Flashcards in L3 Meiosis Deck (30)
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1
What cells are haploid
sperm and eggs
2
What does meiosis produce
sperm and egg cells
3
Diploid definition
organisms with two versions of each chromosome
4
What happens during the S phase of meiosis
DNA is replicated
5
How is genetic diversity created
recombination between homologous chromosomes
6
What does recombination depend on
proximity of chromosomes
7
When are sister chromatids separated in meiosis
anaphase II
8
What is the difference between mitosis and meiosis
meiosis produces haploid gametes, mitosis produces diploid cells
9
What is the function of the synaptoneal complex
facilitates DNA base pairing between homologues
10
What does the synaptoneal complex recognise
double stranded DNA breaks
11
How are homologues bound during recombination
cross linking by transverse filaments, axial cores and cohesin
12
How many crossing over sites occur per bivalent
1-4
13
What are the two types of chromosome abnormality
chromosome number and chromosome structural rearrangements
14
What is aneuploidy
Abnormal number of chromosome material in cells
15
Monosomy
one copy of a chromosome
16
trisomy
3 copies of a chromosome
17
Polyploidy
extra sets of chromosomes
18
Where does polyploidy apper
cell lines
19
Causes of aneuploidy
non-disjunction of chromosomes or sister chromatids
20
Non-disjunction
failure to separate
21
Non-disjunction in which phase of meiosis has more serious consequences
meiosis I
22
Are normal gametes produced if non-disjunction occurs in meiosis I
no
23
Nullsomy
missing pair of chromosomes
24
Embryonic lethal aneuploidy
monosomy, trisomy usually embryonic lethal
25
How lethal is nullsomy
pre-implantation lethal
26
Are embryos with one Y chromosome viable
NO
27
What is a common symptom of chromosomal abnormalities
congenital heart defects
28
Turner's syndrome
complete or partial absence of second X chromosome in phenotypic females
29
Why is lethality exhibited when one X chromosome is lacking
haplo-insufficiency
30
