Brainscape's Knowledge GenomeTM

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


See full index

Medical Cell Biology and Genetics > Topic 11: Mitosis and Meioisis > Flashcards

Topic 11: Mitosis and Meioisis Flashcards

1
Q

What is the relationship between DNA molecules, chromosomes and chromatids?

A

DNA molecules wrap around histones and become beads on a string (nucleosomes), which then coil to become a solenoid, which scrunch together to form a chromatid.

A chromatid has a p arm and a q arm and before DNA replication, chromosomes have 1 chromatid and 2 chromatid after DNA replication.

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

What is the structure of a chromosome?

A

Each replicated chromosome consists of 2 chromatids

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

What is a centromere?

A

Consists of repetitive sequences and links the chromatids

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

What is a telomere?

A

Repeated sequences at each end

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

What is the difference between gene and allele?

A

Genes are DNA sequences, and alleles are different variants of genes.

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

What are the 4 stages of cell cycle?

A

G1, S, G2, M

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

What are the 2 stages of M phase?

A

Mitosis and cytokinesis

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

What is mitosis?

A

Cell division for somatic cells that produces 2 identical daughter cells

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

What are the 5 stages of mitosis?

A

Prophase, prometaphase, metaphase, anaphase, telophase

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

What are the 2 things that happen in early prophase?

A

Chromosome condensation and centrosome separation

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

What are the 2 things that happens in late prophase?

A

Chromosome condensation and nuclear envelope breakdown

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

What are the 3 events in prometaphase?

A 
Nuclear envelope breakdown 
Mitotic spindle assembly (centrioles moved to pole of the cell and spindle fibers connect to kinetochores)
Chromosome capture (by spindle fibers and kinetochore)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the 2 events in metaphase?

A

Bipolar chromosome attachment

Chromosome alignment at metaphase plate

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

What is the event at anaphase?

A

Sister chromatid separation (centromeres divide and sister chromatids move to opposite poles)

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

What are the 3 events at telophase?

A

Nuclear envelope reformation (2!)
Chromosome decondensation
Spindle disassembly (spindle fibers disappear)

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

What happens during cytokinesis?

A

Cytoplasm divides and parent cell becomes 2 daughter cells with identical generic information

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

What is nondisjunction?

A

Missegregation of chromosomes - instead of sister chromatids going to opposite poles, the whole chromosome goes to one pole leading to aneuploidy which is an unusual amount of chromosomes

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

What if mitotic nondisjunction happens during first post-zygotes division (from the fertilized cell)?

A

From a normal cell with 46 chromosomes, it divides but nondisjunction happens so one cell has 47 chromosomes and one has 45.

The one with 45 chromosome (monosomy) cell line is usually lost but the one with 47 will continue to proliferate

Leads to a non-mosaic phenotype - all cells are chromosomally similar (all have 47 chromosomes)

19
Q

What if mitotic nondisjunction occurs in later post-zygotes division?

A

There’ll be some cells with normal 46 chromosomes, but some with 47 chromosomes (monosomy cell lines are lost)

Leads to mosaicism, presence of 2 or more cell lines in an individual

20
Q

What is meiosis?

A

Special cell division for germ line cells that produces four non-identical daughter cells

21
Q

What are the 2 main process of meiosis?

A

Meiosis 1 and 2

22
Q

What is meiosis 1?

A

Homologous pairs of chromosomes line up and separate

23
Q

What are the 4 stages of meiosis 1?

A

Prophase I, metaphase 1, anaphase 1, telophase 1

24
Q

What are the 3 events of prophase I?

A

Nuclear envelope breaks down
Homologous chromosomes pair up
Crossing over of genetic material occurs (recombination = daughter chromosomes are a mixture of parental chromosomes)

25
Q

What is the event during metaphase I?

A

Homologous chromosomes pairs (tetrad - 4 chromatids) line up on the spindle

26
Q

What is the event during anaphase 1?

A

Homologous chromosomes pairs get separated, moves to opposite poles of the cell

27
Q

What are the 2 events during telophase 1?

A

Chromosomes gather at the poles of the cells

Nuclear membrane forms

28
Q

What happens during cytokinesis?

A

Cytoplasm divides

29
Q

What are the 2 events during prophase II?

A

New spindle forms around the chromosomes

Nuclear envelope disintegrates

30
Q

What happens during metaphase II?

A

Chromosomes line up at the equator

31
Q

What are the 3 events that happen during anaphase II?

A

Centromeres divide
Separation of chromatids
Chromatids move to the opposite poles of the cells

32
Q

What happens during telophase II?

A

Nuclear envelope forms around each set of chromosomes

33
Q

What happens during cytokinesis?

A

Cytoplasm divides

34
Q

What are the differences between meiosis I and meiosis II?

A

In meiosis I, homologous pairs of chromosomes line up and separate.

In meiosis II, chromosomes line up and chromatids separate

35
Q

What is spermatogenesis?

A

Cell division to produce male gametes

Spermatocyte (diploid) to 4 sperms (haploids)

36
Q

How long does spermatogenesis take?

A

1 spermatocyte forms 4 sperms in approximately 60 days

37
Q

What is oogenesis?

A

Cell devision to form female gametes

1 oocyte to form 1 egg and 3 polar bodies

38
Q

How long does oogenesis take?

A

1 oocyte to 1 egg + 3 polar bodies in 12-50 years

39
Q

What are 6 key differences between mitosis and meiosis?

A
  1. Mitosis 4 stages meiosis 8 stages
  2. Mitosis happens in somatic cells meiosis happens in germ cells
  3. Purpose of mitosis is cellular proliferation purpose of meiosis is sexual reproduction
  4. Product of mitosis is 2 diploid daughter cells product of meiosis is 4 haploid daughter cells
  5. Number of chromosomes after mitosis is same number of chromosomes halved after meiosis
  6. Mitosis doesn’t affect genetic variation but meiosis increases genetic variation
40
Q

What are the 2 ways that genetic variation created during meiosis?

A
  1. Crossing over of genetic material in prophase 1

2. Random assortments of chromosomes in metaphase 1

41
Q

What happens if there is nondisjunction in meiosis I?

A

Produces 2 gametes with 2 chromatids and 2 gametes without that chromosome

Upon fertilization by a normal gamete, produces 2 zygotes with trisomy and 2 with monosomy

42
Q

What happens if there is non disjunction in meiosis Ii?

A

Produce 1 gamete with 2 chromatids, 1 gamete without that chromosome, 2 normal gametes with 1 chromatid each

Upon fertilization by normal gamete, produces 1 zygote with trisomy, 1 with monosomy, 2 normal gametes

43
Q

What are 3 consequences of faulty meiosis?

A

Miscarriages, infertility and leading cause of mental retardation

Medical Cell Biology and Genetics (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions