cell division W5

Question 1

what are three broad reasons that cell division occurs

Answer 1

repair tissues
reproduction
replace themselves

Question 2

what cells undergo MITOSIS

Answer 2

somatic cells

Question 3

what cells undergo meiosis

Answer 3

Germ cells

Question 4

what does ploidy refer to

Answer 4

number of sets of chromosomes in a cell

Question 5

products of mitosis are ….

Answer 5

diploid and genetically identical

Question 6

products of meiosis are …

Answer 6

haploid and genetically different

Question 7

are gametes (sperm and egg cells) haploid or diploid

Answer 7

haploid

Question 8

what is the symbol for haploid

Answer 8

n

Question 9

what is the symbol for diploid

Answer 9

2n

Question 10

phases of the cell cycle

Answer 10

G1
S
G2
M

Question 11

how many chromosomes does a human cell have

Answer 11

22+sex chromosome

Question 12

G1 phase (gap 1) describe (3)

Answer 12

cell is functioning normally

major period of cell growth

requires protein synthesis

Question 13

S phase (synthesis) 
describe (4)

Answer 13

Dna is replicated

chromosomes are duplicated

minor period of cell growth

also required protein synthesis

Question 14

G2 phase (gap 2)
describe (2)

Answer 14

rapid cell growth and protein synthesis

preparing for M phase

Question 15

M phase (mitosis) 
describe (4)

Answer 15

cell is dividing

no DNA synthesis (chromosomes already duplicated

no protein synthesis

no gene expression

Question 16

what disease is caused by uncontrolable cell division

Answer 16

cancer

Question 17

how is the cell cycle regulated

Answer 17

through specific proteins called CYCLINS

Question 18

what are cyclins

Answer 18

specific proteins that control the cell cycle

Question 19

what is the consequence of inactivation of cyclins

Answer 19

leads to loss of normal control of cell division which can lead to problems such as cancer

Question 20

how are sister chromatids separated during mitosis

Answer 20

spindle fibres attacht to kinetochore

Question 21

chromosonal changes are divided into four phases what are they

Answer 21

prophase
metaphase
anaphase
telophase

Question 22

describe prophase

Answer 22

individual chromosomes become visible as chromatin condenses

Question 23

describe metaphase

Answer 23

chromosomes line up in the middle of the cell

Question 24

describe anaphase

Answer 24

chromosomes separate

Question 25

describe telophase

Answer 25

chromosomes decondense and become chromatin angain

Question 26

what happens when centrioles duplicate

Answer 26

the promote assembly of the mitotic spindle microtubules

Question 27

what is cytokinesis

Answer 27

the division of the sytoplasm to produce two daughtercells

Question 28

what is the ring between the two halves of the cell during cytokinesis called

Answer 28

contractile ring which is in the cleavage furrow

Question 29

where does meiosis occur (2)

to form …

Answer 29

germ cells, in testes and ovaries

to form sperm and eggs

Question 30

what are the main phases of meiosis

Answer 30

meiosis 1

meiosis 2

Question 31

how many cells are produced from mitosis and are they identical to parent cell

Answer 31

2 daughter cells that are identical to parent cell

Question 32

how many cells are produced from meiosis and are they identical to the parent cell, are they identical to each other

Answer 32

four daugher cells
all different
and different to parent cell

Question 33

each daughter cell of meiosis is a …..and contains …copy of each chromasome

Answer 33

hapolid

one

Question 34

do both emiosis and mitosis have phrophase
metaphase
anaphase
telophase

Answer 34

yes

Question 35

what are the phases in meiosis 2

Answer 35

similar to mitosis but no ‘S’ phase

G1
G2
M

Question 36

what happens during meiosis 1

Answer 36

replicated chromosomes exchange DNA and divide

Question 37

what is homologous recombination

Answer 37

exchange of nucleotide sequences between two similar (homologous) DNA molecules

Question 38

meiosis- what is synapsis

Answer 38

formation of tetrad

pairing/fusion of homologous chromasomes

Question 39

meiosis - what is chasma

Answer 39

point where two homologous non sister chromatids exchange genetic material

Question 40

during which phase does rocombination occur

Answer 40

prophase 1

Question 41

what contributes to genetic variation (2)

Answer 41

independent assortment

homologous recombination

Question 42

mitosis and cell cycle role in disease(1)

Answer 42

errors contribute to cancer progression

Question 43

meiosis roles in disease (3)

Answer 43

• problems with chromosome segregation can contribute to genetic disorders such as down syndrome
• infertility
• recombination events associated with genetic disorders