Flashcards in L4 Chromosome Structure Deck (50)
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1
What do diploid eukaryotic cells contain
two copies of each chromosome
2
What can individual chromosomes be easily distinguished
metaphase of mitosis
3
Karotype
organised representation of all chromosomes at metaphase
4
Describe the organisation of individual chromosomes in interphase
occupy distinct subnuclear terriotories
5
Chromosome
highly coiled fibre of chromatin
6
Types of chromatin
euchromatin, heterochromatin
7
Nucleosome
building material of chromosomes
8
Types of histone
4 distinct types
9
Core histones
protein subunit of nucleosome
10
Function of histone tails
interact with proteins, facilitate regulation of chromatin
11
H1
linker histone
12
Function of H1
straps DNA onto histone octamers - limits DNA movement
13
What does H1 facilitate
establishment of transcriptionally silent heterochromatin
14
Interphase chromatin
set of dynamic fractal globules
15
Nuclear periphery in interphase cells composition
transcriptionally inactive DNA
16
Heterochromatin
transcriptionally silent
17
Inner part of the nucleus in interphase cells
RNA transcripts, transcriptionally active genes
18
Telomere
DNA sequences at ends of linear chromosome
19
Telomere function
maintain chromosomal integrity
20
Replication origin
DNA sequence, initiation of DNA replication
21
Centromere
DNA sequences, kinetochore assembly
22
Centromere function
Mediate chromosome segregation
23
Kinetochore
protein complex
24
Kinetochore function
binds microtubules in mitotic spindle
25
Telomerase
DNA polymerase that replicates telomeres
26
True or False - telomeres are double stranded
false
27
Two forms of kinetochore
inner and outer plate
28
Inner kinetochore plate function
binds to chromatin containing alpha satellite DNA
29
Kinetochore outer plate function
binds to protein components of mitotic spindle
30
What do centromeres contain
alpha satellite DNA repeats
31
Alpha satellite DNA repeats function
form condensed heterochromatin with histone octamers
32
CENP-A
specialised histone in centromeric chromatin
33
CENP-A function
connects inner kinetochore plate to methylated histones
34
H3-K4me
methylated histone
35
H3-K4me function
hold sister chromatids together
36
Kinetochore in yeast
Hollow cylinder / basket
37
Kinetochore in yeast function
links single nucleosome of centromeric chromatin to single microtubule
38
Relationship between complex organisms and protein coding genes
More complex organisms, more protein coding genes, more non protein coding DNA
39
Transposons
mobile repeated DNA sequences
40
Types of transposons
DNA transposons, Retroviral retrotransposons, Non-retroviral polyA retrotransposons
41
DNA transposon movement
cut and paste mechanism, without self duplication
42
Requirements of DNA transposon movement
transposase
43
DNA transposon discovery
Maize by Barbara McClintock
44
Retroviral transposons function
replicate via RNA intermediates, produce new DNA copies - integrate at new genomic locations
45
Retroviral transposon requirement
self encoded reverse transcriptase
46
non-retroviral retrotransposons
replicate via RNA intermediate, copy and paste
47
non-retroviral retrotransposon requirement
retrotransposon encoded reverse transcriptase
48
TRUE or FALSE - most transposons are defective
true
49
Large numbers of transposable elements are found in...
genomes of more complex organisms
50
