Practice DNA Assessment
1. The sugars and phosphates in the "backbone" of a DNA strand are held together by:
A. covalent bonds
B. hydrogen bonds
C. ionic bonds
D. both B & C
E. none of the above
2. DNA structure can be described as a twisted ladder. Imagine you are climbing a model of
DNA, just as if you were climbing a ladder. What parts of a nucleotide are your feet touching as
you climb?
A. the sugars and phosphates
B. the sugars and bases
C. the sugars
D. the phosphates and bases
E. the bases
3. Imagine that you are studying a newly discovered bacterium from a hot springs in
Yellowstone National Park. When you examine the nucleotide composition of this organism,
you find that 10% of the nucleotides in its DNA are adenine. What percentage of nucleotides are
guanine? Explain.
A. 10%, because A pairs with G
B. 40%, because A pairs with T (accounting for 20% of the bases), leaving 80% of the
nucleotides as G-C base pairs; half of 80 is 40.
C. 90%, because 100% minus 10% equals 90%
4. Which of the following events occur within a DNA replication bubble?
A. DNA helicase unwinds the double helix at each replication fork within a replication bubble.
B. DNA helicase attaches the phosphate of a free nucleotide to the sugar of the previous
nucleotide in the daughter strand.
C. DNA polymerase helps to break hydrogen bonds between complementary base pairs.
D. none of the above
5. Which of the following options would result from the actions of DNA polymerase during
DNA replication?
A. Two DNA polymerase molecules act to synthesize a short segment of daughter DNA strand
from each parental strand; ligase is used to connect these short segments of both daughter
strands.
B. Two DNA polymerase molecules act to synthesize daughter DNA strands: one via a long
continuous strand that moves in the same direction as the helicase, and a second polymerase
synthesizes short segments of DNA that must be joined by ligase.
C. Two DNA polymerase molecules act to synthesize a long continuous daughter DNA strand
from each parental strand; ligase is not needed.
D. none of the above
6. Why did many scientists have trouble believing that DNA could be the carrier of genetic
information?
A. DNA has only four nucleotides, which seemed too few to encode the vast array of hereditary
traits of organisms.
B. DNA is a monotonous molecule with the same four nucleotides repeating over and over
again.
C. Protein structure is innately more suited to carrying hereditary information
7. Because each base pairs with a complementary base, in every DNA molecule the amount of:
A. each nucleotide is unrelated to all others
B. cytosine equals that of guanine
C. cytosine equals that of thymine
D. cytosine equals that of adenine
E. each nucleotide is equal to all others
8. Semiconservative replication refers to the fact that:
A. mistakes are made during DNA replication
B. certain bases pair with specific bases
C. DNA polymerase uses free nucleotides to synthesize new DNA molecules
D. each parental DNA strand is joined with a new strand containing complementary base pairs
E. each new DNA molecule contains two new single DNA strands
9. Which of the structures in the figure below are composed of RNA?
A.
B.
C.
D.
III and IV
II and IV
III and V
I and V
10. You are given a piece of a molecule and told that it can be described in a shorthand notation
as "CCCGGGCCCGGG". Which of the following is most likely concerning this molecule?
A. It is a piece of DNA which gives enough information to add 12 amino acids to a growing
protein chain.
B. It is a piece of either DNA or RNA. Without some additional information we can't tell.
C. It is a piece of RNA which gives enough information to add 12 amino acids to a growing
protein chain.
D. It is a piece of RNA which gives enough information to add 4 amino acids to a growing
protein chain.
E. It is a piece of DNA which gives enough information to add 4 amino acids to a growing
protein chain.
11. Which of the following is most accurate concerning "exons"?
A. Regions of DNA which contain information used to make protein.
B. Regions of DNA which are NOT used to make protein.
C. Exons are regions found only on the finished messenger RNA and not on DNA.
12. What is the correct number of nitrogenous bases in a codon ?
A. One
B. Two
C. Three
D. twenty
E. six
13. DNA polymerase:
A. cleaves hydrogen bonds that join the two strands of DNA
B. creates a polymer that consists of many molecules of DNA
C. adds appropriate nucleotides to a newly forming DNA strand
D. can advance in either direction along a single strand of DNA
14. For the DNA strand 5'-TACGATCATAT-3' the correct complementary DNA strand is:
A. 3'-TACGATCATAT-5'
B. 3'-ATGCTAGTATA-5'
C. 3' AUGCUAGUAUA-5'
D. 3'-GCATATACGCG-5'
E. 3'-TATACTAGCAT-5
15. Which one of the following nucleotide pair bonds would be found in a rNA molecule?
A. cytosine-uracil
B. guanine-cytosine
C. adenine-thymine
D. adenine-uracil
16. Three types of RNA involved in comprising the structural and functional core for protein
synthesis, serving as a template for translation, and transporting amino acid, respectively are:
A. mRNA, tRNA, rRNA
B. rRNA, tRNA, mRNA
C. tRNA, mRNA, rRNA
D. tRNA, rRNA, mRNA
E. rRNA, mRNA ,tRNA
17. In the diagram below, showing DNA replication, the strand labeled A is the:
A. template strand
B. RNA primer
C. leading strand
18. In a DNA molecule with 20% adenine, the percentage of guanine is:
A. 20%
B. 30%
C. 40%
D. 60 %
19. Which of the following lists the correct order of events in DNA replication?
A. Enzymes unwind the DNA double helix; DNA polymerase makes two new DNA strands
complementary to the old ones; the two DNA molecules wind up into a double helix with one
new strand and one old strand.
B. Two DNA molecules wind up into a double helix with one new strand and one old strand;
DNA polymerase makes two new DNA strands complementary to the old ones; enzymes unwind
the DNA double helix.
C. DNA polymerase makes the new DNA strands complementary to the old ones; enzymes
unwind the DNA double helix; the two DNA molecules wind up into a double helix with one
new strand and one old strand.
20. The two stands of DNA in a DNA helix are:
A. antiparallel
B. complementary
C. exactly the same
D. A and B only
E. A and C only
21. The process of turning DNA into the primary sequence of an amino acids is called:
A. transcription
B. replication
C. translation
D. translocation
E. none of the above
22. Which one of the following nucleotide pair bonds would be found in a DNA molecule?
A. cytosine-uracil
B. guanine-cytosine
C. adenine-guanine
D. adenine-cytosine
23. Transcription is:
A. the copying of DNA
B. mRNA synthesis
C. protein synthesis
D.epimerization of ribose
24. Guanine is a:
A. purine
B. ketone
C. phosphorous base
D.pyrimidine
25. Which of the following nitrogenous bases is not found in RNA?
A. adenine
B. guanine
C. uracil
D. thymine
E. cytosine
26. Under conditions where methionine must be the first amino acid, what protein would be
coded for by the following mRNA? 5'-CCUCAUAUGCGCCAUUAUAAGUGACACACA-3'
A. pro his met arg his tyr lys cys his
B. met arg his tyr lys cys his thr
C. met arg his tyr lys
D. met pro his met arg his tyr lys cys his thr
E. arg his ser glu tyr tyr arg leu tyr ser
27. Using the previous codon chart, determine which mRNA codes for the following
polypeptide?
met arg ser leu glu
A. 3'-AUGCGUAGCUUGGAGUGA-5'
B. 3'-AGUGAGGUUCGAUGCGUA-5'
C. 5'-AUGCGUAGCUUGGAGUGG-3'
D. 1'-AUGCGUAGCUUGGAGUGA-3'
E. 3'-AUGCGUAGCUUGGAGUGA-1'
28. With what mRNA codon would tRNA UAC form a codon-anticodon base pairing
interaction?
A. 3'-AUG-5'
B. 3'-GUA-5'
C. 3'-CAU-5'
D. 3'-UAC-5'
E. 3'-UAG-5'
29. Structure III in the figure below represents a(n):
A. DNA molecule
B. gene
C. amino acid
D. codon
30. Which structure shown below would attract a free cytosine nucleotide?