Mitosis Meiosis long questions

Question 1

Mitosis prophase

Answer 1

1. chromosomes become condense, tightly coiled
   (shorter, thicker, visible under light microscope)

each chromosome consist of two sister chromatids joined tgt at centromere

2. in cytoplasm, spindle fibres begin to form btw centrioles

each pair of centrioles migrates to lie at opposite poles of cell

3. spindle fibres from opposite spindle poles are attached to centromeres of each sister chromatid
4. end of prophase:
   nucleolus disappears
   nucleus membrane disintegrates

Question 2

Metaphase Mitosis

Answer 2

1, centromeres of all chromosomes lined up on metaphase plate

2. spindle fibres now fully formed
3. chromosomes arranged randomly at metaphase plate
   two sister chromatids still attached to each other at centromere
4. metaphase ends:
   centromere divides

Question 3

Anaphase Mitosis

Answer 3

1. two sister chromatids of each chromosome separate at centromere
2. sister chromatids pulled apart to opposite poles by shortening of spindle fibres
3. anaphase ends:
   chromosome reach the poles of cell

Question 4

Telophase Mitosis

Answer 4

1. both sets of chromosomes reach opposite poles of cell
2. chromosomes start to uncoil and revert to chromatin
3. spindle fibres disappear
   new nuclear membrane forms around each set of chromosomes
   nucleolus reforms in each nucleus

Question 5

Prophase 1 meiosis

Answer 5

1. chromosomes condense, become shorter, thicker and clearly visible
2. homologous chromosomes come tgt to form bivalents thru synapsis, crossing over occurs
3. end of prophase 1,
   nucleolus and nuclear membrane disappear
4. two pairs of centrioles migrate to opposite poles of cell

Question 6

metaphase 1 meiosis

Answer 6

1. spindle fibres pull tetrads to middle of cell
2. pairs of homologous chromosomes align at metaphase plate
   (lined up side by side as tetrads)
3. one chromosome of each homologous pair attached its fibres from one pole while homologue attached to fibres from opposite poles
4. centromere does not divide

Question 7

anaphase 1 meiosis

Answer 7

1. spindle fibres pull homologous chromosomes apart
   move them to opposite poles of cell
2. each chromosomes still consist of two sister chromatids which move as single unit
3. end of anaphase 1:
   each pole only has two chromosomes

Question 8

telophase 1 meiosis

Answer 8

1. chromosomes arrive at the poles
   each pole now has a haploid daughter nucleus because it contains only one set of chromosomes
2. spindle fibres disappears
3. nuclear membrane reappears to surround each group of chromosomes
4. nucleolus reappears in each nucleus

Question 9

prophase 2 meiosis

Answer 9

1. nuclear membrane disintegrates

2. spindle fibres reform in each daughter cell

Question 10

metaphase 2 meiosis

Answer 10

1. chromosomes position randomly at metaphase plate

2. each sister chromatid is attached to the spindle fibres at centromere

Question 11

anaphase 2 meiosis

Answer 11

1. the centromeres of sister chromatids separate

2. each individual chromosomes moves towards opposite poles of cell

Question 12

telophase 2 meiosis

Answer 12

1. nucleoli and nuclear membranes reform
2. spindle fibres break down
3. cytokinesis follows, four haploid daughter cells are formed