AL-02 Cell Division 10-11

8/6/2019 AL-02 Cell Division 10-11

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CELL DIVISIONCELL DIVISION


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To describe the events occurring during mitosis.

Aims

To state the characteristic feature/event of each

of the phases of mitosis.

Objectives


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Lecture Outline

Cell division

Cell cycle

Different stages of cell cycle:

Mitosis

Interphase

Review questions


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1Cell(Fertilisation)

75 Trillion Cells(Human Body)


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Cell

Multiplication

Cell

Death

(Damage / Ageing)

Turn Over



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Cell

Multiplication

Cell

Death

(Damage / Ageing)

Turn Over

Rapid ( Epithelial cells (GIT), Epidermis

Slow ( Pancreas, Thyroid

Absent ( Nerve tissue, Cardiac muscle cells



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Interval between one cell division and the

next cell division is known as the .......

Cell Cycle.

CELL CYCLECELL CYCLE

Cell division 1 Cell division 2

Cell Cycle


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Cell division 1 Cell division 2

Cell Cycle

Interphase Mitosis

In one cell cycle, the cell undergoes one

complete passage through interphase and

mitosis.


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INTERPHASEINTERPHASE

MITOSISMITOSIS

G1G1

GGMMGGMM

G2G2

Cell growth

SS

One complete passage of the cell through

interphase and mitosis.

Protein/RNAsynthesis

Organelleduplication

DNAreplication

Proteinsynthesis

Energyproduction


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MITOSIS(nuclear division)

CYTOKINESIS(cytoplasmic division)



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mitos = thread osis = condition

(thread-like chromosomes in the nucleus)

Mitosis = nuclear division ofsomaticcells.

MITOSISMITOSIS

Somatic cells include:

All cells in the body;Except germ cells (sperms or ova)


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mitos = thread osis = condition

(thread-like chromosomes in the nucleus)

Mitosis is a process in which a celldivides and passes a full set of chromosomes

to each of the newly formed daughter cell.

MITOSISMITOSIS


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The genetic material of the mother cell is

accurately duplicated (replicated) and then

distributed to two daughter cells.

Objective of replication:

To copy genetic information in the nucleus

so that one set of chromosome can be given

to each daughter cell.

MITOSISMITOSIS


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Intact.

1 Pair.

Juxtanuclear position.No spindle.

Nuclear Membrane

Centrioles

Thin, long filaments.

Spreadedinnucleus.

Disappear.

2 pairs.

Migrate to opposite poles.Spindle forms.

Thick,short filaments.

Attached to spindle.

Chromosomes

Interphase Mitosis


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Stages of Mitosis

Prophase Metaphase Anaphase Telophase

MITOSISMITOSIS


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Prophase Metaphase Anaphase (After) Telophase

Begin to disappear Disappeared Disappeared Reappear

Nuclear Membrane and Nucleolus

Interphase

Prophase

Centrioles

Chromosomes

2 pairs.At each pole.Spindle (+)

Thick, short.

Attached to spindle



1 pairJuxtanuclear.Spindle (-)

Thick, short.

At equator.

Thick, short.

Go to opposite poles

Thin, long.

Spreaded in nucleus


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Before Mitosis Replication Mitosis

Single Double

Divide longitudinally

Chromosomes

Thick, short.Thin, long. Thin, long.

Single

Thick, short.

ReplicatesSpreaded in nucleus

Single

Spreaded in nucleus

(After) Telophase

Single Single

double

Singles

Single


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Prophase TelophaseAnaphaseMetaphase

Beforeprophase

Prophase


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Thin chromatin filaments change into thick, short

chromosomes.

Prophase

Centrioles duplicate into 2 pairs and migrate to opposite

poles of the cell. Mitotic spindle is formed.

Chromosomes are found to be attached to the mitotic

spindle via centromeres.

End of prophase is marked by disintegration of nuclear

membrane and nucleolus.

Nuclear membrane and nucleolus disappear.Metaphase

Chromosomes migrate to equatorial plane.

Chromosomes divide longitudinally.Anaphase

Chromatids migrate to opposite poles.


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Chromosomes transform back into thin, long filaments.

Telophase

Cytokinesis continues through telophase and the

2 daughter cells begin to separate.

Nuclear membrane and nucleolus reappear.

Mitotic spindle disappears.

1 pair ofcentrioles atjuxtanuclearposition.

(Telophase marks the end of mitosis proper)

Chromatids migrate to opposite poles.


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MITOSIS INTERPHASE


MITOSIS INTERPHASE


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It is the phase during which cells do not divide.

Nuclear membrane is intact.

Long, thin chromatin filaments.

Centrioles (1 pair) atjuxtanuclearposition.

Stages of Interphase

G1 G2S

Preduplication

Stage

Synthetic/Replication

Stage

Postduplication

Stage



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Interphase

Preduplication StageCell growth

Protein/RNA synthesisOrganelle duplication

Replication Stage

DNA replication

Postduplication Stage

Protein synthesisEnergy production/storage


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G1 Phase (First Gap Phase or Preduplication Stage)

Most cells of the body exist in this phase.

Cells are preparing for cell division.

Organelles are duplicated.

Protein and RNA synthesis occurs.


S Phase (Synthetic or Replication Stage)

Cells have completed their preparation.

DNA is replicated.

G2 Phase (Second Gap Phase or Postduplication Stage)

Cells undergo last-minute protein synthesis.

Energy is produced and stored for later use during mitosis.


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G0 Phase

Cell cycle activities are suspended temporarily

or permanently.

Occurs in cells which are not dividing

e.g. muscle cells, nerve cells.


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C

ell cycle activities are suspended indefinitely

G0 Phase

Occurs in non-dividing cells(muscle, nerve cells)


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Mitosis occurs in which type of cells?

Review questions

Which cells undergo G0 Phase?

State the characteristic feature/event of each

of the phases of mitosis.

Name the phases of mitosis, in correct order.

Which cells are somatic cells?


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END OF CELL DIVISIONEND OF CELL DIVISION

AL-02 Cell Division 10-11

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