Biology Chapter 5 Kotchick

Which statement regarding enzyme function is true? a. High temperatures can cause many enzymes to denature. b. Most coenzymes are inorganic substances such as ions of iron or potassium. c. No enzymes can function at a pH lower than 6. d. Higher temperatures allow greater contact between enzymes and substrates; therefore, the higher the temperature the better the enzyme will function.

a. High temperatures can cause many enzymes to denature.

What happens to the portion of chemical energy that is extracted from molecules by cellular activities but that is not used for cellular work? a. The energy contributes to the entropy of the system. b. The energy is recycled by the cell. c. It is used by plant cells for photosynthesis. d. The energy is captured by other cells.

a. The energy contributes to the entropy of the system.

Light is _____ energy, which is converted by plants into molecules that possess _____ energy. a. kinetic ... chemical b. potential ... kinetic c. chemical ... potential d. chemical ... kinetic

a. kinetic ... chemical

Which of these statements describes what occurs in facilitated diffusion? a. Facilitated diffusion requires energy from the cell to drive a concentration gradient. b. Facilitated diffusion of solutes occurs through protein pores in the membrane. c. Facilitated diffusion of solutes occurs through phospholipid pores in the membrane. d. Facilitated diffusion is another name for osmosis.

b. Facilitated diffusion of solutes occurs through protein pores in the membrane.

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP? a. redox b. cellular respiration c. digestion d. potentiation e. anabolism

b. cellular respiration

Which of these are by-products of cellular respiration? a. ATP and water b. heat and water c. ATP d. water e. glucose and water

b. heat and water

Which of the following is a difference between active transport and facilitated diffusion? a. Facilitated diffusion involves transport proteins, and active transport does not. b. Active transport involves transport proteins, and facilitated diffusion does not. c. Facilitated diffusion can move solutes against a concentration gradient, and active transport cannot. d. Active transport requires the expenditure of cellular energy, and facilitated diffusion does not.

d. Active transport requires the expenditure of cellular energy, and facilitated diffusion does not.

Which describes passive transport? a. Passive transport can transport molecules without the assistance of proteins from an area of high concentration to an area of lower concentration. b. Passive transport works with the help of proteins to bring molecules from an area of low concentration to an area of higher concentration. c. Passive transport always requires the help of membrane proteins to bring molecules from an area of high concentration to an area of lower concentration. d. Passive transport requires energy from the cell to move molecules from an area of high concentration to an area of lower concentration.

a. Passive transport can transport molecules without the assistance of proteins from an area of high concentration to an area of lower concentration.

Which of the following is an example of the second law of thermodynamics? a. The aerobic respiration of glucose generates heat, which is dissipated from cells. b. CO2 is released as a by-product of aerobic respiration. c. All types of cellular respiration produce ATP. d. Photosynthesis enables plants to create energy from sunlight.

a. The aerobic respiration of glucose generates heat, which is dissipated from cells.

What is the function of cholesterol in the cell membrane? a. stabilization of the phospholipids b. transport across the plasma membrane c. detection of environmental change d. cell-cell communication e. structural support of the cell

a. stabilization of the phospholipids

The first law of thermodynamics _____. a. states that energy is neither created nor destroyed; therefore, the total amount of energy in the universe is constant b. deals with heat content c. states that entropy spontaneously increases d. predicts the direction of a reaction

a. states that energy is neither created nor destroyed; therefore, the total amount of energy in the universe is constant

Macrophages are white blood cells that roam the body searching for invading microbes. These invaders are destroyed inside macrophage vacuoles. How do the macrophages bring the microbes inside? a. They are taken in by the form of exocytosis known as pinocytosis. b. Microbes are engulfed into the macrophage via phagocytosis. c. The invaders cross the membranes via active transport through specific transport proteins. d. The invaders cross the membranes via facilitated transport through specific transport proteins.

b. Microbes are engulfed into the macrophage via phagocytosis.

Lactase is essential for digesting lactose in milk. This enzyme is specific for this sugar. Why? a. Specificity refers to the action of the enzyme, such as hydrolysis, and relatively few molecules can be hydrolyzed. b. There is a precise compatibility between the active site and the lactose molecule. c. Reaction-specific enzymes assume a fit by folding around the most numerous substrate molecules. d. Molecules and active sites vary in size; only properly sized molecules can fit.

b. There is a precise compatibility between the active site and the lactose molecule.

"Conservation of energy" refers to the fact that _____. a. if you conserve energy you will not be as tired b. energy cannot be created or destroyed but can be converted from one form to another c. no chemical reaction is 100 percent efficient d. the net amount of disorder is always increasing e. the entropy of the universe is always increasing

b. energy cannot be created or destroyed but can be converted from one form to another

The mechanism of enzyme action is to _____. a. change the direction of thermodynamic equilibrium b. lower the energy of the activation of a reaction c. create an energy barrier between substrates d. change endergonic into exergonic reactions

b. lower the energy of the activation of a reaction

Chemical energy is a form of _____ energy. a. kinetic b. potential c. heat d. motion e. entropic

b. potential

Which of the following enables a cell to pick up and concentrate a specific kind of molecule? a. passive transport b. receptor-mediated endocytosis c. osmosis d. diffusion

b. receptor-mediated endocytosis

Aquaporins are proteins that facilitate the transport of __________ across the membrane. a. salt b. water c. urine d. proteins

b. water

Cells A and B are the same size and shape, but cell A is metabolically quiet and cell B is actively consuming oxygen. Oxygen will diffuse more quickly into cell _____ because _____. a. B ... the oxygen molecules inside cell B have a higher kinetic energy b. A ... the diffusion gradient there is shallower c. B ... the diffusion gradient there is steeper d. A ... its membrane transport proteins will not be saturated

c. B ... the diffusion gradient there is steeper

In plant cells, carbon dioxide and water are joined to form carbohydrates. Plant cells can also break down carbohydrates such as glucose, releasing carbon dioxide, water, and energy. No one has ever observed such reactions between water and carbon dioxide outside of living cells. What allows living cells to assemble and disassemble complex molecules, which is not possible in nonbiological environments? a. Cells possess properties not seen in nonliving things, which allow them to run physical processes in reverse. b. Cells are subject to only the first law, not the second law, of thermodynamics. c. Cells couple energy-releasing reactions to energy-requiring reactions. d. Cells are far more efficient in energy transactions than are nonliving substances.

c. Cells couple energy-releasing reactions to energy-requiring reactions.

Why doesn't the antibiotic penicillin harm humans? a. Penicillin attacks the nervous system. b. Penicillin attacks plasma membranes. c. Human cells do not have cell walls. d. The dosage given to kill bacteria is too low to harm humans.

c. Human cells do not have cell walls.

Which of the following statements is true about passive transport? a. Passive transport operates independently of diffusion. b. Passive transport phenomena can never reach equilibrium. c. Passive transport requires no expenditure of cellular energy. d. Passive transport operates independently of concentration.

c. Passive transport requires no expenditure of cellular energy.

What name is given to the process by which water crosses a selectively permeable membrane? a. diffusion b. phagocytosis c. osmosis d. passive transport e. pinocytosis

c. osmosis

The plasma membrane is selectively permeable. Which of the following can pass freely through the membrane with no assistance? a. sodium and hydrogen ions b. glucose and lactose c. oxygen and carbon dioxide d. starch and cellulose

c. oxygen and carbon dioxide

For an enzyme to catalyze a reaction there must be a specific fit between the __________ and the enzyme's __________. a. enzyme ... active site b. cofactor ... coenzyme c. substrate ... active site d. substrate ... product

c. substrate ... active site

You can recognize the process of pinocytosis when _____. a. a receptor protein is involved b. the cell is engulfing a large particle c. the cell is engulfing extracellular fluid

c. the cell is engulfing extracellular fluid

Which of the following statements is true of an exergonic reaction but NOT true of an endergonic reaction? a. activation energy exceeds net energy release b. no kinetic energy is released c. the potential energy of the products is less than the potential energy of the reactants d. activation energy is necessary

c. the potential energy of the products is less than the potential energy of the reactants

Frequently, transplanted organs are rejected by the recipient's body. How is this reaction related to plasma membranes? a. Everyone's organs contain different amounts of cholesterol. b. The phospholipid bilayers become disrupted during transplant and may never re-form, causing the tissues to lose their function. c. The fibers of the extracellular matrix differ from individual to individual. d. Each person has a unique set of glycoproteins with carbohydrate chains attached to his or her plasma membranes.

d. Each person has a unique set of glycoproteins with carbohydrate chains attached to his or her plasma membranes.

Which of these is exhibiting kinetic energy? a. a rock on a mountain ledge b. a person sitting on a couch while watching TV c. an archer with a flexed bow d. a space station orbiting Earth e. the high-energy phosphate bonds of a molecule of ATP

d. a space station orbiting Earth

The phosphorylation of ADP to form ATP is an _____ reaction that _____ energy. a. exergonic ... requires an input of b. exergonic ... releases c. endergonic ... releases d. endergonic ... requires an input of

d. endergonic ... requires an input of

A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via __________. a. passive transport b. active transport c. osmosis d. endocytosis

d. endocytosis

In the process of osmosis, water displays a net movement from an area of __________ water concentration to an area of __________ water concentration. a. lower ... lower b. higher ... equal c. lower ... higher d. higher ... lower

d. higher ... lower

When placed in a hypotonic environment, where the solute concentration is below that of the cell, a houseplant will _____. a. die b. go brown at the edges of its leaves c. go limp and lifeless d. remain standing upright

d. remain standing upright

The lipids in a cell membrane are arranged _____. a. on either side of a single layer of protein b. so that the hydrophilic components are arranged to face each other c. between two layers of protein d. so that the nonpolar parts of two lipids point toward each other

d. so that the nonpolar parts of two lipids point toward each other

Endocytosis moves materials _____ a cell via _____. a. into ... facilitated diffusion b. into ... a transport protein c. out of ... membranous vesicles d. out of ... diffusion e. into ... membranous vesicles

e. into ... membranous vesicles

A white blood cell engulfing a bacterium is an example of _____. a. exocytosis b. receptor-mediated endocytosis c. pinocytosis d. facilitated diffusion e. phagocytosis

e. phagocytosis