, 1. Although the basic structure of the cell plasma membrane is formed by a lipid bilayer,
most of the specific membrane functions are carried out by:
A) Bound and transmembrane proteins
B) Complex, long carbohydrate chains
C) Surface antigens and hormone receptors
D) A gating system of selective ion channels
Ans: A
Feedback:
The functions of plasma membrane depend on the presence of proteins that are bound in
the lipid bilayer and some that have the ability to pass freely into and out of the cell.
Carbohydrate chains form a cell coat that surrounds the membrane and that contain
surface antigens and surface hormone receptors. Some ion channels are gated and open
only when the membrane potential changes significantly.
2. Which describes the function of the nucleus?
A) It is basically the site of protein synthesis in the body.
B) It contains the genetic code for the individual.
C) It is the transformer of cellular energy.
D) It initiates the process of aerobic metabolism.
Ans: B
Feedback:
The nucleus contains DNA, which contains the genetic code that contains the
information that controls cells. Ribosomes synthesize protein. Mitochondria transform
organic compounds into cellular energy. Mitochondria require oxygen for aerobic
metabolism, using hydrogen and carbon combined with oxygen molecules to form
carbon dioxide and water as energy is released.
3. Which of the following aspects of the function of the nucleus is performed by ribosomal
RNA (rRNA)?
A) Copying and carrying DNA instructions for protein synthesis
B) Carrying amino acids to the site of protein synthesis
C) Providing the site where protein synthesis occurs
D) Regulating and controlling protein synthesis
Ans: C
Feedback:
There are three types of ribonucleic acid (messenger RNA, ribosomal RNA, and transfer
RNA) that move to the cytoplasm and carry out the actual synthesis of proteins.
Messenger RNA (mRNA) copies and carries the DNA instructions for protein synthesis
to the cytoplasm; ribosomal RNA (rRNA) is the site of protein synthesis; and transfer
RNA (tRNA) transports amino acids to the site of protein synthesis for incorporation
into the protein being synthesized.
4. Which accurately explains the functions of the organelles lysosomes? They:
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,A) Are sacs filled with enzymes that breakdown and remove foreign substances and worn-
out cell parts
B) Function in association with the endoplasmic reticulum to modify protein end products
and package them into secretory granules or vesicles
C) Are small particles of nucleoproteins that are involved in the synthesis of proteins that
remain in the cell as cytoplasmic structural or functional elements
D) Are a dynamic system of interconnected membranous tubes that functions as a tubular
communication system for transporting various substances from one part of the cell to
another
Ans: A
Feedback:
Lysosomes are sacs that are filled with hydrolytic enzymes that aid in the processing and
removal of unwanted substances within the cytoplasm. The Golgi apparatus functions in
association with the endoplasmic reticulum to modify and package substances in
preparation for secretion, whereas ribosomes are small particles of nucleoproteins that
are involved in the synthesis of proteins. The ER is a tubular communication system for
transporting various substances from one part of the cell to another.
5. Impairment in the function of peroxisomes would result in:
A) Inadequate sites for protein synthesis
B) An inability to transport cellular products across the cell membrane
C) Insufficient energy production within a cell
D) Accumulation of free radicals in the cytoplasm
Ans: D
Feedback:
Peroxisomes function in the control of free radicals; unless degraded, these highly
unstable chemical compounds damage other cytoplasmic molecules. Peroxisomes do not
directly contribute to energy production, protein synthesis, or transport of cellular
secretions.
6. Although energy is not made in mitochondria, they are known as the “power plants” of
the cell because they:
A) Contain RNA for protein synthesis
B) Utilize glycolysis for oxidative energy
C) Extract energy from organic compounds
D) Store calcium bonds for muscle contractions
Ans: C
Feedback:
Mitochondria contain the enzymes needed for transforming organic compounds into
energy that is easily accessible to the cell. Mitochondria contain their own DNA.
Glycolysis is anaerobic metabolism and unrelated to oxidative energy. Mitochondria
store phosphate bonds (such as in ATP) to power cellular functions.
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, 7. Semen analysis indicates that the client's sperm have decreased motility. Which of the
following cellular components may be defective within the client's sperm?
A) Ribosomes
B) Microtubules
C) Mitochondria
D) Microfilaments
Ans: B
Feedback:
Abnormalities in the structure and function of microtubules and consequent dysfunction
of the flagella may contribute to impaired sperm motility. Ribosomes, microfilaments,
and mitochondria do not directly contribute to movement in cells such as cilia and
flagella.
8. When explaining the function of glycolysis as it relates to anaerobic metabolism, the
faculty will mention which of the following key points? Select all that apply.
A) Glycolysis requires the use of oxygen to begin the process.
B) Glycolysis occurs in mitochondrion-lacking cells.
C) Glycolysis provides the majority of the body's energy needs.
D) Pyruvic acid is an end result from a series of reactions that converts glucose.
Ans: B, D
Feedback:
Glycolysis is the anaerobic process by which energy is liberated from glucose, and it is
an important source of energy for cells that lack mitochondria. The process also
provides a temporary source of energy for cells that are deprived of an adequate supply
of oxygen. Glycolysis involves a sequence of reactions that converts glucose to pyruvic
acid, with the concomitant production of ATP from ADP. It accounts for a small
minority of the body's energy needs and results in NADH, hydrogen ions, ATP, and
pyruvic acid.
9. Aerobic metabolism, also known as oxidative metabolism, provides energy to the body
by:
A) Removing the phosphate bonds from ATP
B) Combining hydrogen and oxygen to form water
C) Activating pyruvate stored in the cytoplasm
D) Breaking down glucose to form lactic acid
Ans: B
Feedback:
Aerobic metabolism involves the combination of carbon ions from dietary nutrients,
hydrogen ions, and oxygen. The result is carbon dioxide and water as energy is released,
which is stored in ATP. Phosphate bonds are added (not removed from) to ADP to form
ATP. Pyruvate is formed from glucose in the anaerobic process of glycolysis and is
converted to lactic acid during anaerobic metabolism.
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