Question 1

Starting with a single double-stranded DNA molecule,_______ double-stranded DNA molecules will exist after five rounds of PCR (assuming that the PCR works perfectly).

Accepted Answer

Each round of PCR doubles the number of existing double-stranded DNA molecules. Therefore, after one round of PCR, there will be 2 double-stranded DNA molecules. After two rounds of PCR, there will be 4 double-stranded DNA molecules. After three rounds of PCR, there will be 8 double-stranded DNA molecules. After four rounds of PCR, there will be 16 double-stranded DNA molecules. After five rounds of PCR, there will be 32 double-stranded DNA molecules. Therefore, the correct answer is D.

Question 2

Recall that two hydrogen bonds bind A and T,but three hydrogen bonds bind G and C.The stability of DNA is affected by the number of hydrogen bonds,with more bonds promoting more stability.Double-stranded DNA molecules that have greater stability require more heat to be broken into single strands.Which double-stranded DNA molecules would likely require the lowest temperature in PCR?

Accepted Answer

A molecule with 35 percent T would likely require the lowest temperature in PCR because the A/T base pairs only have two hydrogen bonds, making them easier to break apart compared to the G/C base pairs, which have three hydrogen bonds. Therefore, a DNA molecule with fewer G/C base pairs and more A/T base pairs (higher percentage of T) would require less heat to be broken into single strands, making it easier to denature and amplify in PCR.

Question 3

Mutations are

Accepted Answer

Mutations are changes in the nucleotide sequence of DNA that can be passed on from one organism to another, affecting genetic information.

Question 4

Without DNA repair,the error rate of DNA polymerase is about one for every hundred thousand bases replicated.If an organism has a haploid genome of 2 billion base pairs,how many mutations are likely to occur each time a diploid cell replicates its DNA?

Accepted Answer

The error rate of DNA polymerase is about one for every hundred thousand bases replicated. An organism with a haploid genome of 2 billion base pairs will have a diploid genome of 4 billion base pairs. Each time a diploid cell replicates its DNA, it will replicate 4 billion base pairs. Therefore, the number of mutations that are likely to occur each time a diploid cell replicates its DNA is 4 billion / 100,000 = 40,000.

Question 5

New sequencing techniques reveal that a child is heterozygous for a new mutation.This mutation appears in all of the cells tested from a variety of tissues (including skin,blood,and hair).The mutation is not found in either the mother or the father.Most likely,this is a new _______ mutation that occurred in _______.

Accepted Answer

The answer of New sequencing techniques reveal that a child...

Question 6

Which type of DNA repair system can repair errors in single-stranded DNA?

Accepted Answer

The answer of Which type of DNA repair system can...

Question 7

Under ideal conditions,each round of replication in PCR results in

Accepted Answer

Each round of PCR doubles the number of existing DNA molecules, as each double-stranded DNA molecule is used as a template to create two new double-stranded DNA molecules.

Question 8

The first repair of mistakes during DNA replication is made by

Accepted Answer

The answer of The first repair of mistakes during DNA...

Question 9

Suppose that for a certain gene,nearly 100 percent of the normal level of expression is required to produce the normal phenotype.Based on this requirement,one could predict that a _______ mutation would be _______.

Accepted Answer

A loss of function mutation would be dominant in this scenario because nearly 100 percent of the normal gene expression is required to produce the normal phenotype. If one allele is mutated and loses function, the remaining normal allele cannot compensate, leading to a dominant phenotype.

Question 10

DNA production during PCR can be calculated by the rule of 2ⁿ,where n equals the number of rounds of amplification.Approximately how many rounds of PCR are required to produce a billion DNA molecules from a single molecule,assuming that the PCR works perfectly?

Accepted Answer

To produce a billion (10^9) DNA molecules from a single molecule, you need 2^n = 10^9. Solving for n gives n ≈ 30, since 2^30 is approximately 1.07 billion.

Question 11

The fidelity of eukaryotic DNA replication is astounding.During DNA synthesis,the frequency of errors is about 1 incorrect base in _______ nucleotides inserted.

Accepted Answer

The fidelity of eukaryotic DNA replication is extremely high, with an error rate of about 1 incorrect base per 100,000 nucleotides inserted, due to the proofreading ability of DNA polymerases and other repair mechanisms.

Question 12

In PCR,_______ results in single-stranded DNA template molecules.

Accepted Answer

In PCR, heating the sample causes the double-stranded DNA to denature and separate into single-stranded DNA templates for amplification.

Question 13

You are studying DNA replication using a strain of yeast whose DNA polymerase is reported to have an error rate of 10^-⁶ bases per cell cycle.However,your analyses of DNA sequences after DNA replication indicate that the error rate is closer to 10^-¹⁰.What may explain your results?

Accepted Answer

The fact that the observed error rate is much lower than the reported error rate suggests that the yeast has a mismatch repair system that corrects errors made by the DNA polymerase.

Question 14

A single hair is found at the scene of a crime.Which technology would you use first to determine if the hair could have come from a certain suspect?

Accepted Answer

The answer of A single hair is found at the...

Question 15

Both the father and husband of Queen Victoria of England were not affected by the X-linked disease hemophilia,but her son Leopold was affected,as were many of the royal grandsons and great grandsons who were descended from her daughters.The mutation that caused hemophilia in Leopold and other male descendants probably arose as a _______ mutation in _______.

Accepted Answer

The mutation that causes hemophilia would have been present in the germline cells of Queen Victoria, meaning it would have been passed down to her offspring. Prince Albert was not affected by hemophilia, so it is unlikely that the mutation arose in his germline cells. Somatic mutations occur in non-reproductive cells and are not passed down to offspring. Leopold himself could not have been the site of the mutation, as he inherited it from his mother. Therefore, the most likely scenario is that Queen Victoria herself had the mutation in her germline cells.

Question 16

The polymerase chain reaction

Accepted Answer

The polymerase chain reaction (PCR) is a method used to amplify specific DNA sequences. This is achieved through the use of specific primers designed to anneal to the target sequence, and a heat-stable DNA polymerase that can withstand the high temperatures used to denature the DNA. PCR does not involve DNA sequencing or transcription, and requires the use of specific primers to initiate DNA synthesis.

Question 17

Human germline mutations are often considered more worrisome than somatic ones because germline mutations

Accepted Answer

Germline mutations are transmitted to offspring, which can lead to genetic disorders or diseases. Somatic mutations, on the other hand, only affect the individual with the mutation and are not passed on to offspring. This makes germline mutations more worrisome, as they have the potential to affect multiple generations.

Question 18

Silent mutations have no effect on amino acid sequences because

Accepted Answer

Silent mutations are usually found in noncoding regions of DNA, meaning they do not affect the final amino acid sequence of the protein being produced.

Question 19

What is the correct order for the following events in excision repair of DNA? (1)DNA polymerase I adds correct bases by 5'to 3' replication.
(2)Damaged bases are recognized.
(3)DNA ligase seals the new strand to existing DNA.
(4)Part of a single strand is excised.

Accepted Answer

The correct order is: damaged bases are recognized (2), part of a single strand is excised (4), DNA polymerase I adds correct bases (1), and DNA ligase seals the new strand (3).

Question 20

Which statement concerning somatic mutations or germline mutations is true?

Accepted Answer

Germline mutations occur in the cells that give rise to gametes (sperm or eggs), and therefore can be passed on to offspring. Somatic mutations occur in non-reproductive cells and cannot be inherited by offspring.

Quiz 9: DNA and Its Role in Heredity

Starting with a single double-stranded DNA molecule,_______ double-stranded DNA molecules will exist after five rounds of PCR (assuming that the PCR works perfectly) .

Mutations are

Without DNA repair,the error rate of DNA polymerase is about one for every hundred thousand bases replicated.If an organism has a haploid genome of 2 billion base pairs,how many mutations are likely to occur each time a diploid cell replicates its DNA?

Which type of DNA repair system can repair errors in single-stranded DNA?

Under ideal conditions,each round of replication in PCR results in

The first repair of mistakes during DNA replication is made by

Suppose that for a certain gene,nearly 100 percent of the normal level of expression is required to produce the normal phenotype.Based on this requirement,one could predict that a _ mutation would be _.

DNA production during PCR can be calculated by the rule of 2ⁿ,where n equals the number of rounds of amplification.Approximately how many rounds of PCR are required to produce a billion DNA molecules from a single molecule,assuming that the PCR works perfectly?

The fidelity of eukaryotic DNA replication is astounding.During DNA synthesis,the frequency of errors is about 1 incorrect base in _______ nucleotides inserted.

In PCR,_______ results in single-stranded DNA template molecules.

You are studying DNA replication using a strain of yeast whose DNA polymerase is reported to have an error rate of 10^-⁶ bases per cell cycle.However,your analyses of DNA sequences after DNA replication indicate that the error rate is closer to 10^-¹⁰.What may explain your results?

A single hair is found at the scene of a crime.Which technology would you use first to determine if the hair could have come from a certain suspect?

The polymerase chain reaction

Human germline mutations are often considered more worrisome than somatic ones because germline mutations

Silent mutations have no effect on amino acid sequences because

What is the correct order for the following events in excision repair of DNA? (1) DNA polymerase I adds correct bases by 5'to 3' replication. (2) Damaged bases are recognized. (3) DNA ligase seals the new strand to existing DNA. (4) Part of a single strand is excised.

Which statement concerning somatic mutations or germline mutations is true?

Quiz 9: DNA and Its Role in Heredity

Starting with a single double-stranded DNA molecule,_______ double-stranded DNA molecules will exist after five rounds of PCR (assuming that the PCR works perfectly) .

Mutations are

Without DNA repair,the error rate of DNA polymerase is about one for every hundred thousand bases replicated.If an organism has a haploid genome of 2 billion base pairs,how many mutations are likely to occur each time a diploid cell replicates its DNA?

Which type of DNA repair system can repair errors in single-stranded DNA?

Under ideal conditions,each round of replication in PCR results in

The first repair of mistakes during DNA replication is made by

Suppose that for a certain gene,nearly 100 percent of the normal level of expression is required to produce the normal phenotype.Based on this requirement,one could predict that a _______ mutation would be _______.

DNA production during PCR can be calculated by the rule of 2n,where n equals the number of rounds of amplification.Approximately how many rounds of PCR are required to produce a billion DNA molecules from a single molecule,assuming that the PCR works perfectly?

The fidelity of eukaryotic DNA replication is astounding.During DNA synthesis,the frequency of errors is about 1 incorrect base in _______ nucleotides inserted.

In PCR,_______ results in single-stranded DNA template molecules.

You are studying DNA replication using a strain of yeast whose DNA polymerase is reported to have an error rate of 10-6 bases per cell cycle.However,your analyses of DNA sequences after DNA replication indicate that the error rate is closer to 10-10.What may explain your results?

A single hair is found at the scene of a crime.Which technology would you use first to determine if the hair could have come from a certain suspect?

The polymerase chain reaction

Human germline mutations are often considered more worrisome than somatic ones because germline mutations

Silent mutations have no effect on amino acid sequences because

What is the correct order for the following events in excision repair of DNA? (1) DNA polymerase I adds correct bases by 5'to 3' replication. (2) Damaged bases are recognized. (3) DNA ligase seals the new strand to existing DNA. (4) Part of a single strand is excised.

Which statement concerning somatic mutations or germline mutations is true?

Suppose that for a certain gene,nearly 100 percent of the normal level of expression is required to produce the normal phenotype.Based on this requirement,one could predict that a _ mutation would be _.

DNA production during PCR can be calculated by the rule of 2ⁿ,where n equals the number of rounds of amplification.Approximately how many rounds of PCR are required to produce a billion DNA molecules from a single molecule,assuming that the PCR works perfectly?

You are studying DNA replication using a strain of yeast whose DNA polymerase is reported to have an error rate of 10^-⁶ bases per cell cycle.However,your analyses of DNA sequences after DNA replication indicate that the error rate is closer to 10^-¹⁰.What may explain your results?