Cell Structures
Which organelle often takes up much of the volume of a plant cell?
A) lysosome
B) central vacuole
C) Golgi apparatus
D) chloroplast
B) central vacuole
The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and, therefore, abundant in liver cells?
A) rough endoplasmic reticulum
B) smooth endoplasmic reticulum
C) Golgi apparatus
D) nuclear envelope
B) smooth endoplasmic reticulum
Which of the following frequently imposes a limit on cell size?
A) the absence of a nucleus
B) the number of mitochondria in the cytoplasm
C) ratios of surface area to volume
D) the volume of the endomembrane system
C) ratios of surface area to volume
What kinds of molecules pass through a cell membrane most easily?
A) large and hydrophobic
B) small and hydrophobic
C) large polar
D) small and ionic
B) small and hydrophobic
Which of the following would be most appropriate method to observe the three-dimensional structure and organization of microvilli on an intestinal cell?
A) a hand lens (magnifying glass)
B) standard light microscopy
C) scanning electron microscopy
D) transmission electron microscopy
C) scanning electron microscopy
Which organelle is the primary site of ATP synthesis in eukaryotic cells?
A) lysosome
B) mitochondrion
C) Golgi apparatus
D) peroxisome
B) mitochondrion
A cell with a predominance of smooth endoplasmic reticulum is likely specialized to ________.
A) store large quantities of water
B) import and export large quantities of protein
C) actively secrete large quantities of protein
D) synthesize large quantities of lipids
D) synthesize large quantities of lipids
According to the fluid mosaic model of cell membranes, phospholipids ________.
A) can move laterally along the plane of the membrane
B) frequently flip-flop from one side of the membrane to the other
C) occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane
D) have hydrophilic tails in the interior of the membrane
A) can move laterally along the plane of the membrane
Which of the following statements describes a characteristic feature of a carrier protein in a plasma membrane?
A) It exhibits specificity for a particular type of molecule.
B) It requires the expenditure of cellular energy to function.
C) It works against diffusion.
D) It has no hydrophobic regions.
A) It exhibits specificity for a particular type of molecule.
When a plant cell, such as one from a tulip leaf, is submerged in a hypertonic solution, what is likely to occur?
A) The cell will burst.
B) Plasmolysis will shrink the interior of the cell.
C) The cell will become flaccid.
D) The cell will become turgid.
B) Plasmolysis will shrink the interior of the cell.
Thylakoids, DNA, and ribosomes are all components found in ________.
A) chloroplasts
B) mitochondria
C) lysosomes
D) nuclei
A) chloroplasts
A cell with a predominance of rough endoplasmic reticulum is most likely ________.
A) producing large quantities of proteins for secretion
B) producing large quantities of proteins in the cytosol
C) producing large quantities of carbohydrates to assemble an extensive cell wall matrix
D) producing large quantities of carbohydrates for storage in the vacuole
A) producing large quantities of proteins for secretion
An animal cell lacking carbohydrates on the external surface of its plasma membrane would likely be impaired in which function?
A) transporting ions against an electrochemical gradient
B) cell-cell recognition
C) attaching the plasma membrane to the cytoskeleton
D) establishing a diffusion barrier to charged molecules
B) cell-cell recognition
Which of the following statements about diffusion is true?
A) It is very rapid over long distances.
B) It requires an expenditure of energy by the cell.
C) It is an active process in which molecules move from a region of lower concentration to a region of higher concentration.
D) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
D) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
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 just on this information, the organism is most likely ________.
A) a nonmotile prokaryote
B) a motile bacterium
C) a motile archaea
D) a nonmotile eukaryote
E) a motile eukaryote
E) a motile eukaryote
Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?
A) membrane proteins of the inner nuclear envelope
B) free ribosomes and ribosomes attached to the ER
C) components of the cytoskeleton
D) cellulose fibers in the cell wall
C) components of the cytoskeleton
Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large, complex, undigested lipids. Which cellular organelle is most likely defective in this condition?
A) the lysosome
B) the Golgi apparatus
C) the smooth endoplasmic reticulum
D) the rough endoplasmic reticulum
A) the lysosome
Which of the following statements is a reasonable explanation for why unsaturated fatty acids help keep a membrane more fluid at lower temperatures?
A) The double bonds form kinks in the fatty acid tails, preventing adjacent lipids from packing tightly.
B) Unsaturated fatty acids have a higher cholesterol content, which prevents adjacent lipids from packing tightly.
C) Unsaturated fatty acids are more nonpolar than saturated fatty acids.
D) The double bonds block interaction among the hydrophilic head groups of the lipids.
A) The double bonds form kinks in the fatty acid tails, preventing adjacent lipids from packing tightly.
What will happen to a red blood cell (RBC), which has an internal ion content of about 0.9%, if it is placed into a beaker of pure water?
A) The cell would shrink because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.
B) The cell would shrink because the water in the beaker is hypertonic relative to the cytoplasm of the RBC.
C) The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.
D) The cell will remain the same size because the solution outside the cell is isotonic.
C) The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.
The evolution of eukaryotic cells most likely involved ________.
A) endosymbiosis of an oxygen-using bacterium in a larger bacterial host cell-the endosymbiont evolved into chloroplasts
B) endosymbiosis of a photosynthetic archaeal cell in a larger bacterial host cell to escape toxic oxygen—the anaerobic archaea evolved into chloroplasts
C) endosymbiosis of an oxygen-using bacterium in a larger bacterial host cell-the endosymbiont evolved into mitochondria
D) evolution of an endomembrane system and subsequent evolution of mitochondria from a portion of the smooth endoplasmic reticulum
C) endosymbiosis of an oxygen-using bacterium in a larger bacterial host cell-the endosymbiont evolved into mitochondria
Plant cell walls are composed of cellulose, while fungal cell walls are composed of chitin. A group of scientists hypothesize that this difference means the cell wall has largely different functions in plant cells and fungal cells. Alternatively, another group of scientists hypothesize that despite their biochemical differences, plant and fungal cell walls serve similar functions.
Which of the following observations would best support the alternative hypothesis described above?
A) Plant cell walls are found just outside the plasma membrane, while fungal cell walls are found just beneath the plasma membrane.
B) In both plant cells and fungal cells, the cell wall surrounds the outside of the cell membrane.
C) Some plant cells have secondary cell walls that confer additional rigidity, while fungal cells do not.
D) Photosynthesis occurs in plant cells, but it does not occur in fungal cells.
B) In both plant cells and fungal cells, the cell wall surrounds the outside of the cell membrane.
Cholesterol is an important component of animal cell membranes. Cholesterol molecules are often delivered to body cells by the blood, which transports the molecules in the form of cholesterol-protein complexes. The complexes must be moved into the body cells before the cholesterol molecules can be incorporated into the phospholipid bilayers of cell membranes.
Based on the information presented, which of the following is the most likely explanation for a buildup of cholesterol molecules in the blood of an animal?
A) The animal’s body cells are defective in exocytosis.
B) The animal’s body cells are defective in endocytosis.
C) The animal’s body cells are defective in cholesterol synthesis.
D) The animal’s body cells are defective in phospholipid synthesis.
B) The animal’s body cells are defective in endocytosis.
Organelles such as mitochondria and the endoplasmic reticulum have membranes that compartmentalize reactions and other metabolic processes. To function properly, the organelles must move substances across their membranes.
Which of the following statements describes a feature shared by mitochondria and the endoplasmic reticulum that increases the efficiency of their basic functions?
A) They have rigid, nonfluid membranes.
B) They have highly folded membranes.
C) They have membranes composed of many carbohydrates.
D) They have double membranes, with one membrane enclosed within the other.
B) They have highly folded membranes.
Which of the following statements is true regarding the movement of substances across cell membranes?
A) Ions are unable to move through the phospholipid bilayer because the nonpolar tail regions of the phospholipids are hydrophobic.
B) Ions are able to move through the phospholipid bilayer because the polar head regions of the phospholipids are charged.
C) Water is able to move through the phospholipid bilayer because the nonpolar tail regions of the phospholipids are charged.
D) Water is unable to move through the phospholipid bilayer because the polar head regions of the phospholipids are charged.
A) Ions are unable to move through the phospholipid bilayer because the nonpolar tail regions of the phospholipids are hydrophobic.
Aquaporins are channel proteins that facilitate the transport of water across the cell membrane. One group of researchers hypothesizes that without functional aquaporins, no water will be able to enter the cell. A different group proposes an alternative hypothesis, stating that even with nonfunctional aquaporins, a small amount of water will still cross the cell membrane. An experiment is set up in which plant cells with mutated (nonfunctional) aquaporins and plant cells with normally functioning aquaporins are both placed in distilled water.
Which of the following data would support the alternative hypothesis?
A) Cells with functional aquaporins exhibit low turgor pressure and are hypertonic.
B) Cells with functional aquaporins exhibit high turgor pressure and are hypotonic.
C) Cells with mutated aquaporins exhibit an absence of turgor pressure and are completely plasmolyzed.
D) Cells with mutated aquaporins exhibit moderate turgor pressure and are hypertonic.
D) Cells with mutated aquaporins exhibit moderate turgor pressure and are hypertonic.