mitosis and meiosis

Question 1

what is the purpose of mitosis (examples of mitosis)

Answer 1

the purpose of mitosis is cell regeneration, growth and asexual reproduction

Question 2

what is the purpose of meiosis

Answer 2

the purpose of meiosis is to produce gametes(sperm and egg cells) which factor in sexual reproduction

Question 3

what are the stages of mitosis. explain

Answer 3

the stages of mitosis are interphase, prophase, metaphase, anaphase, telophase and cytokinesis. during interphase, dna replication occurs but the chromosomes aren’t visible. during prophase, the nucleus disappears, the chromosomes appear and spindles start to form. during metaphase, the chromatids meet in the centre of the cell. during anaphase, the chromatids split apart and are pulled apart to the end of the cell. during telophase, the cell pinches in the middle, the nucleus membrane re-appears whilst the chromosomes are no longer visible. and lastly, during cytokinesis, the cytoplasm divides and the cells divide into 2 diploid daughter cells.

Question 4

what are the stages in meiosis. explain

Answer 4

interphase - the dna is replicated and copied
prophase - the nucleus disappears, dna winds up and chromosomes become visible
metaphase - spindle fibres attach to the centromere of each matching chromosome and get pulled in a line in the centre of the cell
anaphase - the matching chromosomes are pulled to opposite ends of the cell using spindle fibres which end up disappearing
telophase - the cell membrane pinches in, the nucleus membrane re-forms and 2 separate nuclei form
cytokinesis - cell pinches completely in 2 daughter cells and each daughter cell has half the genetic info as the parent cell

prophase - nucleus membrane reappears and spindle fibres form in both cells
metaphase - chromosomes move into the centre of the cell where spindle fibres attach to each chromatid and the centromeres start to divide
anaphase - the chromosomes are pulled apart and the chromatids are pulled to opposite ends of the cell
telophase - the nucleus membrane re-forms and the chromosomes are no longer visible
cytokinesis - both cells pinch in half to produce 4 haploid daughter cells, each containing half the amount of dna as was in the parent cell

Question 5

what is mitosis

Answer 5

mitosis is the name of the process where diploid somatic cells make identical copies of themselves

Question 6

what is meiosis

Answer 6

meiosis is the name of the process where the gonads make the haploid gametes

Question 7

what are the 2 forms of reproduction that can occur within organisms

Answer 7

asexual and sexual reproduction

Question 8

where are gametes formed

Answer 8

gametes are formed in the gonads of the male and female. male = testes and females = ovaries

Question 9

what do gametes contain

Answer 9

gametes contain half the genetic information needed to form an offspring

Question 10

what happens when the gametes meet

Answer 10

when the gametes (sperm and egg) meet they form a zygote which eventually turns into the embryo of the organism

Question 11

are the gametes haploid or diploid

Answer 11

haploid

Question 12

what occurs to the gonads in order to form the gametes

Answer 12

meiosis

Question 13

what happens to the gametes after being produced

Answer 13

the gametes undergo fertilisation after being produced

Question 14

what happens to the zygote after being produced

Answer 14

the zygote undergoes mitosis in order to create a child

Question 15

what is the haploid number in humans

Answer 15

23 single chromosomes

Question 16

how many chromosomes does the zygote contain

Answer 16

23 single chromosomes

Question 17

what is the diploid number in humans

Answer 17

46 chromosomes

Question 18

how many chromosomes are in a human gamete

Answer 18

23 chromosomes

Question 19

what is the dna replication process

Answer 19

the dna molecule untwists with the help of an enzyme. the dna then unzips down the middle between the nitrogenous bases, breaking down the hydrogen bonds. this step occurs with the help of an enzyme. another enzyme then very quickly attaches new nucleotides to the exposed nitrogenous bases. the enzyme follows the complimentary rule (adenine pairs with thymine and cytosine pairs with guanine) to ensure that the 2 new dna strands will be identical to the one that has unzipped. the newly added nucleotides are connected together with new bonds which result in 2 identical strands of dna being formed. each strand is one half of the original strand and one half of the newly built one.

Question 20

is the parent cell in meiosis diploid or haploid, state the one for the end daughter cells

Answer 20

parent cell = diploid

daughter cells = haploid