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1 | |
The transforming agent was identified as DNA by |
| | A) | Griffith. |
| | B) | Avery. |
| | C) | Hershey and Chase. |
| | D) | Watson and Crick. |
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2 | |
If a DNA molecule contains 20% A, approximately what percentage of G is present? |
| | A) | 20% |
| | B) | 40% |
| | C) | 30% |
| | D) | 60% |
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3 | |
DNA replication is |
| | A) | semiconservative. |
| | B) | conservative. |
| | C) | dispersive. |
| | D) | semidispersive. |
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4 | |
In the Meselson and Stahl experiment, what percentage of the DNA is labeled with light nitrogen after three generations of replication. |
| | A) | 25% |
| | B) | 50% |
| | C) | 75% |
| | D) | 100% |
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5 | |
Enzymes called ____ catalyze the formation of covalent bonds that hold together the sugar-phosphate backbone of the DNA molecule. |
| | A) | helicases |
| | B) | DNA polymerases |
| | C) | RNA polymerases |
| | D) | ligases |
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6 | |
Replication proceeds in a ____ to _____ direction. |
| | A) | 3' to 3' |
| | B) | 3' to 5' |
| | C) | 5' to 3' |
| | D) | 5' to 5' |
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7 | |
Which strand below would make the sequence 5' AAACGCTT 3' a double stranded DNA molecule? |
| | A) | 5' TTTGCGAA 3' |
| | B) | 5' UUUGCGUU 3' |
| | C) | 5' AAGCGUUU 3' |
| | D) | 5' AAGCGTTT 3' |
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8 | |
How many DNA bases make up the human genome? |
| | A) | 3 thousand |
| | B) | 3 million |
| | C) | 3 billion |
| | D) | 30 billion |
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9 | |
Considering DNA replication along the 5' to 3' template strand, what event takes place first? |
| | A) | DNA polymerase begins adding RNA nucleotides |
| | B) | DNA polymerase begins adding DNA nucleotides |
| | C) | primase adds an RNA primer |
| | D) | primase removes the 5' phosphate |
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10 | |
If Hershey and Chase found S35 in progeny phages rather than P32, their experiment would have demonstrated that |
| | A) | proteins contain phosphorus. |
| | B) | DNA contains sulfur. |
| | C) | phage DNA enters the host cell. |
| | D) | phage protein enters the host cell. |
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11 | |
DNA structure was proposed by |
| | A) | Griffith. |
| | B) | Chargaff. |
| | C) | Avery. |
| | D) | Watson and Crick. |
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12 | |
Energy is required to break the hydrogen bonds holding the bases together. Which pair will be the most difficult to separate? |
| | A) | A - T |
| | B) | C - G |
| | C) | A - C |
| | D) | G - T |
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13 | |
A scientist isolates a cell line characterized by unusual cell division. In these cells, only small fragments of DNA are found. A defective ____ enzyme may be responsible. |
| | A) | DNA polymerase |
| | B) | ligase |
| | C) | primase |
| | D) | exonuclease |
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14 | |
If a nucleic acid is found to contain 20% A and 20% T, the molecule is probably |
| | A) | single-stranded DNA. |
| | B) | double-stranded DNA. |
| | C) | single-stranded RNA. |
| | D) | double-stranded RNA. |
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15 | |
The number of amplified pieces of DNA equals ____ after five cycles of PCR. |
| | A) | 5 |
| | B) | 10 |
| | C) | 25 |
| | D) | 32 |
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16 | |
Is it possible to use PCR to produce many copies of all DNA of one chromosome? |
| | A) | yes, if the correct primers are available |
| | B) | yes, if the telomeres are present |
| | C) | no, PCR cannot copy DNA, only RNA |
| | D) | no, PCR copies short sequences of DNA only |
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17 | |
If DNA polymerase could add bases in the 3' to 5' direction, there would be no need for |
| | A) | DNA ligase. |
| | B) | Okazaki fragments. |
| | C) | helicase. |
| | D) | PCR. |
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18 | |
Which of the following is not a component of a chromosome? |
| | A) | histone proteins |
| | B) | DNA polymerase |
| | C) | RNA |
| | D) | chromosomes contain all of the above |
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19 | |
PCR requires knowledge about parts of a target DNA sequence to be amplified. True or false? |
| | A) | True |
| | B) | False |
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20 | |
Place in order the following steps involved in PCR:(1) newly synthesized strands act as templates(2) temperature lowered; DNA primers and polymerase added(3) heat separates strands of target DNA(4) complementary base pairing between primers and template(5) DNA nucleotide bases added; new strand synthesized |
| | A) | 1 - 2 - 3 - 4 |
| | B) | 3 - 5 - 4 - 2 - 3 - 1 |
| | C) | 3 - 2 - 4 - 5 - 3 - 1 |
| | D) | 2 - 3 - 4 - 5 - 2 - 1 |
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21 | |
DNA replication is extremely accurate. Only about one in ____ bases is incorporated incorrectly. |
| | A) | 100,000 |
| | B) | 1 million |
| | C) | 10 million |
| | D) | 100 million |
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22 | |
Ultraviolet radiation damages DNA by causing an extra ____ bond to form between adjacent ____. |
| | A) | hydrogen, pyrmidines. |
| | B) | covalent, purines. |
| | C) | covalent, pyrmidines. |
| | D) | hydrogen, purines. |
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