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gene Flashcards

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1
Q

What are two ways cells can acquire nucleotides?

A

De novo synthesis & salvage pathways

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2
Q

De novo synthesis of purines can result in the synthesis of ______ that can be converted into _______ & _______

A

Inosine Adenosine & guanosine

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3
Q

What are sources of atoms in a newly synthesized purine?

A

Amino acids: aspartate, glutamine, and glycine, methyl groups from: folic acid and carbon dioxide

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4
Q

_____ & _____ regulate de novo synthesis of purines at multiple points in the pathway

A

ADP and GDP

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5
Q

_____ & _____ can be recycled through the salvage pathway. What is the enzyme involved?

A

Hypoxanthine and guanine HGPRT (hypoxanthine guanine phosphoribosyl transferase)

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6
Q

_____ catalyzes a hydroxylase type reaction leading to the formation of _____ that can be excreted

A

Xanthine oxidase Uric acid

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7
Q

_____ is the cause of gout.

A

excess uric acid

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8
Q

Gout is most often caused by _____ but can also be caused by _____.

A

Low levels of secretion of uric acid Excess production

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9
Q

Crystallization of _____ in the joints leads to a localized inflammatory response.

A

Sodium urate

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10
Q

is used to treat gout. It is a _____ analog. It works by inhibiting _____ to prevent the formation of uric acid

A

Allopurinol Purine Xanthine oxidase

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11
Q

A _____ deficiency causes Lesch-Nyhan Syndrome. What are the effects of this disease?

A

HGPRT Severe retardation, crippling gouty arthritis and self-mutilation

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12
Q

Lesch-Nyhan occurs only in _____. Why?

A

males, HGPRT gene is located on the X chromosome

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13
Q

The breakdown of purines can replenish TCA intermediates through the production of _____.

A

fumarate

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14
Q

The atoms in a pyrimidine ring are derived from _____ & _____

A

Aspartate and carbamoyl phosphate

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15
Q

The first 3 enzymes in the synthesis of pyrimidines are located on _____ number of proteins.

A

One protein (CAD protein)

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16
Q

The pyrimidines _____ & _____ can be interconverted.

A

U and C

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17
Q

_____ is converted to _____ by thymidylate synthase. This enzyme requires the transfer of a methyl group from _____.

A

dUMP TMP tetrahydrofolate

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18
Q

Inhibitors of _____ production are used as therapeutic agents for treating cancer and bacterial infections.

A

tetrahydrofolate

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19
Q

_____ substituted _____ ______ that inhibit thymidylate synthase are used as anticancer agents

A

fluoro; pyrimidine analogs

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20
Q

_____ converts ribonucleotides to deoxyribonucleotides

A

Ribonucleotide reductase

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21
Q

Base pairing in DNA is _____ to _____. In RNA it’s _____ to _____.

A

A-T and G-C A-U and G-C

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22
Q

_____ regions of DNA can be compared among different species to determine phylogenetic relationships

A

homologous

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23
Q

Closely related organisms contain _____ DNA compliments, however they are often arranged _____ on the chromosomes of each species

A

similar; differently

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24
Q

The living world is made up of 3 divisions:

A

Bacteria, archaea and eukaryotes

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25
What are the 4 main processes for generating change in a genome?
Intragenic mutation (single base change) Gene duplication DNA segment shuffling Horizontal transfer (from one cell to another)
26
Bacterial genes are often clustered into groups called an _____ that are transcribed as a \_\_\_\_\_
operon; single unit
27
Eukaryotic genes are often broken up with regions of non-coding DNA called _____ between regions of coding DNA called \_\_\_\_\_
introns; exons
28
In a comparison of the same gene in several closely related species, the _____ will generally be very similar (conserved) while the _____ will vary in size and content.
exons; introns
29
Bacterial chromosomes are densely packed with _____ leaving little room for _____ DNA.
Genes noncoding
30
Most of the DNA in higher eukaryotes, including humans, does not code for \_\_\_\_\_. Most of the human genome is made up of \_\_\_\_\_. Many of these are _____ in the genome.
Proteins Repeated sequences mobile elements (can move around)
31
Bacterial chromosomes are \_\_\_\_\_. Eukaryotic chromosomes are \_\_\_\_\_.
circular; linear
32
In addition to the human genome, the entire genomes of a large number of organisms have been completed including several bacteria that are found in the ____ \_\_\_\_.
oral cavity
33
It is possible to construct ____ \_\_\_\_\_ and compare them with other organisms by examining their entire genome content.
Metabolic pathways
34
Genes can be grouped into families based on _____ sequences found in different organisms.
homologous
35
Homologous sequences can be found in genes of the same organisms that carry out _____ functions. Genes that have similar functions in very distantly related organisms can have \_\_\_\_\_.
Similar but different Homology (similar sequences)
36
The _____ relationships of different organisms can be compared by comparing the DNA sequence of similar genes in the two organisms
phylogenetic
37
DNA polymerase is a _____ dependent DNA synthesizing enzyme.
DNA (uses DNA as a template)
38
RNA Polymerase is a _____ dependent RNA synthesizing enzyme.
DNA (uses DNA as a template)
39
Reverse transcriptase is a _____ dependent DNA synthesizing enzyme.
RNA
40
Primase is a _____ dependent RNA polymerase.
DNA
41
Primase synthesizes a small _____ primer that can be used by _____ polymerase to elongate the chain.
RNA; DNA
42
DNA polymerase minimizes the number of mistakes by using a _____ exonuclease activity that is part of the same protein.
3' to 5'
43
DNA polymerase, as well as all other nucleic acid polymerases, synthesize DNA in the \_\_\_\_\_direction only
5' to 3'
44
During replication, a new nucleotide is added to the _____ on the last nucleotide of the new DNA chain
3’ carbon
45
The base component of each nucleotide is connected to the sugar at the \_\_\_\_\_. The adjacent nucleotides in a DNA chain are attached to the ___ and ___ carbons.
1’ carbon 5’ and 3’
46
In pentose, how are the carbon atoms numbered? How does carbon numbering differ in RNA and DNA?
right to left (counterclockwise) the 2' carbon differs between RNA and DNA
47
DNA polymerase is a _____ enzyme. This means it _____ \_\_\_\_\_ synthesis. Therefore a _____ is required for elongation of a new strand using the DNA polymerase.
An elongating Cannot initiate primer
48
Bacterial chromosomes contain _____ origin(s) of replication.
one
49
Bacterial DNA synthesis proceeds in _____ direction away from the origin until:
Both directions the two replication forks meet at a specific sequence on the other side of the chromosome
50
In bacteria, new rounds of DNA replication begin _____ the previous round is completed.
before
51
Eukaryotic chromosomes contain _____ origin(s) of replication
many
52
In eukaryotes, each chromosome is replicated _____ each cell division. New rounds of replication begin \_\_\_\_\_.
Only once Only after the cell divides
53
Eukaryotic chromosomes are _____ and special structures called _____ are on each end.
linear; telomeres
54
Telomeres are constructed with the enzyme _____ that uses a _____ template to synthesize a short repeated DNA sequence at the ends of chromosomes.
Telomerase RNA
55
Because the polymerase must synthesize new DNA in the __ to ___ direction, two polymerase molecules on opposite strands move _____ from each other.
Away 5’ to 3’
56
\_\_\_\_\_ unwinds the 2 DNA strands before polymerization of the new strands
helicase
57
\_\_\_\_\_ proteins keep the two complementary strands from reforming a double helix
single-stranded binding
58
The polymerase on the leading strand moves _____ the replication fork and the polymerase on the lagging strand moves _____ the fork
toward; away
59
The lagging strand is _____ synthesized What is this called?
Discontinuously; okizaki fragments
60
On the lagging strand, primase initiates synthesis of each _____ by making a short RNA primer
Okazaki fragments
61
The leading strand is synthesized by the _____ movement of the DNA \_\_\_\_\_
continuous; polymerase
62
\_\_\_\_\_ of the DNA signals that the DNA is unreplicated and is ready to be used as a _____ for the next round of synthesis
Methylation template
63
New or modified genes can be generated by one of a combination of 4 events:
Point mutations in the coding region that change the amino acid composition of the protein Duplication of the entire gene Mixing segments of one gene with segments of another gene – segment shuffling Acquisition of new activities by transfer of genes between two organisms – horizontal gene transfer
64
Many genes belong to families that share _____ regions.
homologous
65
Breaks in the DNA facilitate the initiation of \_\_\_\_\_.
recombination
66
A defect in \_\_\_\_\_, that affects joining together of adjacent segments of DNA on a chromosome, can cause abnormal amounts of recombination
DNA ligase
67
Recombination is the _____ \_\_\_\_\_ of genetic information
reciprocal exchange
68
Recombination can be the result of (4):
1. Reciprocal exchange during cell division 2. DNA damage (Xrays) 3. Introduction of foreign DNA 4. Programed recombination during the development or maturation of a cell type (ex. Antibody producing genes during B cell maturation)
69
Gene conversion is the _____ exchange of genetic information
non-reciprocal
70
Recombination between direct repeated sequences on the same chromosome causes the _____ that was between the two repeated segments
loss of DNA
71
Circular DNA can be inserted in a chromosome by recombination between region on a _____ \_\_\_ and a _____ region on the chromosome.
circular molecule; homologous
72
\_\_\_\_\_ and agents that cause _____ in DNA induce recombination.
x-rays; breaks
73
\_\_\_\_\_ _____ are found in all species from bacteria to human
transposable elements
74
Transposable elements move from one location in the DNA to another location \_\_\_\_\_
within the cell
75
Transposable elements can cause changes in the DNA at \_\_\_\_\_
site of insertion
76
What are the 2 major types of transposable elements
1. Contains inverted repeated sequences at the ends and causes a short region of the genome to be duplicated at the site of insertion 2. Structurally similar to a retrovirus and transposes through an RNA intermediate
77
\_\_\_\_\_ _____ is a recombination that resulted from imprecise pairing of tandemly repeated sequences
unequal crossing over
78
Unequal crossing over results in the _____ or _____ of gene copies
Loss or gain
79
What are the 2 types of mutations
DNA rearrangements Base substitutions
80
There are may mechanisms in each cell for _____ DNA
repairing
81
Damage in a nucleotide can lead to _____ or \_\_\_\_\_
repair or permanent mutation
82
What are 2 ways mutations can arise?
Errors during replication Injury to the DNA from chemicals or radiation
83
A small fraction of every genome is made of up _____ \_\_\_\_\_ or large regions of DNA that are present in more than one copy
segmental duplications
84
Duplicated DNA is generated by a process called _____ \_\_\_\_\_
gene amplification
85
Gene amplification can result in 3 scenarios:
1. resistance to drugs 2. transformation into cancerous cells 3. other changes in cell phenotype
86
Several human diseases are due to defects in \_\_\_\_\_
DNA repair enzymes

american lit (6 decks)

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