Brainscape's Knowledge GenomeTM

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


See full index

+ BIOL 121 > Genetics - Week 2 > Flashcards

Genetics - Week 2 Flashcards

1
Q

What are alleles?

A

different versions of the same gene

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

How might homologous chromosomes differ?

A

they may carry the same gene, but different alleles

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

What happens to the alleles after replication?

A

sister chromatids have identical alleles

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

What are genotypes?

A

combination of alleles in a single cell or single individual that relate to specific traits we are interested in

  • alleles belonging to same gene are separated by a ‘/’
  • alleles belonging to different genes are separated by a ‘;’
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The Cell Cycle

What is interphase?

A

G1/S/G2

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

The Cell Cycle

When does DNA replication occur?

A

interphase

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

What is the goal of mitosis?

A
  • to produce daughter cells that are genetically identical to parent cell
  • asexual reproduction (no gametes are produced)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Mitosis

Describe the process.

A

prophase
metaphase
anaphase
telophase

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

Mitosis

What occurs in metaphase?

A

allows splitting of sister chromatids to be shared between two daughter cells

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

What happens go chromosomes after DNA replication?

A

the number of chromosomes do not change, but results in the formation of sister chromatids (which share one centromere)

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

Mitosis

What happens in anaphase?

A

kinetochore microtubules pull the sister chromatids away from each other, breaking them into two individual chromosomes

number of chromosomes has doubled

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

Mitosis

What happens in early telophase?

A
  • chromosomes are still contained within ONE cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is a cell replicated?

A

by undergoing several cell phases in the cell cycle

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

What is the process of the cell cycle?

A
  • Gap 1 (G1): phase for growth
  • G0: resting phase - cell division ceases
  • Synthesis (S): phase for DNA replication
  • Gap 2 (G2): phase for more growth
  • Mitosis and Cytokinesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The Cell Cycle

What are checkpoints?

A

ensure that everything is progressing normally before entering the next stage

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

The Cell Cycle

Where are the checkpoints?

A
  • one between G1/S
  • one in G2
  • one in mitosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The Cell Cycle

What happens if any mistakes are found in DNA?

A

it’s important to fix them before the cell divides in mitosis so that the errors aren’t present in the daughter cells

18
Q

The Cell Cycle

When will the cell still undergo mitosis even though there is some sort of defect?

A

in some cases, mutations occur that will allow the cell to undergo mitosis, despite such defects

19
Q

When can cancer occur?

A

when checkpoints fails to function properly, allowing the cell to divide uncontrollably

20
Q

What is a tumour (neoplasm)?

A

cluster of cells growing abnormally, but have not yet spread to other tissues

21
Q

What is metastasis?

A

occurs when abnormal cells break off and travel through the bloodstream, spreading to other tissues throughout the body

22
Q

Describe cancer cells.

A
  • grow/divide when they aren’t supposed to
  • don’t die when they are supposed to
  • invade parts of the body they aren’t supposed to
23
Q

What can cancer be caused by?

A

an accumulation of mutations and/or nondisjunction events

24
Q

What are mutations?

A

permanent change in nucleotide sequence

25
Q

What are mutations caused by?

A

errors in:

  • DNA replication: incorrect bases are added to new DNA strand
  • DNA repair: ironically, sometimes when the DNA repair machinery is trying to fix a problem, it can make mistakes - if unchecked and isn’t corrected, it can lead to mutations as well
26
Q

When does nondisjunction occur?

A

when chromosomes don’t separate properly during mitosis or meiosis in anaphase, resulting in daughter cells with either too many (or missing) chromosomes

27
Q

What consequences does nondisjunction have on the genomes of the daughter cells?

A

one daughter cell is going to have more than the usual number of copies of a gene, while the other daughter cell is missing a copy

  • parent cell is diploid (2n=2)
  • one daughter cell is haploid (n=1)
  • one daughter cell is triploid (3n=3)

this can have detrimental results on an organism

28
Q

What can nondisjunction cause in humans?

A
  • down syndrome: experience physical growth and cognitive delay
  • turner syndrome: affects development in females and a common feature is short stature in affected individuals, some experience loss of ovarian function
29
Q

What are tumour suppressor genes?

A

act to slow down cell division, repair DNA replication errors, or start apoptosis (programmed cell death)

if both tumor suppressor genes are affected by mutation or lost via nondisjunction, this results in an inability to prevent tumor growth

30
Q

Mitosis vs. Meiosis

How many cell divisions are there?

A

MITOSIS: only one cell division (PMAT)

MEIOSIS: two cell divisions (at end of meiosis I and meiosis II)

31
Q

Mitosis vs. Meiosis

What are the ploidy levels of parent and daughter cells?

A

MITOSIS: ploidy level is the same between parent and daughter cells (ie. parents were diploid, so are the daughter cells)

MEIOSIS: daughter cells have half of the chromosomes compared to the parents (ie. parents were diploid, daughter cells are haploid)

32
Q

Mitosis vs. Meiosis

Describe the pairing of homologs.

A

MITOSIS: no pairing of homologs

MEIOSIS: homologs pair up during prophase I (genetic recombination takes place)

33
Q

Mitosis vs. Meiosis

Describe genetic recombination.

A

MITOSIS: no crossing over or genetic recombination occurs (parent and daughter genotypes are the same)

MEIOSIS: homologs line up across one another during metaphase I, resulting in independent assortment of chromosomes, crossing over of homologs may occur in prophase I

34
Q

What is the result of meiosis?

A

daughter cells are not identical to parent cell, and allows for production of genetically variable offspring

35
Q

What is the process of meiosis?

A

chromosomes align and are split up in such a way that each daughter cell receives only half of all the genetic material in the parent cell

36
Q

What is the function of meiosis?

A

for the purposes of sexual reproduction, the diploid genome has to be split into two haploid genomes

  • if the gametes are not haploid with all genes properly represented, then when two gametes fuse the zygote will have an incorrect number of chromosomes/gene copies
37
Q

What are the two processes that allow for genetic variation?

A

independent assortment

crossing over

38
Q

When does crossing over occur?

A

prophase I (in meiosis I)

39
Q

How does crossing over occur?

A
  • specialized proteins cause deliberate breakage of chromatids
  • during chromatid repair, non-sister chromatids from homologous chromosomes can cross over: if this occurs, then genetic recombination of chromosomes can result
  • if sister chromatids cross over, there is no genetic recombination as sister chromatids are replicates of one another
40
Q

What is a locus?

A

specific location of a gene on chromosome

+ BIOL 121 (11 decks)

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