CH 12 DNA Replication & Manipulation

Failure to recover a specific band in a gel made after PCR can be attributed to: -inappropriate annealing temperature for used primers. -inappropriate design of primers. -inappropriate numbers of cycles for amplification. -All of these choices are correct.

All of these choices are correct.

What is the benefit of using Taq polymerase in PCR? -Because it is taken from bacteria that live in high temperatures, it doesn't have a proofreading function. -Because it is taken from bacteria, this enzyme works much more efficiently than other types of DNA polymerase. -Because it is taken from bacteria that live in high temperatures, it stays active during denaturation steps of the reaction -Because it is taken from bacteria, it makes fewer mistakes. -None of the answer options is correct.

Because it is taken from bacteria that live in high temperatures, it stays active during denaturation steps of the reaction.

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? -Shortening of the DNA is only a problem with nuclear DNA; shortening of mitochondrial DNA isn't catastrophic. -Because they have high telomerase activity. -Because they have high telomerase activity and their DNA is circular and so doesn't shorten in replication. -Because mitochondrial DNA is circular, it doesn't shorten when it replicates. -Since mitochondrial DNA only contains a few genes, it can last a lot longer.

Because mitochondrial DNA is circular, it doesn't shorten when it replicates

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

Both strands get shortened at opposite ends during replication.

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

DNA fragments are joined together.

Why are primers needed for DNA replication? -They help with the joining of Okazaki fragments. -A tiny amount of RNA is needed to tell the cell where genes are located. -DNA polymerase can only add nucleotides to an existing chain. -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 sequencing -DNA denaturation -DNA hybridization -None of the answer options is correct.

DNA sequencing

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

Dideoxynucleotides are needed in Sanger sequencing, but not PCR

Which of the following statements is true regarding chromosome replication in eukaryotes? -During chromosome replication, multiple origins of replication form for all DNA in a cell. -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. -Replication begins at one end of the chromosome and proceeds until it reaches the opposite end. -None of the answer options is correct.

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

If a restriction site of AatII is 5′-GACGTC -3′ then 3′-GACGTC-5′ is also an AatII restriction site. True/False

False

Okazaki fragments are ligated into a continuous DNA molecule after replication is completed. True/False

False

Stem cells located in the gastrointestinal tract would possess more inactive telomerase compared to the amount of telomerase activity in mature neurons of the brain. True/False

False

Telomerase activity in stem cells is very low. True/False

False

Restriction enzymes are an essential component of PCR. True/False

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 -Fish that "glow in the dark" by expressing fluorescent jellyfish proteins -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.

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

Helicase

____ moves outward from the origin of replication and breaks hydrogen bonds between DNA nucleotides. -Helicase -Topoisomerase II -DNA polymerase -RNA primase

Helicase

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

Helicase, primase, DNA polymerase, ligase

The genome of Streptomyces coelicolor has a high CG content, about 72% of base pairs are GC. Compared with a sequence with 50% G and C, how would the high GC content of S. coelicolor affect the number of fragments obtained by digestion of its DNA with the restriction enzyme DraI (restriction site 5′-TTTAAA-3′ )? -More than would be expected from a random sequence -Less than would be expected from a random sequence -Approximately the same number than would be expected from a random sequence -It cannot be determined from the information provided.

Less than would be expected from a random sequence

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? -Normal skin cells would have telomeres that do not shorten during successive rounds of replication. -Malignant melanoma cells would have inactive telomerases and so their telomeres would shorten during successive rounds of replication. -Malignant melanoma cells would have telomeres that do not shorten during successive rounds of replication. -Malignant melanoma cells would have active telomerases that constantly replenish and lengthen telomeres. -Normal skin cells would have active telomerases that constantly replenish and lengthen telomeres.

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

A eukaryotic chromosome has _____ origin(s) of replication, and a bacterial chromosome has ______ origin(s) of replication. -one, one -many, one -one, many -many, two -many, 3

Many, one

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

None of the answers are correct

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

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

The point at which DNA synthesis is initiated is called the: -Primase. -Primer. -Start codon. -Replication fork. -Origin of replication.

Origin of replication

The name of the technique used to amplify specific sequences of DNA is: -Electrophoresis. -Southern blot. -PCR. -Hybridization. -Restriction.

PCR (Polymerase Chain Reaction)

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

Ribosomes

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. -Cancer would be the result. -The cell would die immediately.. -The cell would eventually die as the DNA continued to shorten. -None of the answer options is correct.

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

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

The incoming nucleotide.

During PCR, where does the energy come from that adds the nucleotide to the growing DNA strand? -Taq polymerase -The primers -ATP -The incoming nucleotides -The elevated temperature of the PCR reaction

The incoming nucleotides

All four dideoxynucleotides can be present in a single Sanger sequencing reaction and still be distinguished because: -they are incorporated in the growing chain with different efficiency. -they are labeled with different fluorescent dyes. -the fragments into which they are incorporated have different mobility in a gel. -All of these choices are correct.

They are labeled with different fluorescent dyes

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

True

One application of GMOs is to engineer mice that have particular diseases that scientists wish to study. True/False

True

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

True.

In circular DNA, the DNA molecule is not shortened during replication. True/False

True.

A Southern blot is a technique that relies on hybridization of: -A nucleic acid probe to a complementary RNA. -A nucleic acid probe to a complementary DNA. -Proteins to DNA. -None of the answer options is correct.

A nucleic acid probe to a complementary DNA.

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

ATTAATT

Which of the following reasons explains why bacteria can continually divide? -because they are so simple -because their DNA is circular so the DNA never shortens after replication -because DNA replication is much quicker in bacteria than in eukaryotes -because they have plasmids -because they only have one chromosome

because their DNA is circular so the DNA never shortens after replication.