Test Bank
Chapter 1: Introduction to Cells
MULTIPLE CHOICE
1. Which statement is NOT true of the prokaryotic cell?
a. DNA is circular.
b. It is enclosed by plasma membrane.
c. It lacks a cytoskeletal support structure.
d. Contains many organelles.
ANS: D
Presence of organelles is a distinguishing feature of eukaryotic cells.
2. Plasma membranes expand by
a. de novo synthesis.
b. endocytosis of bacterial membranes.
c. budding of endoplasmic reticulum
d. Do not expand over the lifetime of the cell.
ANS: C
Membranes grow only by expansion of preexisting membranes, usually endoplasmic
reticulum not directly, pass through Golgi first.
,3. The sequence of amino acids in a protein determines its
a. Location in the cell.
b. Function.
c. Transcription.
d. None of the above.
ANS: A
Improperly folded proteins lack biological function.
4. Genetic information
a. is encoded only in eukaryotic cells.
b. is stored in long polymers of DNA.
c. is stored in messenger RNA molecules.
d. None of the above.
ANS: B
DNA, a basic carrier of genetic information, is a linear molecule composed of
complementary nucleotides. Both prokaryotes and eukaryotes use DNA as hereditary
information.
5. The pairing between complementary nucleotide bases in DNA is stabilized by
a. peptide bonds.
b. cytosine bonds.
c. noncovalent bonds.
d. disulfide bonds.
ANS: C
Specific noncovalent bonds stabilize the complementary bases and form a double helix.
,6. Subcellular localization of the protein is determined by
a. signal sequences within protein sequence.
b. signal sequences in the mitochondria.
c. phospholipid synthesis.
d. electrochemical gradients.
ANS: A
Signal recognition sequences that are integral part of the polypeptide sequence direct the
protein to the proper destination.
7. ATP
a. is a common energy “currency” used both by prokaryotes and eukaryotes.
b. can be used to power molecular motors.
c. is a nucleotide used in the assembly of RNA and DNA.
d. All of the above.
ANS: D
Molecular motor proteins require energy to move their cargo. The energy is delivered from
the universal source, ATP both in prokaryotes and eukaryotes.
8. The cytoskeleton
a. is a common feature of all cells.
b. acts as tracks for cellular motors.
c. is necessary for protein targeting.
d. None of the above.
ANS: B
, 9. Activation of cell surface receptors can
a. change cell metabolism.
b. affect gene transcription.
c. cause the cell to die.
d. All of the above.
ANS: D
Activation of cell receptors allows cells to perceive environmental conditions and adapt
their behavior to those conditions.
10. Signal transduction mechanisms
a. are activated by stimulation of the receptor molecules on the cell surface.
b. conserved through phylogenesis.
c. transmit an environmental signal to intracellular effector molecules.
d. All of the above.
ANS: D
Many of the signal transduction systems are very ancient, although some of them have
arisen later in evolution. Their main role is to relay an extracellular signal to a specific
effector molecule to allow the cell to adjust its behavior to environmental signal.
11. The nucleus
a. contains hereditary information submerged in the nucleoplasm.
b. is separated from the cytoplasm by a nuclear envelope in eucaryotic cells.
c. is metabolically isolated from the cytoplasm by the double membrane.
d. Only a and b.
ANS: D