Chapter 12: DNA Replication and Manipulation

Which of the following is a transgenic organism?

A rat with rabbit hemoglobin genes

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

A restriction enzyme; DNA ligase

Which of the following sequences is not a palindrome.

ATTATT

Which of the following sequences is not a palindrome?

ATTATT

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 doesn't shorten when it replicates.

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

Because their DNA is circular so the DNA never shortens after replication

Which of the following is true regarding DNA 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 RNA known as:

CRISPR

What is the result of DNA ligase's action?

DNA fragments are joined together.

Which of the following enzymes is necessary to produce recombinant DNA?

DNA ligase

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

DNA polymerase

RNA is involved in which of the following cellular processes?

DNA replication, transcription, and translation

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

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

False

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

False

During DNA replication, the leading strand contains Okazaki fragments.

False

Recombinant DNA only occurs when you take DNA from another organism and insert it into a bacterium.

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.

False

Telomerase activity in stem cells is very low.

False

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

False

Transformation is the process where DNA is extracted from a plasmid

False

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

False Transformation is the process by which foreign DNA is introduced into a cell.

Which of the following is an example of a transgenic organism?

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?

Helicase

Which of the following enzymes is responsible for unwinding the double helix at the replication fork?

Helicase

____ moves outward from the origin of replication and breaks hydrogen bonds between DNA nucleotides.

Helicase

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′ )?

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?

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

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

None of the answer options is correct.

Okazaki fragments are found to play a role in which of the following?

Okazaki fragments play a role in all of these. - Loss of telomeres - Replication of the lagging strand - Pre-mature aging disorders - The creation of short fragments of DNA by restriction enzymes

Which of the following statements about the strands of a newly replicated DNA molecule is correct?

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

The point at which DNA synthesis is initiated is called the:

Origin of replication

The extrachromosomal DNA often found in bacteria is called a:

Plasmid

_____ is the first enzyme to synthesize a nucleic acid at a replication fork.

RNA primase

Which of the following is not needed for DNA replication?

Ribosomes

Which of the following restriction enzymes produce sticky ends? Select all that apply. (An arrow indicates the restriction site.)

TaiI with the restriction sequence 5′- ACGT↓ -3′

Which of the following statements 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

What would happen if telomerase stopped working in a cell in which it would normally functions at high levels?

The cell would eventually die as the DNA continued 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?

The incoming nucleotide

Okazaki fragments are found on _____ strand of DNA.

The lagging

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.

Why are single-stranded binding proteins necessary for DNA replication?

They prevent the two parental strands from coming together again.

What is the function of the enzyme DNA polymerase?

To synthesize a strand of DNA using DNA as a template

____ relieves the tension on the double helix during DNA replication.

Topoisomerase

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

True

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

True

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

True

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

True

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

True

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

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 occur in the 5' -> 3' direction.

True

The presence of Okazaki fragments demonstrates the antiparallel nature of the double helix.

True

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

True CRISPR - "spacer" sequences are transcribed into short RNA sequences ("CRISPR RNA's" or "crRNAs") capable of guiding the system to matching sequences of DNA. When the target DNA is found, Cas9 - one of the enzymes produced by the CRISPR system- binds to the DNA and cuts it, shutting the targeted gene off

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

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

many, one