Mitosis and Meiosis

Question 1

Prokaryotes vs eukaryotes mitosis

Answer 1

pr: divided by binary fission, DNA replication creates daughter cells
- asexual reproduction

eu: divided by mitosis

Question 2

chromatid

Answer 2

a distinct copy of DNA produced during replication
(one molecule of DNA)

Question 3

Chromosomes

Answer 3

consists of a pair of sister chromatids produced through DNA replication (=2 molecules of DNA)

Question 4

homologous chromosomes

Answer 4

• each consists of pair of homologous sister chromatids

Question 5

purpose of mitosis

Answer 5

• distribute the replicated chromosomes
• one nucleus into 2 nuclei 2 identical daughter cells

Question 6

prophase

Answer 6

• chromosomes condense
• nuclear membrane breaks down
• Centromes begin to move to opposite poled
• Miotitc spindle beginning to form

Question 7

metaphase

Answer 7

• spindles attach to kintochores (centromemeres)
• chromsomes are all attached to spindle
• chromosomes align at metaphase plate

Question 8

anaphase

Answer 8

• sister chromatids seperate
• daughter chromosomes begin to move towards opposite poles
• poles move further apart (cell elongation)

Question 9

telophase and cytokenesis

Answer 9

• daughter chromosomes reach poles and decondense
• nuclear membrane re-forms to produce 2 nuclei
• cytokinesis occurs concurrently

Question 10

cytokinisis in animals vs plants

Answer 10

• cleavage furrow formation in animals until 2 cells have formed
  -in plants it is more complex because of the rigid cell wall
• need to make a new cell wall around 2 duaghter cells

Question 11

meiosis def

Answer 11

• a specialised type of cell division is the basis of genetic diversity and the pre requisite for sexual reproduction

Question 12

Where does meiosis occur?

Answer 12

only occus in specialised germ cells within gonads of males and femals

Question 13

what is the result of meiosis

Answer 13

• it produces gametes, haploid cells that can fuse with other haploids during fertalisation to produce a diploid zygote

Question 14

diploid

Answer 14

cell containing 2 sets of chromosomes

Question 15

haploid

Answer 15

a cell containing only one set of chromosomes

Question 16

similarities of mitosis and meisosis

Answer 16

• begin after cell has progressed through G1,S and G2 phases
• consists of prophase, metaphase, anaphase, telophase

Question 17

differences between meiosis and mitosis

Answer 17

2 successive division in meisosis rather than 1
- homologus chromosomes exchange genetic material which is the source of genetic diversity

Question 18

Meiosis 1- phrophase

Answer 18

• chromosomes condense (one from each parent)
• crossing over involves physical exchange of chromosome pieces
• mitotic spindle forms
• nuclear membrane breaks down

Question 19

Meiosis 1- metaphase

Answer 19

• spindles attach to centromeres
• homologous chromosomes randomly align at metaphase plate in PAIRS
  (independent assortment)

Question 20

Meiosis 1- anaphase

Answer 20

• homologous chromosomes separate from each other
• homologous chromosomes begin to move to opposite poles

Question 21

Meiosis 1- telophase and cytokenisis

Answer 21

• each homolog (containing 2 sister chromatids) reaches poles
• result: 2 haploid dells with half the chromosome number
• daughter cells are genetically distinct from eachother and their parental cell

Question 22

meiosis 2

Answer 22

• 2 cells that enter meiosis 2 are different haploid
• sister chromatids are pulled apart
• end up with 4 haploid cells

Question 23

how does meiosis create genetic diversity

Answer 23

• crossing over in prophase 1
• random assortment in metaphase 1