Brainscape's Knowledge GenomeTM

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


See full index

Biology 1A03 > Theme 4: DNA Replication and Mitosis - Module 4: DNA Mutations > Flashcards

Theme 4: DNA Replication and Mitosis - Module 4: DNA Mutations Flashcards

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

understanding the process of gene expression enables us to further appreciate what?

A

how changes in the genetic information of a cell can affect protein structure and function

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

what can these changes in genetic information create?

A

devastating cellular consequences or beneficial adaptation

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

what are mutations responsible for?

A

the large array of genes and thus the genetic differences that can be found among different organisms

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

what are mutations considered the source of?

A

genetic variation

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

how can mutations be created?

A
  • due to environmental facts
  • arising due to spontaneous mutations
  • errors during DNA replication
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what do errors in DNA replication lead to? can this be corrected?

A
  • changes at the nucleotide level

- can be corrected - but at times are not corrected

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

what happens if the error is not corrected?

A

incorrect nucleotide bases can be used as a template in the next round of replication

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

what does this result in?

A

the propagation of the mutation

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

what are the most common mutations to occur?

A

these spontaneous mutations

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

how do the spontaneous mutations occur?

A

randomly by chance without any cause

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

is a mutation common or rare for any given nucleotide?

A

rare

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

is there variability as to the likelihood that a new mutation will occur at a given nucleotide base pair in a single round of replication across different organisms?

A

yes

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

most multicellular animals have a low probability of incurring a new mutation at a particular nucleotide pair in a given round of DNA replication, however what tends to have a higher mutation rate?

A

viruses

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

which virus has the most probity out of all viruses?

A

RNA viruses

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

what is this due to?

A

the delicate nature of the RNA backbone of RNA viruses and retroviruses (being more prone to damage and breakage)

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

what is another reason?

A

no proofreading capability in RNA genomes

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

genetic information can be mutated in which cells?

A

somatic or germline cells

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

if a mutation occurs in the somatic cell of an individual what will that cell be?

A

progenitor of a population of identical daughter cells following cell division

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

what will the division of a cell with a new mutation lead to?

A

a patch or region of cells with this new mutation

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

what leads to a larger spread of the mutated somatic cell throughout the body of an organism?

A

the earlier the developmental cascade of the mutation in a somatic cell

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

when can the effect of a mutation be largely negligible?

A

if the mutation arises in a cell that is no longer dividing or is post-mitotic in the G0 cycle

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

can somatic cell mutations be inherited?

A

no

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

what mutations can be passed on to offspring?

A

germline mutations

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

why is this?

A

germ cells are the cells that come together to produce new offspring in sexually reproducing organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what does this mean?

A

every cell in the developing embryo will carry the mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what did the experiment by Joshua and Esther Lederberg show?

A

that mutations such as those of antibiotic resistance in bacteria are random and not directed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what did this experimental setup require allowing?

A

bacteria to grow into colonies in a petri dish with non-selective supplemented nutrients (agar)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

why is one of the plates referred to as non-selective?

A

since bacterial cells are able to grow and form colonies on it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what happened once bacterial colonies had grown on the non-selective plate?

A

Lederbergs “stamped” the original plate 1 onto a cloth, and then stamped this cloth onto a new selective plate containing the antibiotic penicillin in the agar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what would this plate only all the growth of?

A

bacteria that are resistant to penicillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what is the stamping process refereed to as? what does it preserve?

A
  • replica plating

- the relative arrangement of colonies on the new plate relative to the first agar plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

over time what appeared?

A

only a few colonies from plate 1 survived the exposure to the penicillin on plate 2 - most other bacteria colonies were killed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what did the Lederbergs predict?

A

these few colonies must carry a mutation that makes them resistant to the antibiotic penicillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what does the process of replica plating mean?

A

the original colony that grew on the penicillin agar could be isolated from the original non-selective agar and used to test the hypothesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what did the Lederbergs do?

A

exposed the suspected mutant colony from the original plate 1 to penicillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

how did they do this?

A

isolated bacteria from the original colony and cultured these cells in medium containing penicillin

37
Q

what did they get in the end?

A

a pure culture of antibiotic-resistant bacteria

38
Q

what is it important to remember?

A

colonies on plate 1 have never been originally exposed to penicillin

39
Q

what can be concluded?

A

the mutation that confers penicillin-resistance excited in the population prior to the bacteria being exposed to penicillin in the experiment

40
Q

what does this provide evidence for?

A

that mutations create random genetic variation that may include the beneficial changes such as antibiotic resistance

41
Q

did the new environment create the beneficial environment?

A

no

42
Q

was the random mutation beneficial in the new environment?

A

yes

43
Q

how often do spontaneous and induced mutations occur?

A

frequently

44
Q

how could this be a problem?

A

if the cell had not evolved some refined mechanism to repair detectable mutations

45
Q

if the mutations are left uncorrected what can it lead to?

A
  • cell death
  • cancer
  • aging
  • disease
46
Q

how else can DNA accrue mutations other than during DNA replication?

A

due to mutagens or agents that can increase the probability of mutations at specific regions along the DNA

47
Q

what can a mutagen include?

A

radiation or chemicals

48
Q

how can most DNA damage be corrected?

A

by specialized repair enzymes of the cell

49
Q

what can DNA ligase do?

A

repair damages in the DNA backbone

50
Q

most cells contain DNA ligase that are involved with what?

A

DNA replication and others that specialize in DNA repair of single stranded breaks

51
Q

how can mismatching of single nucleotide pairs during DNA replication be corrected?

A

by the proofreading capabilities of DNA polymerase

52
Q

what does another proofreading mechanism allow?

A

scanning of the DNA for potential mismatches as a second level quality control in DNA

53
Q

what does a mismatched nucleotide pair create?

A

a kink in the DNA molecule

54
Q

what is this kink recognized by?

A

proteins that scan the DNA for damage and errors

55
Q

what does the identification of a mismatch in the nucleotide sequence lead to?

A

the single stranded cleavage of the mismatched DNA backbone

56
Q

how is this done?

A

by an enzyme some distance away from the mismatched nucleotide region

57
Q

what is the enzyme usually?

A

a DNA cutting enzyme called a nuclease

58
Q

what happens once the correcting nuclease enzyme cuts the backbone?

A

another enzyme is able to remove successive nucleotides from the cut DNA strand, including the mismatched nucleotide

59
Q

what other enzymes are then present?

A

DNA polymerase and DNA ligase

60
Q

what are these enzymes able to do?

A

able to induce DNA synthesis to close the gap

61
Q

what does this create?

A

an intact DNA strand that matches with accurate complementarity to the template DNA strand

62
Q

what does this allow?

A

mismatch repair to be completed

63
Q

what is a more specialized type of repair mechanism?

A

base excision

64
Q

in this mechanism, it is the incorporation of what in DNA that signals that there is a need for DNA repair?

A

incorporation of a Uracil

65
Q

what is Uracil and where is it present?

A
  • is a characteristic nucleotide

- present in RNA molecules

66
Q

what happens if a DNA molecule accidentally incorporates a Uracil into their elongating strands?

A

the actual presence of Uracil is a signal that is detached by a DNA Uracil gylcosylase enzyme which will cleave the uracil from the sugar DNA backbone itself

67
Q

what is left behind?

A

a bare deoxyribose sugar with no attached nitrogenous base

68
Q

what enzyme detects the lack of a nitrogenous base?

A

enzyme called AP endonuclease

69
Q

what does this enzyme do?

A

cleaves the backbone on either side of the area that lacks a base

70
Q

what is left?

A

an open gap

71
Q

what does this gap require?

A

addition of a completely new nucleotide

72
Q

what can now occur at the gap site?

A

DNA synthesis

73
Q

what enzymes facilitate the DNA synthesis?

A

DNA polymerase and DNA ligase

74
Q

what does this allow?

A

addition of a new and properly matched nucleotide base that is a complementary base to the template strand

75
Q

what is another mechanism of DNA repair?

A

Nucleotide excision repair

76
Q

what mechanism does it resemble?

A

the mismatch repair mechanism

77
Q

mismatch repair corrects how many nucleotide pair mismatches?

A

one

78
Q

how many mismatch paris does nucleotide excision repair correct?

A

can remove and replace more than one damaged nucleotide bases

79
Q

what do the damaged bases do?

A

signal to specific enzymes to cleave the DNA backbone on either side or flanking the region of damaged or mismatched bases

80
Q

what happens after removal?

A

DNA synthesis is able to completely fill the excised gap with correctly matched and complementary nucleotides to the template strand

81
Q

are there various types of mutations that escape repair and can be found in our genome?

A

yes

82
Q

what types of mutations can appear?

A

small point mutations or larger scale mutations

83
Q

what are small point mutations

A

involve signal nucleotide pair changes in a DNA sequence

84
Q

what are larger scale mutations?

A

involve changes in large regions of chromosomes

85
Q

when can small scale point mutations arise?

A

during DNA replication

86
Q

which mutations are able to become a permanent change in our genome?

A

mutations that escape the proofreading mechanism of DNA replication

87
Q

what is the most common type of point mutation?

A

single nucleotide pair substitution

88
Q

what is this?

A

where only one base pair is incorrectly replaced by another pair of nucleotides

89
Q

what are these variations also known as?

A

single nucleotide polymorphisms SNPs

Biology 1A03 (5 decks)

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