Question 1

In a hypotonic solution, an animal cell will

Accepted Answer

A)  lyse. 
B)  experience turgor. 
C)  neither gain nor lose water. 
D)  shrivel. 
A)  lyse. 
B)  experience turgor. 
C)  neither gain nor lose water. 
D)  shrivel. A

Question 2

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) C

Question 3

Kinetic energy differs from chemical energy in that

Accepted Answer

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. 
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

Question 4

Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.

Accepted Answer

A)  energy and transport proteins; down 
B)  transport proteins; down 
C)  energy and transport proteins; against 
D)  transport proteins; against 
A)  energy and transport proteins; down 
B)  transport proteins; down 
C)  energy and transport proteins; against 
D)  transport proteins; against

Question 5

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 6

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 7

The molecules responsible for membrane transport are

Accepted Answer

A)  steroids. 
B)  phospholipids. 
C)  carbohydrates. 
D)  proteins. 
A)  steroids. 
B)  phospholipids. 
C)  carbohydrates. 
D)  proteins.

Question 8

Which of the following statements regarding enzymes is true?

Accepted Answer

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. 
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.

Question 9

Which part of the ATP molecule breaks free of the rest when an ATP molecule releases energy?

Accepted Answer

A)  part A 
B)  part B 
C)  part C 
D)  part D 
A)  part A 
B)  part B 
C)  part C 
D)  part D

Question 10

A cell that has neither a net gain of water nor a 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. 
A)  isotonic to its environment. 
B)  hypertonic to its environment. 
C)  hypotonic to its environment.

Question 11

Which characteristic promoted the utilization of lipids as the first cell membrane?

Accepted Answer

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 
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

Question 12

Heating inactivates enzymes by

Accepted Answer

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. 
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.

Question 13

The active site of an enzyme is

Accepted Answer

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. 
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.

Question 14

Most of a cell's enzymes are

Accepted Answer

A)  lipids. 
B)  proteins. 
C)  amino acids. 
D)  carbohydrates. 
A)  lipids. 
B)  proteins. 
C)  amino acids. 
D)  carbohydrates.

Question 15

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 produce phospholipids. 
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 produce phospholipids.

Question 16

The process of a white blood cell engulfing a bacterium is

Accepted Answer

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

Question 17

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

Accepted Answer

A)  a metabolic pathway. 
B)  feedback inhibition. 
C)  passive transport. 
D)  competitive inhibition. 
A)  a metabolic pathway. 
B)  feedback inhibition. 
C)  passive transport. 
D)  competitive inhibition.

Question 18

Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of

Accepted Answer

A)  exocytosis. 
B)  passive transport. 
C)  active transport. 
D)  endocytosis. 
A)  exocytosis. 
B)  passive transport. 
C)  active transport. 
D)  endocytosis.

Question 19

Membrane phospholipids

Accepted Answer

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. 
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.

Question 20

Lipase is an enzyme released by the pancreas that digests fats in the small intestine; however, lipase is also found in bacteria. Researchers examined lipase function in two species of bacteria, species X and species Y. Data regarding the activity of lipase as a function of temperature are shown below for the lipase from bacteria X (white circles) and the lipase from bacteria Y (black circles). Use this information to answer the following three questions.
   Lipase activity as a function of temperature.
-What can you conclude from data in the figure?

Accepted Answer

A)  The lipase from bacteria X is insensitive to changes in pH. 
B)  Only the lipase from bacteria Y denatures at high temperatures. 
C)  Bacteria X likely lives in an environment that undergoes large changes in temperature. 
D)  The lipase from bacteria Y is more active than the lipase from bacteria X at 20°C. 
A)  The lipase from bacteria X is insensitive to changes in pH. 
B)  Only the lipase from bacteria Y denatures at high temperatures. 
C)  Bacteria X likely lives in an environment that undergoes large changes in temperature. 
D)  The lipase from bacteria Y is more active than the lipase from bacteria X at 20°C.

Exam 5: The Working Cell

In a hypotonic solution, an animal cell will

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

Kinetic energy differs from chemical energy in that

Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.

Which of the following is a coenzyme?

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

The molecules responsible for membrane transport are

Which of the following statements regarding enzymes is true?

Which part of the ATP molecule breaks free of the rest when an ATP molecule releases energy?

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

Which characteristic promoted the utilization of lipids as the first cell membrane?

Heating inactivates enzymes by

The active site of an enzyme is

Most of a cell's enzymes are

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

The process of a white blood cell engulfing a bacterium is

Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of

Membrane phospholipids

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

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