Chapter 01: Cellular Biology

MULTIPLE CHOICE

1. Which statement best describes the cellular function of metabolic absorption?

a. Cells can produce proteins.

b. Cells can secrete digestive enzymes.

c. Cells can take in and use nutrients.

d. Cells can synthesize fats.

ANS: C

In metabolic absorption, all cells take in and use nutrients and other substances from their

surroundings. The remaining options are not inclusive in their descriptions of cellular metabolic

absorption.

PTS: 1 DIF: Cognitive Level: Remembering

2. Where is most of a cell’s genetic in4mation, including RNA and DNA, contained?

a. Mitochondria

b. Ribosome

c. Nucleolus

d. Lysosome

ANS: C

The nucleus contains the nucleolus, a small dense structure composed largely of RNA, most of

the cellular DNA, and the DNA-binding proteins, such as the histones, which regulate its

activity. The mitochondria are responsible 4 cellular respiration and energy production.

Ribosomes’ chief function is to provide sites 4 cellular protein synthesis. Lysosomes function

as the intracellular digestive system.

PTS: 1 DIF: Cognitive Level: Remembering

3. Which component of the cell produces hydrogen peroxide (H2O2) by using oxygen to remove

hydrogen atoms from specific substrates in an oxidative reaction?

a. Lysosomes

b. Peroxisomes

c. Ribosomes

d. Endosome

ANS: B

Test Bank - Pathophysiology: The Biologic Basis 4 Disease in Adults and Children (8th) 5

Peroxisomes are so named because they usually contain enzymes that use oxygen to remove

hydrogen atoms from specific substrates in an oxidative reaction that produces H2O2, which is a

powerful oxidant and potentially destructive if it accumulates or escapes from peroxisomes.

Ribosomes are RNA-protein complexes (nucleoproteins) that are synthesized in the nucleolus

and secreted into the cytoplasm through pores in the nuclear envelope called nuclear pore

complexes. Lysosomes are saclike structures that originate from the Golgi complex and contain

more than 40 digestive enzymes called hydrolases, which catalyze bonds in proteins, lipids,

nucleic acids, and carbohydrates. An endosome is a vesical that has been pinched off from the

cellular membrane.

PTS: 1 DIF: Cognitive Level: Remembering

4. Which cell component is capable of cellular autodigestion when it is released during cell injury?

a. Ribosome

b. Golgi complex

c. Smooth endoplasmic reticulum

d. Lysosomes

ANS: D

The lysosomal membrane acts as a protective shield between the powerful digestive enzymes

within the lysosome and the cytoplasm, preventing their leakage into the cytoplasmic matrix.

Disruption of the membrane by various treatments or cellular injury leads to a release of the

lysosomal enzymes, which can then react with their specific substrates, causing cellular selfdigestion. The chief function of a ribosome is to provide sites 4 cellular protein synthesis. The

Golgi complex is a network of flattened, smooth vesicles and membranes often located near the

cell nucleus. The smooth endoplasmic reticulum is involved in steroid hormone production and

removing toxic substances from the cell.

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5. Which cAMP-mediated response is related to antidiuretic hormone?

a. Increased heart rate and 4ce of contraction

b. Secretion of cortisol

c. Increased retention of water

d. Breakdown of fat

ANS: C

Antidiuretic hormone leads to increased retention of water in the body. Epinephrine causes

increases in heart rate and 4ce of contraction. Increased cortisol secretion is due to ACTH.

Breakdown of fat is due to glucagon.

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6. During which phase of the cell cycle is DNA synthesized?

a. G1

b. S

c. G2

d. M

Test Bank - Pathophysiology: The Biologic Basis 4 Disease in Adults and Children (8th) 6

ANS: B

The four designated phases of the cell cycle are: (1) the G1 phase (G = gap), which is the period

between the M phase (M = mitosis) and the start of DNA synthesis; (2) the S phase (S =

synthesis), during which DNA is synthesized in the cell nucleus; (3) the G2 phase, during which

RNA and protein synthesis occurs, the period between the completion of DNA synthesis and the

next phase (M); and (4) the M phase, which includes nuclear and cytoplasmic division.

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7. What organic compound facilitates transportation across cell membranes by acting as receptors,

transport channels 4 electrolytes, and enzymes to drive active pumps?

a. Lipids

b. Proteases

c. Proteins

d. Carbohydrates

ANS: C

Proteins have several functions, including acting as receptors, transport channels 4 electrolytes,

and enzymes to drive active pumps Lipids help act as the “glue” holding cell membranes

together. Proteases cause the breakdown of protein. Carbohydrates are involved in cellular

protection and lubrication and help produce energy via oxidative phosphorylation.

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8. Understanding the various steps of proteolytic cascades may be useful in designing drug therapy

4 which human diseases?

a. Cardiac and vascular disorders

b. Autoimmune and malignant disorders

c. Gastrointestinal and renal disorders

d. Endocrine and gastrointestinal disorders

ANS: B

Understanding the various steps involved in this process is crucial 4 designing drug

interventions. Dysregulation of proteases features prominently in many human diseases,

including cancer, autoimmunity, and neurodegenerative disorders. Cardiac, vascular,

gastrointestinal, renal, and endocrine disorders do not involve this process.

PTS: 1 DIF: Cognitive Level: Remembering

9. Which structure prevents water-soluble molecules from entering cells across the plasma

membrane?

a. Carbohydrate chains

b. Glycoprotein channels

c. Membrane channel proteins

d. Lipid bilayer

ANS: D

Test Bank - Pathophysiology: The Biologic Basis 4 Disease in Adults and Children (8th) 7

The bilayer’s structure accounts 4 one of the essential functions of the plasma membrane. It is

impermeable to most water-soluble molecules (molecules that dissolve in water) because the

water-soluble molecules are insoluble in the oily core region. The bilayer serves as a barrier to

the diffusion of water and hydrophilic substances while allowing lipid-soluble molecules, such as

oxygen (O2) and carbon dioxide (CO2), to diffuse through it readily. Carbohydrate chains,

glycoprotein channels, and membrane channel proteins do not prevent water-soluble molecules

from entering cells across the cell membrane.

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10. A student asks 4 an explanation of the absolute refractory period of the action potential. What

response by the professor is best?

a. A stronger than normal impulse will evoke another response.

b. No stimulus is able to evoke another response at this time.

c. Multiple stimuli can produce more rapid action potentials.

d. The hyperpolarized state means a weaker stimulus produces a response.

ANS: B

During the absolute refractory state of the action potential, no stimulus is able to evoke another

response from the cell. A stronger than normal impulse may generate a response in the relative

refractory period. This period of time is not related to the number of stimuli. A hyperpolarized

state means a stronger than normal stimulus would be needed to generate a response.

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11. Which 4m of cell communication is used to communicate within the cell itself and with other

cells in direct physical contact?

a. Protein channel (gap junction)

b. Plasma membrane-bound signaling molecules

c. Hormone secretion such as neurotransmitters

d. Extracellular chemical messengers such as ligands

ANS: B

Cells communicate in three main ways; they display plasma membrane-bound signaling

molecules that affect the cell itself and other cells in direct physical contact with it, they affect

receptor proteins inside the target cell, and they 4m protein channels (gap junctions) that

directly coordinate the activities of adjacent cells. Neurotransmitters are released by neurons and

cross the synaptic cleft to communicate with the cells they innervate. Ligands are involved in

binding processes.

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12. Which mode of chemical signaling uses blood to transport communication to cells some distance

away?

a. Paracrine

b. Autocrine

c. Neurotransmitter

d. Hormonal

Test Bank - Pathophysiology: The Biologic Basis 4 Disease in Adults and Children (8th) 8

ANS: D

Chemical signaling can be classified into three categories: (1) local-chemical mediator, (2)

hormone, and (3) neurotransmitter. Hormones are released by one set of cells and travel through

tissues or the bloodstream to another set of cells where they produce a response by those cells. In

paracrine signaling, cells secrete local chemical mediators that are quickly absorbed, destroyed,

or immobilized. Paracrine signaling requires close membrane-to-membrane contact. Paracrine

signaling usually involves different cell types; however, cells also may produce signals that they,

themselves, respond to, which is called autocrine signaling. Neurotransmitters are released by

neurons and cross the synaptic cleft to communicate with the cells they innervate.

PTS: 1 DIF: Cognitive Level: Remembering

13. Which mode of chemical signaling uses local chemical mediators that are quickly taken up,

destroyed, or immobilized?

a. Paracrine

b. Autocrine

c. Neurotransmitter

d. Hormone

ANS: A

In paracrine signaling, cells secrete local chemical mediators that are quickly taken up,

destroyed, or immobilized. Autocrine signaling occurs when the target cells produce signals that

they themselves respond to. Neurotransmitters are released by neurons and cross the synaptic

cleft to communicate with the cells they innervate. Hormones are released by one set of cells and

travel through tissues or the bloodstream to another set of cells where they produce a response by

those cells.