Chromosome and Prokaryotic Vs Eukaryotic Cell

1. NUCLEAR MEMBRANE, NUCLEOLUS,
CHROMOSOME
3rd December

2. •Nuclear Membrane:
• A membrane separating nuclear material from
cytoplasmic content.
• It is double membrane and also called nuclear
membrane.
• Outer membrane has direct connection with
Endoplasmic reticulum while
• Inner membrane has contact with nuclear material.
• Outer and inner membrane are continue and at
certain places fuse to form openings called
NUCLEAR PORES through these pores the mRNA
made inside nucleus could leave nucleus and enter
into cytoplasm.

4. • The number of nuclear pores are highly variable.
• In undifferentiated cells like eggs they are about 30,000 per nucleus.
• In differentiated cells like Erythrocytes have only 3-4 pores.
• Every pore has specific size and structure to control the traffic passing through it.
•Nucleolus:
• It is darkly stained body within nucleus
• It does not have any membrane to separate it from
other nuclear material.
• It could vary from 1 to more

5. •FUNCTION:
•Formation of ribosomal RNA and
ribosomes.
•REGIONS:
• Composed of two regions:
• Peripheral granular area composed of precursor of
ribosomes
• Central fibril area consisting of molecules of DNA
and RNA.
•

6. •CHROMOSOMES:
• If nucleus is stained with Basic dyes it is stained deeply due to
chromatin material.
• During cell division chromatin material become dense and
visible in thread-like form called Chromosome.
• Composition:
• Under compound microscope it appears to be made of arms and
centromere.
• CENTROMERE: A place on chromosome where
spindle fibres are attached during cell division.
• Kinetochore: The kinetochore is a protein complex
assembled on the centromeric region of DNA. It
provides the major attachement point for the
spindle microtubules during mitotic or meiotic
division to pull the chromosomes apart.

7. •COMPOSITIONOF CHROMOSOMES:
•Each chromosome consist of identical
chromatids which are held together by
centromere during cell division.
CHROMATIDS
CENTROMERE

8. • Chromosome consist of DNA and Protein.
• All information to continue and perform the functions of life is present on these
Chromosome in form of Genes which are transferred from one generation to next.
NO. Of Chromosomes in body cells:
In a certain species the number of chromosome remain specific from
one generation to another.
In man the number of chromosome is 46 in each cell.
In frog number of chromosome is 26 in each cell.
In Chimpanzee it is 48.
In Drosophila 6 chromosomes occur in a cell.
In onion it is 6, 48 in potato, 14 in garden pea.

9. •NO. of ChromosomesinGametes:
•In gametes the number of chromosome is half and is called
haploid and as the chromosomes in other body cells exist in
form of pair called Diploid.
•EXAMPLE: Human gametes have 23 chromosomes and other
body cells have 46 chromosomes.

10. •PROKARYOTICCELL EUKARYOTICCELL
No membrane bound organelles Membrane bound organelles
Chromatin material is in direct contact
with cytoplasm
Chromosomes and DNA are bound by
nuclear membrane
Ribosomal larger sub unit is 50S and
smaller subunit is 30S.
Ribosomal larger sub unit is 60S and
smaller sub unit is 40S.
Cell wall is composed of polysaccharide
chains bound covalently to amino acids
forming Peptidoglycan or Murein.
Cell wall is present only in Plants and
absent in animal cell and is composed
of Cellulose and Pectin.
Cell wall is often regarded as single huge
molecule or molecular complex called
Sacculus.
Cell wall is composed of
cellulose, lignin and pectin.
Examples: Cyanobacteria, fungi,
Protista, bacteria.
Examples: Plants and Animals