, it causes cell differentiation. It produces genetic changes that lead to evolution. The nuclear envelop separates the cytoplasm from the nucleoplasm. It is made up of an outer and an inner unit membrane. Each unit membrane is a trilaminar lipoprotein, similar to the plasma membrane, and is about 75Å thick. The inter membrane or perinuclear space, which divides the two unit membranes, is present between them. Its width is about 250Å. Ribosomes and polysomes are found in abundance on the outer, or cytoplasmic, surface of the outer membrane, which is also rough. These ribosomes continue to produce proteins. RER and the outer membrane occasionally blend together. As a result, the channels of the RER are continuous with the perinuclear space. Ribosomes are absent from the inner membrane of the nuclear envelope, but it has a thick layer called the nuclear lamina that is closely connected to its inner or nucleoplasmic surface.
The nuclear lamina is a network of filaments that ranges in thickness from 30 to 100 nm and is made up of lamin A, B, and C proteins. The inner membrane is supported and given shape by the nuclear lamina. The majority of the chromosomes are kept outside the nucleus by this connection between chromatin and the inner membrane. During mitosis, it also affects how the nuclear envelope degrades and then reforms. Nuclear Pores: The nuclear pores, which regulate the passage of some molecules and parti
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?
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3. • The nucleus is a membrane-enclosed organelle
found in eukaryotic cells. It contains most of the
cell's genetic material, organized as multiple
long linear DNA molecules in complex with a
large variety of proteins . The genes within these
chromosomes are the cell's nuclear genomeThe
function of the nucleus is to maintain the integrity
of these genes and to control the activities of the
cell by regulating gene expression
4. STRUCTURE OF NUCLEUS
• The main structures making up the nucleus are
the nuclear envelope, a double membrane that
encloses the entire organelle and separates its
contents from the cellular cytoplasm, the nuclear
lamina, a meshwork within the nucleus that adds
mechanical support, much like the cytoskeleton
supports the cell as a whole. Because the nuclear
membrane is impermeable to most molecules,
nuclear pores are required to allow movement of
molecules across the envelope . These pores
cross both of the membranes, providing a channel
that allows free movement of small molecules and
ions.
5. • The movement of larger molecules such as proteins is
carefully controlled, and requires active transport
regulated by carrier proteins.. Nuclear transport is
crucial to cell function, as movement through the
pores is required for both gene expression and
chromosomal maintenance. a number of subnuclear
bodies exist, made up of unique proteins, RNA
molecules, and particular parts of the chromosomes.
The best known of these is the nucleolus, which is
mainly involved in the assembly of ribosomes.They
are exported to the cytoplasm where they translate
mRNA .
6.
7. • In mammalian cells, the average diameter of the
nucleus is approximately 6 micrometers which
occupies about 10% of the total cell volume.The
viscous liquid within it is called nucleoplasm, and is
similar in composition to the cytosol found outside the
nucleus It appears as a dense, roughly spherical
organelle arranged parallel to one another and
separated by 10 to 50 nanometers (nm). The nuclear
envelope completely encloses the nucleus and
separates the cell's genetic material from the
surrounding cytoplasm, serving as a barrier to prevent
macromolecules from diffusing freely between the
nucleoplasm and the cytoplasm.
8. • The outer nuclear membrane is continuous with the
membrane of the rough endoplasmic reticulum
(RER), and is similarly studded with ribosomes.
The space between the membranes is called the
perinuclear space and is continuous with the RER
lumen .
• Nuclear pore
• They are large protein complexes that cross the
nuclear envelope, There are about on average
2000 nuclear pore complexes in the nuclear
envelope of a vertebrate cell .
9. • The proteins that make up the nuclear pore complex
are known as nucleoporins . Nuclear pore
complexes allow the transport of water-soluble
molecules across the nuclear envelope. This
transport includes RNA and ribosomes moving from
nucleus to the cytoplasm and proteins (such as DNA
polymerase and lamins), carbohydrates, signal
molecules. The nuclear pore complex (NPC) can
actively conduct 1000 translocations per complex
per second
10. • Smaller molecules simply diffuse through the pores,
larger molecules may be recognized by specific signal
sequences and then be diffused with the help of
nucleoporins into or out of the nucleus. Each of the
eight protein subunits surrounding the actual pore (the
outer ring) projects a spoke-shaped protein into the
pore channel. The center of the pore often appears to
contain a plug-like structure. The entire nuclear pore
complex (NPC) has a diameter of about 120 nm the di
ameter of the opening (functional diameter) is about 9
nm wide and its "depth" is about 200 nanometers.
11. • The gap through which molecules freely diffuse is only
about 9 nm wide, due to the presence of regulatory
systems within the center of the pore. This size allows
the free passage of small water-soluble molecules
while preventing larger molecules, such as nucleic
acids and larger proteins, from inappropriately
entering or exiting the nucleus. The nucleus of a
typical mammalian cell will have about 3000 to 4000
pores throughout its envelope each of which contains
a donut-shaped, eightfold-symmetric ring-shaped
structure at a position where the inner and outer
membranes fuse.
12. • Most proteins, ribosomal subunits, and some RNAs
are transported through the pore complexes in a
process mediated by a family of transport factors
known as karyopherins. karyopherins that mediate
movement into the nucleus are also called importins,
while those that mediate movement out of the nucleus
are called exportins. Steroid hormones such as
cortisol and aldosterone, as well as other small lipid-
soluble molecules involved in intercellular signaling
can diffuse through the cell membrane and into the
cytoplasm, where they bind nuclear receptor proteins
that are trafficked into the nucleus.