BIOS 195 Exam 2 - complexes in their cellular environments withou...

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BIOS 195 Exam 2

• Which of the following microscopy techniques is best suited for visualizing protein

complexes in their cellular environments without the use of preserva- tives?–Answer Cryo-electron microscopy

• Which of the following are surface appendages that allow a bacterium to stick to a surface?

–Answer Fimbriae

• What is a function of a bacterium's capsule?

–Answer Protection

• The DNA-containing region of this bacterial cell is indicated by the letter

.–Answer D

• Where is a bacterial cell's DNA found?

–Answer Nucleoid region

• In a bacterium, where are proteins synthesized?

–Answer Ribosomes

• What name is given to the rigid structure, found outside the plasma mem- brane, that

surrounds and supports the bacterial cell?–Answer Cell wall

• The is the bacterial structure that acts as a selective barrier, allowing nutrients to

enter the cell and wastes to leave the cell.–Answer 1 / 4

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Plasma membrane

• The structure that regulates the passage of material into and out of this bacterial cell is

indicated by the letter .–Answer C

• Which of the following clues would tell you if a cell is prokaryotic or eukaryotic?

–Answer Whether or not the cell is generally partitioned by internal membranes

• Which of the following structures are found in plant, animal, and bacterial cells?

–Answer Ribosomes

• Which of the following parameters is most likely to limit the maximum size of a cell?

–Answer The ratio of surface area to volume of cytoplasm

• A newly discovered unicellular organism isolated from acidic mine drainage is found to

contain a cell wall, a plasma membrane, two flagella, and peroxisomes. Based on this information only, the organism is most likely to be .–Answer A motile eukaryote

• When H. V. Wilson exposed two species of differently pigmented sponges to a chemical

that disrupted intercellular junctions, the cells of the sponges dissociated. Wilson then removed the chemical that caused dissociation and mixed the cells of the two species. He found that the sponges reassembled and that the cells from one species did not interact or form associations with the cells of the other species.Which of the following statements provides the most plausible explanation for the results of this experiment?–Answer The molecules responsible for cell-cell adhesion (cell junctions) differed between the two species of sponge.

• Disruption of nuclear pore complexes in a eukaryotic cell will most likely interfere with

the transport of which of the following molecules into the nucleus?–Answer 2 / 4

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Ribosomal proteins

• The nuclear lamina is an array of intermediate filaments that line the inner surface of the

nuclear membrane. Disassembly of the lamina by chemical treatment would most likely result in which of the following consequences?–Answer A change in the shape of the nucleus

• The liver is involved in detoxification of many poisons and drugs. Which of the following

structures is abundant in liver cells and primarily responsible for detoxification processes?–Answer Smooth endoplasmic reticulum

• Which of the following organelles is primarily responsible for the pro- duction and

modification of polysaccharides that will be secreted?–Answer Golgi apparatus

• Pancreatic cells, which secrete a large amount of digestive enzymes, are labeled with

radioactive leucine and then chased for several hours with non- radioactive leucine.Photographic emulsions are prepared at different times during the chase.Where would the black spots appear on an emulsion prepared 3 hours after the pulse?–Answer Exterior of the cell

• What path does a protein in the secretory pathway take, starting from its site of synthesis?

–Answer Rough ER, Golgi apparatus, secretory vesicles, plasma membrane

• During a different pulse-chase experiment, photographic emulsions were prepared at

different times during the chase, and radioactive spots were detected at the following times and locations – Which of the following conclusions can be drawn from these results?–Answer The final destination of the proteins was the lysosome. 3 / 4

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• What scientific hypotheses can be tested by a pulse-chase experiment?

–Answer - Movement of molecules through a cell over time

• True or false? Proteins produced during the "chase" phase of a pulse-chase experiment are

labeled with radioactive material.–Answer False

• What is the first step in a pulse-chase experiment?

–Answer Incubating cells with a labeled molecule

• A cell has formed a food vacuole as it ingested a food particle. Which of the following

events is associated with the breakdown of that food particle?-

–Answer Digestion of the food particle occurs in a vesicle enclosed by a membrane that separates the digestion from the cytoplasm

• Which of the following statements best describes some aspect of protein secretion from

prokaryotic cells?–Answer Proteins secreted by prokaryotes are likely syn- thesized on ribosomes bound to the cytoplasmic surface of the plasma membrane.

• A cell with a predominance of smooth endoplasmic reticulum is most likely specialized to

carry out which of the following processes?–Answer Synthesis of large quantities of lipids

• Tay-Sachs disease is a human genetic disorder that results in cellular accumulation of very

large, complex, undigested lipids. Which of the following organelles is most likely defective in Tay-Sachs disease?–Answer The lysosome

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