bio final 8

) Most of a cell's enzymes are A) lipids. B) proteins. C) amino acids. D) nucleic acids. E) carbohydrates.

B

) 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. E) usually enter the cell via endocytosis.

a

) When a cell uses chemical energy to perform work, it couples a(n) __________ reaction with a(n) __________ reaction. A) exergonic . . . endergonic B) endergonic . . . exergonic C) exergonic . . . spontaneous D) spontaneous . . . exergonic E) endergonic . . . spontaneous

a

All the following are important functions of the cytoskeleton EXCEPT: A) storage of food molecules. B) assistance during cell division. C) movement of organelles. D) maintenance of shape. E) maintenance of organization in the cell

a

Resolving power 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) ability of an optical instrument to estimate the size of an image. E) distance between the lenses of a microscope.

a

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 becomes a product. D) it acts as a reactant. E) None of the choices are correct.

a

Which one of the following is not a function of the plasma membrane? The plasma membrane A) forms a selective barrier around the cell. B) plays a role in signal transduction. C) has receptors for chemical messages. D) is the control center of the cell. E) is involved in self-recognition.

a

Which structure above represents an amino acid? A) A B) B C) C D) D E) None of the above

a

) Most of a cell's enzymes are A) lipids. B) proteins. C) amino acids. D) nucleic acids. E) carbohydrates.

b

) 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) cholesterol cannot enter the cell. E) plasma membranes must be very thick.

b

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

Collagen and hemoglobin are examples of ________, whereas glucose and cellulose are examples of ________. A) proteins; lipids B) proteins; carbohydrates C) carbohydrates; proteins D) nucleic acids; lipids

b

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) cholesterol cannot enter the cell. E) plasma membranes must be very thick.

b

Which one of the following statements is false? Cellular respiration A) consumes glucose. B) is a single chemical reaction with just one step. C) produces water. D) produces carbon dioxide. E) releases heat.

b

Which structure above represents a nucleotide? A) A B) B C) C D) D E) None of the above

b

) The transfer of a phosphate group to a molecule or compound is called A) carboxylation. B) ionization. C) phosphorylation. D) hydrogen bonding. E) hydrogenation.

c

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. E) None of the choices are correct.

c

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. E) None of the choices are correct.

c

Which one of the following processes is endergonic? A) the burning of wood B) the release of heat from the breakdown of glucose C) the synthesis of glucose from carbon dioxide and water D) the breakdown of glucose E) cellular respiration

c

) Which one of the following is true about the ATP molecule? A) It contains two phosphate groups. B) Extremely stable bonds link the second and third phosphate groups. C) It contains the six-carbon sugar hexose. D) It contains a nitrogenous base molecule called adenine. E) None of the choices are correct

d

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. E) None of the choices are correct.

d

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 depends on the movement of atoms, whereas chemical energy depends on the movement of molecules. C) kinetic energy can be converted into various forms of energy, whereas chemical energy can only be converted into heat. D) kinetic energy is the energy of a moving object, whereas chemical energy is the potential energy of molecules. E) chemical energy is a particular form of kinetic energy.

d

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 involve the formation of bonds; endergonic reactions involve the breaking of bonds. D) Exergonic reactions release energy; endergonic reactions absorb it. E) In exergonic reactions, the reactants have less chemical energy than the products; in endergonic reactions, the opposite is true.

d

Which one of the following is not a function of the plasma membrane? The plasma membrane A) forms a selective barrier around the cell. B) plays a role in signal transduction. C) has receptors for chemical messages. D) is the control center of the cell. E) is involved in self-recognition.

d

) The term anaerobic means A) without bacteria. B) without ATP. C) without CO2. D) with O2. E) without O2.

e

) Which of the following energy transfers is/are possible in living systems? A) light energy to chemical energy B) chemical energy to kinetic energy C) potential energy to kinetic energy D) light energy to potential energy E) All of the choices are correct

e

The energy required to initiate an exergonic reaction is called A) exergonic energy. B) endergonic energy. C) nothing; spontaneous reactions do not require an input of energy. D) hydrolytic energy. E) the energy of activation.

e

The fiber in your diet is actually: A) protein. B) ATP. C) starch. D) glycogen. E) cellulose

e