Biology 101 Exam 1

Chapter 1: 1-20 Chapter 2: 21-62 Chapter 3: 63-109

A controlled experiment is one that

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A. proceeds slowly enough that a scientist can make careful records of the results.

B. tests experimental and control groups in parallel.

C. is repeated many times to make sure the results are accurate.

D. keeps all variables constant.

E. is supervised by an experienced scientist.

B.

The main source of energy for producers in an ecosystem is

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A. light energy.

B. kinetic energy.

C. thermal energy.

D. chemical energy.

E. ATP.

A.

Why is it important that an experiment include a control group?

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A. The researcher predetermines the results for the control group.

B. The control group provides a reserve of experimental subjects.

C. A control group is required for the development of an “if…then” statement.

D. A control group assures that an experiment will be repeatable.

E. Without a control group, there is no basis for knowing if a particular result is due to the variable being tested.

E.

Imagine there is a species-specific fishing regulation that mandates only adult fish of this species that are 75 cm or longer may be kept and shorter fish must be released. Based on your knowledge of natural selection, you would predict that the average length of the adult fish population will

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A. remain unchanged.

B. gradually decline.

C. rapidly increase.

D. gradually increase.

B.

Which of the following best describes the logic of scientific inquiry?

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A. If I generate a testable hypothesis, tests and observations will support it.

B. If my prediction is correct, it will lead to a testable hypothesis.

C. If my observations are accurate, they will support my hypothesis.

D. If my hypothesis is correct, I can expect certain test results.

E. If my experiments are set up right, they will lead to a testable hypothesis.

D.

In a high school laboratory, which of the following constitutes an experiment? II. being able to examine swimming protists under a microscope III. seeking to identify the pigments present in a leaf IV. preparing root tips for examination by staining them.

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A. learning to use microscope by examining fixed specimens on slides.

B. I only

C. II only

D. III only

E. II and III only

F. II, III, and IV

D.

Why is Darwin considered original in his thinking?

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A. He provided examples of organisms that had evolved over time.

B. He demonstrated that evolution is continuing to occur now.

C. He described the relationship between genes and evolution.

D. He proposed the mechanism that explains how evolution takes place.

E. He observed that organisms produce large numbers of offspring.

D.

Which of the following is an example of qualitative data?

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A. The temperature decreased from 20°C to 15°C.

B. The plant’s height is 25 centimeters (cm).

C. The fish swam in a zigzag motion.

D. The six pairs of robins hatched an average of three chicks.

E. The contents of the stomach are mixed every 20 seconds.

C.

Which of the following types of cells have deoxyribonucleic acid (DNA) as their genetic material but do not have their DNA encased within a nuclear envelope?

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A. animal

B. plant

C. archaea

D. fungi

E. protists

C.

Prokaryotes are classified as belonging to two different domains. What are the domains?

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A. Bacteria and Eukarya

B. Archaea and Monera

C. Eukarya and Monera

D. Bacteria and Protists

E. Bacteria and Archaea

E

Which of the following taxonomic categories is least likely to be later revised for a particular organism?

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A. kingdom

B. class

C. order

D. phylum

E. domain

E

Through time, the lineage that led to modern whales shows a change from four-limbed land animals to aquatic animals with two limbs that function as flippers. This change is best explained by

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A. natural philosophy

B. reductionism

C. the hierarchy of the biological organization of life

D. natural selection

E. feedback inhibition

D.

An organization has been isolated from decomposing organic matter. This organism has a cell wall but no chloroplasts. How would you classify this organism?

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A. domain Bacteria, kingdom Prokaryota

B. domain Archaea, kingdom Bacteria

C. domain Eukarya, kingdom Plantae

D. domain Eukarya, kingdom Protista

E. domain Eukarya, kingdom Fungi

E.

To understand the chemical basis of inheritance, we must understand the molecular structure of DNA. This is an example of the application of which concept to the study of biology?

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A. evolution

B. emergent properties

C. reductionism

D. the cell theory

E. feedback regulation

C.

Which of the following is (are) true of natural selection?

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A. It requires genetic variation.

B. It results in descent with modification

C. It involves differential reproductive success

D. It results in descent with modification and involves differential reproductive success.

E. It requires genetic variation, results in descent with modification, and involves differential reproductive success.

E.

Which of the following statements best distinguishes hypotheses from theories in science?

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A. Theories are hypotheses that have been proved.

B. Hypotheses are guesses; theories are correct answers.

C. Hypotheses usually are relatively narrow in scope; theories have broad explanatory power.

D. Hypotheses and theories are essentially the same thing.

E. Theories are proved true; hypotheses are often falsified.

C.

Which of these provides evidence of the common ancestry of all life?

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A. ubiquitous use of catalysts by living systems

B. near universality of the genetic code

C. structure of the nucleus

D. structure of cilia

E. structure of chloroplasts

B.

A localized group of organisms that belong to the same species is called a

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A. biosystem

B. community

C. population

D. ecosystem

E. family

C.

What is the major distinguishing characteristic of fungi?

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A. gaining nutrition through ingestion

B. being sedentary

C. being prokaryotic

D. absorbing nutrients

D.

The application of scientific knowledge for some specific purpose is known as

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A. technology

B. deductive science

C. inductive science

D. anthropologic science

E. pure science

A

The chemical behavior of an atom depends primarily upon which of the following?

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A. the number of neutrons in the nucleus

B. the number of protons in the nucleus

C. the number of electrons in the valence shell

D. the total number of electrons contained by the atom

E. the number of electron shells contained by the atom

C.

The nucleus of a nitrogen atoms contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen?

\
A. The nitrogen atom has a mass number of 7 and an atomic number of 14.

B. The nitrogen atom has a mas number of 14 and an atomic number of 7.

C. The nitrogen atom has a mass of 14 and an atomic number of 14.

D. The nitrogen atom has a mass number of 7 and an atomic number of 21.

E. The nitrogen atom has a mass number of 14 and an atomic number of 21.

B.

One difference between carbon-12 (C) and carbon-14 (C) is that carbon-14 has

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A. two more protons than carbon-12.

B. two more electrons than carbon-12.

C. two more neutrons than carbon-12.

D. two more protons and two more neutrons than carbon-12.

E. two more electrons and two more protons than carbon-12.

C

Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates?

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A. nitrogen

B. calcium

C. iodine

D. sodium

E. phosphorus

C.

From the atomic mass, one can deduce the number of _______ in each atom of an element.

\
A. protons

B. neutrons

C. electrons

D. protons plus electrons

E. protons plus neutrons

E.

Molybdenum has an atomic number of 42. Several common isotopes exist, with mass numbers of 92, 94, 95, 96, 97, 98, and 100. Therefore, which of the following is true?

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A. Molybdenum atoms can have between 50 and 58 neutrons.

B. The isotopes of molybdenum have different electron configurations.

C. The isotopes of molybdenum can have between 50 an d58 protons.

D. The isotopes of molybdenum have between 50 and 58 neutrons and have different electron configurations.

E. The isotopes of molybdenum have between 50 and 58 protons and have different electron configurations.

A.

Fluorine has an atomic number of 9 and a mass number of 19. How many electrons are needed to complete the valence shell of a fluorine atom?

\
A. 1

B. 3

C. 0

D. 7

E. 9

A.

The atomic number of each atom is given to the left of each of the following elements. Which of the atoms has the same valence as carbon (C)?

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A. 7N nitrogen

B. 9F fluorine

C. 10Ne neon

D. 12Mg magnesium

E. 14Si silicon

E

Argon has atomic number 18. Which of the following statements about argon is true?

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A. It has 10 electrons in its outer shell.

B. It is inert.

C. It has an atomic mass of 18 Daltons.

D. It has six valence electrons.

E. It resides in the first column of the periodic table.

B

The atomic number of sulfur is 16, which indicates that a sulfur atom contains

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A. 16 neutrons.

B. 16 protons.

C. 16 protons and 16 neutrons.

D. 8 electrons in its outermost electron shell.

E. 8 protons and 8 neutrons.

B

An atom has 6 electrons in its outer shell. How many unpaired electrons does it have?

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A. 0

B. 2

C. 4

D. 6

E. 2 or 4

B.

Oxygen has an atomic number of 8 and a mass number of 16. What is the atomic mass of an oxygen atom?

\
A. approximately 8 grams

B. approximately 8 Daltons

C. approximately 16 grams

D. approximately 16 Daltons

E. approximately 24 grams

D.

Two atoms that have the same mass number must have the same

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A. atomic number.

B. number of electrons.

C. protons.

D. number of protons + neutrons.

E. chemical properties

D.

Phosphorus-32, a radioactive isotope of phosphorus-31 (atomic number 15), undergoes a form of radioactive decay whereby a neutron turns into a proton, which is retained in the nucleus, and emits radiation in the form of an electron. What is the product of such radioactive decay of phosphorus-32?

\
A. phosphorus-31

B. a positively charged phosphorus-31 ion

C. a negatively charged phosphorus-32 ion

D. sulfur-32 (atomic number 16)

E. the conversation of the phosphorus-32 atom into pure energy.

D.

About 20-25% of the 92 natural elements are known to be essential to life. Which four of these elements make up approximately 96% of living matter?

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A. carbon, sodium, hydrogen, nitrogen

B. carbon, oxygen, phosphorus, hydrogen

C. oxygen, hydrogen, calcium, nitrogen

D. carbon, hydrogen, nitrogen, oxygen

E. carbon, oxygen, nitrogen, calcium

D.

The atomic number of nitrogen is 7. Nitrogen-15 is heavier than nitrogen-14 because the atomic nucleus of nitrogen-15 contains how many neutrons?

\
A. 6

B. 7

C. 8

D. 12

E. 14

C.

A covalent bond is likely to be polar when

\
A. one of the atoms sharing electrons is much more electronegative than the other atom.

B. the two atoms sharing electrons are equally electronegative.

C. oxygen is one of the two atoms sharing electrons.

D. the two atoms sharing electrons are the same element.

A.

If a salamander clings to surfaces through hydrogen bonds, it would have the most difficulty clinging to which of the following surfaces?

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A. a surface coated with a thin film of water

B. a surface coated with a thin film of vinegar (acetic acid)

C. a surface coated with a thin film of vegetable oil

D. a surface coated with a thin film of ammonia (NH3)

C.

Which of the following are the strongest molecular interactions?

\
A. van der Waals interactions

B. van der Waals interactions in a nonpolar environment

C. ionic bonds in an aqueous environment

D. covalent bonds

E. hydrogen bonds

D.

Which of the following are considered compounds?

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A. H2O, O2, and CH4

B. H2O and O2

C. O2 and CH4

D. CH4 and O2, but not H2O

E. H2O and CH4, but not O2

E.

Which bond or interaction would be most difficult to disrupt when compounds are put into water?

\
A. covalent bond

B. hydrogen bond

C. van der Waals interaction

D. ionic bond

A.

The most stable interaction between magnesium (atomic number 12) and chlorine (atomic number 17) forms

\
A. MgCl, in which atoms are joined by covalent bonds.

B. MgCl, in which atoms are joined by ionic bonds.

C. Mg2Cl, in which atoms are joined by ionic bonds.

D. MgCl2, in which atoms are joined by covalent bonds.

E. MgCl2, in which atoms are joined by ionic bonds.

E.

Why does ice float in liquid water?

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A. The high surface tension of liquid water keeps the ice on top.

B. The ionic bonds between the molecules in ice prevent the ice from sinking.

C. Ice always has air bubbles that keep it afloat.

D. Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.

E. The crystalline lattice of ice causes it to be denser than liquid water.

D.

What type of bond must be broken for water to vaporize?

\
A. ionic bonds

B. both hydrogen bonds and ionic bonds

C. polar covalent bonds

D. hydrogen bonds

E. both polar covalent bonds and hydrogen bonds

D.

What is the maximum number of hydrogen atoms that can be covalently bonded in a molecule containing two carbon atoms?

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A. 2

B. 3

C. 4

D. 6

E. 8

D.

Which of the following takes place as an ice cube cools a drink?

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A. Molecular collisions in the drink increase.

B. Kinetic energy in the drink decreases.

C. A calorie of heat energy is transferred from the ice to the water of the drink.

D. The specific heat of the water in the drink decreases.

E. Evaporation of the water in the drink increases.

B.

Which of the following effects is produced by the high surface tension of water?

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A. Lakes don’t freeze solid in winter despite low temperatures.

B. A water strider can walk across the surface of a small pond.

C. Organisms resist temperature changes, although they give off heat due to chemical reactions.

D. Evaporation of sweat from the skin helps to keep people from overheating.

E. Water flows upward from the roots to the leaves in plants.

B.

What is the maximum number of covalent bonds an element with atomic number 8 can make with hydrogen?

\
A. 1

B. 2

C. 3

D. 4

E. 6

B.

Which of the following correctly describes any reaction that has reached chemical equilibrium?

\
A. The concentration of the reactants equal the concentration of the products.

B. The rate of the forward reaction is equal to the rate of the reverse reaction.

C. All of the reactants have been converted to the products of the reaction.

D. All of the products have been converted to the reactants of the reaction.

B.

What results from an unequal sharing of electrons between atoms?

\
A. a nonpolar covalent bond

B. a polar covalent bond

C. an ionic bond

D. a hydrophobic interaction

B.

An ionic bond is formed by

\
A. sharing of a pair of electrons between two atoms.

B. sharing of a single electron between two atoms.

C. sharing of a pair of protons between two atoms.

D. transfer of an electron from one atom to another.

E. transfer of a proton from one atom to another.

D

What is the hydrogen ion (H+) concentration of a solution of pH 8?

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A. 8 M

B. 8 x 10-6 M

C. 0.01 M

D. 10-8 M

E. 10-6 M

D.

If the pH of a solution is increased form pH 5 to pH 7, it means that the

\
A. concentration of H+ is twice (2x) what it was at pH 5.

B. concentration of H+ is one-half (1/2) what it was at pH 5.

C. concentration of OH- is 100 times greater than what it was at pH 5.

D. concentration of OH- is one-hundredth (0.01x) what it was at pH 5.

E. concentration of H+ is 100 times greater than what it was at pH 5.

C.

CO2 absorbed by the oceans combines with water to form H2CO3. Which of the following will result from increasing the concentration of H2CO3 in the oceans?

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A. Ocean pH will be stabilized by the buffering capacity of H2CO3.

B. Ocean pH will increase.

C. Ocean pH will decrease.

D. The concentration of carbonate ions (CO32-) in the ocean will increase.

E. The concentration of bicarbonate ions (HCO3-) in the ocean will decrease.

C.

Which of the following dissociates completely in aqueous solution and is therefore considered to be a strong base (alkali)?

\
A. NaCl

B. HCl

C. NH3

D. H2CO3

E. NaOH

E.

What is the pH of a solution with a hydroxyl ion (OH-) concentration of 10-12 M?

\
A. pH 2

B. pH 4

C. pH 10

D. pH 12

E. pH 14

A.

If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, this means that

\
A. the concentration of hydrogen ions is tenfold higher in the cytoplasm than in the mitochondrial matrix.

B. the concentration of hydrogen ions is tenfold higher in the mitochondrial matrix than in the cytoplasm.

C. the concentration of hydrogen ions in the cytoplasm is 7/8 the concentration in the mitochondrial matrix.

D. the mitochondrial matrix is more acidic than the cytoplasm.

E. the concentration of hydrogen ions in the cytoplasm is 8/7 the concentration in the mitochondrial matrix.

A.

A strong acid like HCl

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A. dissociates completely in an aqueous solution.

B. increases the pH when added to an aqueous solution.

C. is a strong buffer at high pH.

D. is a strong buffer at low pH.

A.

If acid rain has lowered the pH of a particular lake to pH 4.0 which of the following statements about this lake is true?

\
A. The hydrogen ion concentration is 1 x 10-10 moles per liter of lake water.

B. The hydrogen ion concentration is 4.0 moles per liter of lake water.

C. The hydrogen ion concentration is 1 x 10-4 moles per liter of lake water.

D. The hydroxyl ion concentration is 1 x 10-10 moles per liter of lake water.

E. The hydroxyl ion concentration is 1 x 10-4 moles per liter of lake water.

C.

Buffers are substances that help resist shifts in pH by

\
A. releasing H+ to a solution when acids are added.

B. accepting OH- to a solution when bases are added.

C. releasing OH- to a solution when bases are added.

D. accepting H+ from a solution when acids are added.

D.

If the pH of a solution is decreased from pH 8 to pH 6, it means that the

\
A. concentration of H+ is twice (2x) what it was at pH 8.

B. concentration of H+ is one-half (1/2) what it was at pH 8.

C. concentration of OH- is 100 times greater than what it was at pH 8.

D. concentration of OH- is one-hundredth (0.01x) what it was at pH 8.

E. concentration of H+ is one-hundredth (0.01x) what it was at pH 8.

D.

What is the hydroxyl ion (OH-) concentration of a solution of pH 8?

\
A. 8 M

B. 8 x 10-6 M

C. 0.01 M

D. 10-8 M

E. 10-6 M

E.

If cells are grown in a medium containing radioactive 15N, which of these molecules will be labeled?

\
A. fatty acids only

B. nucleic acids only

C. proteins only

D. both fatty acids and proteins

E. both proteins and nucleic acids

E.

Which of the following descriptions best fits the class of molecules known as nucleotides?

\
A. a nitrogenous base and a phosphate group

B. a nitrogenous base and a pentose sugar

C. a nitrogenous base, a phosphate group, and a pentose sugar

D. a phosphate group and an adenine or uracil

E. a pentose sugar and a purine or pyrimidine

C.

The most important element (because it can make a wide diversity of bonds) present in all organic molecules is

\
A. hydrogen

B. oxygen

C. carbon

D. nitrogen

E. phosphorus

C.

Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers, that is, molecules that

\
A. have identical formulas but differ in the branching of their carbon skeletons.

B. are mirror images of one another.

C. exist in either linear chain or ring forms.

D. differ in the location of their double bonds.

E. differ in the arrangement of atoms around their double bonds.

B.

What is the chemical reaction mechanism by which cells make polymers from monomers?

\
A. phosphodiester linkages

B. hydrolysis

C. dehydration reactions

D. ionic bonding of monomers

E. the formation of disulfide bridges between monomers

C.

Amino acids are acids because they always possess which functional group?

\
A. amino

B. carbonyl

C. carboxyl

D. phosphate

E. hydroxyl

C.

Misfolding of polypeptides is a serious problem in cells. Which of the following diseases is (are) associated with an accumulation of misfolded polypeptides?

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A. Alzheimer’s only

B. Parkinson’s only

C. diabetes mellitus only

D. Alzheimer’s and Parkinson’s only

E. Alzheimer’s, Parkinson’s, and diabetes mellitus

D.

There are 20 different amino acids. What makes one amino acid different from another?

\
A. different side chains (R groups) attached to a carboxyl carbon

B. different side chains (R groups) attached to the amino groups

C. different side chains (R groups) attached to an α (alpha) carbon

D. different structural and optical isomers

E. different asymmetric carbons

C.

If one strand of a DNA molecule has the sequence of bases 5’ATTGCA3’, the other complementary strand would have the sequence

\
A. 5’TAACGT3’

B. 5’TGCAAT3’

C. 5’UAACGU3’

D. 3’UAACGU5’

E. 5’UGCAAU3’

B.

What determines whether a carbon atom’s covalent bonds to other atoms are in a tetrahedral configurations or a planar configuration?

\
A. the presence or absence of bonds with oxygen atoms

B. the presence or absence of double bonds between the carbon atom and other atoms

C. the polarity of the covalent bonds between carbon and other atoms

D. the presence or absence of bonds with nitrogen atoms

E. the solvent that the organic molecule is dissolved in

B.

The experimental approach taken in current biological investigations presumes that

\
A. simple organic compounds can be synthesized in the laboratory from inorganic precursors, but complex organic compounds such as carbohydrates and proteins can only be synthesized by living organisms.

B. a life force ultimately controls the activities of living organisms, and this life force cannot be studied by physical or chemical methods.

C. although a life force, or vitalism, exists in living organisms, this life force cannot be studied by physical or chemical methods.

D. living organisms are composed of the same elements present in nonliving things, plus a few special trace elements found only in living organisms or their products.

E. living organisms can be understood in terms of the same physical and chemical laws that can be used to explain all natural phenomena.

E.

A molecule with the formula C18H36O2 is probably a

\
A. carbohydrate.

B. fatty acid.

C. protein.

D. nucleic acid.

B.

At which level(s) of protein structure are interactions between the side chains (R groups) most important?

\
A. primary.

B. secondary.

C. tertiary.

D. quaternary.

E. primary, secondary, tertiary, and quaternary.

C.

Which of the following statements concerning saturated fats is not true?

\
A. They are more common in animals than in plants.

B. They have multiple double bonds in the carbon chains of their fatty acid.

C. They generally solidify at room temperature.

D. They contain more hydrogen than unsaturated fats having the same number of carbon atoms.

E. They are one of several factors that contribute to atherosclerosis.

B.

Which of the following is true regarding saturated fatty acids?

\
A. They are the predominant fatty acid in corn oil.

B. They have double bonds between the carbon atoms of the fatty acids.

C. They are the principal molecules in lard and butter.

D. They are usually liquid at room temperature.

E. They are usually prodcued by plants.

C.

A molecule with the chemical formula C6H12O6 is probably a

\
A. carbohydrate.

B. lipid.

C. monosaccharide.

D. carbohydrate and lipid only.

E. carbohydrate and monosaccharide only.

E.

The complexity and variety of organic molecules is due to

\
A. the chemical versatility of carbon atoms.

B. the variety of rare elements in organic molecules.

C. the fact that they can by synthesized only in living organisms.

D. their interaction with water.

E. their tremendously large sizes.

A.

What is the structural feature that allows DNA to replicate?

\
A. sugar-phosphate backbone

B. complementary pairing of the nitrogenous bases

C. disulfide bonding (bridging, of the two helixes)

D. twisting of the molecule to form an α helix

E. three-component structure of the nucleotides

B.

Which of the following is true of both starch and cellulose?

\
A. They are both polymers of glucose.

B. They are cis-trans isomers of each other.

C. They can both be digested by humans.

D. They are both used for energy storage in plants.

E. They are both structural components of the plant cell wall.

A.

All of the following are polysaccharides except

\
A. lactose

B. glycogen

C. chitin

D. cellulose

E. amylopectin

A.

Which level of protein structure do the α helix and the β pleated sheet represent?

\
A. primary

B. secondary

C. tertiary

D. quaternary

E. primary, secondary, tertiary, and quaternary

B

Which of the following statements best summarized the differences between DNA and RNA?

\
A. DNA encodes hereditary information, whereas RNA does not.

B. The bases in DNA form base-paired duplexes, whereas the bases in RNA do not.

C. DNA nucleotides contain a different sugar than RNA nucleotides.

D. DNA contains the base uracil, whereas RNA contains the base thymine.

E. DNA encodes hereditary information, whereas RNA does not; the bases in DNA form base-paired duplexes, whereas the bases in RNA do not; and DNA nucleotides contain a different sugar than RNA nucleotides.

E.

Which of the following are nitrogenous bases of the pyrimidine type?

\
A. guanine and adenine

B. cytosine and uracil

C. thymine and guanine

D. ribose and deoxyribose

E. adenine and thymine

B.

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down?

\
A. starch

B. cellulose

C. chitin

D. starch and chitin only

E. starch, cellulose, and chitin

A.

A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of

\
A. 120 adenine and 120 uracil molecules.

B. 120 thymine and 120 adenine molecules.

C. 120 cytosine and 120 thymine molecules.

D. 120 adenine and 120 cytosine molecules.

E. 120 guanine and 120 thymine molecules.

B.

Which of the following classes of biological molecules consist of both small molecules and macromolecular polymers?

\
A. lipids

B. carbohydrates

C. proteins

D. nucleic acids

E. lipids, carbohydrates, proteins, and nucleic acids all consist of only macromolecular polymers

B.

Differences among organisms are caused by

\
A. large differences in elemental composition from organism to organism.

B. differences in the types and relative amounts of organic molecules synthesized by each organism.

C. differences in the elements that bond with carbon in each organism.

D. differences in the sized of the organic molecules in each organism.

E. differences in the inorganic compounds present in each organism.

B.

DNase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with DNase?

\
A. The two strands of the double helix would separate.

B. The phosphodiester bonds between deoxyribose sugars would be broken.

C. The purines would be separated from the deoxyribose sugars.

D. The pyrimidines would be separated from the deoxyribose sugars.

E. All bases would be separated from the deoxyribose sugars.

B.

Dehydration reactions are used in forming which of the following compounds?

\
A. triaclyglycerols

B. polysaccharides

C. proteins

D. triaclyglycerols and proteins only

E. triacylglycerols, polysaccharides, and proteins

E.

If 14C-labeled uracil is added to the growth medium of cells, what macromolecules will be labeled?

\
A. phospholipids

B. DNA

C. RNA

D. both DNA and RNA

E. proteins

C.

A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound?

\
A. It lacks an asymmetric carbon, and it is probably a fat or lipid.

B. It should dissolve in water.

C. It should dissolve in a nonpolar solvent.

D. It won’t form hydrogen bonds with water.

E. It is hydrophobic.

B.

The label on a container of margarine lists “hydrogenated vegetable oil” as the major ingredient. What is the result of adding hydrogens to vegetable oil?

\
A. The hydrogenated vegetable oil has a lower melting point.

B. The hydrogenated vegetable oil stays solid at room temperature.

C. The hydrogenated vegetable oil has more “kinks” in the fatty acid chains.

D. The hydrogenated vegetable oil has fewer trans fatty acids.

E. The hydrogenated vegetable oil is less likely to clog arteries.

B

How will brief heating (to 95°C) affect macromolecular structures in aqueous solution?

\
A. DNA duplexes will unwind and separate.

B. Proteins will unfold (denature).

C. Starch will hydrolyze into monomeric sugars.

D. Proteins will hydrolyze into amino acids.

E. DNA duplexes will unwind and separate, and proteins will unfold (denature).

E.

What maintains the secondary structure of a protein?

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A. peptide bonds

B. hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond

C. disulfide bonds

D. hydrophobic interactions

E. hydrogen bonds between the R groups

B.

Changing a single amino acid in a protein consisting of 325 amino acids would

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A. alter the primary structure of the protein but not its tertiary structure or function.

B. cause the tertiary structure of the protein to unfold.

C. always alter the biological activity or function of the protein.

D. always alter the primary structure of the protein and disrupt its biological activity.

E. always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein, and sometimes affect its biological activity.

E.

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

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A. Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.

B. Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes water permeable.

C. Dehydration reactions can occur only after hydrolysis.

D. Hydrolysis creates monomers, and dehydration reactions break down polymers.

E. Dehydration reactions ionize water molecules and add hydroxyl groups to polymers; hydrolysis reactions release hydroxyl groups from polymers.

A.

If a DNA sample were composed of 10% thymine, what would be the percentage of guanine?

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A. 10

B. 20

C. 40

D. 80

E. Impossible to tell from the information given

C.

Which of the following polymers contain nitrogen?

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A. starch

B. glycogen

C. cellulose

D. chitin

E. amylopectin

D.