CHAPTER 5: GENETICS

Anaphase I (Away // Asing)Topic 5 GENETICS

• Homologous chromosomes separate and
move towards the opposite poles of the cell.
同源染色体分离并向细胞的相反两极移动

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Telophase I (Two // Terbahagi dua)Topic5 GENETICS

• Cytoplasm divides. 细胞质分裂
• Last stage of meiosis I ends.

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Topic 5 GENETICS

Meiosis II

Cell divides into two, then continue:
分为两部分，然后继续

Prophase II
Metaphase II
Anaphase II
Telophase II

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Prophase II Topic 5 GENETICS

• Spindle fibres begin to form. 纺锭纤维开始形
成

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Metaphase II Topic 5 GENETICS

• Chromosomes are arranged in an equatorial
plane .染色体排列在赤道平面内

• The spindle fibres are attached to the
centromere.

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Anaphase II Topic 5 GENETICS

• Centromere splits into two.着丝粒分裂为两个
• The sister chromatids separate and move

towards the opposite poles of the cell.姐妹染色
单体分离并向细胞的相反两极移动。

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Telophase II Topic 5 GENETICS

• The cytoplasm divides and nuclear membrane forms
again.细胞质分裂并再次形成核膜

• Four non-identical不相同daughter cells are formed.
These are gametes (with half the number of
chromosomes of the parent cell, (haploids, n- 23
chromosomes) ).这些子细胞的染色体是亲代细胞染
色体数目的一半

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Telophase II Topic 5 GENETICS

Four non-identical不相同
daughter cells are formed.

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Topic 5 GENETICS
PN NORAZLIN -Science Form 4 2020

Topic 5 GENETICS

Cell Division

Similarities Between Mitosis
And Meiosis

Cell division occurs.

Replication of chromosome occur once only.

New cells are produced.

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Topic 5 GENETICS

Cell Division

Differences Between Mitosis And Meiosis

Mitosis Meiosis

Occurs in somatic cell to produce new Occurs in reproductive organ to produce
body’s cell. gametes
Number of chromosomes in the daughter Number of chromosomes in the daughter
cell is same as the parent cell. cell is half of what the parent cell has.
Two daughter cells are produced in each cell Four daughter cells are produced in each
division process. cell division process.

Crossing over does not happen. Crossing over happens.

Cell division occurs one only. Cell division occurs twice.

Daughter cell has the same genetic make- Daughter cell has different genetic make-up
up compare to the parent cell. compare to the parent cell.
Importance for growth and asexual Importance to produce gametes for sexual
reproduction. reproduction.

Topic 5 GENETICS

Cell Division

The Importance Of Mitosis And Meiosis In Human

Male (diploid, 2n) Female (diploid, 2n)
(46 chromosomes) (46 chromosomes)

Meiosis

Sperm (haploid, n) Ovum (haploid, n)
(23 chromosomes) (23 chromosomes)

PN NORAZLIN -Science Form 4 2020 Fertilisation Sperm fuses with ovum

Zygote (diploid, 2n)
(46 chromosomes)

Foetus

Baby Mitosis

Child

Adult

Topic 5 GENETICS
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