Meiosis

Question 1

What are advantages of asexual reproduction?

Answer 1

It’s rapid so organisms can take advantage of resources in the environment, can occur is sexual reproduction fails and all offspring have genetic material to survive is current environment

Question 2

What are disadvantages of asexual reproduction?

Answer 2

No genetic variety so weaknesses are inherited an if environment change, all are susceptible

Question 3

What are the stages in meiosis 1?

Answer 3

Prophase I, Metaphase I, Anaphase I and telophase I

Question 4

What happens during prophase I?

Answer 4

Chromatids condense (46 chromosomes in humans x2 = 92 chromatids), homologous chromosomes pair up and crossing ver occurs at points called chias where DNA is exchanged

Question 5

What happened during metaphase I?

Answer 5

Bivalents randomly line up at metaphase plate

Question 6

What happens during anaphase I?

Answer 6

Pairs of chromosomes move apart and independently segregate

Question 7

What happens during telophase I?

Answer 7

Two cells are formed with 46 chromatids, each with different combinations of genetic information from mother and father

Question 8

What are the stages in meiosis II?

Answer 8

Prophase II, metaphase II, anaphase II and telophase II

Question 9

What happens during prophase II?

Answer 9

Each daughter cell contains 46 chromatids and chromosomes recondense

Question 10

What happens during metaphase II?

Answer 10

Pairs of chromatids line up along the equator at 90 degrees to previous division

Question 11

What happens in telophase II?

Answer 11

Four daughter cells formed each with 23 chromosomes

Question 12

What are haploid chromosomes?

Answer 12

They have the same genes

Question 13

How many chromosomes are in diploid cells?

Answer 13

46

Question 14

How many chromosomes are in haploid cells?

Answer 14

23

Question 15

What are bivalents?

Answer 15

Pairs of homologous chromosomes

Question 16

What is a gene?

Answer 16

A section of DNA that codes for a polypeptid

Question 17

What is a locus?

Answer 17

It is something every gene has which is its physical position on a chromosome

Question 18

What are alleles?

Answer 18

The different forms of every gene

Question 19

What are the two kinds of chromosomes within an organism?

Answer 19

Long and short

Question 20

What are the versions of chromosomes in a diploid cell?

Answer 20

There are 2 versions, one from the mother and one from the father

Question 21

What’s the result of genetic variation?

Answer 21

Some organisms will be better adapted to survive

Question 22

What are the sources of genetic variation?

Answer 22

Crossing over, independant assortment of chromosomes at metaphase I, independant assortment of chromosomes at metaphase II, random fertilisation and gene mutation

Question 23

What is the result of crossing over?

Answer 23

It shuffles alleles

Question 24

How is independant assortment of chromosomes at metaphase I a source of genetic variation?

Answer 24

The pole to which chromosomes is pulled to is random and independent of any other chromosomes

Question 25

How is independant assortment of chromosomes at metaphase II a source of genetic variation?

Answer 25

After crossing over has occurred, the two chromatids of a chromosome are genetically different and alignment is random and independant

Question 26

How is random fertilisation genetic variation?

Answer 26

It takes place when 2 gametes fuse to form a zygote and each gamete has a unique combination of genes and any of the numerous male gametes can fertilise the egg

Question 27

How is gene mutation genetic variation?

Answer 27

DNA is very stable but bases can change during DNA replication and mutations in gametes will be present in all cells of the offspring

Question 28

What happens at anaphase II?

Answer 28

Individual chromosomes are pulled apart