2.1.6 cell division, diversity, organisation

Question 1

cell cycle 4 stages

Answer 1

G1 (growth 1)
Synthesis
G2 (growth 2)
Mitosis (cytokineses)

Question 2

what triggers going from one phase to enouther

Answer 2

cyclins

Question 3

3 parts of interphase

Answer 3

g1
s
g2

Question 4

what happes in G1

Answer 4

• growth
• PROTEIN SYNTHESIS, cells make enzymes, proteins for growth
• CHECKPOINT: dna damage etc, approve going to the next

Question 5

what happens in g2

Answer 5

• more growing
• DNA is error checked and repaired

Question 6

does the cell grow during mitosis

Answer 6

no

Question 7

in whcih part of cell cycle is there the most mRNA produced

Answer 7

• G1
• protein syntehsis and production of mRNA in transcription

Question 8

product of mitosis

Answer 8

2 genetically identical daughter cells

Question 9

4 stages of mitosis

Answer 9

Prophase
Metaphase
Anaphase
Telophase

Question 10

how many chromosomes in human nucleus

Answer 10

46 (23 pairs)

Question 11

Prophase

Answer 11

• chromosomes SUPERCOIL and become visible
• nuclear envelope disintegrate
• nucleolus disappears
• centrioles move to opposite poles

Question 12

metaphase

Answer 12

• chromosomes line up at equator of cell
• SF attach to centromeres

Question 13

anaphase

Answer 13

• sister chromatides pulled apart at centromre
• SF shorten
• separated chromatids pulled to opposite poles by microtubule spindle fibres

Question 14

telophase

Answer 14

• nuclear enevlope reforms
• SF breaks down
• new nucleoluses formed

Question 15

cytokineses

Answer 15

cytoplasm and organelles divides into 2

Question 16

structure of chromosome (post DNA rep)

Answer 16

2 identical chromatids joined together at CENTROMERE

Question 17

centrosome

Answer 17

pair of centrioles

Question 18

what in plants can you use to study mitosis

Answer 18

meristem tissue (root tip)

Question 19

purpose of mitosis

Answer 19

1. growth
2. replace cells, repair tissues
3. asexual reproduction eg ameoba

Question 20

what type of cells does mitosis produce

Answer 20

diploid

Question 21

what type of cells does meiosis produce

Answer 21

haploid gametes

Question 22

meoisis 1

Answer 22

PMATC (1)

Question 23

P1

Answer 23

• nuclear envelope breaks down into vesicles
• nucleolus disintegrates
• chromosomes condense and become visible
• CROSSING OVER occurs

Question 24

crossing over is

Question 25

what is a bivalent

Answer 25

a pair of homologous chromosomes

Question 26

M1

Answer 26

- chromosomes line up along equator - spindle fibres formed and attach to ccentromere - INDEPENDENT ASSORTMENT

Question 27

A1

Answer 27

- centrioles pull apart chromosomes to opporite ends

Question 28

T1

Answer 28

- chromosomes at opposite poles - SF break down - nuclear envlopes reform and nucleoluses

Question 29

cytokineses 1

Answer 29

- cytoplasm divides

Question 30

product of meiosis 1

Answer 30

2x haploid cells (NOT GENETICALLY IDENTICAL)

Question 31

what happens between m1 and m2

Answer 31

- no interphase

Question 32

p2

Answer 32

- nuclear enevlope breaks down, nucleolus disintegrates - chromosomes condense

Question 33

m2

Answer 33

- chromosomes line up at equaotr - spindle fibres form and attach to centromeres

Question 34

a2

Answer 34

-chromatids separate and move to opposite poles

Question 35

t2

Answer 35

- nuclear envelope reforms - nucleoli reform

Question 36

cytokineses 2

Answer 36

- cytoplasm divides

Question 37

total product of meiosis

Answer 37

- 4 haploid cells

Question 38

how do you count chroosomes

Answer 38

by number of centromeres present

Question 39

p1

Answer 39

- chromosomes supercoil, visible - nuclear envelop breaks down, nucleous disintigerates - CHROMOSOMES COME TOGETHER AS HOMOLOGOUS PAIRS - crossing over occurs

Question 40

waht is crossing over

Answer 40

PROPHASE 1 - non sister chromatids swap sections of DNA - CHROMATIDS HAVE NEW ALLELE COMBO - the more they cross over depends on how close they are

Question 41

M1

Answer 41

- pairs of homologous chromosomes line up at equator - spindle attaches to centromere - INTEPENDENT ASSORTMENT

Question 42

independent assortment

Answer 42

METAPHASE 1 (snd2) - Homologous chromosome pairs line up at equator - maternal and paternal can end up facing either pole - maternal and paternal have different alleles - PRODUCES LARGE NUMBER OF ALLELE COMBOS

Question 43

a1

Answer 43

- each chromosome (containing 2 chromatids) in the homolgous pair is pulled to an opposite pole

Question 44

t1

Answer 44

- 2 nuclear envelpoes reform - then cytokinesis - HAPLOID