What is an important consequence of sequence variation in DNA acted upon differently by natural selection in different environments of tandem repeat DNA?

It makes it useful for DNA fingerprinting

A student uses restriction enzymes to cut a DNA molecule into fragments. The digested DNA is loaded into the wells of an agarose gel and the gel is subjected to an electric current. Upon completion of the run, the gel is stained.
111. The rate of migration of the DNA fragments through the agarose gel is determined by the
(A) ratio of adenine to cytosine in the fragment
(B) presence of hydrogen bonds between base pairs
(C) length of time the electrophoresis unit is allowed to operate
(D) number of nucleotides in the fragment
(E) volume of the starting sample

D

A student uses restriction enzymes to cut a DNA molecule into fragments. The digested DNA is loaded into the wells of an agarose gel and the gel is subjected to an electric current. Upon completion of the run, the gel is stained.

112. Which of the following is true of the dye used to stain the fragments?

(A) It increases the contrast between the agar and the DNA fragments.
(B) It must be accounted for when calculating the molecular weight of the fragments.
(C) Its charged areas interfere with the migration of the DNA.
(D) It is bonded only to the sticky ends of the fragments and can directly determine the sequence of the DNA fragments.
(E) It gives a three-dimensional view of the structure of the DNA fragments.

A

A student uses restriction enzymes to cut a DNA molecule into fragments. The digested DNA is loaded into the wells of an agarose gel and the gel is subjected to an electric current. Upon completion of the run, the gel is stained.

113. The type and density of the gel are important because
(A) they influence the rate of migration of the fragments
(B) they may cause some DNA molecules to replicate
(C) some DNA nucleotides may be lost due to chemical reactions with the gel
(D) some DNA molecules may sink to the bottom and not migrate
(E) some DNA molecules may cross-link

A

A student uses restriction enzymes to cut a DNA molecule into fragments. The digested DNA is loaded into the wells of an agarose gel and the gel is subjected to an electric current. Upon completion of the run, the gel is stained.

114. The procedures described can be used to do all of the following EXCEPT
(A) isolate and purify certain DNA fragments
(B) synthesize novel DNA molecules
(C) study the activity of restriction enzymes
(D) calculate the size of DNA fragments
(E) identify the source of DNA material

B

65. Enzyme used to position nucleotides during DNA replication

(A) DNA ligase
(B) DNA polymerase
(C) RNA polymerase
(D) Restriction enzyme
(E) Reverse transcriptase

B

73. Used to carry the genetic code

(A) Proteins
(B) Carbohydrates
(C) Nucleic acids
(D) Lipids
(E) Steroids

C

Porkaryotic and eukaryotic cells generally have wich of the following features in common?
a. A membrane-bound nucleus
b. A cell wall made of cellulose
c. Ribosomes
d. Flagella or cilia that contain microtubules
e. Linear chromosomes made of DNA and protein

C

Plates that have only ampicillin-resistant bacteria growing include which of the following? (A) I only (B) III only (C) IV only (D) I and II

c

Which of the following best explains why there is no growth on plate II? (A) The initial E. coli culture was not ampicillinresistant. (B) The transformation procedure killed the bacteria. (C) Nutrient agar inhibits E. coli growth. (D) The bacteria on the plate were transformed.

a

Plates I and III were included in the experimental design in order to (A) demonstrate that the E. coli cultures were viable (B) demonstrate that the plasmid can lose its ampr gene (C) demonstrate that the plasmid is needed for E. coli growth (D) prepare the E. coli for transformation

a

Which of the following statements best explains why there are fewer colonies on plate IV than on plate III? (A) Plate IV is the positive control. (B) Not all E. coli cells are successfully transformed. (C) The bacteria on plate III did not mutate. (D) The plasmid inhibits E. coli growth.

b

In a second experiment, the plasmid contained the gene for human insulin as well as the ampr gene. Which of the following plates would have the highest percentage of bacteria that are expected to produce insulin? (A) I only (B) III only (C) IV only (D) I and III

c

Sticky ends are

a. produced by PCR

b. used by mRNA to attach to ribosomes

c. produced by the action of DNA ligase

d. unpaired DNA nucleotides

C

The process of making multiple copies of a gene by inserting it into a host genome and culturing the host is an example of

gene cloning

A collection of cloned DNA fragments that include an organism's entire genome is called a

genomic library

Sticky ends are

Single-stranded ends of fragments of double-stranded DNA

What name is given to a region of DNA that varies from person to person

genetic marker

3) What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium?

I. Transform bacteria with a recombinant DNA molecule.
II. Cut the plasmid DNA using restriction enzymes.
III. Extract plasmid DNA from bacterial cells.
IV. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments.
V. Use ligase to seal plasmid DNA to nonplasmid DNA.

A) I, II, IV, III, V
B) II, III, V, IV, I
C) III, II, IV, V, I
D) III, IV, V, I, II
E) IV, V, I, II, III

C

4) A principal problem with inserting an unmodified mammalian gene into a BAC, and then getting that gene expressed in bacteria, is that
A) prokaryotes use a different genetic code from that of eukaryotes.
B) bacteria translate polycistronic messages only.
C) bacteria cannot remove eukaryotic introns.
D) bacterial RNA polymerase cannot make RNA complementary to mammalian DNA.
E) bacterial DNA is not found in a membrane-bounded nucleus and is therefore incompatible with mammalian DNA.

C

16) Why is it so important to be able to amplify DNA fragments when studying genes?
A) DNA fragments are too small to use individually.
B) A gene may represent only a millionth of the cell's DNA.
C) Restriction enzymes cut DNA into fragments that are too small.
D) A clone requires multiple copies of each gene per clone.
E) It is important to have multiple copies of DNA in the case of laboratory error.

B

23) Which of the following produces multiple identical copies of a gene for basic research or for large-scale production of a gene product?
A) restriction enzymes
B) gene cloning
C) DNA ligase
D) gel electrophoresis
E) reverse transcriptase

B

26) Which of the following cuts DNA molecules at specific locations?
A) restriction enzymes
B) gene cloning
C) DNA ligase
D) gel electrophoresis
E) reverse transcriptase

A

5. Multigene families are
A) groups of enhancers that control transcription
B) usually clustered at the telomeres
C) equivalent to the operons of prokaryotes
D) collections of genes who expression is controlled by the regulatory proteins
E) identical or similar genes that have evolved by gene duplication

E

21) What characteristic of short tandem repeat DNA makes it useful for DNA fingerprinting?
A) The number of repeats varies widely from person to person or animal to animal.
B) The sequence of DNA that is repeated varies significantly from individual to individual.
C) The sequence variation is acted upon differently by natural selection in different environments.
D) Every racial and ethnic group has inherited different short tandem repeats.

A

24) What is it that can be duplicated in a genome?
A) DNA sequences above a minimum size only
B) DNA sequences below a minimal size only
C) entire chromosomes only
D) entire sets of chromosomes only
E) sequences, chromosomes, or sets of chromosomes

E

26) Unequal crossing over during Prophase I can result in one sister chromosome with a deletion
and another with a duplication. A mutated form of hemoglobin, known as hemoglobin Lepore, is
known in the human population. Hemoglobin Lepore has a deleted set of amino acids. If it was
caused by unequal crossing over, what would be an expected consequence?
A) If it is still maintained in the human population, hemoglobin Lepore must be selected for in
evolution.
B) There should also be persons born with, if not living long lives with, an anti-Lepore mutation
or duplication.
C) Each of the genes in the hemoglobin gene family must show the same deletion.

B

27) When does exon shuffling occur?
A) during splicing of DNA
B) during mitotic recombination
C) as an alternative splicing pattern in post-transcriptional processing
D) as an alternative cleavage or modification post-translationally
E) as the result of faulty DNA repair

C

Multigene families include two or more nearly identical genes or genes sharing nearly identical
sequences. A classical example is the set of genes for globin molecules, including genes on human
chromosomes 11 and 16.

How might identical and obviously duplicated gene sequences have gotten from one
chromosome to another?

a. normal meitoic recombination

b. normal mitotic recombination between sister chromatids

c. transcription followed by recombination

d. chromosomal translocation

D

Multigene families include two or more nearly identical genes or genes sharing nearly identical
sequences. A classical example is the set of genes for globin molecules, including genes on human
chromosomes 11 and 16.

Several of the different globin genes are expressed in humans, but at different times in
development. What mechanism could allow for this?

A) exon shuffling

B) intron activation

C) pseudogene activation

D) differential translation of mRNAs

E) differential gene regulation over time

E

B

24) Which of the following seals the sticky ends of restriction fragments to make recombinant DNA?
A) restriction enzymes
B) gene cloning
C) DNA ligase
D) gel electrophoresis
E) reverse transcriptase

C

Which of the following best describes the complete sequence of steps occurring during every cycle of PCR?
1. The primers hybridize to the target DNA.

2. The mixture is heated to a high temperature to denature the double-stranded target DNA.

3. Fresh DNA polymerase is added.

4. DNA polymerase extends the primers to make a copy of the target DNA.

2,1,4

Some strains of the bacterium Streptococcus pyogenes secrete poisonous substances called exotoxins. The genes encoding the exotoxins are though to have originated in the bacteriophages, which are viruses that infect bacteria. Which of the following is the most likely mechanism by which the S. pyogenes acquired the ability to produce the extoxins?

A. Bacteriophages engulfed cellular debris from dead bacteria

B. Bacteriophages in the environment activated debris from dead bacteria

C. Bacteriophage DNA became integrated in the bacterial chromosomes

D. Bacteriophage proteins were absorbed into bacteria cells by endocytosis

C