Download Unit 3 Practice Exam

Unit 3 Practice Exam
1. A chain of _____ results in a polypeptide chain that folds up into a _____.
a. RNA bases ... transcript
b. amino acids ... gene
c. proteins ... ribosome
d. DNA bases ... gene
e. amino acids ... protein
2. What mRNA sequence signals the start of a sequence to be translated?
a. ATG
b. UGA
c. AUG
d. UAG
e. UAA
3. Each nucleotide triplet in mRNA that specifies a particular amino acid is called a(n)
a.
mutagen.
c.
anticodon.
b.
codon.
d.
exon.
Use the diagram below of a strand of an mRNA and the genetic code shown there to answer the
following questions:
mRNA: CUCAAGUGCUUC
Genetic Code:
4. Refer to the illustration above. What is the portion of the protein molecule coded for by the
piece of mRNA shown in the diagram?
a. Ser—Tyr—Arg—Gly
c. Leu—Lys—Cys—Phe
b. Val—Asp—Pro—His
d. Pro—Glu—Leu—Val
5. Refer to the illustration above. The anticodons for the codons in the mRNA in the diagram are
a. GAG—UUC—ACG—AAG.
c. CUC—GAA—CGU—CUU.
b. GAG—TTC—ACG—AAG.
d. CUU—CGU—GAA—CUC.
6. Transfer RNA
a. carries an amino acid to its correct codon.
b. synthesizes amino acids as they are needed.
c. produces codons to match the correct anticodons.
d. converts DNA into mRNA.
7. codon : mRNA::
a. P site : RNA molecules
b. ribosome : DNA molecules
c. DNA : protein
d. anticodon : tRNA
8. “Genetic engineering” refers to the process of
a. creating new DNA molecules from nucleotide sequences.
b. rearranging nucleotides in a gene of an organism so that new traits appear in the
development of an embryo.
c. moving genes from a chromosome of one organism to a chromosome of a different
organism.
d. building a new species by combining genes of different organisms.
9. Although controversial, DNA fingerprinting has been used in criminal investigations because
a. criminals leave DNA samples behind them when they touch an object at a crime scene.
b. DNA analysis is believed to allow investigators to distinguish body cells of different
individuals, who are unlikely to have the same DNA.
c. bacterial DNA on the hands of criminals may provide a clue as to where that person was
when the crime was committed.
d. DNA found on murder weapons is easy to identify.
10. Natural selection is the process by which
a. the age of selected fossils is calculated.
b. organisms with traits well suited to their environment survive and reproduce at a greater
rate than less well-adapted organisms in the same environment.
c. acquired traits are passed on from one generation to the next.
d. All of the above
11. The process by which a species becomes better suited to its environment is known as
a. accommodation.
c. adaptation.
b. variation.
d. selection.
12. Refer to the illustration above. An analysis of DNA from these organisms would indicate that
a. They have identical DNA.
b. they all have gill pouches.
c. their nucleotide sequences show many similarities.
d. they all have the same number of chromosomes.
13. Refer to the illustration above. The similarity of these structures suggests that the organisms
a. have a common ancestor.
c. evolved slowly.
b. all grow at different rates.
d. live for a long time.
14. A human embryo exhibits all of the following during development except
a. gill pouches.
c. fins.
b. a bony tail.
d. a coat of fine fur.
15. Beak shape in finches is affected by
a. the number of predators in the area.
b. the size of the finch.
c. the color of the finch.
d. the availability of food.
16. Viruses
a. are cellular organisms.
b. reproduce only in living cells.
c. have nuclei and organelles.
d. are surrounded by a polysaccharide coat.
17. viruses : host cells::
a. photosynthetic bacteria : chemosynthetic bacteria
b. bacteria : viruses
c. antibiotics : bacteria
d. cyanobacteria : chlorophyll
18. One difference between the cells in a human body and bacterial cells is that bacterial cells
have
a. an outer cell wall made up of lipids.
b. an outer cell wall made up of polysaccharides and proteins.
c. no DNA.
d. no ribosomes.
19. Refer to the illustration above. The shape represented by Organism A in the diagram applies
to the bacterial genus
a. Streptococcus, which causes strep throat.
b. Leptospira, which can cause urinary tract infections in humans.
c. Bacillus, which produces antibiotics.
d. Penicillium, which produces penicillin.
20. Refer to the illustration above. Which of the diagrams has a shape like the Bacillus bacterial
genus?
a. Organism A
c. Organism C
b. Organism B
d. None of the above
21. Antibiotics are ineffective against viral infections because
a. viruses are protected inside their host cells.
b. viruses have enzymes that inactivate the antibiotics.
c. antibiotics interfere with metabolic processes that viruses do not perform.
d. viral protein coats block the antibiotics from entering the virus.
22. Transcription and translation are stages in the process of ____________________
____________________.
23. Small circular forms of bacterial DNA are called ____________________.
24. Closely related species show more ____________________ in nucleotide sequences than
distantly related species.
25. Bacteria that obtain their energy from organic molecules, rather than obtaining energy from
the sun, are called ____________________ bacteria.
Answers
1. e
2. c
3. b
4. c
5. a
6. a
7. d
8. c
9. b
10.
11. c
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
b
c
a
c
d
b
c
b
a
b
c
protein synthesis
plasmids
similarities
heterotrophic