Genetics: Chromosomes Part 2 Flashcards

1
Q

Why is it important to study the processes controlling cell division?

A

So we can try and fix or manipulate these processes for our own benefits. For example, we could try and improve regenerative mechanisms

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

What is apoptosis? When does it occur

A

Programmed cell death. It occurs when it fails a checkpoint and has damaged chromosomes

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

How are telomeres extended in the germ cells?

A

There’s a complex called telomerase which adds telomeres to the chromosomes

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

Meiosis produces _ gametes while mitosis produces _ daughter cells

A

4, 2

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

What is the cell cycle?

A

The sequence of events from a cell’s formation until its own division into two daughter cells.

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

What phases are part of the cell cycle?

A

Interphase and the cell division phase (mitosis and cytokinesis)

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

What is the general process for mitosis? What are the 6 official phases?

A

Duplicate chromosomes and separate the duplicated chromosomes so that each cell receives one copy.

Interphase, prophase, prometaphase, metaphase, anaphase, telophase/cytokinesis

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

What phases does interphase consist of?

A

Growth 0/1, S phase (chromosome duplication), Growth 2 (check for damaged or unduplicated DNA)

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

The cell cycle is under tight ________ in eukaryotes. This causes several __________ in the cycle that send stop or go signals

A

regulation, checkpoints

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

What sort of checkpoints exist to stop the cell cycle?

A
  • Check for favourable environmental conditions
  • Check for DNA damage or stalled replication forks
  • Check for damaged or unduplicated DNA
  • Check for chromosome attachment to mitotic spindle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What helps the cell actually split in animal and plant cells?

A

Animal: Contractile ring (which makes the cleavage furrow)
Plant: Golgi Vesicles and cell plates

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

Some organisms like _________ can regenerate amputated limbs via activation of _____ _______ to supply new cells in the growing limb

A

salamanders, cell division

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

How do hydras reproduce?

A

A mass of cells divide by mitosis to form a bud, which developers into a small hydra that detaches from the parent

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

What is asexual reproduction?

A

Reproduction from oneself

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

What is cancer often caused by?

A

A series of mutations in chromosomes DNA

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

Why do cancer cells reproduce uncontrollably?

A

Cancer cells do not respond normally to the cell cycle control system

17
Q

What are telomeres? What are they used for?

A

Sequences of DNA capping off chromosome ends. They are essential for DNA replication, is the enzyme attaches to them.

18
Q

What happens to telomeres as cells divide? What are the implications of this?

A

Telomeres get shorter each time a cell divides. Once they are short enough, the prevent cell division, which leads to senescence and possibly oncogenic transformation of cells

19
Q

Learning how plants clone themselves via mitosis can enable plant breeders to _______ these plant propagation techniques

A

optimise

20
Q

What did Thomas Hunt Morgan’s work with fruit flies uncover in relation to genetic diversity?

A

It showed recombination, and how genes on the same chromosome could recombine during meiosis to produce novel phenotypes

21
Q

Describe Thomas Hunt Morgan’s work that allowed him to discover recombination

A

He noticed that certain traits were linked and always inherited together: Grey/Long vs Black/Short

Both these traits are carried on the X-chromosome. Since the fly inherits one whole chromosome from mother and father, one would expect that the traits are inherited together.

However, he noticed some flies with Grey/Short and Black/Long

22
Q

What does sexual reproduction depend on?

A

Meiosis and fertilization

23
Q

What is meiosis?

A

The process in which haploid gametes are created from diploid cells

24
Q

Describe the human life cycle for the gametes.

A
  • Meiosis occurs to produce haploid gametes
  • Fertilisation combines the haploid paternal and maternal genomes to produce a diploid zygote
  • The diploid zygote undergoes mitosis to produce identical diploid cells
25
Q

All adult body cells are _______ with two _________, for a total of 46 chromosomes

A

diploid, genomes

26
Q

All gametes are _______ with one genome for a total of 23 chromosomes

A

haploids

27
Q

The diploid zygote in human reproduction has __ chromosomes

A

46

28
Q

The haploid gametes generated from meiosis are ________ unique from each other and from the parent cell

A

genetically

29
Q

Describe the process of meiosis?

A
  1. Chromosomes duplicate
  2. Duplicated pair of homologous chromosomes align together (this is important, as crossover can happen here). These are called sister chromatids. (4 chromosomes total)
  3. Homologous chromosomes separate into 2 cells (2 * 2 chromosomes total)
  4. Sister chromatids separate (4 * 1 chromosomes total)
30
Q

What are 3 ways novel combinations of different alleles can be formed in the offspring?

A
  1. Meiosis 1: Crossing over between maternal and paternal chromosomes
  2. Meiosis 2: Independent assortment of each homologous chromosome pair
  3. Fertilisation and combining maternal and paternal genomes
31
Q

Why does independent chromosome assortment increase diversity?

A

Chromosome pairs from mom and dad are randomly sorted into daughter cells, resulting in 4 possible combinations in gametes

32
Q

What is the total number of chromosome combinations that can appear in the gametes due to independent assortment?

A

2^23 = around 8.4 million

33
Q

How many chromosome combinations are possible with independent assortment and fertilization?

A

8.4m * 8.4m = >70 trillion combinations

34
Q

What is recombination?

A

When 2 homologous chromosomes swap genes`and create new combinations of alleles

35
Q

Alfred Henry Sturtevant noticed that the frequency of __________ was related to the distance between genes

A

recombination

36
Q

What is a linkage map?

A

It shows gene positions on chromosomes

37
Q

What is a centiMorgan?

A

A unit for measuring genetic linkage. It is the distance between chromosome position for which the expected average number of crossovers in a single generation is 0.01

38
Q

Why do genes that are further apart more likely to be recombined?

A

They are more separated, so when the gene splits, it’s less likely they will be part of the same chunk that split.