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Flashcards in Meiosis and sexual reproduction Deck (93)
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1

What does asexual reproduction leave population vulnerable to

changes in the environment

2

Whats the difference between mitosis and meiosis in term of daughter cells

mitosis:
daughter cells re identical to parent cells
meiosis:
daughter cells are not identical to parent cells

3

Give examples of organisms in which sexual reproduction is the main type of reprodution

animals and flowering plants

4

What is sexual production

The production of a new individual resulting from the joining of two specialised cells known as gametes

5

Whats a great advantage if sexual reproduction

Increases genetic variations

6

What is a diploid cells (2n)

A cell containing two full sets of chromosomes

7

What are haploid cells

A cell containing one complete set of chromosomes

8

When does sexual reproduction occur
What is this process called

When two haploid nuclei fuse to form a new diploid cell known as a zygote
Fertilisation

9

Where are gametes formed

In special sex organs

10

What are gonads

sex organs in animals

11

What is polypidy

When a cell or organism has more than two sets of chromosomes

12

In plants what is the following:
1)anthers
2)Ovaries

a)Anthers-male sex organs
b)Ovaries-female sex organs

13

Where are the male gametes in plants formed

In pollen

14

Where are the female gametes in plants formed

Ovules

15

What is the male gonad in animals
what does it produce

Testes
sperm

16

What is the female gonad in animals
what does it produce

Ovaries
Ova/eggs

17

Why does the number of chromosomes in both daughter cells need to be halved in meiosis

To give the necessary haploid nuclei

18

What is meiosis

A reduction division and occurs only in sex organs

19

What special cells does meiosis in flowering plants form for:
Males
Females



Microspores
Megaspores

20

In meiosis what does the two nuclear divisions cause

It gives rise to four haploid daughter cells, each with its own unique combination of genetic material

21

What are the differences between the stages of meiosis and mitosis

1)The two chromosomes of each pair (homologous chromosomes) stay close together
2)Crossing over or recombination takes place
3)Centromere does not split in the first division, so pairs of chromatid move to opposite sides of pole
4)Cytokinesis takes place giving 4 haploid daughter cells
5)Daughter cells later develop into gametes

22

What are chromosome mutations

When during meiosis, parts of the chromosomes break off and become reattached to the wrong place

23

Whats one of the most common forms of chromosome mutations
When does this type of chromosomal mutation take place

Translocation
When one pair of homologous chromosome breaks off and reattaches to one of a completely different pair of chromosomes

24

Are all translocations bad/unhealthy

No if its balanced its healthy but if its unbalanced it causes huge changes within the phenotype of an individual

25

In humans what should each gamete carry

Contain 23 chromosomes, including ONE SEX CELL

26

What is non-disjunction

The process that occurs when members of a pair of chromosomes fail to seperate during the reduction division of meiosis, resulting in one gamete with two copies of a chromosome and one gamete with no copies if that chromosome

27

What happens if one of these abnormal gametes joins with a normal gamete and is fertilised

The individual who results will either have monosomy with only one member of the homologous pairs present from the normal gamete or polysomy with three or more rather than two chromosome of a particular type

28

What is meant by Aneuploidy

When a cell contains too few or too many chromosomes

29

What is an example of:
a)Polysomy disease
b)monosomy disease


a)down syndrome
b)Turners syndrome

30

What are people that have down syndrome born with

They are born with trisomy of chromosome 21