Evolve Review Questions
Exam 1
Chapter 1
1. It is true that a eukaryotic cell
A. is smaller than a prokaryotic cell.
B. contains structures called organelles. Correct
C. lacks a well-defined nucleus.
D. does not contain histones.
Eukaryotic cells contain organelles and histones, they have a well-defined nucleus, and are larger
than prokaryotic cells.
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2. The function of a histone found in a eukaryote cell focuses on cellular
A. division.
B. movement.
C. activities.
D. deoxyribonucleic acid (DNA) folding. Correct
The histones are binding proteins that cause the supercoiling of DNA into chromosomes and do
not affect cellular division, movement, or activities.
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3. An organelle that is responsible for the metabolism of cellular energy is referred to as
a/an
A. Golgi complex.
B. mitochondrion. Correct
C. endoplasmic reticulum.
D. nucleolus.
Mitochondria play a role in cellular metabolism, cellular respiration, and energy production. The
Golgi complex is responsible for processing and packaging proteins from the endoplasmic
reticulum, where they are synthesized. The nucleolus is a small, dense structure that contains the
ribonucleic acid (RNA), DNA, and DNA-binding proteins.
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4. Which statement best describes a desmosome?
A. A desmosome is a barrier to diffusion.
B. Desmosomes hold cells together by continuous bands. Correct
C. A desmosome is a communicating tunnel.
D. Desmosomes function as a zona occludens.
The desmosome is a type of cell junction. The other two types include tight junctions and gap
junctions. Desmosomes hold cells together by forming a continuous band of epithelial tissue or
belt (or button-like) points of contact. They are also a source of structural stability. Tight
junctions serve as barriers to diffusion and prevent the movement of substances through transport
proteins. Gap junctions are clusters of communicating tunnels.
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5. Which statement describes the function of a second messenger?
A. Binds with membrane-bound receptors via a ligand
B. Triggers a cascade of intracellular events Correct
C. Opens specific channels in the cell membrane
D. Blocks a membrane-bound receptor signal
The binding of a ligand to a cell surface receptor triggers the activation of intracellular second
messengers. Second messengers activate signal transduction pathways in the cell that can initiate
different intracellular events. Cyclic adenosine monophosphate (cAMP) and calcium (Ca++) are
the two major second-messenger pathways. First messengers are the extracellular ligands that
bind to cell surface receptors. Binding of first messengers can result in the opening or closing of
specific cell membrane channels or the activation of second messengers.
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6. Which statement is correct regarding cellular energy?
A. Glycolysis is the building of sugar molecules.
B. Oxidative cellular metabolism is a single reaction making adenosine triphosphate
(ATP).
C. Oxidative phosphorylation occurs in the mitochondria. Correct
D. Anaerobic glycolysis occurs in the presence of oxygen.
Oxidative phosphorylation occurs in the mitochondria. This is the mechanism by which the
energy produced from carbohydrates, fats, and proteins is transferred to ATP. Glycolysis is a
process that breaks down glucose molecules; it produces a net of two ATP molecules. Oxidation
is a process during which a pair of electrons are removed and transferred. Oxidative cellular
metabolism involves 10 biochemical reactions. Anaerobic glycolysis occurs in the absence of
oxygen. Aerobic means in the presence of oxygen.
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7. Movement of a solute molecule from an area of high concentration to an area of low
concentration is called
A. diffusion. Correct
B. filtration.
C. osmosis.
D. hydrostatic pressure.
Diffusion is the movement of a solute from an area of high concentration to an area of low
concentration. Osmosis is the movement of water down a concentration gradient from an area of
higher water concentration to an area of lower water concentration. Filtration is the movement of
water and solute through a membrane because of a greater pushing pressure on one side of the
membrane than the other. Hydrostatic pressure is the mechanical force of water pushing against a
cell membrane.
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8. Which is an example of an energy-releasing process?
A. Anabolism
B. Catabolism Correct
C. Substrate-induced reaction
D. Second messenger system
Catabolism is an energy-releasing process. The energy-using process is anabolism. A substrate is
a specific substance that is converted to a product in the reaction. A second messenger is a “passit-on signal.” This occurs when a first messenger activates a receptor that then triggers a pass-iton signal.
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9. Which describes an amphipathic molecule?
A. It is permeable to water only.
B. It is a nonpolar molecule.
C. It is both hydrophobic and hydrophilic. Correct
D. It is a one-layered structure.
The amphipathic molecule is both hydrophobic and hydrophilic. A hydrophilic molecule is a
charged, water-loving molecule. A hydrophobic molecule is an uncharged or water-hating
molecule. A polar molecule is another name for an amphipathic molecule.
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10. Which are the roles of relay chains in signal transduction? (Select all that apply.)
A. Transfer the signal Correct
B. Converge the signal
C. Amplify the signal Correct
D. Distribute the signal Correct
The functions of relay chains include transferring the signal from its reception point to another
part of the cell where it is expected; amplifying the signal received and making it stronger; and
distributing the signal so that it influences several processes in parallel. The signal can diverge,
not converge, and be relayed to several different intracellular targets.
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11. Which are functions of a protein? (Select all that apply.)
A. Pores or transport channels Correct
B. Enzymes that drive pumps Correct
C. Cell surface markers Correct
D. Synapses for cells
Proteins may act as transport channels, pores, cell surface markers, enzymes that drive pumps,
catalysts, and cell adhesion molecules (CAMs), or they may act as the key components of ATP
synthesis. Synapses are the connections between two nerve cells.
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Chapter 2