test 1 Flashcards
(98 cards)
1
Q
Viral chromosomes exist in a variety of conformations and can be made up of ________.
A
DNA or RNA
2
Q
In E. coli, the genetic material is composed of ________.
A
circular, doublestranded DNA
3
Q
The E. coli chromosome is circular and doublestranded DNA.
A
true
4
Q
Viral genomes are always linear, doublestranded DNA.
A
false
5
Q
what makes up the protein component of a nucleosome?
A
two tetramers of histone proteins
6
Q
what is the first order of chromatin packing?
A
coiling around nucleosomes
7
Q
the second order of chromatin packing occurs when nucleosomes coil together to form a fiber that is 300nm in diameter
A
false
8
Q
what makes up the protein component of a nucleosome?
A
two tetramers of histone proteins
9
Q
Each human contains an identical set of VNTRs
A
false
10
Q
which is not an example of repetitive dna?
A
telomerase gene DNA
11
Q
what is true about heterochromatin
A
have relatively few genes, remain relatively condensed during the cell cycle, is found in the telomeres and centromere
12
Q
TATAGCGTAGCTAGCT repeated in tandem over and over is a gene sequence that codes for a protein.
A
false
13
Q
LINES and SINES are repetitive sequences that make up about _________ percent of the human genome.
A
~ 35%
14
Q
CGCGCGCGCGCGCGCGCGCGCGCGCGCG represents a sequence we wouldl categorize as a:
A
short tandem repeat (SINE)
15
Q
A sequence of about 300 base pairs is found at different locations on many different chromosomes in the genome. The sequence shows up about 550,000 times in the genome. This illustrates a:
A
SINE
16
Q
In humans, it appears that the 20,000 functional genes occupy less than ______ of the human genome.
A
2%
17
Q
What are examples of heterochromatin?
A
centromeric DNA, repetitive DNA, telomeric DNA
18
Q
Chromatin is made of
A
DNA and proteins
19
Q
Which of the following have circular chromosomes made of doublestranded DNA?
A
chloroplasts, prokaryotes, mitochondria.
20
Q
Living organisms are categorized into two major groups based on the presence or absence of a nucleus. What group is defined by the presence of a nucleus?
A
eukaryotic organisms
21
Q
The relationship between a gene and a messenger RNA is that ________.
A
mRNAs are made from genes
22
Q
RNA synthesis from a DNA template is called __________.
A
transcription
23
Q
It has been recently determined that the gene for Duchenne muscular dystrophy (DMD) is more than 2000 kb (kilobases) in length; however, the mRNA produced by this gene is only about 14 kb long. What is a likely cause of this discrepancy?
A
The introns have been spliced out during mRNA processing.
24
Q
An intron is a section of an RNA that gets spliced out.
A
true
25
The promoter is bound by which enzyme?
RNA polymerase
26
What is the process of synthesizing proteins from mRNA sequences?
translation
27
What kind of bond is formed between successive amino acids during translation?
peptide bond
28
What does the central dogma of biology describe?
The fact that hereditary information flows from DNA through RNA to proteins, which form the functional products of genes
29
What is a promoter?
A DNA sequence that specifies the start site for transcription
30
The genetic code consists of a total of how many different codons?
64
31
What is the relationship and sequence correspondence of the RNA transcript and the DNA template strand with respect to transcription?
- The template DNA strand and the RNA transcript are complementary.
- The template DNA strand and the RNA transcript are antiparallel to each other.
32
What is the relationship and sequence correspondence of the mRNA transcript to the DNA coding strand?
- The coding DNA strand and the RNA transcript are identical, except that thymidine nucleotides in the DNA are uridine nucleotides in corresponding sites of the mRNA transcript.
- The coding DNA strand and the RNA transcript are parallel to each other.
33
During translation, what molecule bears the anticodon?
tRNA
34
The codon?
mRNA
35
Introns are known to contain termination codons (UAA, UGA, or UAG), yet these codons do not interrupt the coding of a particular protein. Why?
Introns are removed from mRNA before translation.
36
The triplet AUG is commonly used as a start codon during translation.
true
37
You should have watched, the Biology of skin color, https://www.hhmi.org/biointeractive/biology-skin-color
A person with very dark skin has a great deal of:
eumelanin
38
What is the major reason humans have melanin?
To protect folate from being broken down.
39
High UV intensity at equators and high altitude correlates with
dark skin
40
Light skin is an adaptation to
absorb UVB and make vitamin D
41
Who is most likely to be vitamin D deficient? (Assume equal amount of time in the sun)
A dark skinned individual living in Canada
42
At a particular location in the human genome is the sequence AATGGAGTC on one of the chromosomes. This sequence occurs in about 75% of the population.
Choose any of the following that is an example of a SNP in the population.
- AATGGAGTT
| - AATAGAGTC
43
A single SNP is often not telling, but looking at the combination of multiple SNPs, or a ______________ is often more informative when determining if there is an association with a SNP and a response to medication.
haplotype
44
A linked SNP is
is located outside of a gene
| does not affect protein production or function
45
True or False?
If a person had results from a direct to consumer (DTC) test that they did not understand, the majority of Americans would consult their primary doctor to get answers.
true
46
Many physicians are not adequately trained to appropriately order or interpret and communicate results from
even single-gene tests, let alone tests incorporating the full genome.
true
47
All EXCEPT which of the following are characteristics of the genetic material?
It is composed of protein.
48
What observation did Griffith make in his experiments with Streptococcus pneumoniae?
The mouse did not survive when injected with a mixture of live, avirulent (rough) Streptococcus pneumoniae and heat-killed, virulent Streptococcus pneumoniae.
49
The classic Hershey and Chase (1952) experiment that offered evidence in support of DNA being the genetic material in bacteriophages made use of which of the following labeled component(s)?
phosphorus and sulfur
50
The Hershey and Chase experiments involved the preparation of two different types of radioactively labeled phage. Which of the following best explains why two preparations were required?
It was necessary that each of the two phage components, DNA and protein, be identifiable upon recovery at the end of the experiment.
51
Which of the following statements best represents the central conclusion of the Hershey-Chase experiments?
DNA is the identity of the hereditary material in phage T2.
52
Which of the following outcomes would be most likely if the Hershey-Chase experiments were repeated without the step involving the blender?
Both preparations of infected bacteria would exhibit radioactivity.
53
DNA has no sulfur, and proteins have no phosphorus.
true
54
Reverse transcriptase is an enzyme found in association with retroviral activity. It has the property of ________.
synthesis of DNA from an RNA template
55
G and C are present in both DNA and RNA.
true
56
If 15% of the nitrogenous bases in a sample of DNA from a particular organism is thymine, what percentage should be cytosine?
35%
57
In an analysis of the nucleotide composition of double-stranded DNA to see which bases are equivalent in concentration, which of the following would be true?
A + C = G + T
58
When considering the structure of DNA, we would say that complementary strands are antiparallel.
TRUE
59
Guanine and adenine are purines found in DNA.
TRUE
60
Which of the following statements about DNA structure is true?
The nucleic acid strands in a DNA molecule are oriented antiparallel to each other, meaning they run in opposite directions.
61
What is the complementary DNA sequence to 5′ ATGCTTGACTG 3′?
5′ CAGTCAAGCAT 3′
62
RNA differs from DNA in all EXCEPT which of the following ways?
the 5'-3' orientation of the polynucleotide strand
63
1. ____is the process that leads to the production of identical copies of the existing genetic information.
2. ___ is the processing of genetic information that results in synthesis of proteins which contribute to the phenotype of the organism.
3. The genetic material must be stable enough to maintain information in ___ from one cell to the next and one organism to the next.
4. ___ is the random variation of genetic material that provides the basis for evolution.
1. Replication
2. Expression
3. storage
4. Mutation
64
When Avery and his colleagues had obtained the transforming factor from the IIIS virulent cells, they treated the fraction with proteases, ribonuclease, and deoxyribonuclease, followed by the assay for retention or loss of transforming ability.
What was the purpose of these experiments?
To determine the exact molecular species of the "transforming principle"
65
What was the result? What conclusions were drawn?
The DNA was proven to be the "transforming principle".
| Treatment with deoxyribonuclease resulted in the loss of transforming ability.
66
What is the physical state of DNA after being denatured by heat?
single- stranded
67
Why is Tm related to base composition?
The more hydrogen bonds between bases, the higher the temperature needed to separate the pair.
68
The S strain of the pneumococcal bacteria is virulent and kills mice. When the S strain is heat-killed, it is no longer virulent and doesn't kill mice. The R strain is non-virulent. However, when the heat-killed S strain is mixed with the live R strain, a transformed virulent R strain is created. What conclusion(s) could Griffith draw from his experiment? Select all that apply.
A transforming factor from a virulent strain of bacteria can make a non-virulent strain virulent.
69
In general, DNA replicates semiconservatively and bidirectionally.
true
70
In the Meselson-Stahl experiment, which mode of replication was eliminated based on data derived after one generation of replication?
conservative
71
Which statement explains why 14N-DNA and 15N-DNA form bands at different positions after density-gradient centrifugation?
14N has 7 protons and 7 neutrons, whereas 15N has 7 protons and 8 neutrons. Therefore, 15N has a greater atomic mass, making 15N-DNA denser than 14N-DNA.
72
The data obtained from the Meselson–Stahl experiment after one generation of replication eliminated the dispersive model of DNA replication.
false
73
Which enzyme catalyzes the addition of nucleotides to a growing DNA chain?
DNA polymerase
74
Which of the following statements about DNA replication is true?
Single‑strand binding proteins stabilize the open conformation of the unwound DNA.
75
DNA strand replication begins with an RNA primer.
true
76
the discontinuous aspect of replication of DNA in vivo is caused by _______
the 5' to 3' polarity restrictions
77
Which of the following statements about DNA replication is true?
DNA synthesis is continuous on the leading strand and discontinuous on the lagging strand.
78
Which three steps constitute a PCR cycle?
denaturation, annealing, and extension
79
All EXCEPT which of the following differentiates eukaryotic chromosomes from chromosomes found in prokaryotes
In eukaryotes and prokaryotes, there is one origin of replication per chromosomes
80
All EXCEPT which of the following are related to telomeres
found in eukaryotes and prokaryotes
81
Which three steps constitute a single PCR cycle?
denaturation, annealing, and extension
82
In a typical PCR, primers are used to cleave specific regions of the DNA template.
False
83
During a PCR, heat is provided to inactivate the polymerase enzyme.
false
84
In a PCR, primers are complementary to stretches of DNA with which they anneal.
true
85
A ____ mutation leads to early termination of protein synthesis.
nonsense
86
Protein synthesis ends when a stop ____ is produced
codon
87
A change in any triplet of bases in the mRNA sequence may or may not affect the coding of a(n) ____ and change the structure of the synthesized protein.
amino acid
88
A ____ mutation results in the insertion of the same amino acid as was coded for by the original nucleotide sequence.
silent
89
Base substitution mutations alter a(n)____ in the original DNA sequence
nucleotide
90
A ____ mutation can dramatically alter protein structure because it results in the insertion of a different amino acid than was coded for by the original nucleotide sequence.
missense
91
Generally speaking, which of the following mutations would most severely affect the protein coded for by a gene?
a frameshift deletion at the beginning of the gene
92
When treating an organism with a mutagen, although it is possible that homozygous mutations will occur, it is more likely that most new mutations will be heterozygous or hemizygous.
true
93
A missense mutation causes premature chain (protein) termination.
false
94
the purpose of the Ames Test is to _______.
test the mutagenic effects of chemicals
95
In the Ames Test, the appearance of his+ revertants in the presence of a non-mutagenic control compound indicates that _______.
some of the reversion mutations are not caused by the mutagen being tested
96
Many chemicals are more mutagenic after being processed in the liver.
true
97
The Ames test is used to determine whether or not a compound causes __________.
gene mutations
98
Why are frameshift mutations likely to be more detrimental than point mutations, in which a single pyrimidine or purine has been substituted?
because they are likely to change more than one amino acid
