Question 1

All cells are enclosed by a plasma membrane that is similar in ________ and ________.

Accepted Answer

A) thickness; composition 
B) permeability; content 
C) lucidity; texture 
D) structure; function 
A) thickness; composition 
B) permeability; content 
C) lucidity; texture 
D) structure; function

Question 2

Small, nonpolar, hydrophobic molecules such as fatty acids

Accepted Answer

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. 
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.

Question 3

Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing

Accepted Answer

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. 
B) chemical energy into potential energy. 
C) kinetic energy into potential energy. 
D) kinetic energy into thermal energy.

Question 4

Which of the following statements regarding active transport is false?

Accepted Answer

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. 
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.

Question 5

A cell that has neither a net gain of water nor net loss of water when it is immersed in a solution must be

Accepted Answer

A) isotonic to its environment. 
B) hypertonic to its environment. 
C) hypotonic to its environment. 
D) metabolically inactive. 
A) isotonic to its environment. 
B) hypertonic to its environment. 
C) hypotonic to its environment. 
D) metabolically inactive.

Question 6

Cells acquire low-density lipoproteins (LDLs)by

Accepted Answer

A) diffusion. 
B) receptor-mediated endocytosis. 
C) pinocytosis. 
D) phagocytosis. 
A) diffusion. 
B) receptor-mediated endocytosis. 
C) pinocytosis. 
D) phagocytosis.

Question 7

Which of the following statements regarding membrane protein function is false?

Accepted Answer

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. 
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.

Question 8

Which of the following substances would have the most trouble crossing a biological membrane by diffusing through the lipid bilayer?

Accepted Answer

A) O₂ 
B) CO₂ 
C) Na⁺ 
D) a small, nonpolar molecule such as butane (C₄H₁₀) 
A) O₂ 
B) CO₂ 
C) Na⁺ 
D) a small, nonpolar molecule such as butane (C₄H₁₀)

Question 9

Inhibition of an enzyme is irreversible when

Accepted Answer

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. 
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.

Question 10

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?

Accepted Answer

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. 
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.

Question 11

Which of the following is a coenzyme?

Accepted Answer

A) zinc 
B) vitamin B₆ 
C) iron 
D) iodine 
A) zinc 
B) vitamin B₆ 
C) iron 
D) iodine

Question 12

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?

Accepted Answer

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 
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

Question 13

Which of the following statements regarding thermodynamics is false?

Accepted Answer

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. 
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.

Question 14

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

Accepted Answer

A) competitive inhibition. 
B) noncompetitive inhibition. 
C) feedback inhibition. 
D) irreversible inhibition. 
A) competitive inhibition. 
B) noncompetitive inhibition. 
C) feedback inhibition. 
D) irreversible inhibition.

Question 15

The fluid mosaic model describes the plasma membrane as consisting of

Accepted Answer

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. 
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.

Question 16

Which of the following substances could be a cofactor?

Accepted Answer

A) a protein 
B) a polypeptide 
C) a zinc atom 
D) a ribosome 
A) a protein 
B) a polypeptide 
C) a zinc atom 
D) a ribosome

Question 17

Most of the functions of a cell membrane, including transport and enzymatic function, are performed by

Accepted Answer

A) glycolipids. 
B) proteins. 
C) phospholipids. 
D) cholesterol. 
A) glycolipids. 
B) proteins. 
C) phospholipids. 
D) cholesterol.

Question 18

The process of a white blood cell engulfing a bacterium is

Accepted Answer

A) osmosis. 
B) receptor-mediated endocytosis. 
C) pinocytosis. 
D) phagocytosis. 
A) osmosis. 
B) receptor-mediated endocytosis. 
C) pinocytosis. 
D) phagocytosis.

Question 19

Osmosis can be defined as

Accepted Answer

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. 
B) the diffusion of nonpolar molecules. 
C) active transport. 
D) the diffusion of a solute.

Question 20

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.

Accepted Answer

A) isotonic 
B) hypotonic 
C) hypertonic 
D) hydrophilic 
A) isotonic 
B) hypotonic 
C) hypertonic 
D) hydrophilic

Exam 5: The Working Cell

All cells are enclosed by a plasma membrane that is similar in ________ and ________.

Small, nonpolar, hydrophobic molecules such as fatty acids

Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing

Which of the following statements regarding active transport is false?

A cell that has neither a net gain of water nor net loss of water when it is immersed in a solution must be

Cells acquire low-density lipoproteins (LDLs)by

Which of the following statements regarding membrane protein function is false?

Which of the following substances would have the most trouble crossing a biological membrane by diffusing through the lipid bilayer?

Inhibition of an enzyme is irreversible when

Which of the following is a coenzyme?

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?

Which of the following statements regarding thermodynamics is false?

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

The fluid mosaic model describes the plasma membrane as consisting of

Which of the following substances could be a cofactor?

Most of the functions of a cell membrane, including transport and enzymatic function, are performed by

The process of a white blood cell engulfing a bacterium is

Osmosis can be defined as

Biology: Exploring Life

The Chemical Basis of Life

The Molecules of Cells

A Tour of the Cell

How Cells Harvest Chemical Energy

Photosynthesis: Using Light to Make Food

The Cellular Basis of Reproduction and Inheritance

Patterns of Inheritance

Molecular Biology of the Gene

How Genes Are Controlled

DNA Technology and Genomics

How Populations Evolve

The Origin of Species

Tracing Evolutionary History

Microbial Life: Prokaryotes and Protists

The Evolution of Plant and Fungal Diversity

The Evolution of Invertebrate Diversity

The Evolution of Vertebrate Diversity

Unifying Concepts of Animal Structure and Function

Nutrition and Digestion

Gas Exchange

Circulation

the Immune System

Control of Body Temperature and Water Balance

Hormones and the Endocrine System

Reproduction and Embryonic Development

Nervous Systems

the Senses

How Animals Move

Plant Structure, Growth, and Reproduction

Plant Nutrition and Transport

Control Systems in Plants

the Biosphere: an Introduction to Earths Diverse Environments

Behavioral Adaptations to the Environment

Population Ecology

Communities and Ecosystems

Conservation Biology

Filters

All cells are enclosed by a plasma membrane that is similar in and .