Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry Exam 2 > Leys Material > Flashcards

Leys Material Flashcards

1
Q

Cells acquire nucleotides through what two processes?

A

De novo synthesis and salvage pathway

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

De novo synthesis of purines results in what?

A

Synthesis of inosine that can be converted into adenosine and guanosine

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

Atoms in newly synthesized purines are derived from what sources? (3)

A

Amino acids aspartate, glutamine, and glycine, methyl groups supplied by folic acid, and carbon dioxide

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

What two things regulate the de novo synthesis of purines at multiple points in the pathway?

A

ADP and GDP

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

Hypoxanthine and guanine can be recycled through the salvage pathway with what enzyme?

A

Hypoxanthine guanine phosphoribosyl transferase (HGPRT)

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

Xanthine oxidase catalyzes a hydroxylase type reaction leading to the formation of what?

A

Uric acid that can be excreted

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

What is the main cause of gout?

A

Excess uric acid

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

What are two main reasons one would have excess uric acid in their system?

A

Excess production or low levels of secretion

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

Crystallization of Sodium urate in the joints leads to what?

A

A localized inflammatory response

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

What is used to treat gout? Hint, it is a purine analog.

A

Allopurinol, that hint didn’t help at all did it…

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

What does allopurinol do during treatment?

A

This is used to treat gout and does so by inhibiting xanthine oxidase which prevents the formation of uric acid.

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

A HGPRT deficiency causes what syndrome?

A

Lesch-Nyhan syndrome that results in severe retardation, crippling gouty arthritis and self-mutilation

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

Lesch-Nyhan occurs in what sex and why?

A

Males only because the HGPRT gene is located on the X chromosome

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

The breakdown of purines can replenish intermediates used in what cycle?

A

TCA, through the production of fumarate

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

The atoms in a purine ring are derived from what?

A

Aspartate and carbamoyl phosphate

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

The first 3 enzymes in the synthesis of pyrimidines are located on the same protein which is what?

A

CAD protein

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

What pyrimidines can be interconverted?

A

U and C

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

dUMP is converted to TMP by what enzyme and what does it do?

A

Thymidylate synthase, an enzyme requiring the transfer of a methyl group from tetrahydrofolate

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

Inhibitors of tetrahydrofolate production are used as therapeutic agents for treating what?

A

Cancer and bacterial infections

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

Fluro substituted pyrimidine analogs that inhibit thymidylate synthase are used to as what?

A

Anticancer agents

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

Ribonucleotide reductase converts ribonucleotides to what?

A

Deoxyribonucleotides

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

What are the base pairs in DNA and RNA?

A

DNA: A-T; G-C
RNA: A-U; G-C

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

Homologous regions of DNA can be compared among different species to determine what?

A

Phylogenetic relationships

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

Closely related organisms contain similar DNA compliments, so what is the main genetic difference between them?

A

They are often arranged differently on the chromosomes of each species

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

The living world is made up of what 3 divisions, or domains?

A

Bacteria, archaea and eukaryotes

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

What are the 4 main processes for generating change in a genome?

A

Intragenic mutation (single base change), gene duplication, DNA segment shuffling, horizontal transfer (from one cell to another).

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

Bacterial genes are usually clustered into groups called what?

A

Operons, that are then transcribed as a single unit

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

What are the noncoding parts of DNA called?

A

Introns

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

What are the coding parts of DNA called?

A

Exons

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

In a comparison of the same gene in several closely related species will the exons and introns be similar?

A

The exons will generally be very similar (conserved) but the introns will vary in size and content

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

Do bacterial genes have non coding portions?

A

No, it is very dense with coding information

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

Is most of the DNA in higher eukaryotes coding or noncoding?

A

Noncoding, most of the genome is repeated sequences that are mobile elements that can move around in the genome

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

Describe the general shape of bacterial chromosomes and eukaryotic chromosomes?

A

Bacterial is circular and eukaryotic is linear

34
Q

Can metabolic pathways between organisms be compared through their genome?

A

Yes

35
Q

Genes can be grouped into families based on what?

A

Similar (homologous) sequences found in different organisms

36
Q

The phylogenetic relationships of different organisms can be compared by comparing what?

A

The DNA sequence of similar genes in the two organisms

37
Q

What is the DNA dependent (uses DNA as a template) DNA synthesizing enzyme?

A

DNA polymerase

38
Q

Is RNA polymerase DNA or RNA dependent?

A

DNA

39
Q

What does RNA polymerase synthesize?

A

RNA

40
Q

What is reverse transcriptase?

A

An RNA dependent DNA synthesizing enzyme

41
Q

What is primase?

A

A DNA dependent RNA polymerase

42
Q

What does primase do?

A

Primase synthesizes a small RNA “primer” that can be used by the DNA polymerase to elongate the chain

43
Q

DNA polymerase minimizes the number of mistakes (mis-incorporated nucleotides) by doing what?

A

Using a 3’ to 5’ exonuclease (or proofreading) activity that is part of the same protein

44
Q

DNA polymerase as well as all other nucleic acid polymerases synthesize DNA in what direction only?

A

5’-3’

45
Q

The base component of each nucleotide is connected to the sugar at what carbon?

A

1’ carbon

46
Q

What carbon differs between DNA and RNA?

A

2’ carbon

47
Q

Bacterial chromosomes contain how many origins of replication?

A

One

48
Q

In bacteria, can new rounds of DNA replication begin before the previous round is completed?

A

No

49
Q

Eukaryotes contain how many origins of replication?

A

Many, and they may change during teh development of the organism

50
Q

In eukaryotes, each entire chromosome is replicated how many times during each cell division?

A

Only once

51
Q

During replication, when can new round of eukaryotic replication begin?

A

Until after the cell divides

52
Q

What are the special structures that are placed at the end of linear eukaryotic chromosomes?

A

Telomeres

53
Q

Telomeres are constructed with what enzyme?

A

Telomerase

54
Q

How does telomerase work?

A

Uses an RNA template to synthesize a short repeated DNA sequence at the ends of chromosomes

55
Q

What unwinds (separates) the 2 DNA strands before polymerization of the new strands?

A

Helicase

56
Q

What do single stranded binding proteins do?

A

Keeps single strands of DNA from reforming a double helix

57
Q

The polymerase on the leading strand moves (1)________ the replication fork and the polymerase on the lagging strand moves (2)_____ from it.

A

(1) toward

(2) away

58
Q

The lagging strand is synthesized in short fragments called what?

A

Okazaki fragments

59
Q

What initiates the synthesis of each Okazaki fragments?

A

Primase

60
Q

Which DNA strand is created continuously?

A

The leading strand

61
Q

What on the DNA signals that the DNA is unreplicated and is ready to be used as a template for the next round of synthesis?

A

Methylation

62
Q

New or modified genes can be generated by one or a combination of what 4 events?

A

1) point mutations in the coding region that change the amino acid composition of the protein.
2) duplication of the entire gene.
3) Mixing of segments of one gene with segments of another gene – segment shuffling.
4) Acquisition of new activities by transfer of genes between two organisms -horizontal gene transfer

63
Q

Breaks in the DNA (especially double stranded breaks) facilitate the initiation of what?

A

Recombination

64
Q

A defect in DNA ligase, that affects joining together of adjacent segment of DNA on a chromosome, can cause what?

A

Abnormal amounts of recombination

65
Q

What is the definition of genetic recombination?

A

The reciprocal exchange of genetic information

66
Q

Recombination can be the result of what 4 things?

A

1) reciprocal exchange during cell division. 2) DNA damage, e.g. X-ray damage.
3) Introduction of foreign DNA.
4) Programmed recombination during the development or maturation of a cell type, e.g. antibody producing genes during B-cell maturation

67
Q

What is gene conversion?

A

It is the non-reciprocal exchange of genetic information

68
Q

Recombination between direct repeated sequences on the same chromosome causes what?

A

The loss of DNA that was between the two repeated segments

69
Q

Circular DNA can be inserted in a chromosome by what method?

A

By recombination between a region on of circular molecule and an homologous region on the chromosome

70
Q

X-rays and other agents that cause breaks in DNA induce what?

A

Recombination

71
Q

Transposable elements are found in what species?

A

All

72
Q

What do transposable elements do?

A

Move from one location in the DNA to another location within that cell

73
Q

Transposable elements can cause changes in the DNA specifically where?

A

At the site of insertion

74
Q

What are two major types of transposable elements?

A

One type that contains inverted repeated sequences at the ends and causes a short region of the genome to be duplicated at the site of insertion and a second type that is structurally similar to a retrovirus and transposes through an RNA intermediate

75
Q

Unequal crossing-over is recombination that resulted from what?

A

Imprecise pairing of tandemly repeated sequences

76
Q

Unequal crossing over results in what?

A

Loss or gain of gene copies

77
Q

What are the two types of mutations?

A

DNA rearrangements and base substitutions

78
Q

What are the two outcomes when there is damage to a nucleotide?

A

Can either be repaired or lead to a permanent mutation

79
Q

Mutations can be caused by what?

A

Errors during replication or by injury to the DNA from chemicals or radiation

80
Q

What percent of every genome is made up of segmental duplications or large regions of DNA that are present in more than one copy

A

A small percent, 3%

81
Q

Gene amplification can result in what?

A

Resistance to drugs, transformation into cancerous cells or other changes in the cell phenotype

Biochemistry Exam 2 (1 decks)

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