Cell structure and function: Cell division

Question 1

Cell cycle

Answer 1

Interphase:
G1- most cellular activities and growth
S - DNA synthesis
G2 - checks correct DNA synth, growth and prep for mitosis - centrosome replication
Mitotic (M):
prohphase
metaphase
anaphase
telophase/cytokinesis

Question 2

Interphase

Answer 2

complete envelope, uncondensed chromosome, later centrosomes and chromosomes replicate

Question 3

mitosis Prophase

Answer 3

spindle forms and chromosomes condense. nuclear envelope breaks up. centrosomes go to poles

Question 4

mitosis metaphase

Answer 4

individual condensed chromosomes align in cell

Question 5

mitosis anaphase

Answer 5

sister chromatids separated (pulled apart at centromere)

Question 6

telophase

Answer 6

cells divide fully, and nuclear envelope reforms

Question 7

G1 checkpoint

Answer 7

is dna undamaged
is size and nutrition okay
appropriate signals
if no, may exit to G0 repair may occur

Question 8

M checkpoints

Answer 8

are all chromosme attatched to spindles
if no, mitosis no occur

Question 9

Stages of Meiosis

Answer 9

Meisosis 1:
prophase 1 - synapsis and crossover
metaphase 1 - pairs of chromosomes line up
anaphase 1 - homologues separated
telophase 1 - cells divide
Meisosis 2:
prophase 2 -
metaphase 2 - line up in middle
anaphase 2 - sisters separate
telophase 2

Question 10

synapsis (in prophase 1)

Answer 10

two sister chromatids of each pair of homologues pair up. 4 chromatids =tetrad. non-sisters cross over at the chiasmata (recombination)

Question 11

differences between mitosis and meiosis

Answer 11

meiosis has four haploid daughter cells
in metaphase pairs line up
independant assortment and segregation

Question 12

independant assortment

Answer 12

how the homologues line up and are sorted into daughter cells at anaphase 1, is random, and independant of other chromosome pairs