Brainscape's Knowledge GenomeTM

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


See full index

Semester 1-MCBG > Session 3-Mitosis And Meiosis > Flashcards

Session 3-Mitosis And Meiosis Flashcards

1
Q

What is a telomere?

A

Repeated sequence (TTAGGG) in humans at each end of chromosome/chromatid. Telomere becomes shorter every time cell divides

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

What is a chromatid?

A

One of two threadlike strands formed by division during mitosis and meiosis

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

What is a centromere?

A

Links sister chromatids and consists of repetitive sequences

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

What is the difference between sister and non-sister chromatids?

A

They both have the same genes but may have different alleles

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

What is the cell division for somatic cells called?

A

Mitosis

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

What does mitosis produce?

A

Two identical daughter cells with same chromosome content as parent cell

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

What happens in the G0 stage of the cell cycle?

A

Cells can leave the cell cycle and enter the inactive state of G0

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

What is the synthesis (S) phase of the cell cycle?

A

The interval when DNA replication takes place (chromosomes are duplicated)

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

What is the G1 phase of the cell cycle?

A

Interval of cell growth before DNA replication (chromosomes unduplicated)

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

Which phases are included in interphase?

A

G1, S and G2

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

What happens in the G2 phase of the cell cycle?

A

Interval following DNA replication when the cell prepares to divide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
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
13
Q

What happens in prophase?

A

Nuclear membrane disappears
Chromosomes become visible
Spindle fibres appear

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

What happens in prometaphase?

A

Microtubule spindles attach to centromere

Chromosomes condense

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

What happens in metaphase?

A

Chromosomes line up in middle (metaphase plate)

Random alignment of chromosomes

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

What happens in anaphase?

A

Microtubule spindles pull each replicated chromosome apart and chromatids separate and go to separate poles of cell

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

What is the name given when the chromatids are separated in anaphase?

A

Chromosome (46 chromosomes left in each cell)

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

What happens in telophase?

A

Spindles disappear
Nuclear membrane reappears
Cleavage forms (where the cell is cleaved)

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

What does meiosis produce?

A

Four non-identical haploid cells (produces eggs and sperm)

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

What happens in meiosis I?

A

Homologous pairs of chromosomes line up and separate

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

What are the stages of meiosis I?

A

Prophase I
Metaphase I
Anaphase I
Telophase I

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

What happens in prophase I?

A

Chromosomes are replicated
Nuclear membrane disappears
Homologous chromosomes “find” each other because near/identical sequence
Recombination occurs

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

What happens in metaphase I?

A

Homologous pairs line up in metaphase plane

24
Q

What happens in anaphase I?

A

Homologous chromosomes separate

25
Q

What happens in telophase I?

A

Nuclear membrane reforms

Spindles disappear

26
Q

What is a homologous chromosome?

A

Pair of chromosomes of similar size and shape and same identical gene loci. One from mother, one from father.

27
Q

What is a bivalent?

A

Homologous chromosomes attached to each other by chiasmata during first division of meiosis

28
Q

What happens in meiosis II?

A

Chromosomes line up and chromatids separate

29
Q

What are the stages of meiosis II?

A

Prophase II
Metaphase II
Anaphase II
Telophase II

30
Q

What happens in prophase II?

A

Microtubules move one member of centriole pair to opp spindle pole in each of two daughter cells
Microtubules attach to chromosomes
Chromosomes recoil and shorten

31
Q

What happens in metaphase II?

A

Microtubules, motor proteins and duplicated chromosomes interact, positioning all of the duplicated chromosomes midway between two spindle pairs
Unpaired chromosomes align at equator of cell

32
Q

What happens in anaphase II?

A

Attachment between sister chromatids (centromere) of each chromosome breaks and two are moved to opp spindle poles
Each former sister is now a chromosome on its own

33
Q

What happens in telophase II?

A

After cytoplasmic division, each daughter cell is haploid
All chromosomes are in an unduplicated state
Chromosomes uncoil and nuclear envelope reforms

34
Q

What are the consequences of meiosis?

A

Maintains constant chromosome number from generation to generation
Generation of genetic diversity by random assortment of chromosomes and crossing over

35
Q

How long does spermatogenesis take?

A

60 days

36
Q

When and where does spermatogenesis start?

A

In the testes as soon as puberty starts

37
Q

Why do spermatogonia go through mitosis as well as meiosis?

A

If only meiosis took place, you would run out of germ cells

38
Q

Define spermatogonium

A

Cell produced at an early stage in the formation of the spermatozoa. Spermatogonia first appear in the testes of the foetus but do not multiply significantly until after puberty

39
Q

Define spermatocyte

A

Cell produced in intermediate stage in the formation of the spermatozoa. Develop from spermatogonia

40
Q

What happens in meiosis I in spermatogenesis?

A

Primary spermatocyte (diploid) becomes secondary spermatocyte (haploid)

41
Q

What happens in meiosis II of spermatogenesis?

A

Sister chromatids separate and end up with four unique daughter cells which are called spermatids. These eventually mature (lose cytoplasm, get head and tail etc) in testes and eventually become sperm

42
Q

How long does oogenesis take?

A

12-50 years

43
Q

Why does mitosis take place in oogenesis?

A

To make more oogonium or to make a primary oocyte

44
Q

When does oogenesis begin and when does it stop temporarily?

A

Begins in the foetal stage and stops in prophase I of meiosis during foetal development

45
Q

How often does a primary oocyte go through meiosis and become an ovum?

A

Once a month

46
Q

What is the goal of oogenesis?

A

Produce one big “egg” with all the cytoplasm, nutrients etc

47
Q

What happens to the secondary oocyte if it is not fertilised?

A

It is shed during menstruation

48
Q

What happens to the secondary oocyte if it is fertilised?

A

Meiosis II will be completed and it becomes a zygote

49
Q

What are the consequences of missegregation in meiosis?

A

Third of all identified miscarriages
Infertility
Leading cause of mental retardation

50
Q

What is nondisjunction?

A

The failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, resulting in abnormal distribution of chromosomes in daughter nuclei

51
Q

What is aneuploidy?

A

Error in cell division resulting in daughter cells having an incorrect number of chromosomes

52
Q

Why does aneuploidy of the sex chromosomes have fewer adverse effects than aneuploidy of autosomes?

A

Everyone has at least one X chromosome so an incorrect number of sex chromosomes will not have as adverse an effect as having an incorrect number of autosomes as this would be lethal. Extra sex chromosomes would simply condense into one/inactivate.

53
Q

What is a karyotype?

A

Number and visual appearance of chromosomes in a cell nuclei of an organism or species

54
Q

What is mitotic nondisjunction?

A

The failure in mitosis for two members of a chromosome pair to separate normally so both the chromosomes go to one daughter cell while none go to the other daughter cell.

55
Q

What is mosaicism?

A

The presence of two or more cell lines in an individual

Semester 1-MCBG (20 decks)

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