L3 Meiosis

Question 1

What cells are haploid

Answer 1

sperm and eggs

Question 2

What does meiosis produce

Answer 2

sperm and egg cells

Question 3

Diploid definition

Answer 3

organisms with two versions of each chromosome

Question 4

What happens during the S phase of meiosis

Answer 4

DNA is replicated

Question 5

How is genetic diversity created

Answer 5

recombination between homologous chromosomes

Question 6

What does recombination depend on

Answer 6

proximity of chromosomes

Question 7

When are sister chromatids separated in meiosis

Answer 7

anaphase II

Question 8

What is the difference between mitosis and meiosis

Answer 8

meiosis produces haploid gametes, mitosis produces diploid cells

Question 9

What is the function of the synaptoneal complex

Answer 9

facilitates DNA base pairing between homologues

Question 10

What does the synaptoneal complex recognise

Answer 10

double stranded DNA breaks

Question 11

How are homologues bound during recombination

Answer 11

cross linking by transverse filaments, axial cores and cohesin

Question 12

How many crossing over sites occur per bivalent

Answer 12

1-4

Question 13

What are the two types of chromosome abnormality

Answer 13

chromosome number and chromosome structural rearrangements

Question 14

What is aneuploidy

Answer 14

Abnormal number of chromosome material in cells

Question 15

Monosomy

Answer 15

one copy of a chromosome

Question 16

trisomy

Answer 16

3 copies of a chromosome

Question 17

Polyploidy

Answer 17

extra sets of chromosomes

Question 18

Where does polyploidy apper

Answer 18

cell lines

Question 19

Causes of aneuploidy

Answer 19

non-disjunction of chromosomes or sister chromatids

Question 20

Non-disjunction

Answer 20

failure to separate

Question 21

Non-disjunction in which phase of meiosis has more serious consequences

Answer 21

meiosis I

Question 22

Are normal gametes produced if non-disjunction occurs in meiosis I

Answer 22

no

Question 23

Nullsomy

Answer 23

missing pair of chromosomes

Question 24

Embryonic lethal aneuploidy

Answer 24

monosomy, trisomy usually embryonic lethal

Question 25

How lethal is nullsomy

Answer 25

pre-implantation lethal

Question 26

Are embryos with one Y chromosome viable

Answer 26

NO

Question 27

What is a common symptom of chromosomal abnormalities

Answer 27

congenital heart defects

Question 28

Turner’s syndrome

Answer 28

complete or partial absence of second X chromosome in phenotypic females

Question 29

Why is lethality exhibited when one X chromosome is lacking

Answer 29

haplo-insufficiency

Question 30

Why can it be difficult for foetus to survive post-implantation

Answer 30

defective placental development