Mastering Biology Chapter 20

Which enzyme(s) will produce a DNA fragment that contains the entire vgp gene (shown in red) and has "sticky ends"? Select all that apply.

BamHI HindIII

This is a DNA fingerprint exhibiting samples from a victim, two suspects, and the crime scene. Which of these DNA fragments is common to both the victim and Suspect 2?

C

During which step in the PCR cycle do primers form bonds with a single-stranded template?

Annealing

This is a DNA fingerprint exhibiting samples from a victim, two suspects, and the crime scene. Which of these DNA fragments is common to both the victim and Suspect 1?

B

In gel electrophoresis DNA molecules migrate from _____ to _____ ends of the gel.

negative...positive

DNA fragment B consists of _____ base pairs.

1,405

The questions below will help determine which restriction enzyme should be used to make a plasmid that contains both an intact vgp gene and a functional ampR gene. Answer questions 1-4 by selecting from the answer choices on the left. Drag the correct answer to the right of each question.

1. BamHI, HaeIII, and HindIII 2. BamHI, EcoRI, HaeIII 3. BamHI, EcoRI, HindIII 4. BamHI only

What defect causes pituitary dwarfism?

Lack of growth hormone

Part D - Screening the plasmid library

TCACACTG-GAATTCAT

How many DNA molecules would there be after four rounds of PCR if the initial reaction mixture contained two molecules?

32

During which step in the PCR cycle are nucleotides used?

Extension

Part C - Transformation and selection of recombinant bacteria

will grow only in medium without ampicillin: no plasmid will grow in both media: nonrecombinant, recombinant with vgp gene, recombinant with no vgp gene

The sticky end of the DNA restriction fragment shown here will pair with a DNA restriction fragment with the sticky end _____.

-ACGT

In this example the marker DNA includes fragments that have 23,130, 9,416, 6,557, 4,361, 2,322, 2,027, and 564 base pairs. Approximately how many base pairs are in the DNA fragment indicated by the letter A?

6,557

What is the polymerase chain reaction (PCR)?

A method to amplify a fragment of DNA.

What is genetic cloning?

A method to produce many copies of a gene

What enzyme forms covalent bonds between restriction fragments?

DNA ligase

Which of these DNA molecules is the shortest?

E

True or false? The use of growth hormone isolated from cadavers was banned mainly because there were not enough cadavers to supply the hormone.

False

Which of the following statements best describes the function of reverse transcriptase?

It makes complementary DNA (cDNA) from mRNA.

Which of the following steps would be performed last when screening a cDNA library?

Match the region of radioactivity on the filter with the corresponding plate.

How can large quantities of protein be produced from a bacterial colony containing the gene of interest?

Put a cDNA encoding the protein into a plasmid with a bacterial promoter sequence.

Why is Suspect 1 considered more likely to have committed the crime than Suspect 2?

The crime scene sample contains DNA fragments from both the victim and Suspect 1.

What information can not be obtained from the sequence of a gene?

Whether the gene is methylated.

In order to insert a human gene into a plasmid, both must _____

be cut by the same restriction enzyme

In this example the marker DNA includes fragments that have 23,130, 9,416, 6,557, 4,361, 2,322, 2,027, and 564 base pairs. Approximately how many base pairs are in the DNA fragment indicated by the letter B?

between 6,557 and 4,361 base pairs

True or false? The Taq enzyme is a type of DNA polymerase that allows researchers to separate the DNA strands during the annealing step of the PCR cycle without destroying the polymerase.

false

The unpaired nucleotides produced by the action of restriction enzymes are referred to as _____.

sticky ends

True or false? Comparison of the sequences of the same gene across species can give some insight into the existence of a common ancestor with that gene.

true

True or false? The term "sticky ends" refers to the overhanging ends on DNA that are generated by restriction enzymes, which can base pair with any DNA molecules that contain complementary sticky ends.

true