Brainscape's Knowledge GenomeTM

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


See full index

Genetics > Genetics Test 2 > Flashcards

Genetics Test 2 Flashcards

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

What is Denaturation?

A

Loss of native configuration of a macromolecule, usually accompanied by loss of biological activity.
Denatured proteins often unfold their polypeptide chains and express changed properties of solubility.

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

What is Renaturation?

A

If the complementary single strands of DNA are cooled slowly, they find each other and re-form base-paired double helices

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

What does the rate of renaturation depend on

A

-Complexity of the sequence
-Concentrations of the renaturing DNA sequences (amount)

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

In a sample of genomic DNA from an organism, what DNA sequences are more concentrated? Why?

A

The repetitive DNA sequences are relatively more concentrated than the unique DNA sequences
Because they are present many times over; consequently, the repetitive sequences
re-form duplex molecules at a faster rate than the unique DNA sequences.

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

What is the degree of repetition called?

A

copy number

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

How many complex copies can be found in the prokaryotes genome?

A

1 copy

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

How many complex (unique) copies can be found in a eukaryote genome? # and %

A

1-10 copies (30-85%)

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

How many moderately repetitive copies can be found in a eukaryotic genome?

A

10-10^5
5-80%

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

How many highly repetitive copies can be found in a eukaryotic genome

A

> 10^5
50%

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

What do the moderately repetitive copies in a genome do?

A

-ribosomal proteins
-help in the cytoskeleton as actin or myosin
-transposable elements (make up 44% of the genome)

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

What do the highly repetitive copies in a genome do?

A

-are usually the functioning regions such as on centromeres and telomeres
-used for protection of DNA (non-coding)
-used for structurization and recombination

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

What are transposable elements?

A

LINES

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

What are LINES

A

They are non long terminal repeats which help with protection of the sequencing

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

What does LINES stand for?

A

-Stands for long interspersed nuclear elements

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

How many base pairs are in LINES?
How much of the genome do they make up?

A

-6-10 kb (6000-10,000 base pairs)
-20%

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

What are the subdivision of LINES

A

L1
L2
L3

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

What does L1 do?

A

-L1 is only active in mammals
-they have an internal promoter that is
recognized by RNA polymerase II
-they have two open reading frames: ORF1 and ORF2

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

What is the size of L1

A

-6 kb in size (6000 base pairs)

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

How many L1 can be found in the human genome

A

3000 and 5000 complete L1 elements

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

What is ORF1 and ORF2

A

-ORF1 encodes a nucleic acid-binding protein
-ORF2, which encodes a protein with endonuclease and reverse transcriptase activities

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

What happens in L1 transposition?

A

L1 transposition involves the transcription of a complete L1 element into RNA
and the reverse transcription of this RNA into DNA

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

Where does L1 transposition occur

A

Both processes take place in the nucleus

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

What happens before the L1 RNA is reverse transcribed

A

it journeys to the cytoplasm where it is translated into polypeptides that remain associated with it when it returns to the nucleus

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

What does the polypeptide encoded by ORF2 possess?

A

possesses an endonuclease function that catalyzes cleavage of one strand of the DNA
duplex at a prospective insertion site in a chromosome

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

What does the exposed 3′ end of the cleaved DNA strand serve as during transposition?

A

Serves as a primer for DNA synthesis using the L1 RNA as a template and the reverse transcriptase activity provided by the ORF2 polypeptide

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

How many copies of L2 and L3 do humans have?

A

L2= 315,000 copies
L3=37,000 copies
Both are inactive

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

What does SINES stand for?

A

short interspersed nuclear elements

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

How much of the genome do SINES make up?

A

13%
Second most abundant behind LINES

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

What do all retroposons have?

A

they have a sequence of A:T base pairs at one end

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

What do SINES do?

A

-transpose through a process that involves reverse transcription of an RNA that has been transcribed by RNA polymerase III from an internal promoter.
-do not code for anything; but good at moving things

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

What do SINES use as their reverse transcriptase?

A

the reverse transcriptase needed for
the synthesis of DNA from the SINE RNA is furnished by a LINE-type element

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

True or False.
SINES rely on the LINES to multiply and insert within the genome.

A

True

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

What is the only transpositionally active element found in SINES

A

Alu elements

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

What are Cut and Paste transposons?

A

-3% of genome
-not active

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

What are the 4 basic types of transposable elements found in the human genome?

A

LINEs,
SINEs,
retroviruslike elements
cut-and-paste transposons

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

True or False.
L1 LINE and the Alu SINE are the only transpositionally active transposons.

A

True

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

What do transposons have the ability to do?

A

the ability to change position in the genome—that is, they are mobile.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What percentage of the human genome is transposable?

A

44%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

The coding region of a retroviruslike elements contain a small number of genes.
What are these three genes?
What do they code for?

A

gag=encodes a structural
protein of the virus capsule (glycoprotein)

pol= encodes a reverse transcriptase/
integrase protein (polymerase)

env=encodes a protein component of the virus envelope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What does LTR stand for?

A

long terminal repeats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What do LTRs do?

A

They are required for integration of the viral genome into the DNA of the host cell.

The initiation site for transcription of the viral genome.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What do you want in a centromere?

A

-Attachment and separation
-A-T rich (easily breakable)
-high copy number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

At what stage do sister chromatids of the duplicated chromosome move to the opposite poles of a cell?

A

anaphase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

The movement of sister chromatids to opposite poles depends on what?

A

This movement depends on the
attachment of spindle microtubules to the kinetochores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What are kinetochores

A

Complex protein structures associated with the centromeres of each of the sister chromatids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is a key step in the transition from metaphase to anaphase?

A

The production of two functional centromeres

46
Q

How many copies of alpha satellite sequences do humans have? (repeats)

A

5000 to 15,000 copies of a 171 base-pair-long sequence called the alpha satellite sequence (repeats)

47
Q

How big is an alpha satellite region in humans?

A

40 nm or 110 nucleotides long

48
Q

What is heterochromatin?

A

Chromatin staining darkly even during interphase, often containing repetitive DNA with few genes.

49
Q

What is euchromatin?

A

Genetic material that is not stained so intensely by certain dyes during interphase and that comprises many different kinds of genes

50
Q

What is CENP-A

A

A protein variant of histone H3

51
Q

What are the ends of chromosomes called?

A

telomeres

52
Q

What does CENP-A do?

A

-binds to the centromeres of eukaryotes
-even to the small centromeres of yeast
-helps with kinetochore formation
-helps with left hand assembly of DNA

53
Q

What are the 3 important functions of telomeres?

A

-They prevent dioxyribonucleases from degrading the ends of linear DNA molecules
-They prevent fusion of the ends with other DNA molecules
-They facilitate the replication of these ends without the loss of material

54
Q

Where would you find the sequence.
What is it?
5′ TTAGGG 3′

A

-The telomeres of eukaryotic chromosomes
-A short nucleotide sequence present as a tandem repeat
-Most frequently observed

55
Q

In a normal human cell, how many tandem repreats are found on a telomere?

A

-500 to 3000 TTAGGG repeats and gradually shorten with age.

56
Q

True or False.
Telomeres of germ-line cells and cancer cells shorten with age.

A

False.
Telomeres of germ-line cells and cancer cells do not shorten with age.

57
Q

How do most telomeres terminate?

A

With a G-rich single-stranded region in the DNA strand with the 3′ end (a so-called 3′ overhang)

58
Q

What is a t-loop?

A

The single strand at the 3′ terminus invades an upstream telomeric repeat (TTAGGG in mammals) and pairs with the complementary strand, displacing the
equivalent strand

59
Q

What does shelterin do in the t-loop process that effects DNA

A

The DNA in these t-loops is protected from degradation and/or modification by DNA repair processes

60
Q

What is Shelterin?

A

telomere-specific protein complex

61
Q

What are the 6 different proteins found in Shelterin?

A

-TRF1
-TRF2
-POT1
-TIN2
-TPP1
-RAP1

62
Q

What is common to all methods involving probe binding to complementary sequences?

A

The use of hybridization probes that are linked to fluorescent dyes or antibodies
tagged with fluorescent compounds

63
Q

What does colchicine do?

A

It is known that colchicine binds to microtubules and prevents the formation of functional spindle fibers. As a result, daughter chromosomes do not undergo their normal anaphase separation.

64
Q

What is the function of Autoradiography?

A

Autoradiography is a method for detecting and localizing radioactive isotopes in cytological preparations or macromolecules by exposure to a photographic emulsion that is sensitive to low-energy radiation

65
Q

Where is Thymidine found?

A

Thymidine is incorporated almost exclusively into DNA;

66
Q

What is the single origin of replication in e. coli chromosomes?

A

oriC (245 bp)

67
Q

What conserved component of e. coli causes the replication bubble

A

One 13-bp sequence is present as three tandem repeats. These three repeats are rich in A:T base pairs, facilitating the formation of a localized region of strand separation referred to as the replication bubble.

68
Q

What is another conserved component of e. coli that causes the binding of proteins in order to create the replication bubble

A

9-bp sequence that is repeated four times and is interspersed with other non random sequences

69
Q

How many proteins bind due to the 9-bp sequence in e. coli?

A

4

70
Q

What is cooperative binding

A

-a few bind, causing more to bind because of it
-causes stabalization

71
Q

What proteins are the key to unwinding the origin of replication, noting the order of assembly?

A

The DnaA protein appears to be largely responsible for the localized strand separation at oriC during the initiation process.

72
Q

In what direction can DNA polymerase add nucleotides onto a strand of DNA

A

They can only add nucleotides onto the 3′ end of a DNA strand—that is, they
synthesize DNA only in the 5′ to 3′ direction

73
Q

What does DNA ligase do

A

an important enzyme that seals single-strand breaks in DNA double helices

74
Q

True or False.
The replication of prokaryotes is unidirectional

A

false.
The replication of e.coli is bidirectional

75
Q

What is satellite DNA? What is it made up of?

A

It is repetitive DNA sequences.
It a DNA made up from G-C rich or A-T rich sequences.

76
Q

Where is moderately repetitive DNA found? What can they do?

A

They are found in the arms of a chromosome; some in tandem arrays while others occupy dispersed sites.
They are mobile; they move in the genome

77
Q

What is a key step in the transition from metaphase and anaphase?

A

The production of two functional centromeres

78
Q

What happens if a chromosome or chromosome fragment lacks a centromere?

A

It dies during cell division

79
Q

What does flanking mean?

A

refers to the nucleotide sequences adjacent to a specific DNA sequence of interest. Flanking sequences can be found on either side of the target sequence and are typically used as reference points or landmarks

80
Q

What is heterochromatin Protein 1 (HP1) and what does it do?

A

A protein associated with centromeric heterochromatin and may be involved with the packaging of DNA of the centromeric heterochromatin

81
Q

What does “Pericentric Heterochromatin” mean?

A

It is the heterochromatin which is flanking the centromere (beside the centromere)

82
Q

What does the Pericentric Heterchromatin consist of?

A

mainly of repetitive, nongenic DNA;does contain some genes

83
Q

What are the three functions of telomeres

A
  1. Prevent DNase from degrading the ends of linear DNA molecules
    2.Prevent fusion of the ends of other DNA molecules
    3.They facilitate the replication of ends (without the loss of material) rep. ends
84
Q

How long is the average “overhang” in humans

A

50-500 bases

85
Q

What do telomeres usually terminate with? (sequence)

A

a G-rich single stranded region in the DNA strand with the 3’ end (3’ overhang)

86
Q

What is the point of the t-loop

A

To help stop degradation of the strand and/or modification of DNA repair processes by shelterin

87
Q

What is the job of DNA ligase?

A

It seals single stranded breaks in DNA double helices

88
Q

What is DNA ligase used for in ALL organisms?

A
  1. DNA replication
  2. DNA repair
  3. Recombination between DNA molecules
89
Q

What converts the phage lambda chromosome from its hydrogen bonded form to its covalently bonded form?

A

DNA Ligase

90
Q

What is the first thing that occurs when a lambda chromosome is injected into a host cell?

A

It forms a covalently closed circular molecule

91
Q

How is e. coli DNA coiled?

A

it is negatively supercoiled

92
Q

What is needed for DNA replication to occur in e.coli?

A

DNA gyrase activity

93
Q

What is considered the “replicase” in e.coli?

A

DNA Polymerase III

94
Q

The initiation of the okazaki fragments on the lagging strand is carried out by what?

A

primosome

95
Q

What is a Primosome

A

a protein complex containing DNA primase and DNA helicase (works by ATP)

96
Q

What does a primosome do?

A

It unwinds the DNA and DNA primase synthesises the RNA primers needed for the attachment of okazaki fragments

97
Q

How are the RNA primers extended in e.coli?

A

They are covalently extended with the addition of deoxyribonucleotides by DNA pol III

98
Q

what is apart of the replisome of DNA polymerase III in e.coli

A
  1. DNA polymerase III holoenzyme
  2. 2 Catalytic cores (one does the leading and one does the lagging strand)
  3. The primosome unwinds the DNA + synthesis of RNA primers
99
Q

How is a change in the conformation of PCNA achieved?

A

Rf-C induces a change in the conformation of PCNA that allows it to encircle DNA, providing the essential sliding clamp

100
Q
A
101
Q

At what stage are histones created

A

during s phase

102
Q

what occurs in g1 and g2 of mitosis

A

protein synthesis

103
Q

What does NAP-1 do

A

it transports histones from their site of synthesis into the cytoplasm to the nucleus

104
Q

What does CAF-1 do

A

it carries them to the sites of replication by binding to PCNA clamps that tether DNA polymerase delta to the DNA template

105
Q

What are NAP-1 and CAF-1 apart of

A

the disassembly and assembly of nucleosomes during chromosome replication in eukaryotes

106
Q

What do NAP-1 and CAF-1 stand for?

A

-Nucleosome assembly protein 1
-chromatin assembly factor 1

107
Q

What is used to slow down the process of telomere shortening?

A

telomerase

108
Q

What does telomerase do?

A

-it recognizes the g rich overhang and extends it 5’-3’ one repeat at a time
-it extends the 3’ end of the template strand

109
Q

where does translation occur?

A

ribosomes

110
Q

what is an intron?

A

non coding sequences

111
Q

what do introns do?

A

they separate the expressed sequences or exons of the genes

112
Q

In strand selection, there is a template strand and a non-template strand, what is the m-RNA (sense strand) the same as (minus an adjustment)

A

the non-template strand; however, the T’s are switched to U’s

Genetics (9 decks)

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