Cell Division Flashcards
Independent Assortment
2 marks
Process that takes place during meiosis, in which chromosomes are reassorted.
In order to grow - most living organisms
2 marks
Increase their cell number - Cells double in number by splitting in half.
2 types of cell division
2 marks
Mitosis + Meiosis
Mitosis -
Explained
(5 marks)
Used to grow/replace worn out cells + repair damaged tissue.
- produces 2 new (daughter) Cells in 1 division.
Number of Cells produced in Mitosis
2 marks
2 new cells (daughter cells) in 1 division.
Cells produces during Mitosis
3 marks
Daughter cells - genetically identical (clones) to parent cell + each other.
What does Mitosis ensure
3 marks
Every cell in the growing organism contains the same genes + chromosomes.
Human sex cells contain:
-Meiosis-
(2 marks)
1 chromosome from each of the 23 pairs.
Meiosis -
Explained
(5 marks)
Occurs in testes + ovaries
1 diploid cell produces 4 haploid gametes, in 2 divisions - this is reduction division.
Meiosis -
Simplified
(3 marks)
1 diploid cell produces 4 haploid gametes, in 2 divisions
Where does Meiosis take place?
2 marks
Testes + Ovaries
Produced during Meiosis
4 marks
Haploid Gametes -
Sex Cells such as sperm/ovum with half the number of Chromosomes.
Haploid conditions:
In detail
(3 marks)
1 copy of each Chromosome; non-homologous Chromosomes.
Diploid conditions:
In detail
(3 marks)
2 copies of each chromosome; pairs of homologous Chromosomes (of maternal + paternal origin).
Haploid gametes
2 marks
Human sex cells - contain 1 chromosome from each of the 23 pairs.
4 gametes produced in meiosis are
3 marks
Genetically different - process of independent assortment leads to all gametes being different.
Independent assortment + the random nature of fertilisation lead to
(3 marks)
Variation in living organisms – no 2 organisms are the same (apart from identical twins).
Variation in living organisms
2 marks
No 2 organisms are the same (apart from identical twins).
During fertilisation the Haploid Nucleus of a Sperm Cell + the Haploid Nucleus of an Egg Cell
(2 marks)
Fuse together to form a Diploid Zygote.
Diploid Zygote
5 marks
Fusion of Sperm cells Haploid Nucleus + Egg cells Haploid Nucleus in a fertilised ovum (Zygote)
- 2 weeks after fertilisation becomes an Embryo with the full number of Chromosomes (23 pairs)
Fertilised ovum
1 mark
Zygote
After Cell division a fertilised ovum (zygote) develops into a
(1 mark)
Embryo
Diploid Zygote becomes a
- the Next stage-
(1 mark)
Embryo
Number of Chromosomes passed down from each parent during Fertilisation/Cell Division
(3 marks)
23 from Mother
23 from Father
= 46 Chromosomes
Number of Chromosomes passed down from each parent during Fertilisation/Cell Division when the child has Down Syndrome
(3 marks)
23 from one parent + 24 from the other
= 47 Chromosomes
The Sperm Cell carries __ Chromosomes to the Ovum during Fertilisation (typically)
(1 mark)
23
The Ovum carries 23 ___________ (typically)
1 mark
Chromosomes
Stages of Mitosis (in order)
7 marks
- Interphase
- Prophase
- Prometaphase (Late prophase)
- Metaphase
- Anaphase
- Telophase
- Cytokinesis (Daughter Cells )
All Stages of Meiosis (in order)
15 marks
Meiosis I
- Interphase
- Prophase I
- Prometaphase I (Late Prophase)
- Metaphase I
- Anaphase I
- Telophase I
- Cytokinesis
Meiosis II
- Prophase II
- Prometaphase II
- Metaphase II
- Anaphase II
- Telophase II
- Cytokinesis
Stages of Meiosis I (in order)
7 marks
- Interphase
- Prophase I
- Prometaphase I (Late Prophase)
- Metaphase I
- Anaphase I
- Telophase I
- Cytokinesis
Stages of Meiosis II in order
6 marks
- Prophase II
- Prometaphase II
- Metaphase II
- Anaphase II
- Telophase II
- Cytokinesis
