Cell Structure and Function Practice Test Questions

Which of the following describes how regions of phospholipids are arranged in the cell membrane?

Hydrophobic fatty acid regions face each other within the interior of the cell membrane. Hydrophobic fatty acid regions can't associate with the aqueous environments on either side of the cell membrane. So, the hydrophobic tails of fatty acids must face each other to form the hydrophobic interior of the cell membrane.

Which of the following statements about cell structures best supports the common ancestry of all living things?

All cells contain ribosomes. All cells use ribosomes to synthesize proteins. This suggests that ribosomes originated in a common ancestral cell early in the evolutionary process.

Which of the following must be true about the amino acids that make up the protein?

Amino acids with charged side groups are in contact with the phosphate region of the cell membrane. Amino acids with charged side groups are hydrophilic. These hydrophilic amino acids associate with the hydrophilic phosphate region of the cell membrane.

Which of the following is true about the amino acids that make up a transmembrane protein?

Amino acids with nonpolar side groups are in contact with the fatty acid region of the cell membrane. Amino acids with nonpolar side groups are hydrophobic. These hydrophobic amino acids associate with the hydrophobic fatty acid region of the cell membrane.

Which of the following best describes how high levels of cholesterol affect the cell membrane at certain temperatures?

At high temperatures, high amounts of cholesterol decrease the fluidity of the cell membrane. When temperatures are high, the fluidity of the cell membrane may increase to a point that makes it nonfunctional. Cholesterol prevents this by decreasing the movement of phospholipids, which decreases the fluidity of the cell membrane.

Which of the following best describes how the internal environment of a lysosome compares to the environment of the cytosol?

The internal environment of a lysosome is more acidic than the cytosol. The internal environment of a lysosome has a pH of 4.5 to 5 while the pH of the cytosol is 7 to 7.4. The acidic environment of the lysosome allows specialized enzymes to function in digestion and waste removal.

Why is it bad if chloroplast breaks

During photosynthesis, glucose is produced as a fuel source for the cell. Damaged chloroplasts will be unable to perform this function.

A cell is treated with a toxin that prevents the synthesis of new lysosomes. However, the cell continues to produce the hydrolytic enzymes normally found in lysosomes. In which of the following structures are the hydrolytic enzymes most likely to accumulate?

Golgi complex Lysosomes are synthesized by the Golgi complex. If new lysosomes aren't synthesized, and the hydrolytic enzymes continue to be produced, the hydrolytic enzymes will accumulate in the Golgi complex.

Which of the following statements is true for both prokaryotic and eukaryotic cells?

Ribosomes synthesize proteins using mRNA sequences. All cells use ribosomes to synthesize proteins. In prokaryotic cells, ribosomes are found free-floating in the cytosol. In eukaryotic cells, ribosomes are found in the cytosol or bound to the rough ER.

Which of the following most accurately explains why the Golgi complex is often near the rough ER?

The Golgi complex modifies and packages proteins that are produced in the rough ER. The rough ER has ribosomes bound to its surface. These ribosomes produce proteins that are sent to the Golgi complex for packaging and further transport.

Which of the following correctly describes how high levels of fatty acid structures contribute to the rigidity of the cell membrane?

The cell membrane becomes more rigid as the amount of saturated fatty acids with a straight structure increases. Saturated fatty acids have hydrocarbon tails with a straight structure. A straight structure allows many saturated fatty acids to be densely packed together, which makes the cell membrane more rigid.

Which of the following best describes how kinks within lipids contribute to the fluidity of the cell membrane?

The hydrocarbon tails of unsaturated fatty acids form kinks that prevent dense packing of components within the cell membrane. Kinks form in the hydrocarbon tails of unsaturated fatty acids due to double bonds between carbon atoms. These kinks increase the spacing between cell membrane components, so this prevents dense packing and promotes fluidity within the cell membrane.

Which of the following best explains why excess lipids accumulate in individuals with Wolman disease?

The lysosomes contain an insufficient amount of lipid-digesting enzymes. Lysosomes are responsible for digesting excess lipids using digestive enzymes. If there is a build-up of lipids in the cell, it is likely due to a shortage of digestive enzymes.

Which of the following is the most likely outcome of Leigh syndrome on affected mitochondria?

The mitochondria cannot produce sufficient ATP to power normal cellular processes. The main function of mitochondria is to produce ATP, a major energy source in the cell. In individuals with Leigh syndrome, affected mitochondria are unable to produce enough ATP to fuel cellular functions.

Which of the following best describes a difference between the rough ER and the smooth ER?

The rough ER has ribosomes on its surface, but the smooth ER does not. The rough ER has ribosomes bound to its surface, which give it a "rough" appearance. The smooth ER does not have ribosomes bound to it, so it has a "smooth" appearance.

Which of the following best describes how the central vacuole helps support the structure of a plant cell?

When the central vacuole is full of water, it applies pressure to the cell wall and maintains the shape of the cell. When the central vacuole stores a large amount of water, it occupies most of the cell. This applies pressure against the cell membrane, allowing the cell to keep its rigid shape.

What do lysosomes do

digest excess materials, such as accumulated gangliosides. If gangliosides accumulate, it is likely due to lysosomal dysfunction.

A damaged cell is unable to properly modify proteins after they are synthesized, which causes the proteins to misfold. Which of the following structures is most likely damaged in the cell?

endoplasmic reticulum The endoplasmic reticulum (ER) modifies proteins that are synthesized by ribosomes. So, a damaged ER results in improper modifications that lead to protein misfolding.