Question 1

The X-ray diffraction photography of Rosalind Franklin and Maurice Wilkins was critical to showing that

Accepted Answer

A)  DNA has a double-helix structure. 
B)  the bases of DNA were held together by hydrogen bonds. 
C)  DNA has equal numbers of purines and pyrimidines. 
D)  DNA has deoxyribose sugar rather than ribose sugar. 
E)  the four bases of DNA are adenine, guanine, cytosine, and thymine.

Question 2

Which of the following describes a function of the DNA helicase?

Accepted Answer

A)  connects the Okazaki fragments and seals any breaks in the sugar-phosphate backbone 
B)  adds nucleotides to the growing 3' end of the new DNA strand 
C)  creates the lagging strand in semiconservative replication 
D)  unwinds and "unzips" the double-stranded DNA by breaking the weak hydrogen bonds between the paired bases 
E)  re-creates the broken hydrogen bonds so that DNA becomes double-stranded again

Question 3

The individual(s) given the most credit for the discovery of the structure of DNA is (are)

Accepted Answer

A)  Alfred Hershey and Martha Chase. 
B)  James Watson and Francis Crick. 
C)  Erwin Chargaff. 
D)  Rosalind Franklin and Maurice Wilkins. 
E)  Charles Darwin and Gregor Mendel.

Question 4

DNA segments at the ends of chromosomes that shorten every time a cell divides are called

Accepted Answer

A)  transposons. 
B)  mutagens. 
C)  activated chromatin. 
D)  operons. 
E)  telomeres.

Question 5

Which level of primary control in eukaryotic gene activity involves using differences in the poly-A tail or the guanine cap to determine how long a particular transcript remains active before it is destroyed?

Accepted Answer

A)  pretranscriptional control 
B)  transcriptional control 
C)  posttranscriptional control 
D)  translational control 
E)  posttranslational control

Question 6

Which part of a mRNA molecule is edited out?

Accepted Answer

A)  exons. 
B)  introns. 
C)  transposons. 
D)  inducers. 
E)  promoters.

Question 7

Which of the following nucleotide bases is found only in RNA?

Accepted Answer

A)  guanine 
B)  adenine 
C)  thymine 
D)  uracil 
E)  cytosine

Question 8

In DNA, the amount of adenine is always equal to the amount of

Accepted Answer

A)  cytosine. 
B)  uracil. 
C)  guanine. 
D)  thymine. 
E)  ATP.

Question 9

Chargaff's rules of DNA structure states that

Accepted Answer

A)  A + T = G + C. 
B)  A = T, C = G 
C)  A = C, T = G. 
D)  A = G, T = C. 
E)  the number of purines in DNA never equals the number of pyrimidines.

Question 10

Which of the following is associated with cancer?

Accepted Answer

A)  It can establish new tumors distant from the site of the primary tumor. 
B)  It forms new blood vessels and brings nutrients and oxygen to the tumor. 
C)  Cancer cells can undergo cell division repeatedly and indefinitely. 
D)  Tumors invade surrounding tissues and are filtered by lymph nodes. 
E)  All of the answer choices describe cancer.

Question 11

Sometimes a newly folded protein must be modified before becoming functional. What level of gene control is this?

Accepted Answer

A)  transcriptional 
B)  posttranscriptional 
C)  translational 
D)  posttranslational 
E)  operon

Question 12

The addition of a poly-A tail to mRNA occurs after which of the following?

Accepted Answer

A)  replication 
B)  transcription 
C)  translation 
D)  translocation 
E)  termination

Question 13

In the Watson-Crick model of DNA, the "sides" of the ladder are composed of

Accepted Answer

A)  sugars. 
B)  bases. 
C)  hydrogen bonds. 
D)  sugar-phosphate molecules. 
E)  phosphate groups.

Question 14

Which level of primary control in eukaryotic gene activity involves the speed of transport of mRNA from the nucleus into the cytoplasm?

Accepted Answer

A)  pretranscriptional 
B)  transcriptional control 
C)  posttranscriptional control 
D)  translational control 
E)  posttranslational control

Question 15

In semiconservative DNA replication, each new double helix formed will have

Accepted Answer

A)  two new strands and two old strands. 
B)  one new and one old strand in each helix. 
C)  three new strands in one helix and three old strands in the second helix. 
D)  two new and one old strand in one helix and two old and one new strand in the second helix. 
E)  two new strands in one helix and two old strands in the other helix.

Question 16

A cell of the pancreas specializes in producing insulin, while a muscle cell specializes in the production of the protein myosin. This means that

Accepted Answer

A)  the pancreas and muscle cells are both actively using the genes for insulin and myosin. 
B)  the pancreas cells are actively using the insulin gene, while the muscle cells are actively using both the insulin and myosin genes. 
C)  the pancreas cells are actively using the gene that produces insulin, while muscle cells are actively using the gene that produces myosin. 
D)  neither the pancreas cells nor the muscle cells are specialized. 
E)  only muscle cells can produce proteins.

Question 17

A nucleotide contains

Accepted Answer

A)  DNA and RNA. 
B)  a sugar and a phosphate. 
C)  complementary purines and pyrimidines. 
D)  RNA, protein, and lipids. 
E)  a sugar, a phosphate, and a nitrogen-containing base.

Question 18

Which is the process by which a protein is constructed in the cytoplasm of eukaryotic cells?

Accepted Answer

A)  translation 
B)  transcription 
C)  replication 
D)  transformation 
E)  translocation

Question 19

Summarize the process of DNA replication.

Accepted Answer

The answer of Summarize the process of DNA replication....

Question 20

Because every DNA molecule contains one old strand and one new strand, the process of DNA replication is called

Accepted Answer

A)  conservative. 
B)  semiconservative. 
C)  mixed. 
D)  dispersive.

Exam 25: Dna Structure and Gene Expression