Question 1

What features of DNA make it possible to make recombinant DNA in the lab?

Accepted Answer

A) Restriction enzymes cut DNA from all species. 
B) The genetic code is the same for all organisms. 
C) Two double helices from different sources can be ligated together. 
D) None of the other answer options is correct. 
A) Restriction enzymes cut DNA from all species. 
B) The genetic code is the same for all organisms. 
C) Two double helices from different sources can be ligated together. 
D) None of the other answer options is correct.

Question 2

Incorrect nucleotides are sometimes incorporated into DNA during the process of replication. In the sequences shown here, the template strand is shown on top and the replicating daughter strand at the bottom. The nucleotide shown in bold is incorrect in that its base does not undergo pairing with the base in the template strand. In the situation shown in (A) the proofreading function of DNA polymerase removes the incorrect nucleotide from the daughter strand and replaces it with the correct one, but in situation (B) the polymerase has moved on and the incorrect nucleotide cannot be repaired. Can you explain why the error in situation (B) cannot be fixed by DNA polymerase?
(A) $\begin{array}{l}
3 \text { '-GAAACTGCCATG-5 ' } \
5 \text { '-CTTTGG }
\end{array}$ (B) $\begin{array}{l}
3 \text { '-GAAACTGCCATG-5 ' } \
5 \text { '-CTTTGGC }
\end{array}$

Accepted Answer

The proofreading function can act only o

Question 3

If you were able to find a drug that could inhibit the reactivation of telomerase activity in cancer cells, the cancer cells would:

Accepted Answer

A) stop dividing immediately. 
B) become less invasive. 
C) eventually die from lack of energy. 
D) slowly erode their chromosome ends. 
E) gradually revert to normal cells. 
A) stop dividing immediately. 
B) become less invasive. 
C) eventually die from lack of energy. 
D) slowly erode their chromosome ends. 
E) gradually revert to normal cells.

Question 4

DNA polymerase is the enzyme that separates the two strands of DNA during DNA replication.

Accepted Answer

A) True 
 B)False

Question 5

Which of the following reasons explains why bacteria can continually divide?

Accepted Answer

A) because they are so simple 
B) because their DNA is circular so the DNA never shortens after replication 
C) because DNA replication is much quicker in bacteria than in eukaryotes 
D) because they have plasmids 
E) because they only have one chromosome 
A) because they are so simple 
B) because their DNA is circular so the DNA never shortens after replication 
C) because DNA replication is much quicker in bacteria than in eukaryotes 
D) because they have plasmids 
E) because they only have one chromosome

Question 6

The technique of Sanger sequencing takes advantage of the fact that dideoxynucleotides (nucleotides in which the 3F1F1F1S1F1F1F10 hydroxyl group is absent) act as:

Accepted Answer

A) palindromic sites. 
B) restriction sites. 
C) chain terminators. 
D) probes. 
E) None of the other answer options is correct. 
A) palindromic sites. 
B) restriction sites. 
C) chain terminators. 
D) probes. 
E) None of the other answer options is correct.

Question 7

All four dideoxynucleotides can be present in a single Sanger sequencing reaction and still be distinguished because:

Accepted Answer

A) they are incorporated in the growing chain with different efficiency. 
B) they are labeled with different fluorescent dyes. 
C) the fragments into which they are incorporated have different mobility in a gel. 
D) All of these choices are correct. 
A) they are incorporated in the growing chain with different efficiency. 
B) they are labeled with different fluorescent dyes. 
C) the fragments into which they are incorporated have different mobility in a gel. 
D) All of these choices are correct.

Question 8

Imagine that a doctor is culturing cells from a malignant melanoma and from a normal skin sample. How would you expect these two cell populations to differ?

Accepted Answer

A) Malignant melanoma cells would have telomeres that do not shorten during successive rounds of replication. 
B) Normal skin cells would have telomeres that do not shorten during successive rounds of replication. 
C) Malignant melanoma cells would have inactive telomerases and so their telomeres would shorten during successive rounds of replication. 
D) Normal skin cells would have active telomerases that constantly replenish and lengthen telomeres. 
E) Malignant melanoma cells would have active telomerases that constantly replenish and lengthen telomeres. 
A) Malignant melanoma cells would have telomeres that do not shorten during successive rounds of replication. 
B) Normal skin cells would have telomeres that do not shorten during successive rounds of replication. 
C) Malignant melanoma cells would have inactive telomerases and so their telomeres would shorten during successive rounds of replication. 
D) Normal skin cells would have active telomerases that constantly replenish and lengthen telomeres. 
E) Malignant melanoma cells would have active telomerases that constantly replenish and lengthen telomeres.

Question 9

Energy is required in order to add a nucleotide to the growing strand of DNA during replication. From where does that energy come?

Accepted Answer

A) DNA polymerase 
B) DNA ligase 
C) helicase 
D) primase 
E) the incoming nucleotide 
A) DNA polymerase 
B) DNA ligase 
C) helicase 
D) primase 
E) the incoming nucleotide

Question 10

Sheep that produce a human protein in their milk used to treat a human disorder is an example of a genetically modified organism.

Accepted Answer

A) True 
 B)False

Question 11

A solution of DNA fragments of known sizes is sometimes placed in one of the wells during electrophoresis and used for size comparison.

Accepted Answer

A) True 
 B)False

Question 12

Which of the following statements is TRUE regarding origins of replication?

Accepted Answer

A) Circular DNA always has between two and three origins of replication. 
B) Eukaryotic DNA always has one origin of replication. 
C) The replication bubbles associated with different origins of replication never fuse. 
D) Origins of replication are synonymous with replication forks. 
E) None of the other answer options is correct. 
A) Circular DNA always has between two and three origins of replication. 
B) Eukaryotic DNA always has one origin of replication. 
C) The replication bubbles associated with different origins of replication never fuse. 
D) Origins of replication are synonymous with replication forks. 
E) None of the other answer options is correct.

Question 13

What is the name of the class of enzymes that recognizes and cuts a specific sequence of DNA?

Accepted Answer

A) DNA polymerases 
B) topoisomerases 
C) restriction enzymes 
D) helicases 
E) primases 
A) DNA polymerases 
B) topoisomerases 
C) restriction enzymes 
D) helicases 
E) primases

Question 14

What feature of double-stranded DNA makes it necessary to have a leading strand and a lagging strand during replication?

Accepted Answer

A) the hydrogen bonding between bases 
B) the base stacking of the bases 
C) the negative charge on the sugar-phosphate backbone 
D) the antiparallel orientation of the strands 
A) the hydrogen bonding between bases 
B) the base stacking of the bases 
C) the negative charge on the sugar-phosphate backbone 
D) the antiparallel orientation of the strands

Question 15

The BIGGEST remaining obstacle for personal genome sequencing is still:

Accepted Answer

A) the cost. 
B) sequencing speed. 
C) gel electrophoresis. 
D) heat-stable DNA polymerase. 
E) the labor intensiveness of Southern blots. 
A) the cost. 
B) sequencing speed. 
C) gel electrophoresis. 
D) heat-stable DNA polymerase. 
E) the labor intensiveness of Southern blots.

Question 16

You discover a virus with a number of unusual properties, and decide to assign it the name virus U238. The genome of U238 consists of double-stranded DNA. To study the mode of DNA replication in U238, you carry out a Meselson-Stahl type of experiment, and first observe that viral DNA containing only normal "light" nitrogen (14N) has a density of 1.715 gm/cm3. You then allow the virus to replicate in the presence of nucleotides containing "heavy" nitrogen (15N) until both strands of its genome are "heavy." At this point the density of the viral DNA is 1.722 gm/cm3. You allow the virus with "heavy" DNA to undergo one round of replication in the presence of only "light" nucleotides, and you observe that half of the viral progeny have DNA with a density of 1.722 gm/cm3 and the other half of the viral progeny have DNA with a density of 1.715 gm/cm3. How would you interpret these results?

Accepted Answer

A) The viral DNA is replicated like any other double-stranded DNA molecule. 
B) The viral DNA is replicated in very short pieces that reassociate at random. 
C) After replication, pairing of the parental strands is restored. 
D) This result is impossible and is therefore most likely due to an error. 
A) The viral DNA is replicated like any other double-stranded DNA molecule. 
B) The viral DNA is replicated in very short pieces that reassociate at random. 
C) After replication, pairing of the parental strands is restored. 
D) This result is impossible and is therefore most likely due to an error.

Question 17

In gel electrophoresis, DNA fragments are separated based on:

Accepted Answer

A) their sequence. 
B) their size. 
C) their charge. 
D) how many adenine bases are in the fragment. 
E) how many thymine bases are in the fragment. 
A) their sequence. 
B) their size. 
C) their charge. 
D) how many adenine bases are in the fragment. 
E) how many thymine bases are in the fragment.

Question 18

What is the result of DNA ligase's action?

Accepted Answer

A) DNA is broken up at specific sites. 
B) DNA fragments are joined together. 
C) DNA translation occurs. 
D) DNA transcription occurs. 
E) DNA is condensed to chromosomes. 
A) DNA is broken up at specific sites. 
B) DNA fragments are joined together. 
C) DNA translation occurs. 
D) DNA transcription occurs. 
E) DNA is condensed to chromosomes.

Question 19

What feature is shared by restriction fragments produced by the restriction enzymes BclI (TF1F1F1S1F1F1F10GATCA) and BglII (AF1F1F1S1F1F1F10GATCT)? (The downward arrow denotes the site of cleavage in each strand.)

Accepted Answer

A) Both fragments have the same 5-base overhang at the 3'-end. 
B) Both fragments have the same 5-base overhang at the 5'-end. 
C) Both fragments have blunt ends. 
D) Both fragments have the same 5-base overhang but one at the 3'-end and the other at the 5'-end. 
E) These fragments do not have anything in common. 
A) Both fragments have the same 5-base overhang at the 3'-end. 
B) Both fragments have the same 5-base overhang at the 5'-end. 
C) Both fragments have blunt ends. 
D) Both fragments have the same 5-base overhang but one at the 3'-end and the other at the 5'-end. 
E) These fragments do not have anything in common.

Question 20

As in the development of computer hardware, interest in large-scale DNA sequencing has stimulated the development of sequencing devices that:

Accepted Answer

A) are smaller. 
B) have improved capacity through automation. 
C) have improved capacity through open-source software development. 
D) require less energy to operate. 
E) None of the other answer options is correct. 
A) are smaller. 
B) have improved capacity through automation. 
C) have improved capacity through open-source software development. 
D) require less energy to operate. 
E) None of the other answer options is correct.

Exam 12: Dna Replication and Manipulation

What features of DNA make it possible to make recombinant DNA in the lab?

If you were able to find a drug that could inhibit the reactivation of telomerase activity in cancer cells, the cancer cells would:

DNA polymerase is the enzyme that separates the two strands of DNA during DNA replication.

Which of the following reasons explains why bacteria can continually divide?

The technique of Sanger sequencing takes advantage of the fact that dideoxynucleotides (nucleotides in which the 3 hydroxyl group is absent) act as:

All four dideoxynucleotides can be present in a single Sanger sequencing reaction and still be distinguished because:

Imagine that a doctor is culturing cells from a malignant melanoma and from a normal skin sample. How would you expect these two cell populations to differ?

Energy is required in order to add a nucleotide to the growing strand of DNA during replication. From where does that energy come?

Sheep that produce a human protein in their milk used to treat a human disorder is an example of a genetically modified organism.

A solution of DNA fragments of known sizes is sometimes placed in one of the wells during electrophoresis and used for size comparison.

Which of the following statements is TRUE regarding origins of replication?

What is the name of the class of enzymes that recognizes and cuts a specific sequence of DNA?

What feature of double-stranded DNA makes it necessary to have a leading strand and a lagging strand during replication?

The BIGGEST remaining obstacle for personal genome sequencing is still:

In gel electrophoresis, DNA fragments are separated based on:

What is the result of DNA ligase's action?

What feature is shared by restriction fragments produced by the restriction enzymes BclI (TGATCA) and BglII (AGATCT)? (The downward arrow denotes the site of cleavage in each strand.)

As in the development of computer hardware, interest in large-scale DNA sequencing has stimulated the development of sequencing devices that:

Life: Chemical, Cellular, and Evolutionary Foundations

The Molecules of Life

Nucleic Acids and Transcription

Translation and Protein Structure

Organizing Principles: Lipids, Membranes, and Cell Compartments

Making Life Work: Capturing and Using Energy

Cellular Respiration: Harvesting Energy From Carbohydrates and Other Fuel Molecules

Photosynthesis: Using Sunlight to Build Carbohydrates

Cell Signaling

Cell and Tissue Architecture: Cytoskeleton, Cell Junctions, and Extracellular Matrix

Cell Division: Variations, Regulation, and Cancer

Genomes

Mutation and Dna Repair

Genetic Variation

Mendelian Inheritance

Inheritance of Sex Chromosomes, Linked Genes, and Organelles

The Genetic and Environmental Basis of Complex Traits

Genetic and Epigenetic Regulation

Genes and Development

Evolution: How Genotypes and Phenotypes Change Over Time

Species and Speciation

Evolutionary Patterns: Phylogeny and Fossils

Human Origins and Evolution

Cycling Carbon

Bacteria and Archaea

Eukaryotic Cells: Origins and Diversity

Being Multicellular

Plant Structure and Function: Moving Photosynthesis Onto Land

Plant Reproduction: Finding Mates and Dispersing Young

Plant Growth and Development

Plant Defense: Keeping the World Green

Plant Diversity

Fungi: Structure, Function, and Diversity

Animal Nervous Systems

Animal Sensory Systems and Brain Function

Animal Movement: Muscles and Skeletons

Animal Endocrine Systems

Animal Cardiovascular and Respiratory Systems

Animal Metabolism, Nutrition, and Digestion

Animal Renal Systems: Water and Waste

Animal Reproduction and Development

Animal Immune Systems

Animal Diversity

Animal Behavior

Population Ecology

Species Interactions, Communities, and Ecosystems

Biomes and Global Ecology

The Anthropocene: Humans As a Planetary Force

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