1. Which statement best describes the cellular function of metabolic absorption?
a. Cells can produce proteins. c. Cells can take in and use nutrients.
b. Cells can secrete digestive enzymes. d. Cells can synthesize fats.
ANS: C
In metabolic absorption, all cells take in and use nutrients and other substances from theirÂ
surroundings. The remaining options are not inclusive in their descriptions of cellularÂ
metabolic absorption.
PTS: 1 REF: Page 2
2. Most of a cell’s genetic information, including RNA and DNA, is contained in the:
a. Mitochondria c. Nucleolus
b. Ribosome d. Lysosome
ANS: C
The nucleus contains the nucleolus, a small dense structure composed largely of RNA, mostÂ
of the cellular DNA, and the DNA-binding proteins, such as the histones, which regulate itsÂ
activity. The other options do not contain most of a cell’s genetic information.
PTS: 1 REF: Page 2
3. Which component of the cell produces hydrogen peroxide (H2O2) by using oxygen to removeÂ
hydrogen atoms from specific substrates in an oxidative reaction?
a. Lysosomes c. Ribosomes
b. Peroxisomes d. Oxyhydrosomes
ANS: B
Peroxisomes are so named because they usually contain enzymes that use oxygen to removeÂ
hydrogen atoms from specific substrates in an oxidative reaction that produces H2O2, which isÂ
a powerful oxidant and potentially destructive if it accumulates or escapes from peroxisomes.Â
Ribosomes are RNA-protein complexes (nucleoproteins) that are synthesized in the nucleolusÂ
and secreted into the cytoplasm through pores in the nuclear envelope called nuclear poreÂ
complexes. Lysosomes are saclike structures that originate from the Golgi complex andÂ
contain more than 40 digestive enzymes called hydrolases, which catalyze bonds in proteins,Â
lipids, nucleic acids, and carbohydrates. Oxyhydrosomes are involved in enzyme production.
PTS: 1 REF: Page 8
4. Which cell component is capable of cellular autodigestion when it is released during cellÂ
injury?
a. Ribosome c. Smooth endoplasmic reticulum
b. Golgi complex d. Lysosomes
ANS: D
The lysosomal membrane acts as a protective shield between the powerful digestive enzymesÂ
within the lysosome and the cytoplasm, preventing their leakage into the cytoplasmic matrix.Â
Disruption of the membrane by various treatments or cellular injury leads to a release of theÂ
lysosomal enzymes, which can then react with their specific substrates, causing cellular
self-digestion. The other options do not correctly describe this process.
PTS: 1 REF: Pages 7-8
5. What is the sequence of steps in the development of a digestive enzyme by the pancreas cellsÂ
from the initial transcription to the release from the cell?
a. The enzyme is transcribed from DNA by RNA in the nucleus, proceeds to theÂ
ribosome for synthesis, and is transported in a secretory vesicle to the cellÂ
membrane.
b. The enzyme is transcribed from RNA by DNA in the nucleus, proceeds to theÂ
lysosome for synthesis, and is transported in an encapsulated membrane to the cellÂ
membrane.
c. The enzyme is transcribed by the mitochondria in the nucleus, proceeds to theÂ
ribosome for synthesis, and is transported in a cytoskeleton to the cell membrane.
d. The enzyme is transcribed from DNA by RNA in the nucleus, proceeds to theÂ
Golgi complex for synthesis, and is transported in a cytosol to the cell membrane.
ANS: A
The enzyme is transcribed from DNA by RNA in the nucleus, proceeds to the ribosome forÂ
synthesis, and is transported in a secretory vesicle to the cell membrane. The other options doÂ
not correctly describe this process.
PTS: 1 REF: Page 7 | Figure 1-5
6. During which phase of the cell cycle is DNA synthesized?
a. G1 c. G2
b. S d. M
ANS: B
The four designated phases of the cell cycle are: (1) the G1 phase (G = gap), which is theÂ
period between the M phase (M = mitosis) and the start of DNA synthesis; (2) the S phase (SÂ
= synthesis), during which DNA is synthesized in the cell nucleus; (3) the G2 phase, duringÂ
which RNA and protein synthesis occurs, the period between the completion of DNAÂ
synthesis and the next phase (M); and (4) the M phase, which includes nuclear andÂ
cytoplasmic division.
PTS: 1 REF: Page 37
7. What organic compound facilitates transportation across cell membranes by acting asÂ
receptors, transport channels for electrolytes, and enzymes to drive active pumps?
a. Lipids c. Proteins
b. Proteases d. Carbohydrates
ANS: C