Test Bank for Cell Biology, 4th Edition by Thomas D. Pollard
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Cours
Cell Biology
Établissement
Cell Biology
Test Bank for Cell Biology 4e 4th Edition by Thomas D. Pollard, William C. Earnshaw, Jennifer Lippincott-Schwartz, Graham Johnson. Full Chapters test bank are included - Chapter 1 to 48
SECTION I
Introduction to Cell Biology
1 Cells as the Basis of Life on Earth
2 Evolution of Life on Earth
...
1. About what time did the common ancestor of all life on earth live?
a. 3 to 4 thousand years ago
b. 3 to 4 million years ago
c. 3 to 4 billion years ago
d. 3 to 4 trillion years ago
Ans: C
The common ancestor lived a relatively short time after the planet formed (4.5 billion
years ago).
2. What are the four nucleotides that comprise DNA?
a. Adenine, cytosine, guanine, and thymine
b. Adenine, cytosine, guano, and thymine
c. Adenine, cytoproct, guanide, and thymine
d. Adenine, cytosine, guanyin, and thymine
Ans: A
All nucleotides end in “ine.”
3. What enzymes transcribe DNA into RNA?
a. RNA transcribases
b. RNAases
c. RNA polymerases
d. RNA transcriptases
Ans: C
RNA polymerases form polymers of RNA using DNA as templates.
4. Which of the following best describes the ribosome?
a. Bodies found in blackcurrants
b. Bodies that translate mRNA into polypeptides
c. Enzymes that break down proteins
d. Enzymes that break down sugars
Ans: B
Ribosomes use mRNA as templates to synthesize polypeptides.
5. Cellular membranes are composed of which of the following?
a. Only proteins
b. Proteins and lipids in bilayers
c. Proteins and lipid in monolayers
d. Only bilayers of lipids
, Ans: B
Membranes are composed of about equal masses of proteins and lipids, and the lipids
are predominantly arranged in bilayers.
6. Which of the following statements with regard to subcellular localization of proteins
is true?
a. Short sequences in proteins facilitate their passage through nuclear pores into the
nucleus.
b. Short sequences in proteins facilitate their passage into the lysosome.
c. Neither of the above
d. Both of the above
Ans: D
Specific receptors recognize sequences within proteins and guide the proteins to
specific locations to many different compartments within cells.
7. Which of the following statement(s) are true about eukaryotic cells?
a. Eukaryotes include bacteria, archaea, and plants.
b. Eukaryotes include animals, fungi, and protozoans.
c. Eukaryotes include animals, plants, and fungi.
d. Eukaryotes include archaea, fungi, and plants.
Ans: B and C
Bacteria and archaea are prokaryotes; the others mentioned are eukaryotes.
8. Approximately when did the first eukaryotes appear?
a. 3 billion years ago
b. 300 million years ago
c. 800 million years ago
d. 1 to 2 billion years ago
Ans: D
An approximate consensus between the fossil record and molecular clock calculations
is that eukaryotes arose around 1.5 billion years ago.
9. Which of the following statements is true regarding the nuclear membrane?
a. It is a single membrane that separates the cytosol from the nucleus.
b. It is a single membrane that also surrounds the nucleolus.
c. It is a double membrane that separates the cytoplasm from the nucleus.
d.It is a double membrane that separates the cytoplasm from the nucleus, and the
nucleolus from the nucleus.
Ans: C
The double membrane system contains pores to allow the selective transport of
material in and out of the nucleus.
10. In humans, what percentage of the 3 billion base pairs making up the genome encode
proteins?
, a. 0.02%
b. 0.2%
c. 2.0%
d. 20%
Ans: C
The remainder of the genome either performs regulatory functions or
consists of repeated DNA sequences that have no known function.
11. What occurs to proteins within the Golgi apparatus?
a. Sugars are added to proteins.
b. RNA is added to proteins.
c. Proteins are digested.
d. Proteins are synthesized.
Ans: A
The addition of sugars to proteins is called glycosylation and is necessary for the
functions of many extracellular proteins.
12. What is a protein kinase?
a. A protein that moves.
b. A protein that hydrolyses other proteins by proteolysis.
c. A protein that lyses bacteria by digesting the bacterial cell wall.
d. A protein that adds a phosphate to proteins or other molecules.
Ans: D
A kinase transfers a phosphate, usually from ATP to another protein or a lipid, or
other molecule. A phosphatase reverses this phosphorylation.
1. What is the best estimate of the number of genes in the first cell, the universal
common ancestor?
a. 6
b. 60
c. 600
d. 6000
Ans: C
About 600 genes is the minimum to carry out the biochemistry that we would today
count as being a viable self-renewing cell.
2. Other than carrying genetic information, what other property does RNA have that
makes it likely to have been the “spark” that kindled life?
a. It may have catalytic activity.
b. It is very stable in water.
c. It can form membranes in water.
d. It contains all the essential elements for life.
Ans: A
The catalytic activity of some RNAs allows it to self-replicate, self-cleave, and
catalyse formation of peptide bonds. Other catalytic activities may have contributed to
the essence of early life.
3. Which other material likely worked with RNA in the prebiotic world?
a. Silica
b. Biotite mica
c. Calcium carbonate
d. Montmorillonite clay
Ans: D
Interaction with clay allows RNA to fully unfold so that it can act as a template for
replication.
4. What is the name given to genes that occur in the same cell that have resulted from
duplication and mutation?
a. Homologs
b. Paralogs
c. Captinslogs
d. Orthologs
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