cell divison

Question 1

function of mitosis

Answer 1

1. growth of multicellular organsims
2. repair of worn out tissues , replace worn out cells
3. asexual reporduction

Question 2

what does homolgous chromosome mean

Answer 2

a pair of chromosomes with the same shape, length and order of gene loci.
one chromosome in the pair frm mother and other from father

Question 3

need for reduction division in meiosis process prior to fertilisation in sexual repro

Answer 3

• gametes with half the numberof chromosomes as parents cells are produced
• during fertilisation, nuclei of female gamete fuses with nuclei of male gamete to form a zygote with dilpoid number of chromosomes
• this restores th diploid number of chromosomes to ensurethe number of chromosomes in cells do not double over the generations

Question 4

haploid meaning

Answer 4

haploid cell: 1 set of chromosome
haploid number: 23 chromosomes in cell

Question 5

diploid meaning

Answer 5

diploid cell: 2 sets of chromosomes, 1 frm each parent
diploid number: 46 chromosomes in cell

Question 6

how meiosis leads to variation

Answer 6

1. Prophase I - crossing over of non sister chromatids of HC to form chiasma -> new combinations of alleles in the chromosome of gametes
2. metaphase I - independent assortment of HC -> diff combinations of chromosomes in gametes at the end of meiosis

Question 7

how meiosis leads to variation

Answer 7

1. Prophase I pf meiosis- crossing over of non sister chromatids of HC to form chiasma -> new combinations of alleles in the chromosome of gametes
2. metaphase I of meiosis - independent assortment of HC -> diff combinations of chromosomes in gametes at the end of meiosisr

Question 8

role of meiosis

Answer 8

1. produces haploid gametes so that diploid gametes can be restored during fertiliasation - reduction explanation
2. promoting genetic variation to ensure survival of oragsnism when there are changes to envt - explanantion

Question 9

fertilisation’s role in promiting genetic variation

Answer 9

• fertilisation is random
  -variations in gametes
• variation in offspring

Question 10

the need for the production of genetically identical cells

Answer 10

maintai genetic stability:
- 2 udaghter nuclei contain same number of chromosomes and are genetically identical as parent nucleus
- interphase in mitosis - replication of chromosomes
- metaphase in mitosis - random assortemnt of sister chromatids at equator of spindle
- anaphase in mitosis - separation of sister chromatids

Question 11

mitosis def

Answer 11

a form of nuclear division that produces 2 denetically identical daughter nuclei containing the same nuber of chromosome as parent cell

Question 12

why dna replication in mitosis b=must be precsiely controleld

Answer 12

1. enusres all daughter cells have smame genetic info as parent -> genetically identical
2. error in replication -> diff DNA strand formed -> mutation -> oassed onto daughter cell -> harmful changes to gene -> produce abnormal proteins
3. gee mutation -> uncomtrolled cell division -> cancer -> fatal

Question 13

interphase of mitosis

Answer 13

• replication of DNA

Question 14

what structures in a cell replicates during interphase

Answer 14

chromosome, mutochondria, chloroplasts