Chapter 4: A Tour of the Cell and Chapter 5: The Working Cell
Which of the following statements about electron microscopes is true? A) Electron microscopes focus electron beams to create a magnified image of an object. B) Scanning electron microscopes are used to study the details of internal cell structure. C) Transmission electron microscopes are mainly used to study cell surfaces. D) Specimens must be sectioned to be viewed under a scanning electron microscope.
A) Electron microscopes focus electron beams to create a magnified image of an object.
In the lab, you use a special balloon that is permeable to water but not sucrose to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the following will occur? A) Water will leave the balloon. B) Water will enter the balloon. C) Sucrose will leave the balloon. D) Sucrose will enter the balloon.
A) Water will leave the balloon.
If you were working for a pharmaceutical company as part of a drug discovery team, which of these enzyme inhibitors would you suggest as a productive avenue for drug development? A) a drug to treat high blood pressure that reversibly inhibits an enzyme catalyzing production of a chemical that causes blood vessels to contract B) a drug to treat diabetes that irreversibly inhibits an enzyme in the metabolic pathway to synthesize glucose C) a compound that acts as a competitive inhibitor for a digestive enzyme produced only in the presence of certain foods D) a compound that inhibits enzymes by significantly changing the pH throughout the body
A) a drug to treat high blood pressure that reversibly inhibits an enzyme catalyzing production of a chemical that causes blood vessels to contract
A scientist wants to examine living cells lining the respiratory tract to determine how the cells use tiny hairs to move dirt and mucus away from the lungs. Which of the following instruments would be best, and why? A) a light microscope, because it allows observations of whole, live cells B) a transmission electron microscope, because it has high resolution C) a scanning electron microscope, because it can reveal structures on cell surfaces D) a scanning electron microscope, because it can be used to observe whole cells without slicing them
A) a light microscope, because it allows observations of whole, live cells
Relaying a message from a membrane receptor to a molecule that performs a specific function within a cell occurs when A) a signaling molecule binds to a protein that extends to the outside of the cell. B) a protein receptor on the interior of the membrane become bounds by a signaling molecule. C) the extracellular matrix is moved to the inside of the cell. D) glycoproteins are recognized by other cells.
A) a signaling molecule binds to a protein that extends to the outside of the cell.
Resolution is the A) ability of an optical instrument to show two close objects as separate. B) size of an image. C) ability of an optical instrument to magnify an image. D) distance between the lenses of a microscope.
A) ability of an optical instrument to show two close objects as separate.
Aquaporins A) allow water to cross the plasma membrane via facilitated diffusion. B) allow water to cross the plasma membrane against its concentration gradient. C) allow for the active transport of water. D) are found in all cells.
A) allow water to cross the plasma membrane via facilitated diffusion.
In the plasma membrane, the phospholipid heads A) are hydrophilic and face outward toward the aqueous solution on both sides of the membrane. B) are hydrophilic and face inward, shielded from water. C) are hydrophobic and face outward toward the aqueous solution on both sides of the membrane. D) are hydrophobic and face inward, shielded from water.
A) are hydrophilic and face outward toward the aqueous solution on both sides of the membrane.
You are told that the cells on a microscope slide are plant, animal, or bacterial. You look at them through a microscope and see cell walls and membrane-bound organelles. You conclude correctly that the cells A) are plant cells. B) are animal cells. C) are bacterial cells. D) could be either plant or bacterial cells.
A) are plant cells.
Which of the following cells has the greatest surface-to-volume ratio? A) bacterium B) human red blood cell C) human muscle cell D) ostrich egg
A) bacterium
A plant cell in a hypotonic solution A) becomes turgid because of an inflow of water. B) bursts because of an inflow of water. C) shrivels because of an outflow of water. D) wilts because of an outflow of water.
A) becomes turgid because of an inflow of water.
Tay-Sachs disease A) causes an accumulation of lipids in brain cells. B) involves damage to liver cells. C) is due to the absence of an enzyme that digests polysaccharides. D) prevents the breakdown of glycogen.
A) causes an accumulation of lipids in brain cells.
The function of mitochondria is A) cellular respiration. B) lipid synthesis. C) photosynthesis. D) intracellular digestion.
A) cellular respiration.
Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing A) chemical energy into kinetic energy. B) chemical energy into potential energy. C) kinetic energy into potential energy. D) kinetic energy into thermal energy.
A) chemical energy into kinetic energy.
Unlike animal cells, plant cells have ________ and ________. Unlike plant cells, animal cells have ________. A) chloroplasts; cell walls; centrioles B) centrioles; chloroplasts; cell walls C) chloroplasts; cell walls; a nucleus D) centrioles; cell walls; large central vacuoles
A) chloroplasts; cell walls; centrioles
The complex of proteins and DNA in a nondividing cell is called A) chromatin. B) a nucleolus. C) a ribosome. D) a lysosome.
A) chromatin.
The nucleoid region of a prokaryotic cell A) contains the cell's DNA. B) separates the RNA from the cytoplasm. C) is surrounded by a nucleoid membrane. D) contains the cell's nucleoli.
A) contains the cell's DNA.
Small, nonpolar, hydrophobic molecules such as fatty acids A) easily pass through a membrane's lipid bilayer. B) very slowly diffuse through a membrane's lipid bilayer. C) require transport proteins to pass through a membrane's lipid bilayer. D) are actively transported across cell membranes.
A) easily pass through a membrane's lipid bilayer.
When a cell uses chemical energy to perform work, it uses the energy released from a(n) ________ reaction to drive a(n) ________ reaction. A) exergonic; endergonic B) endergonic; exergonic C) exergonic; spontaneous D) spontaneous; exergonic
A) exergonic; endergonic
When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will A) exhibit a net movement to the side with lower free water concentration. B) exhibit a net movement to the side with higher free water concentration. C) exhibit a net movement to the side with lower solute concentration. D) exhibit an equal movement in both directions across the membrane.
A) exhibit a net movement to the side with lower free water concentration.
A cell that has neither a net gain of water nor net loss of water when it is immersed in a solution must be A) isotonic to its environment. B) hypertonic to its environment. C) hypotonic to its environment. D) metabolically inactive.
A) isotonic to its environment.
When an enzyme catalyzes a reaction, A) it lowers the activation energy of the reaction. B) it raises the activation energy of the reaction. C) it acts as a reactant. D) it is used once and discarded.
A) it lowers the activation energy of the reaction.
In a hypotonic solution, an animal cell will A) lyse. B) experience turgor. C) neither gain nor lose water. D) shrivel.
A) lyse.
Which organelle is involved in the catabolism of fatty acids and the detoxification of alcohol? A) peroxisome B) Golgi apparatus C) smooth ER D) ribosomes
A) peroxisome
Archaea are composed of ________ cells. A) prokaryotic B) bacterial C) eukaryotic D) animal
A) prokaryotic
Which of the following processes is classified as a metabolic pathway? A) protein synthesis B) osmosis C) cell lysis D) passive diffusion
A) protein synthesis
Anything that prevents ATP formation will most likely A) result in cell death. B) force the cell to rely on lipids for energy. C) force the cell to rely on ADP for energy. D) have no effect on the cell.
A) result in cell death.
Insulin is a protein that is produced by pancreatic cells and secreted into the bloodstream. Which of the following options correctly lists the order of the structures through which insulin passes from its production to its exit from the cell? A) rough ER, transport vesicles, Golgi apparatus, transport vesicles, cell membrane B) rough ER, lysosomes, transport vesicles, cell membrane C) rough ER, Golgi apparatus, smooth ER, cell membrane D) rough ER, transport vesicles, Golgi apparatus, vacuole, cell membrane
A) rough ER, transport vesicles, Golgi apparatus, transport vesicles, cell membrane
Smooth endoplasmic reticulum A) stores calcium ions in muscle cells. B) is the major site of carbohydrate synthesis in eukaryotic cells. C) produces proteins for cell membranes. D) helps assemble ribosomes for protein synthesis.
A) stores calcium ions in muscle cells.
Osmosis can be defined as A) the diffusion of water. B) the diffusion of nonpolar molecules. C) active transport. D) the diffusion of a solute.
A) the diffusion of water.
The stroma is the A) thick fluid enclosed by the inner chloroplast membrane. B) watery fluid enclosed by the inner membrane of a mitochondrion. C) space between the inner and outer membranes of a chloroplast. D) space between the inner and outer membranes of a mitochondrion.
A) thick fluid enclosed by the inner chloroplast membrane.
Cyanide inhibits mitochondrial function; as a result, the rate of A) ATP synthesis increases. B) ATP synthesis decreases. C) photosynthesis increases. D) protein synthesis increases.
B) ATP synthesis decreases.
Which of the following statements regarding cells is false? A) All cells are enclosed in a membrane that maintains internal conditions different from the surroundings. B) All cells have a cell wall. C) All cells can interconvert forms of energy. D) All cells have DNA as their genetic material.
B) All cells have a cell wall.
Which of the following statements about cells is true? A) All cells have cell walls. B) All cells have internal structures that move. C) All cells are attached to other cells. D) All cells are motile.
B) All cells have internal structures that move.
A child is brought to the hospital with a fever of 107°F. Doctors immediately order an ice bath to lower the child's temperature. Which of the following statements offers the most logical explanation for this action? A) Elevated body temperature will increase reaction rates in the child's cells and overload the limited number of enzymes found in the cell. B) Elevated body temperatures may denature enzymes. This would interfere with the cell's abilities to catalyze various reactions. C) Elevated body temperatures will increase the energy of activation needed to start various chemical reactions in the body. This will interfere with the ability of enzymes to catalyze vital chemical reactions. D) Elevated body temperatures cause molecules to vibrate more quickly and prevent enzymes from easily attaching to reactants. This would slow vital body reactions.
B) Elevated body temperatures may denature enzymes. This would interfere with the cell's abilities to catalyze various reactions.
Your throat is dry, and you want the last cough drop in the box to last a long time in your mouth. What should you do? A) Break the cough drop into little pieces and put them all in your mouth. Since each little piece must be dissolved separately, the drop will last longer. B) Keep the cough drop whole. This maintains the largest surface-to-volume ratio and slows the dissolution of the cough drop. C) Break the cough drop into little pieces and put them all in your mouth. This decreases the surface-to-volume ratio and slows the dissolution of the cough drop. D) It doesn't matter if the cough drop is in one piece or many pieces; the total amount of cough drop is all that matters.
B) Keep the cough drop whole. This maintains the largest surface-to-volume ratio and slows the dissolution of the cough drop.
Which of the following statements about lysosomes is false? A) Lysosomes help to digest worn-out or damaged organelles. B) Lysosomes synthesize proteins from the recycled amino acids. C) Lysosomes fuse with food vacuoles to expose nutrients to lysosomal enzymes. D) Lysosomes destroy harmful bacteria engulfed by white blood cells.
B) Lysosomes synthesize proteins from the recycled amino acids.
Which of the following statements about the cytoskeleton is false? A) The cytoskeleton helps to support cells. B) Once laid down, the elements of the cytoskeleton are fixed and remain permanently in place. C) The cytoskeleton is composed of three types of fibers: microfilaments, microtubules, and intermediate filaments. D) The cytoskeleton plays an important role in amoeboid motion.
B) Once laid down, the elements of the cytoskeleton are fixed and remain permanently in place.
________ cells lack a membrane-enclosed nucleus. A) Plant B) Prokaryotic C) Eukaryotic D) Fungal
B) Prokaryotic
Which of the following statements is true for all types of passive transport? A) Proteins are needed to transport molecules across the membrane. B) The concentration gradient is the driving force. C) Only small polar molecules are able to cross the plasma membrane. D) Ions never cross the plasma membrane by passive transport.
B) The concentration gradient is the driving force.
Aspirin and other nonsteroidal anti-inflammatory drugs (NSAID)inhibit inflammation by inhibiting an enzyme in the prostaglandin pathway, but by inhibiting this enzyme and this pathway they also inhibit pathways that protect the stomach from damage by stomach acid and that prevent aggregation of blood platelets to form blood clots. What can you conclude from this? A) The enzyme inhibition is nonreversible. B) The enzyme is found in many different types of cells. C) Prostaglandins cause blood clotting. D) Aspirin should not be given to people who people who need to synthesize enzymes.
B) The enzyme is found in many different types of cells.
A scientist wants to magnify a pollen grain 8,000 times and examine the ridges and pores on its surface. Which of the following instruments would be best? A) a transmission electron microscope B) a scanning electron microscope C) a fluorescence confocal microscope D) an inverted light microscope
B) a scanning electron microscope
The endosymbiosis hypothesis proposes that A) two separate cells worked cooperatively and one benefited from the other. B) a small cell lived inside a larger cell to the benefit of both cells. C) a large cell engulfed and digested a smaller cell, exposing its enzymes for use by the larger cell. D) two cells merged into one cell, improving the enzyme function of the new cell.
B) a small cell lived inside a larger cell to the benefit of both cells.
The membranous compartmentalization of a cell A) divides the cell into two equal-sized halves. B) allows different chemical conditions to be maintained in different parts of the cell. C) requires the presence of a cell wall. D) is common to both prokaryotes and eukaryotes.
B) allows different chemical conditions to be maintained in different parts of the cell.
Skin cells are fastened into strong sheets by A) basal bodies. B) anchoring junctions. C) tight junctions. D) communicating junctions.
B) anchoring junctions.
A scanning electron microscope is used to study ________, whereas a transmission electron microscope is used to study ________. A) live cells; dead cells B) cell surfaces; internal cell structures C) dead cells; live cells D) internal cell structures; cell surfaces
B) cell surfaces; internal cell structures
Phagocytosis is to eating as pinocytosis is to A) osmosis. B) drinking. C) chewing. D) lysis.
B) drinking.
An immune system cell called the plasma cell produces thousands of antibodies per second for release into the body. What type of intracellular structure would you expect to be very prominent within the cell? A) nucleus B) endoplasmic reticulum C) peroxisome D) microtubules
B) endoplasmic reticulum
Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach. This enzyme is a protein. Which of the following processes could be responsible for its secretion? A) endocytosis B) exocytosis C) diffusion D) pinocytosis
B) exocytosis
A manufacturing company dumps its wastes into a nearby pond. One of the wastes is found to paralyze the contractile vacuoles of certain protists. A biologist looking at individual samples of these organisms taken from the pond would find that they A) have lost water and shrunk. B) have gained water and burst. C) have died of malnutrition. D) have died because wastes have built up in the cytoplasm.
B) have gained water and burst.
The cholesterol associated with animal cell membranes A) is attached to membrane proteins and extends into the watery environment surrounding the cell. B) helps to keep phospholipids from being too close to one another. C) is an abnormality resulting from a diet high in cholesterol. D) helps solidify the membranes when the room temperature is below freezing.
B) helps to keep phospholipids from being too close to one another.
In the lab, you use a special balloon that is permeable to water but not sucrose to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. The solution in the balloon is ________ relative to the solution in the beaker. A) isotonic B) hypotonic C) hypertonic D) hydrophilic
B) hypotonic
Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of these organelles tells you that the environment A) is isotonic to the protozoan. B) is hypotonic to the protozoan. C) contains a higher concentration of solutes than the protozoan. D) is hypertonic to the protozoan.
B) is hypotonic to the protozoan.
Tay-Sachs disease results from the malfunction of A) mitochondria. B) lysosomes. C) endoplasmic reticulum. D) nucleoli.
B) lysosomes.
The endosymbiosis hypothesis is supported by all of the following pieces of evidence except the fact that A) mitochondria have circular DNA like prokaryotes. B) mitochondria lack ribosomes like prokaryotes. C) chloroplasts have ribosomes like prokaryotes. D) chloroplasts reproduce through a splitting process like certain prokaryotes
B) mitochondria lack ribosomes like prokaryotes.
Many physiological conditions are related to particular proteins in cell membranes. The number of insulin receptors in membranes is related to the amount of insulin present around those cells. If the presence of increased insulin results in a decrease in receptors and a decrease in insulin results in an increase in insulin receptors, this would be an example of A) a metabolic pathway. B) negative or regulatory feedback. C) passive transport. D) competitive inhibition.
B) negative or regulatory feedback.
Which of the following structures is exclusively associated with prokaryotic cells? A) membrane-bound nucleus B) nucleoid C) chromosome D) ribosomes
B) nucleoid
Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of A) exocytosis. B) passive transport. C) active transport. D) endocytosis.
B) passive transport.
Which location in the cell is unlikely to contain ribosomes or ribosomal subunits? A) nuclear envelope B) plasma membrane C) endoplasmic reticulum D) cytoplasm
B) plasma membrane
A woman is having trouble becoming pregnant. Examination of her partner's sperm indicates that dynein feet are missing from the flagella in his sperm cells. A physician explains that this could interfere with fertility by A) preventing the sperm from attaching to the egg cell. B) preventing the sperm from swimming to the egg cell. C) preventing the sperm from producing enough energy to power swimming. D) interfering with the attachment of the flagella to the sperm.
B) preventing the sperm from swimming to the egg cell.
Most of a cell's enzymes are A) lipids. B) proteins. C) amino acids. D) carbohydrates.
B) proteins.
Most of the functions of a cell membrane, including transport and enzymatic function, are performed by A) glycolipids. B) proteins. C) phospholipids. D) cholesterol.
B) proteins.
Cells acquire low-density lipoproteins (LDLs) by A) diffusion. B) receptor-mediated endocytosis. C) pinocytosis. D) phagocytosis.
B) receptor-mediated endocytosis
The cells that produce hair made of protein contain a lot of ________, while the cells that produce the oils that coat the hair contain a lot of ________. A) smooth endoplasmic reticulum; lysosomes B) rough endoplasmic reticulum; smooth endoplasmic reticulum C) smooth endoplasmic reticulum; rough endoplasmic reticulum D) microbodies; lysosomes
B) rough endoplasmic reticulum; smooth
Which characteristic promoted the utilization of lipids as the first cell membrane? A) spontaneous degradation of the intracellular environment B) self-assembly into a simple membrane C) ability to form an impermeable membrane D) formation of a semi-solid membrane
B) self-assembly into a simple membrane
A basal body is A) composed of nine microtubule triplets surrounding a central pair of microtubules. B) similar in structure to centrioles. C) composed of nine microtubule doublets surrounding a central pair of microtubules. D) identical in structure to cilia.
B) similar in structure to centrioles.
The Golgi apparatus A) is composed of stacks of membranous vesicles that are continuous with one another. B) stores, modifies, and packages proteins. C) strings together amino acids to produce proteins. D) is the site of carbohydrate breakdown.
B) stores, modifies, and packages proteins.
Intermediate filaments A) guide the movements of chromosomes. B) surround the nucleus. C) guide the movements of organelles. D) support the inner mitochondrial membrane.
B) surround the nucleus.
According to ________, energy cannot be created or destroyed. A) Aristotle's first principle B) the first law of thermodynamics C) the second law of thermodynamics D) the third law of thermodynamics
B) the first law of thermodynamics
Plasma membranes are selectively permeable. This means that A) anything can pass into or out of a cell as long as the membrane is intact and the cell is healthy. B) the plasma membrane allows some substances to enter or leave a cell more easily than others. C) glucose cannot enter the cell. D) plasma membranes must be very thick.
B) the plasma membrane allows some substances to enter or leave a cell more easily than others.
A steer must eat at least 100 pounds of grain to gain less than 10 pounds of muscle tissue. This illustrates A) the first law of thermodynamics. B) the second law of thermodynamics. C) that some energy is destroyed in every energy conversion. D) that energy transformations are typically 100% efficient.
B) the second law of thermodynamics.
Which of the following processes is endergonic? A) the burning of wood B) the synthesis of glucose from carbon dioxide and water C) the breakdown of glucose D) cellular respiration
B) the synthesis of glucose from carbon dioxide and water
The function of the nucleolus is A) to manufacture polypeptides. B) to manufacture ribosomal RNA. C) intracellular digestion. D) to store chromatin.
B) to manufacture ribosomal RNA.
A pathologist who wants to examine a patient's liver cells to determine if the mitochondria have an internal structural defect will likely need to use a A) light microscope. B) transmission electron microscope. C) scanning electron microscope. D) chromatin stain.
B) transmission electron microscope.
Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient. A) energy and transport proteins; down B) transport proteins; down C) energy and transport proteins; against D) transport proteins; against
B) transport proteins; down
Which of the following is a coenzyme? A) zinc B) vitamin B6 C) iron D) iodine
B) vitamin B6
As cell size increases, the A) volume and surface area decrease. B) volume increases proportionally more than the surface area. C) surface area increases proportionally more than the volume
B) volume increases proportionally more than the surface area.
One centimeter = ________ millimeters. A) 0.01 B) 0.10 C) 10 D) 100
C) 10
The diameter of most animal and plant cells ranges from A) 0.1 to 1.0 micrometers. B) 1.0 to 10 micrometers. C) 10 to 100 micrometers. D) 100 to 1000 micrometers.
C) 10 to 100 micrometers.
Which of the following statements regarding cells is false? A) All cells are enclosed in a membrane that maintains internal conditions different from the surroundings. B) All cells have a cell wall. C) All cells can interconvert forms of energy. D) All cells have DNA as their genetic material
C) All cells can interconvert forms of energy.
Which of the following statements about cellular metabolism is false? A) Cellular metabolism includes different processes that require different conditions. B) Cellular metabolism can occur within organelles. C) Cellular metabolism occurs in animal but not plant cells. D) Cellular metabolism often occurs on the surfaces of internal membranes.
C) Cellular metabolism occurs in animal but not plant cells.
Which of the following statements regarding diffusion is false? A) Diffusion is a result of the thermal energy of atoms and molecules. B) Diffusion requires no input of energy into the system. C) Diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated. D) Diffusion occurs even after equilibrium is reached and no net change is apparent.
C) Diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated.
Which of the following statements regarding enzyme function is false? A) An enzyme's function depends on its three-dimensional shape. B) Enzymes are very specific for certain substrates. C) Enzymes are used up when they catalyze a chemical reaction so must be synthesized for each new chemical reaction. D) Enzymes emerge unchanged from the reactions they catalyze.
C) Enzymes are used up when they catalyze a chemical reaction so must be synthesized for each new chemical reaction.
Which of the following statements regarding enzymes is true? A) Enzymes are inorganic. B) An enzyme's function is unaffected by changes in pH. C) Enzymes catalyze specific reactions. D) All enzymes depend on protein cofactors to function.
C) Enzymes catalyze specific reactions.
What is the basic difference between exergonic and endergonic reactions? A) Exergonic reactions involve ionic bonds; endergonic reactions involve covalent bonds. B) Exergonic reactions involve the breaking of bonds; endergonic reactions involve the formation of bonds. C) Exergonic reactions release energy; endergonic reactions absorb it. D) In exergonic reactions, the reactants have less chemical energy than the products; in endergonic reactions, the opposite is true.
C) Exergonic reactions release energy; endergonic reactions absorb it.
White blood cells (WBCs) are more resistant to lysis than red blood cells (RBCs). When looking at a sample of blood for WBCs, what could you do to reduce interference from RBCs? A) Mix the blood in a salty solution to cause the RBCs to lyse. B) Mix the blood in an isotonic solution and allow the WBCs to float to the top. C) Mix the blood in a hypotonic solution, which will cause the RBCs to lyse. D) Mix the blood in a hypertonic solution, which will cause the RBCs to lyse.
C) Mix the blood in a hypotonic solution, which will cause the RBCs to lyse.
Which of the following substances would have the most trouble crossing a biological membrane by diffusing through the lipid bilayer? A) O2 B) CO2 C) Na+ D) a small, nonpolar molecule such as butane (C4H10)
C) Na+
Which of the following statements about plant cell walls is false? A) Plant cell walls consist of cellulose fibers embedded in a matrix of polysaccharides and proteins. B) Plant cell walls are multilayered structures. C) Plant cell walls protect plant cells by forming an impermeable layer around the cell. D) Wood is primarily composed of plant cell walls.
C) Plant cell walls protect plant cells by forming an impermeable layer around the cell.
Which of the following statements regarding the Golgi apparatus is false? A) The Golgi apparatus works closely with the endoplasmic reticulum. B) The Golgi apparatus serves as a molecular warehouse and finishing factory. C) The Golgi apparatus decreases in size when a cell increases its protein production. D) The Golgi apparatus modifies chemicals received from the endoplasmic reticulum.
C) The Golgi apparatus decreases in size when a cell increases its protein production.
Which of the following statements about the functions of a plant cell central vacuole is false? A) The central vacuole of a plant cell may help increase the size of cells by absorbing water. B) The central vacuole of a plant cell may store waste products. C) The central vacuole of a plant cell may digest chemicals for recycling. D) The central vacuole of a plant cell may store poisons.
C) The central vacuole of a plant cell may digest chemicals for recycling.
Which of the following substances could be a cofactor? A) a protein B) a polypeptide C) a zinc atom D) a ribosome
C) a zinc atom
Membrane phospholipids A) have hydrophobic heads that face the center of the membrane and are shielded from water. B) have hydrophilic tails that face outward and are exposed to water. C) are able to drift about in the plasma membrane. D) remain fluid because they are tightly packed against one another.
C) are able to drift about in the plasma membrane.
Dynein feet A) are present in cilia but not in flagella. B) are knobs of carbohydrate that are essential to the movement of cilia and flagella. C) are found on microtubules in cilia and flagella and cause movement by grabbing and pulling at adjacent microtubule doublets. D) are the anchoring proteins in basal bodies.
C) are found on microtubules in cilia and flagella and cause movement by grabbing and pulling at adjacent microtubule doublets.
Microfilaments differ from microtubules in that microfilaments A) are thicker than microtubules. B) are found only in plants, whereas microtubules are found in both plant and animal cells. C) are mainly composed of actin, whereas microtubules are composed of tubulin. D) help to anchor organelles, whereas microtubules primarily function to help cells change shape and move.
C) are mainly composed of actin, whereas microtubules are composed of tubulin.
The idea that all living things are composed of cells and that all cells come from other cells defines A) the laws of inheritance. B) organelle theory. C) cell theory. D) inheritance of acquired characteristics.
C) cell theory.
During cell reproduction, chromatin fibers coil up into structures called A) ribosomes. B) lysosomes. C) chromosomes. D) nucleoli.
C) chromosomes.
Cilia differ from flagella in that A) cilia contain nine microtubule doublets surrounding a central pair of microtubules, whereas flagella contain only nine microtubule doublets. B) the protein filaments of cilia are "naked," whereas those of flagella are wrapped in an extension of the cell membrane. C) cilia are typically more numerous and shorter than flagella. D) cilia are anchored only in the proteins of the cell membrane, whereas flagella are anchored in a special structure called the basal body.
C) cilia are typically more numerous and shorter than flagella.
Mitochondria differ from chloroplasts in that mitochondria A) convert light energy from the sun to chemical energy, whereas chloroplasts convert one form of chemical energy to another. B) contain three different membrane-bound compartments, whereas chloroplasts contain two. C) contain membrane folds called cristae, whereas chloroplasts contain disk-like vesicles in stacks called grana. D) are not found in plants, whereas chloroplasts are not found in animals
C) contain membrane folds called cristae, whereas chloroplasts contain disk-like vesicles in stacks called grana.
The nucleus of a cell A) is surrounded by a single layer of membrane. B) is contained within the nucleolus. C) contains DNA. D) is the primary location of protein synthesis.
C) contains DNA.
The ________ of a mitochondrion is/are an adaptation that increases the surface area and enhances a mitochondrion's ability to produce ATP. A) stroma B) intermembrane space C) cristae D) matrix
C) cristae
Living systems A) violate the first law of thermodynamics. B) violate the second law of thermodynamics. C) decrease their entropy while increasing the entropy of the universe. D) are examples of a closed system.
C) decrease their entropy while increasing the entropy of the universe.
Most animal cells are A) surrounded by a cell wall. B) attached to each other via plasmodesmata. C) embedded in an extracellular matrix. D) embedded in a lipid matrix.
C) embedded in an extracellular matrix.
ATP can be used as the cell's energy exchange mechanism because A) endergonic reactions can be fueled by coupling them with the formation of ATP from ADP. B) ATP is the most energy-rich small molecule in the cell. C) endergonic reactions can be fueled by coupling them with the hydrolysis of high-energy phosphate bonds in ATP. D) ATP is a disposable form of chemical energy, used once and then discarded by the cell.
C) endergonic reactions can be fueled by coupling them with the hydrolysis of high-energy phosphate bonds in ATP.
Bacterial production of the enzymes needed for the synthesis of the amino acid tryptophan declines with increasing levels of tryptophan and increases as tryptophan levels decline. This is an example of A) competitive inhibition. B) noncompetitive inhibition. C) feedback inhibition. D) irreversible inhibition.
C) feedback inhibition.
The extracellular matrix attached to cells via glycoproteins may then bind to ________ in the plasma membrane. A) dynein B) collagen C) integrins D) polysaccharides
C) integrins
Which of the following would be most affected by a mutation that prevented cells from forming tight junctions? A) attachment of cells to the surrounding matrix B) direct flow of water and small molecules from one cell to another C) integrity of the inner lining of the digestive tract D) attachment of the cytoskeleton to the inside of the plasma membrane
C) integrity of the inner lining of the digestive tract
Protein synthesis requires the use of mRNA, which A) is made in the nucleolus. B) must be made by the ribosomes. C) is translated by the ribosomes into the amino acid sequences of proteins. D) carries the message to the nucleus to synthesize new DNA during cell division.
C) is translated by the ribosomes into the amino acid sequences of proteins
Kinetic energy differs from chemical energy in that A) kinetic energy is stored energy that has the potential to do work, and chemical energy is the energy of movement. B) kinetic energy can be converted into various forms of energy, whereas chemical energy can only be converted into heat. C) kinetic energy is the energy of a moving object, whereas chemical energy is the potential energy of molecules. D) chemical energy is a particular form of kinetic energy.
C) kinetic energy is the energy of a moving object, whereas chemical energy is the potential energy of molecules.
A bacterial cell's DNA is found in its A) ribosomes. B) nucleus. C) nucleoid region. D) capsule.
C) nucleoid region.
The endomembrane system includes all of the following organelles except the A) plasma membrane. B) endoplasmic reticulum. C) peroxisome. D) Golgi apparatus.
C) peroxisome.
Which of the following cell structures are associated with the breakdown of harmful substances? A) chloroplasts B) mitochondria C) peroxisomes D) centrioles
C) peroxisomes
The transfer of a phosphate group to a molecule or compound is called A) carboxylation. B) ionization. C) phosphorylation. D) hydrogenation.
C) phosphorylation.
The function of chloroplasts is A) cellular respiration. B) lipid synthesis. C) photosynthesis. D) intracellular digestion.
C) photosynthesis.
Contractile vacuoles A) are generally found in protists that inhabit salt water. B) help in the excretion of excess salt. C) prevent cells from bursting as a result of the influx of excess water. D) allow organisms to avoid dehydration by absorbing water from the environment.
C) prevent cells from bursting as a result of the influx of excess water.
An energy barrier A) is the amount of energy that must be produced by the reactants to end a chemical reaction. B) is higher than the activation energy of a reaction. C) prevents the spontaneous breakdown of molecules in the cell. D) can only be overcome with the use of enzymes.
C) prevents the spontaneous breakdown of molecules in the cell.
In the reaction A → B + C + heat, A) there is a net input of energy. B) the potential energy of the products is greater than that of the reactant. C) the potential energy of the products is less than that of the reactant. D) entropy has decreased.
C) the potential energy of the products is less than that of the reactant.
The active site of an enzyme is A) the region of a substrate that is changed by an enzyme. B) the highly changeable portion of an enzyme that adapts to fit the substrates of various reactions. C) the region of an enzyme that attaches to a substrate. D) the region of a product that detaches from the enzyme.
C) the region of an enzyme that attaches to a substrate.
Light microscopes A) typically provide more resolution than an electron microscope. B) work by reflecting electrons off the surface of an object being studied. C) use light and glass lenses to magnify an image. D) are generally not used to view bacteria.
C) use light and glass lenses to magnify an image.
A cell is exposed to a substance that prevents it from dividing. The cell becomes larger and larger. This situation A) should present no problem to the cell, since it can continue to perform all other necessary functions. B) should present no problem to the cell, because the surface area of the cell will increase as the volume of the cell increases. C) will eventually be problematic, since the cell's ability to absorb nutrients through its outer membrane will not keep increasing as quickly as its cytoplasmic needs. D) should be beneficial, since the cell will be able to divert the ATP normally used for cell division to other processes.
C) will eventually be problematic, since the cell's ability to absorb nutrients through its outer membrane will not keep increasing as quickly as its cytoplasmic needs.
You are adrift in the Atlantic Ocean and, being thirsty, drink the surrounding seawater. As a result, A) you quench your thirst. B) your cells become turgid. C) you dehydrate yourself. D) your cells lyse from excessive water intake.
C) you dehydrate yourself.
A child dies following a series of chronic bacterial infections. At the autopsy, the physicians are startled to see that the child's white blood cells are loaded with vacuoles containing intact bacteria. Which of the following explanations could account for this finding? A) A defect in the Golgi apparatus prevented the cells from processing and excreting the bacteria. B) A defect in the rough endoplasmic reticulum prevented the synthesis of the antibodies (defensive proteins) that would have inactivated the bacteria. C) A defect in the cell walls of the white blood cells permitted bacteria to enter the cells. D) A defect in the lysosomes of the white blood cells prevented the cells from destroying engulfed bacteria.
D) A defect in the lysosomes of the white blood cells prevented the cells from destroying engulfed bacteria.
Which of the following statements regarding active transport is false? A) Active transport uses ATP as an energy source. B) Active transport can move a solute against its concentration gradient. C) Active transport requires the cell to expend energy. D) Active transport is driven by the concentration gradient.
D) Active transport is driven by the concentration gradient.
Which of the following statements regarding thermodynamics is false? A) Thermodynamics is the study of energy transformations that occur in a collection of matter. B) A single cell or the planet Earth could be a thermodynamic system. C) An open system exchanges both energy and matter with its surroundings. D) An automobile engine is a closed system because it does not exchange energy and matter with its surroundings.
D) An automobile engine is a closed system because it does not exchange energy and matter with its surroundings.
How does inhibition of an enzyme-catalyzed reaction by a competitive inhibitor differ from inhibition by a noncompetitive inhibitor? A) Competitive inhibitors interfere with the enzyme; noncompetitive inhibitors interfere with the reactants. B) Competitive inhibitors bind to the enzyme reversibly; noncompetitive inhibitors bind to it irreversibly. C) Competitive inhibitors change the enzyme's tertiary structure; noncompetitive inhibitors cause polypeptide subunits to dissociate. D) Competitive inhibitors bind to the active site of the enzyme; noncompetitive inhibitors bind to a different site.
D) Competitive inhibitors bind to the active site of the enzyme; noncompetitive inhibitors bind to a different site.
Which of the following statements about internal membranes in eukaryotic cells is false? A) In eukaryotic cells, internal membranes greatly increase a cell's total membrane area. B) In eukaryotic cells, internal membranes provide an additional area for many metabolic processes to occur. C) In eukaryotic cells, internal membranes form membranous compartments called organelles. D) In eukaryotic cells, internal membranes standardize the internal environment of all cellular organelles.
D) In eukaryotic cells, internal membranes standardize the internal environment of all cellular organelles.
Which of the following statements about the ATP molecule is true? A) It contains five phosphate groups. B) Extremely stable bonds link the second and third phosphate groups. C) It contains the sugar glucose. D) It releases energy when one phosphate group leaves ATP.
D) It releases energy when one phosphate group leaves ATP.
Which of the following statements regarding membrane protein function is false? A) Membrane proteins serve as enzymes. B) Membrane proteins act as receptors to molecules like hormones. C) Membrane proteins form junctions between cells. D) Membrane proteins transfer genetic information to the cytoplasm.
D) Membrane proteins transfer genetic information to the cytoplasm.
Which of the following statements regarding plasmodesmata is false? A) Plasmodesmata penetrate plant cell walls. B) Plasmodesmata carry chemical messages between plant cells. C) Plasmodesmata carry nutrients between plant cells. D) Plasmodesmata are found in plants as well as some single-celled organisms.
D) Plasmodesmata are found in plants as well as some single-celled organisms.
Which of the following statements regarding the endomembrane system is false? A) The endomembrane system is involved in the synthesis, storage, and export of important molecules. B) The endomembrane system includes the rough and smooth endoplasmic reticulum. C) The endomembrane system includes the nuclear envelope. D) The endomembrane system is a system of interrelated membranes that are all physically connected.
D) The endomembrane system is a system of interrelated membranes that are all physically connected.
Which of the following statements regarding membrane function is false? A) The plasma membrane forms a selective barrier around the cell. B) The plasma membrane plays a role in transferring signals to the cell's interior. C) The plasma membrane has receptors for chemical messages. D) The plasma membrane is the control center of the cell.
D) The plasma membrane is the control center of the cell.
Which of the following is a typical feature of an ATP-driven active transport mechanism? A) The transport protein must cross to the correct side of the membrane before the solute can bind to it. B) The transport protein is irreversibly phosphorylated as transport takes place. C) The transport protein catalyzes the conversion of ADP to ATP. D) The solute moves against the concentration gradient.
D) The solute moves against the concentration gradient.
The energy required to initiate an exergonic reaction is called A) exergonic energy. B) endergonic energy. C) input energy. D) activation energy.
D) activation energy.
Substrates bind to an enzyme's ________ site. A) allosteric B) inhibitory C) phosphate D) active
D) active
Which of the following processes can move a solute against its concentration gradient? A) osmosis B) passive transport C) facilitated diffusion D) active transport
D) active transport
Which of the following structures is/are used by prokaryotes for attaching to surfaces? A) flagella B) nucleoid C) anchoring junctions D) capsule
D) capsule
Heating inactivates enzymes by A) breaking the covalent bonds that hold the molecule together. B) removing phosphate groups from the enzyme. C) causing enzyme molecules to stick together. D) changing the enzyme's three-dimensional shape.
D) changing the enzyme's three-dimensional shape.
Inhibition of an enzyme is irreversible when A) a competitive inhibitor is involved. B) a noncompetitive inhibitor is involved. C) the shape of the enzyme is changed. D) covalent bonds form between inhibitor and enzyme.
D) covalent bonds form between inhibitor and enzyme.
The fluid mosaic model describes the plasma membrane as consisting of A) a phospholipid bilayer with embedded carbohydrates. B) two layers of phospholipids with cholesterol sandwiched between them. C) carbohydrates and phospholipids that can drift in the membrane. D) diverse proteins embedded in a phospholipid bilayer.
D) diverse proteins embedded in a phospholipid bilayer.
it is essential for heart muscle cells to beat in a coordinated fashion. The cell junctions that would best facilitate this are A) occluding junctions. B) anchoring junctions. C) tight junctions. D) gap junctions.
D) gap junctions.
Which of the following direct energy transfers is impossible in living systems? A) light energy to chemical energy B) chemical energy to kinetic energy C) light energy to potential energy D) heat to light energy
D) heat to light energy
The main function of the rough endoplasmic reticulum is the production of A) mitochondria and proteins secreted by the cell. B) hydrogen peroxide and steroid hormones secreted by the cell. C) ribosomes and steroid hormones. D) membrane and proteins secreted by the cell.
D) membrane and proteins secreted by the cell
Oxygen crosses a plasma membrane by A) osmosis. B) active transport. C) pinocytosis. D) passive transport.
D) passive transport.
The process of a white blood cell engulfing a bacterium is A) osmosis. B) receptor-mediated endocytosis. C) pinocytosis. D) phagocytosis.
D) phagocytosis.
The molecules responsible for membrane transport are A) steroids. B) phospholipids. C) carbohydrates. D) proteins.
D) proteins.
Secretory proteins are A) produced by ribosomes on the smooth endoplasmic reticulum. B) chemically modified in the nucleus. C) produced by the cell for internal use. D) released from the cell through the plasma membrane.
D) released from the cell through the plasma membrane.
All cells are enclosed by a plasma membrane that is similar in ________ and ________. A) thickness; composition B) permeability; content C) lucidity; texture D) structure; function
D) structure; function
A drug that interferes with microtubule formation is likely to completely disrupt A) the amoeboid motion of a cell. B) the function of lysosomes. C) contraction of muscle cells. D) the movements of sperm cells.
D) the movements of sperm cells.
If placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What accounts for this difference? A) the expulsion of water by the plant cell's central vacuole B) the relative impermeability of the plant cell wall to water C) the fact that plant cells are isotonic to tap water D) the relative inelasticity and strength of the plant cell wall
D) the relative inelasticity and strength of the plant cell wall
When a cell is deprived of oxygen, its lysosomes tend to burst and release their contents into the cell. As a result of this, that cell will A) recycle damaged organelles. B) undergo cell division. C) produce replacement lysosomes. D) undergo self-digestion and die.
D) undergo self-digestion and die.
