Bio 1107 - Chapter 12

You want to amplify by PCR 450 base pairs of C. elegans gene cloned into plasmid. You designed primers 22 nucleotides in length that are complementary to the plasmid sequence immediately adjacent to both ends of the cloning site. What would be the exact size of the amplified fragment? - 900 - 494 - 472 - 450

494

Which of the following sequences is not a palindrome? - ATTTAAAT - ATTATT - GGCGCGCC - GGATCC - TTAATTAA

ATTATT

RNA is involved in which cellular processes? - translation - DNA replication - All of these choices are correct. - transcription

All of these choices are correct.

Mitochondria contain their own double-stranded, circular DNA and replicate on their own. Why don't they suffer the same consequences as our cells in terms of limited division? - Because mitochondrial DNA is circular, it does not shorten when it replicates. - Shortening of the DNA is only a problem with nuclear DNA; shortening of mitochondrial DNA is not catastrophic. - because they have high telomerase activity, and their DNA is circular, so it doesn't shorten in replication - because they have high telomerase activity - Since mitochondrial DNA only contains a few genes, it can last a lot longer.

Because mitochondrial DNA is circular, it does not shorten when it replicates.

Which reason explains why bacteria can continually divide while they maintain the length of their chromosome? - because they only have one chromosome - because they have plasmids - because DNA replication is much quicker in bacteria than in eukaryotes - because they are so simple - Because their DNA is circular, it never shortens after replication.

Because their DNA is circular, it never shortens after replication.

What feature is shared by restriction fragments produced by the restriction enzymes BclI (T↓GATCA) and Mph1103 (AGATC↓T)? The downward arrow denotes the site of cleavage in each strand. - Both fragments have blunt ends. - Both fragments have the same 5-base overhang only at the 3′-end. - Both fragments have the same 5-base overhang only at the 5′-end. - Both fragments have the same 4-base overhang, but one at the 5'-end and the other at the 3'-end. - These fragments do not have anything in common.

Both fragments have the same 4-base overhang, but one at the 5'-end and the other at the 3'-end.

Which of the following is true regarding DNA replication of a linear chromosome? - Both strands get shortened at the same end during replication. - Only the lagging strand gets shortened after every other round of replication. - Only the leading strand gets shortened during replication. - Both strands get shortened at opposite ends during replication. -Only the lagging strand gets shortened during replication.

Both strands get shortened at opposite ends during replication.

One method for changing the DNA sequence of a gene in its original location in the cell uses a type of technology known as: - CRISPR-Cas9. - microarrays. - ELISA. - RISK. - PCR-RLFP.

CRISPR-Cas9.

What is the result of DNA ligase's action? - DNA is condensed to chromosomes. - DNA transcription occurs. - DNA fragments are joined together. - DNA is broken up at specific sites. - DNA translation occurs.

DNA fragments are joined together.

Why are primers needed for DNA replication? - DNA polymerase can only add nucleotides to an existing chain. - A tiny amount of RNA is needed to tell the cell where genes are located. - They help with the joining of Okazaki fragments. - The primers help with the proofreading function of DNA polymerase. - They help direct the placement of the telomeres.

DNA polymerase can only add nucleotides to an existing chain.

What procedure could be used after PCR is complete to make certain that the amplification process worked properly and that the correct sequence was amplified? - gel electrophoresis - DNA denaturation - None of the answer options is correct. - DNA sequencing - DNA hybridization

DNA sequencing

What is the difference between PCR and Sanger sequencing with regard to the materials needed to perform these reactions? - Primers are needed in PCR but not in Sanger sequencing. - DNA polymerase is needed in Sanger sequencing but not in PCR. - Primers are needed in Sanger sequencing but not in PCR. - DNA polymerase is needed in PCR but not in Sanger sequencing. - Dideoxynucleotides are needed in Sanger sequencing but not in PCR.

Dideoxynucleotides are needed in Sanger sequencing but not in PCR.

Which statement is true regarding chromosome replication in eukaryotes? - None of the answer options is correct. - During chromosome replication, multiple origins of replication form for all DNA in a cell. - Replication begins at one end of the chromosome and proceeds until it reaches the opposite end. - Replication bubbles remain distinct, isolated structures during chromosome replication and never fuse with one another. - In humans, it takes several days to replicate an entire chromosome.

During chromosome replication, multiple origins of replication form for all DNA in a cell.

Imagine that a doctor is culturing two types of cells: one from a malignant melanoma and one from a normal skin sample. How would you expect these two cell populations to differ? - Malignant melanoma cells would have active telomerases that constantly replenish and lengthen telomeres. - Normal skin cells would have telomeres that do not shorten during successive rounds of replication. - Malignant melanoma cells would have inactive telomerases, so their telomeres would shorten during successive rounds of replication. - Normal skin cells would have active telomerases that constantly replenish and lengthen telomeres. - Malignant melanoma cells would have telomeres that shorten during successive rounds of replication.

Malignant melanoma cells would have active telomerases that constantly replenish and lengthen telomeres.

Which statement is true regarding origins of replication? - The replication bubbles associated with different origins of replication never fuse. - None of the answer options is correct. - Circular DNA always has between 2 and 3 origins of replication. - Eukaryotic DNA always has one origin of replication. - Origins of replication are synonymous with replication forks.

None of the answer options is correct.

Which statement about the strands of a newly replicated DNA molecule is correct? - One strand is new, and the other is from the original molecule. - Both strands are made up of newly assembled nucleotides. - Both strands contain some nucleotides from the original molecule. - The base pairs are conserved, and new sugar-phosphate backbones are built up on them. - The sugar-phosphate chains are conserved, and new bases are inserted between them.

One strand is new, and the other is from the original molecule.

What is the first enzyme to synthesize a nucleic acid at a replication fork? - DNA polymerase - helicase - RNA primase - topoisomerase II

RNA primase

Which statement is true regarding telomeres? - Telomeres contain non-essential genes that are not necessary for cell survival. - Telomeres are repaired to the same extent in germ cells and somatic cells. - Telomeres are enzymes that repair telomerases, which cap the end of linear chromosomes. - Telomeres can contain repeated base sequences. - Telomeres are typically only a few base pairs in size.

Telomeres can contain repeated base sequences.

What would happen if telomerase stopped working in a cell in which it normally functions at high levels? - The cells would be able to divide indefinitely. - The cell would eventually die as the DNA continued to shorten. - None of the answer options is correct. - Cancer would be the result. - The cell would die immediately.

The cell would eventually die as the DNA continued to shorten.

Why are single-stranded binding proteins necessary for DNA replication? - They provide the energy necessary to separate the two strands of DNA. - They direct the primase where to lay down the primer. - None of the answer options is correct. - They prevent the two parental strands from coming together again. - They direct where replication will start.

They prevent the two parental strands from coming together again.

Select the correct order of steps during PCR. - denaturation, annealing, extension - initiation, denaturation, extension - initiation, extension, termination - denaturation, extension, termination - annealing, initiation, termination

denaturation, annealing, extension

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

false

During DNA replication, the leading strand contains Okazaki fragments.

false

In gel electrophoresis, DNA fragments migrate toward the negative pole of the electric field.

false

Massive parallel sequencing techniques can reliably determine the sequence of hundreds of base pairs but require more time than Sanger sequencing.

false

Okazaki fragments are ligated to form a continuous DNA molecule after replication is completed.

false

Restriction enzymes are an essential component of PCR.

false

Telomerase activity in stem cells is very low.

false

The first step of PCR, called annealing, is performed by DNA polymerase.

false

The semiconservative model of DNA replication means that each DNA strand of the double helix consists of some newly synthesized DNA and some parental DNA.

false

Transformation is the process where DNA is extracted from a plasmid.

false

Which of the following is an example of a transgenic organism? - a human infected with the virus Hepatitis-C who expresses viral proteins - a bacteria population in which a mutation conferring antibiotic resistance spontaneously arose - a patient who has received a heart valve from a pig - a patient who has received a kidney transplant from a close relative - fish that "glow in the dark" by expressing fluorescent jellyfish proteins

fish that "glow in the dark" by expressing fluorescent jellyfish proteins

What is the name of the enzyme that separates the two strands of DNA during replication? - DNA polymerase - helicase - DNA ligase - primase - topoisomerase

helicase

The following enzymes play important roles in DNA replication: DNA polymerase, primase, ligase, helicase. In what order do they work during replication? - helicase, primase, DNA polymerase, ligase - primase, helicase, ligase, DNA polymerase - DNA polymerase, helicase, primase, ligase - DNA polymerase, primase, ligase, helicase - ligase, helicase, DNA polymerase, primase

helicase, primase, DNA polymerase, ligase

A DNA molecule is cut with two different restriction enzymes known to cleave it only once each. After gel electrophoresis, three different DNA fragments are detected. This result means that the original DNA molecule was: - linear. - circular. - It is not possible to make this determination from the information provided.

linear.

A eukaryotic chromosome has _____ origin(s) of replication, and a bacterial chromosome has ______ origin(s) of replication. - many, many - one, one - one, many - many, one

many, one

The point at which DNA synthesis is initiated is called the: - start codon. - primase. - primer. - origin of replication. - replication fork.

origin of replication.

What is the name of the class of enzymes that recognizes and cuts a specific sequence of DNA? - helicases - topoisomerases - primases - restriction enzymes - DNA polymerases

restriction enzymes

Which of the following is not needed for DNA replication? - DNA - nucleotides - ribosomes - None of the answer options is correct. - enzymes

ribosomes

In gel electrophoresis, DNA fragments are separated based on their: - sequence. - how many adenine bases are in the fragment. charge. - how many thymine bases are in the fragment. - size.

size

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

the incoming nucleotide

The name of the technique used to amplify specific sequences of DNA is: - restriction. - the polymerase chain reaction (PCR). - Southern blot. - electrophoresis. - hybridization.

the polymerase chain reaction (PCR).

What is the function of the enzyme DNA polymerase? - to synthesize a strand of mRNA using DNA as a template - to synthesize a strand of DNA using a polypeptide as a template - to synthesize a strand of mRNA using mRNA as a template - to synthesize a polypeptide using DNA as a template - to synthesize a strand of DNA using DNA as a template

to synthesize a strand of DNA using DNA as a template

A daughter strand of DNA produced during chromosome replication can be composed of leading and lagging strands from different replication bubbles.

true

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

true

A transgenic organism is synonymous with a genetically modified organism, as both can contain recombinant DNA.

true

DNA polymerase requires both a template and a free 3′ end to elongate a nucleotide chain.

true

Denaturation of DNA is a necessary step in Southern blotting procedure because it separates double stranded DNA into single stranded DNA.

true

In addition to introducing mutations in a gene, DNA editing by means of CRISPR can also correct mutations in a gene.

true

In circular DNA, the DNA molecule is not shortened during each round of replication.

true

Restriction enzymes recognize certain DNA sequences and some of them will cut straight through, and others will leave an overhang at both ends of the cut.

true

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

true

Synthesis of nucleic acids always occurs in the 5′ → 3′ direction.

true

Forensic technicians unearth a skeleton from a shallow grave. They extract a tiny amount of DNA from the pulp found in the teeth. How could they obtain sufficient DNA for an analysis of the victim's genes? - use the polymerase chain reaction - use a nucleic acid probe - subject the DNA to restriction enzymes - subject the DNA to gel electrophoresis - None of the other answers is correct

use the polymerase chain reaction