Biology 160 - Chapter 5: Multiple Choice

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

lower the energy of the activation of a reaction

The diffusion of water across a selectively permeable membrane is called __________. active transport dehydration osmosis exocytosis

Osmosis

Overall, membranes seem to have a great deal in common, but on closer inspection it is revealed that membranes of different cells have unique properties. What is the primary component of membranes that gives membranes cell-specific properties? phospholipids cytoskeleton proteins cholesterol

Proteins

The concentration of solutes in a red blood cell is about 2%. Sucrose cannot pass through the membrane, but water and urea can. Osmosis would cause red blood cells to shrink the most when immersed in which of the following solutions? a hypotonic sucrose solution a hypertonic urea solution a hypotonic urea solution a hypertonic sucrose solution

a hypertonic sucrose solution

Cellular respiration is an example of __________. an endergonic process bioenergetics thermodynamics an exergonic process

an exergonic process

During enzymatic reactions, substrates are converted to products. A property of enzymes that facilitates this reaction is that they are catalysts and therefore _____. provide activation energy for the reactions they facilitate can make an endergonic reaction exergonic change the rate of a reaction without being consumed by the reaction are proteins

change the rate of a reaction without being consumed by the reaction

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 __________. endocytosis osmosis active transport passive transport

endocytosis

Light is _____ energy, which is converted into _____ energy by plants. potential ... kinetic kinetic ... chemical chemical ... potential chemical ... kinetic

kinetic ... chemical

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

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

Which statement best describes phagocytosis? Cells use this process to export products such as insulin or thyroxine. Small droplets of extracellular fluid and all the dissolved solutes enter the cell by this process. A cell engulfs a particle by wrapping pseudopodia around it and packaging it within a vacuole. A receptor on the plasma membrane binds to a molecule, and the cell engulfs both the receptor and the molecule.

A cell engulfs a particle by wrapping pseudopodia around it and packaging it within a vacuole.

Most cellular work is accomplished by _____ energizing molecules by _____ them. coenzyme ... activating enzymes ... activating substrates ... phosphorylating ATP ... phosphorylating

ATP ... phosphorylating

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

Oxygen and carbon dioxide

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

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

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 ... its membrane transport proteins will not be saturated A ... the diffusion gradient there is shallower B ... the oxygen molecules inside cell B have a higher kinetic energy B ... the diffusion gradient there is steeper

B ... the diffusion gradient there is steeper

Green olives may be preserved in brine, which is a 20-30% salt solution. How does this method prevent contamination by microorganisms? High salt concentrations raise the pH, thus inhibiting the process of glycolysis. Bacteria can't survive in a hypertonic solution because they lose water. High salt concentrations lower the pH, thus inhibiting the process of glycolysis. Bacterial cell walls are shriveled up by salt, causing the cell to burst.

Bacteria can't survive in a hypertonic solution because they lose water.

The movement of atoms, ions, or molecules from a region of higher concentration to regions of lower concentration is called _____. spontaneous combustion diffusion active transport crenation

Diffusion

Which statement regarding enzyme function is true? Most coenzymes are inorganic substances such as ions of iron or potassium. Enzymes cannot function at a pH lower than 6. Higher temperatures allow greater contact between enzymes and substrates; therefore, the higher the temperature the better the enzyme will function. Excessive salt ions can cause an enzyme to denature.

Excessive salt ions can cause an enzyme to denature.

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

Reaction-specific enzymes assume a fit by folding around the most numerous substrate molecules.

Which of these statements about enzyme inhibitors is true? A noncompetitive inhibitor does not change the shape of the active site. A competitive inhibitor binds to the enzyme outside the active site. The action of competitive inhibitors may be reversible or irreversible. When the product of an enzyme or a series of enzyme-catalyzed reactions acts as its inhibitor, this is known as positive feedback.

The action of competitive inhibitors may be reversible or irreversible.

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

The aerobic respiration of glucose generates heat.

Cells store energy that they use for work in the _____. arrangement of atoms within molecules thermal energy of molecules water that is moved inside the cell oxygen cells take in

arrangement of atoms within molecules

The phosphorylation of ADP to form ATP is an _____ reaction that _____ energy. endergonic ... releases exergonic ... requires an input of endergonic ... requires an input of exergonic ... releases kinetic

endergonic ... requires an input of

You're on the pilot episode of a new game show called "The Transport Factor." The host hands you three different amino acids, four different sugars, and two different ions. Then the host shouts, "How many different proteins does the cell need to move these molecules across the plasma membrane using facilitated transport?" Quickly, you correctly respond: _____. one nine five three

nine

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

receptor-mediated endocytosis

The transport of molecules of a particular solute from inside an animal cell across the cell membrane to the extracellular fluid always requires energy when _____. the concentration of the solute is higher inside the cell than outside it the lipid bilayer is permeable to the solute a transport protein is involved in the movement of the molecules the concentration of the solute is lower inside the cell than outside it

the concentration of the solute is lower inside the cell than outside it

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

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

Review the figure below of passive transport, then choose one of the following statements as being descriptive of this process. Passive transport always requires the help of proteins to bring molecules from an area of high concentration to an area of lower concentration. Passive transport can transport molecules without the assistance of proteins from an area of high concentration to an area of lower concentration. Passive transport works with the help of proteins to bring molecules from an area of low concentration to an area of higher concentration. Passive transport requires energy from the cell to move molecules from an area of high concentration to an area of lower concentration.

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 statements is true about passive transport? Passive transport phenomena can never reach equilibrium. Passive transport operates independently of diffusion. Passive transport requires no expenditure of cellular energy. Passive transport operates independently of concentration.

Passive transport requires no expenditure of cellular energy.

The first law of thermodynamics _____. states that energy is neither created nor destroyed deals with heat content states that entropy spontaneously increases predicts the direction of a reaction

states that energy is neither created nor destroyed