Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOL 207 > Topic 1: Chromosomes and Cell Cycles > Flashcards

Topic 1: Chromosomes and Cell Cycles Flashcards

1
Q

What is the n-value?

A

number of chromosomes and it’s ploidy

diploid cells carry two sets of genetic information

haploid cells carry one set of genetic information

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the c-value or genome size?

A

actual amount of DNA in the haploid cell

measured in picograms (c-value) or bp (genome size)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the number of genes?

A

function of the DNA in the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are homologous pairs?

A

same genes in the same order

might have different alleles of genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the conversion rates of base pairs?

A

bp = base pairs
kb = kilo base pairs = 1000
Mb = mega = 1 million bps
gb = giga bps = 1 billion bps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the c-value paradox?

A

the size of the genome doesn’t tell you anything about the organisms complexity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is non-gene DNA comprised of?

A

unique sequence DNA: present one or a few times

protein coding genes + families

non-protein coding genes/DNA (code for functional RNAs, e.g. tRNA and rRNA)

repetitive DNA

centromeres: moderately repetitive, tandemly repeating

telomeres: 6 bp repeats, tandem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is moderately repetitive DNA?

A

150-300 bps

found in many different places in the genome

transposons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is highly repetitive DNA?

A

less than 10 bps

microsats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are centrosomes?

A

constricted region of a chromosome where spindle fibers attach

moderately repetitive DNA in heterochromatin form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are telomeres?

A

repetitive sequence at the end of linear chromosomes

solves end replication problem

provides stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the T-loop?

A

G-rich strand folds over and pairs with a short stretch of DNA

found in mammals, provides stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the G0 phase of the cell cycle?

A

stable, nondividing period of variable length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the G1 phase of the cell cycle?

A

growth and development of the cell

G1/S checkpoint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the S phase of the cell cycle?

A

synthesis of DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the G2 phase of the cell cycle?

A

preparation for division

G2/M checkpoint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is prophase in the cell cycle?

A

chromosomes condense and mitotic spindles form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is prometaphase in the cell cycle?

A

nuclear envelope disintegrates, and spindle microtubules anchor to kinetochores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is metaphase in the cell cycle?

A

chromosomes align on the metaphase plate

spindle-assembly checkpoint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is anaphase in the cell cycle?

A

sister chromatids separate, becoming individual chromosomes that migrate toward spindle poles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is telophase in the cell cycle?

A

chromosomes arrive at the spindle poles

the nuclear envelope re-forms

condensed chromosomes relax

22
Q

What is cytokinesis in the cell cycle?

A

cytoplasm divides

cell wall forms in plant cells

23
Q

What are the genetic consequences of the mitotic cell cycle?

A

produces two cells that are genetically identical (to each other and parent)

new cells contain full complement of chromosomes (2n –> 2n)

each new cell contains half the cytoplasm of parent cell

24
Q

How does the n-value change during the mitotic cell cycle?

A

2n = 4 in interphase all the way to anaphase where it briefly becomes 2n = 8

returned to 2n = 4 in telophase and cytokinesis

25
Q

How does the c-value change during the mitotic cell cycle?

A

of DNA strands is 4 until S phase where it doubles to 8

stays at 8 until anaphase where it gradually transitions back to 4 in telophase and cytokinesis

26
Q

What is meiosis?

A

haploid gametes are produced (2n –> n)

27
Q

What is fertilization?

A

fusion of two haploid cells (n –> 2n)

28
Q

What is genetic variation?

A

a consequence of meiosis

29
Q

What is interphase in meiosis?

A

same as mitosis (G1, S, G2)

30
Q

What is meiosis I?

A

separation of homologous chromosome pairs

reduction division

2n –> n

metaphase plate homologs line up

31
Q

What is meiosis II?

A

separation of sister chromatids

equational division

n –> n

no change in ploidy, same as mitosis

32
Q

What are the three processes that occur in prophase I?

A

synapsis
tetrad
crossing over

33
Q

What is synapsis?

A

close pairing of homologous chromosomes

process of the pairing (the verb)

34
Q

What is a tetrad?

A

the pair of homologous chromosomes connected with each other

synaped chromosomes (the noun)

35
Q

What is crossing over?

A

exchange of genetic material between homologous chromosomes

36
Q

What happens in middle prophase I?

A

chromosomes condensing

centrosomes connecting

37
Q

What happens in late prophase I?

A

homologs pairing

synapsis happens forming tetrads

chiasmata form

crossing over happens

38
Q

What happens in metaphase I?

A

tetrads line up on metaphase plate

39
Q

What happens in anaphase I?

A

separation of homologous chromosomes

chromosomes segregate independently (chromosome shuffle)

40
Q

What is interkinesis?

A

stage between meiosis I and meiosis II

41
Q

How does the separation of sister chromatids and homologous chromosomes occur?

A

tubulin subunits

both separations happen because of spindle action

the tubules grow and shrink via polymerization and depolymerization

42
Q

What is cohesion?

A

ring-like heterotrimer

separase cleaves it in anaphase

43
Q

What is the shugoshin?

A

protects cohesion from separase

add to cohesion near centromeres

44
Q

What happens in prophase I?

A

chromosomes condense

homologous chromosomes synapse

crossing over takes place

the nuclear envelope breaks down

the mitotic spindle forms

45
Q

What are the consequences of meiosis and genetic variation?

A

four cells are produced from each original cell

chromosome number: reduced by half, diploid –> haploid, 2n –> n

newly formed cells from meiosis are genetically different from one another and from the parental cell

genetic variation resulting from independent segregation of chromosomes, there are 4 possible alignments at metaphase I, gives a shuffling of maternal and parental chromosomes

genetic variation resulting from recombination via crossing over, shuffling of alleles

chiasmata: crossing over event, aka recombination

46
Q

How does the n-value change during meiosis?

A

is 2n until dropping to n after meiosis I

stays n after meiosis II is completed

47
Q

How does the c-value change during meiosis?

A

of DNA strands doubles during S phase

starts declining at the start of meiosis I and eventually decreases to half of what it started with by the end of meiosis II

48
Q

What is the overall process of mitosis?

A

cell division: yes
reduction in chromosome number: no
genetic variation produced: no
crossing over: no
random distribution of maternal and paternal chromosomes: no
metaphase: individual chromosomes line up
anaphase: chromatids separate

49
Q

What is the overall process of meiosis I?

A

cell division: yes
reduction in chromosome number: yes
genetic variation produced: yes
crossing over: yes
random distribution of maternal and paternal chromosomes: yes
metaphase: homologous pairs line up
anaphase: homologous chromosomes separate

50
Q

What is the overall process of meiosis II?

A

cell division: yes
reduction in chromosome number: no
genetic variation produced: no
crossing over: no
random distribution of maternal and paternal chromosomes: no
metaphase: individual chromosomes line up
anaphase: chromatids separate

BIOL 207 (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions