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.

2. Presentation topic:
NUCLEUS
slides made by:
Ammara,Tehreem,fatima,
Kalsoom, Zainab,Bushra

3. NUCLEUS

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).

11. AUGUST WEISMANN
In 1873,
August
Weismann
postulated the
equivalence of
the maternal and
paternal germ
cells for heredity.

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

14. STRUCTURE OF
NUCLEUS

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.

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.

24. NUCLEAR PORE

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.

27. STRUCTURE OF NPC

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.

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

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.

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

41. Chromosomes
• Contain the genetic
material: DNA, RNA
Chromatin
• Is the chromosomal
material in its
decondensed, threadlike
state.

42. Eukaryotes
possess multiple
large linear
chromosomes
nucleus.
eukaryotes have
a small
circular mitocho
ndrial genome,
and some may
have additional
small circular or
linear cytoplasmi
chromosomes.

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.

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.

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.

55. FUNCTIONS OF NUCLEUS
Nucleus is the control center and
manager of 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.

58. PRTEIN SYNTHESIS FROM NUCLEUS

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

60. RIBOSOMES
IN NUCLEUS

61. FUNCTIONS OF RIBOSOMES
Genetic information
Nucleus Proteins

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

63. TRANSPORT THROUGH
NUCLEAR PORES

64. 5. TRANSCRIPTION
• Transcription is the
process in which a
gene's DNA sequence
is copied (transcribed)
to make an RNA
molecule.

65. TRANSCRIPTION PROCESS

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.

67. NUCLEUS FUNCTIONS
Nucleus
perform
many
functions in
the cell
But major
functions of
nucleus are
describe
following

68. NUCLEUS CHROMATIN
The nucleus contain all the
genetics information
in its chromatin

70. GENETIC INFORMATION
Nucleus take
part in
transmission of
genetic
Information
from parent
cells to its
daughter
cells
From one
generation to
next
generation

71. DIVISION OF NUCLEUS

72. Nucleus form
ribosome
On its
nucleolus
Nucleolus are
known as
protein
factories
protein factories

73. CELLULAR METABOLISM
Maintain
cellular
metabolism
through
controlling
synthesis
of
particular
type of
enzymes

74. FUNCTIONING OF GENE
Differential functioning of gene
Result in cell differentiation
And development of particular
morphology

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

76. HEREDITY CHARACTERISTICS
Nucleus also
controls
heredity
characteristics
of an organism.

77. NUCLEUS FUNCTIONS
Nucleus is
responsible
for
Cell division
differentiation
growth
Protein
synthesis

78. GENE EXPRESSION
It also
regulates
integrity of
genes
and gene
expression.

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.

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.

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.

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.

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

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.

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.

98. REFERENCES
• https://micro.magnet.fsu.edu/cells/nucleus/nucleus.html
• https://www.thoughtco.com/the-cell-nucleus-373362
• https://www.news-medical.net/life-sciences/Structure-and-Function-of-
the-Cell-Nucleus.aspx
• http://www.perkinselearning.org/activity/nucleus-structure-and-functions
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC99041/
• http://www.biologyreference.com/Mo-Nu/Nuclear-Transport.html
• https://www.nature.com/scitable/definition/transcription-dna-transcription-
87