Brainscape's Knowledge GenomeTM

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


See full index

BIOL 2321 - Cell Bio Lab > Mitotic Chromosome Structure > Flashcards

Mitotic Chromosome Structure Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Where is hereditary information found in eukaryotic cells? What form does hereditary information take?

A

hereditary information in the form of genes is found along many linear DNA molecules

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

What is a chromosome?

A

an individual DNA molecule + associated histone + non-histone proteins

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

What allows a chromosome to have 2 arms?

A

a centromere

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

What is a centromere?

A

a point on a chromosome where the spindle fibers attach during mitosis and meiosis

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

What is chromatin?

A

the complex of DNA and histone proteins that make up a chromosome

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

T or F: the appearance and arrangement of the chromatin in the nucleus is the same at all stages of the cell cycle

A

FALSE! it differs at different stages of the cycle

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

What is the most dominant component of an interphase nucleus?

A

chromatin - it makes up 80-90% of the nuclear mass

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

How does the chromatin appear in the interphase nucleus?

A

fine, intertwined fibers or threads

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

What are the two classifications of interphase nuclear chromatin?

A

euchromatin

heterochromatin

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

How is the interphase nuclear chromatin divided into the two classifications?

A

based on its appearance and possible activity level

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

Describe the structure of euchromatin

A

the interphase nuclear chromatin that appears as loosely packed threads

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

How does euchromatin appear under an electron microscope?

A

it is less densely stained and appears as if the threads are dispersed

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

What is the transcription activity level of euchromatin?

A

transcriptionally active

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

Describe the structure of heterochromatin

A

densely packed mass around the periphery of the nucleus

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

How does heterochromatin appear under an electron microscope?

A

densely stained

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

What is the transcription activity level of heterochromatin?

A

inactive

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

When are chromosomes at their most condensed and compact state?

A

during metaphase of mitosis or meiosis

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

When can chromosomes be visualized with a light microscope?

A

during metaphase

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

What are the stages of the cell cycle

A 
G1
S
G2
Mitosis or meiosis 
C
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What occurs during the G1 phase of the cell cycle?

A

gap phase

growth or regular cell function - anything that isn’t cell division

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

What occurs during the S phase of the cell cycle?

A

DNA synthesis

duplication of DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe the structure of chromosomes at metaphase of mitosis

A

two identical sister chromatids attached at their centromeres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How do the centromeres appear at metaphase of mitosis?

A

narrowed or constricted areas along the length of the chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is another term for centromeres?

A

primary constriction

25
Q

How do researchers see and count the number of chromosomes in a single cell?

A

by preparing a slide with cells held at metaphase and exposing them to a hypotonic solution to burst the cells and release the chromosomes

26
Q

What is karyotyping?

A

determining the chromosomal complement of cells by staining and taking a picture of released chromosomes from a cell and pairing them with their homologue and arranging them according to size and structure

27
Q

How are the characteristic morphology of metaphase chromosomes determined?

A

by their size and location of centromere

28
Q

What are the 4 classifications of chromosomes?

A

metacentric

submetacentric

acrocentric

telocentric

29
Q

Describe metacentric chromosomes

A

chromosomes with a centromere that is equidistant between the 2 arms and the 2 arms are of equal length

30
Q

Describe submetacentric chromosomes

A

chromosomes with an off centered centromere (slightly different arm lengths)

31
Q

Describe acrocentric chromosomes

A

chromosomes with a centromere that is closer to one end than to the other (very different arm lengths)

32
Q

Describe telocentric chromosomes

A

chromosomes with the centromere AT the end of the chromosome

33
Q

Which 2 types of chromosomes have 2 arms of unequal lengths?

A

submetacentric

acrocentric

34
Q

How are two unequal arms of submetacentric or acrocentric chromosomes classified?

A

the shorter arm = the p arm

the longer arm = the q arm

35
Q

Which arm is the p arm?

A

the shorter arm

can remember as p for ‘petite’ arm

36
Q

Which arm is the q arm?

A

the longer arm

can remember that p = petite and q comes after p

37
Q

the movement of sister chromatids of each chromosome pair toward the poles of cell depends on what?

A

the development of a kinetochore on each centromere

38
Q

Where are kinetochores located?

A

on centromeres of chromosomes

39
Q

Where do sister chromatids separate from?

A

their centromeres

40
Q

Describe a kinetochore

A

a large multiprotein complex that appears in the EM as a plate-like trilaminar structure

41
Q

How does a kinetochore appear in an EM?

A

as a plate-like trilaminar structure

42
Q

How many centromeres are there in a chromosome consisting of 2 sister chromatids?

A

2

43
Q

How many kinetochores are there in a chromosome consisting of 2 sister chromatids?

A

2

44
Q

Where do microtubule spindle fibers attach on a sister chromatid? What stages of mitosis does this occur?

A

to its kinetochore on its centromere during prophase and metaphase

45
Q

What does the kinetochore do during anaphase?

A

it climbs the microtubule while digesting it along the way and this pulls the sister chromatid along with it

46
Q

T or F: the kinetochore is providing the force that pulls sister chromatids apart and towards the poles, NOT the spindle fiber microtubules

A

true

47
Q

What is another term for the secondary constriction?

A

Nuclear Organizer Region (NOR)

48
Q

Describe the NOR/secondary constriction

A

a large cluster of repeating rRNA genes that marks the site of nucleolar formation during interphase

49
Q

What does secondary constriction/NOR do to the appearance of a metaphase chromosome?

A

the NOR can be so narrow that it makes the distal portion of an arm appear to be completely detached from the rest of the chromosome

50
Q

What is a satellite?

A

the distal portion of a metaphase chromosome that appears to be separated from the chromosome because of the NOR/secondary constriction

51
Q

T or F: every species has the same number of NORs/secondary constrictions on their chromosomes

A

false! it varies from species to species

52
Q

How many NORs do human chromosomes have?

A

5 pairs

53
Q

Which human chromosomes have NORs?

A

13, 14, 15, 21, 22

54
Q

What are telomeres?

A

the ends of linear chromosomes

55
Q

What are telomeres made of?

A

long stretches of repetitive nucleotide sequences covered with protein complexes

56
Q

What are the 3 major function of telomeres?

A
  1. to protect the chromosome from fusing with other chromosomes
  2. to protect transcriptionally valuable DNA from being lost
  3. preventing uncontrolled cell division (cancer) due to telomere loss initiating apoptosis
57
Q

What happens to telomeres with every round of cell division?

A

they shorten by a few hundred base pairs

58
Q

How is the total number of cell division limited? Why?

A

by the length of telomeres because they shorten with every round of cell division

59
Q

How do telomeres prevent uncontrolled cell division?

A

the loss of telomeres (after rounds of cell division) initiates apoptosis

BIOL 2321 - Cell Bio Lab (10 decks)

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