Biology 1610 Ch 12 learning curve and quiz questions

Failure to recover a specific band in a gel made after PCR can be attributed to

-inappropriate annealing temperature for used primers. -inappropriate numbers of cycles for amplification. -inappropriate design of primers.

You run a PCR reaction for five cycles starting with a single DNA duplex. Theoretically, how many copies of your sequence would you now have?

32

During DNA replication in a cell, RNA primase synthesizes a primer that is complementary to the region in the sequence shown in bold:

5'-GUUGUAGGUUUC-3'

What is the benefit of using Taq polymerase in PCR?

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?

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 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 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 opposite ends during replication.

What is the result of DNA ligase's action?

DNA fragments are joined together.

Which enzyme is the first to bind to the DNA sequences at the origin of replication?

DNA helicase

In observing DNA replication in the lab, you notice that in some cells, a defect occurs where DNA replication proceeds, but the RNA primers are not removed and replaced with DNA. Which enzyme is most likely to be defective in this system?

DNA polymerase I

Why are primers needed for DNA replication?

DNA polymerase can only add nucleotides to an existing chain

RNA is involved in which of the cellular processes?

DNA replication transcription translation

RNA is involved in which cellular processes?

DNA replication translation transcription

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?

DNA sequencing

Which statement is true regarding chromosome replication in eukaryotes?

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

During DNA replication, the leading strand contains Okazaki fragments T/F

False

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

False

Which statement is true regarding telomeres?

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 cell would eventually die as the DNA continued to shorten

Why are telomeres a necessary component of linear chromosomes?

They maintain the length of a chromosome because DNA is shortened every time it is replicated

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

True

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

True

In recombinant DNA experiments, ______ is used to cut pieces of DNA, and ______ joins these segments.

a restriction enzyme; DNA ligase

The function of DNA polymerase III is to

elongate the newly synthesized DNA strand

Restriction enzymes are an essential component of PCR TF

false

The template strand and the parental strand are two different strands of DNA TF

false

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

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

many, one

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

This difference between a leading strand and a lagging strand is that

the lagging strand is built away from the replication fork while the leading strand is built toward the replication fork

The name of the technique used to amplify specific sequences of DNA is:

the polymerase chain reaction (PCR)

The role of dideoxynucleotides in Sanger sequencing is:

the termination of DNA synthesis at specific bases

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

they are labeled with different fluorescent dyes

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

true

Stem cells located in the gastrointestinal tract would possess more active telomerase compared to the amount of telomerase activity in mature neurons of the brain. TF

true