Deck 3: Proteins, Carbohydrates, and Lipids

Question 1

Which of the following is not a macromolecule?

A) RNA
B) DNA
C) Vitamin D, E, or K
D) A protein
E) Salt

Answer 1

E

Question 2

The amino acid leucine

A) is found in all proteins.
B) cannot form peptide linkages.
C) has a hydrophobic side chain.
D) has a hydrophilic side chain.
E) is identical to the amino acid lysine.

Answer 2

C

Question 3

Which of the following statements regarding the carbon atoms in a molecule and its functional groups is false?

A) They determine how the molecule interacts with other molecules in the environment.
B) They determine the shape of the molecule.
C) They determine the specific properties of the molecule.
D) They may have interactions with specific functional groups on the same molecule.
E) They are antagonistic to each other, thereby creating multiple forces that drive chemical reactions.

Answer 3

E

Question 4

The quaternary structure of a protein

A) consists of four subunits-hence the name quaternary.
B) is unrelated to the function of the protein.
C) may be either alpha or beta.
D) depends on covalent bonding among the subunits.
E) depends on the primary structures of the subunits.

Question 5

Which of the following is not a carbohydrate?

A) Glucose
B) Starch
C) Cellulose
D) Hemoglobin
E) Deoxyribose

Question 6

The amphipathic nature of phospholipids is

A) determined by the fatty acid composition.
B) important in membrane structure.
C) polar but not nonpolar.
D) shown only if the lipid is in a nonpolar solvent.
E) important in energy storage by lipids.

Question 7

The bonds that form between the atoms of polymeric macromolecules are _______ bonds.

A) hydrogen
B) peptide
C) disulfide
D) covalent
E) ionic

Question 8

An essential functional group involved in cellular energy transfer is the _______ group.

A) phosphate
B) amino
C) sulfhydryl
D) hydroxyl
E) saccharide

Question 9

Which of the following does not represent a correct monomer/polymer pairing?

A) Monosaccharide/polysaccharide
B) Amino acid/protein
C) Triglyceride/cellulose
D) Nucleotide/nucleic acid
E) Monosaccharide/oligosaccharide

Question 10

Large molecules that contain carbon and are held together by covalent bonds are categorized as

A) proteins.
B) polymers.
C) nucleic acids.
D) macromolecules.
E) monomers.

Question 11

All proteins

A) are enzymes.
B) consist of one or more polypeptide chains.
C) are amino acids.
D) have quaternary structures.
E) are more soluble in nonpolar solvents than in water.

Question 12

Which of the following statements about condensation reactions is not true?

A) Protein synthesis results from them.
B) Polysaccharide synthesis results from them.
C) They involve covalent bonds.
D) They consume water as a reactant.
E) Different condensation reactions produce different kinds of macromolecules.

Question 13

All lipids are

A) triglycerides.
B) polar.
C) hydrophilic.
D) polymers of fatty acids.
E) more soluble in nonpolar solvents than in water.

Question 14

Which of the following functional groups is the most polar?

A) Hydroxyl
B) Aldehyde
C) Keto
D) Carboxylic acids
E) Sulfhydryl

Question 15

Molecules containing a large number of hydroxyl groups are

A) basic.
B) highly stable structurally.
C) involved in reactions forming more complex molecules.
D) nonpolar.
E) highly soluble in water.

Question 16

All carbohydrates

A) are polymers.
B) are simple sugars.
C) consist of one or more simple sugars.
D) are found in biological membranes.
E) are more soluble in nonpolar solvents than in water.

Question 17

Which of the following statements about the primary structure of a protein is not true?

A) It may be branched.
B) It is held together by covalent bonds.
C) It is unique to that protein.
D) It determines the tertiary structure of the protein.
E) It is the sequence of amino acids in the protein.

Question 18

The most abundant molecule in the cell is

A) a carbohydrate.
B) a lipid.
C) a nucleic acid.
D) a protein.
E) water.

Question 19

The amino and carboxyl functional groups tend to form bases and acids by attracting or dropping

A) a neutron.
B) a proton.
C) an electron.
D) a proton and an electron.
E) a neutron and a proton.

Question 20

Aldehydes and ketones are very similar in that they both contain

A) phosphorus atoms.
B) sulfur atoms.
C) a carbonyl group (C=O).
D) nitrogen atoms.
E) two "R" groups.

Question 21

The shape of a folded protein is often determined by

A) its tertiary structure.
B) the sequence of its amino acids.
C) whether the peptide bonds have $\alpha$ or $\beta$ linkages.
D) the number of peptide bonds.
E) the base-pairing rules.

Question 22

Which of the following statements about proteins is true?

A) They are insoluble in water.
B) They are the structural units of glycogen.
C) They possess glycosidic linkages between amino acids.
D) Some function as enzymes.
E) They are involved in information storage.

Question 23

Polymerization reactions in which polysaccharides are synthesized from monosaccharides

A) require the formation of phosphodiester bonds between the amino acids.
B) occur in the nucleus of the cell.
C) are hydrolysis reactions.
D) depend upon van der Waals forces to hold the amino acids together.
E) result in the formation of water.

Question 24

Which of the following is responsible for making every amino acid unique?

A) Amino group
B) Hydrogen
C) Carboxyl group
D) "R" group
E) Carbon

Question 25

During the formation of a peptide linkage, a(n) _______ is formed.

A) molecule of water
B) disulfide bridge
C) hydrophobic bond
D) hydrophilic bond
E) ionic bond

Question 26

Leucine and valine do not interact with water; therefore, they

A) are hydrophilic.
B) are nonpolar.
C) have sulfur atoms in their side chains.
D) are electrically charged.
E) form only left-hand isomers.

Question 27

There are _______ different types of tripeptides (molecules with three amino acids linked together) that can exist using the 20 common amino acids.

A) 3
B) 20
C) 60
D) 900
E) 8,000

Question 28

A protein can best be defined as a polymer

A) of amino acids.
B) containing one or more polypeptide chains.
C) containing 20 amino acids.
D) containing 20 peptide linkages.
E) containing double helices.

Question 29

Aspartate and glutamate are highly soluble in water; therefore, they

A) are hydrophobic.
B) have sulfur atoms in their side chains.
C) have electrically charged side chains.
D) are nonpolar.
E) form only left-hand isomers.

Question 30

What type of amino acid side chains would you expect to find on the surface of a protein embedded in a cell membrane?

A) Cysteine
B) Hydrophobic
C) Hydrophilic
D) Charged
E) Polar, but not charged

Question 31

Polysaccharides, polypeptides, and polynucleotides

A) contain simple sugars.
B) are broken down in hydrolysis reactions.
C) are found in cell membranes.
D) contain nitrogen.
E) have molecular weights less than 30,000 daltons.

Question 32

Enzymes are

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

Question 33

Peptide chains have a(n) _______ and a(n) _______ end.

A) start; stop
B) +; -
C) N terminus; C terminus
D) 5'; 3'
E) A; Z

Question 34

An amino acid that is small enough to fit into tight corners of protein molecules is

A) proline.
B) glycine.
C) cysteine.
D) asparagine.
E) glutamine.

Question 35

In condensation reactions, the atoms that make up a water molecule are derived from

A) oxygen.
B) only one of the reactants.
C) both of the reactants.
D) carbohydrates.
E) enzymes.

Question 36

What is the theoretical number of different proteins that you could make from 50 amino acids?

A) 50²⁰
B) 20 $\times$ 50
C) 20⁵⁰
D) 10⁵⁰
E) 2⁵⁰

Question 37

Amino acids can be classified by the

A) number of monosaccharides they contain.
B) number of carbon-carbon double bonds in their fatty acids.
C) number of peptide bonds they can form.
D) number of disulfide bridges they can form.
E) characteristics of their side chains, or "R" groups.

Question 38

The side chain of leucine is a hydrocarbon. In a folded protein, where would you expect to find leucine?

A) In the interior of a cytoplasmic enzyme
B) On the exterior of a protein embedded in a membrane
C) On the exterior of a cytoplasmic enzyme
D) Both a and b
E) Both a and c

Question 39

The amino acids of the protein keratin are arranged in a helix. This secondary structure is stabilized by

A) covalent bonds.
B) peptide bonds.
C) glycosidic linkages.
D) polar bonds.
E) hydrogen bonds.

Question 40

Which of the following amino acids does not have an optical isomer?

A) Arginine
B) Cysteine
C) Alanine
D) Glycine
E) Methionine

Question 41

Which of the following protein structures is destroyed by denaturation?

A) Primary
B) Secondary
C) Tertiary
D) Both b and c
E) All of the above

Question 42

Sucrose, known as common table sugar, is a

A) hexose.
B) lipid.
C) disaccharide.
D) glucose.
E) simple sugar.

Question 43

A type of molecule very often drawn with a single six-sided ring structure is

A) sucrose.
B) an amino acid.
C) glucose.
D) a fatty acid.
E) a steroid.

Question 44

The difference between $\alpha$ - and $\beta$ -glucose is

A) in the number of covalent bonds present.
B) in the placement of OH and H atoms.
C) in the type of R group attached to the terminal carbon.
D) that $\alpha$ -glucose is polar, whereas $\beta$ -glucose is nonpolar.
E) that $\alpha$ -glucose is a pentose, whereas $\beta$ -glucose is a hexose.

Question 45

A(n) _______ protein is a protein that has become nonfunctional due to the loss of its three-dimensional structure.

A) permanent
B) reversible
C) denatured
D) hydrolyzed
E) environmentalized

Question 46

A molecule with the formula C₁₆H₃₀O₁₅ is a

A) hydrocarbon.
B) carbohydrate.
C) lipid.
D) protein.
E) nucleic acid.

Question 47

A type of protein that functions by helping other proteins fold correctly is called a

A) foldzyme.
B) renaturing protein.
C) chaperone protein.
D) hemoglobin.
E) denaturing protein.

Question 48

Starch and glycogen, which are both polysaccharides, differ structurally in that glycogen _______, whereas starch _______.

A) is highly branched; is moderately branched
B) consists of parallel strands; is highly branched
C) consists of a combination of branching and parallel strands; is moderately branched
D) is moderately branched; consists of parallel strands
E) is highly branched; consists of parallel strands

Question 49

A simple sugar with the formula C₅H₁₀O₅ can be classified as a

A) hexose.
B) polysaccharide.
C) disaccharide.
D) pentose.
E) lipid.

Question 50

The monomers that make up polymeric carbohydrates like starch are called

A) nucleotides.
B) trisaccharides.
C) monosaccharides.
D) nucleosides.
E) fatty acids.

Question 51

Maltose and lactose are similar in that they both are

A) simple sugars.
B) amino acids.
C) insoluble in water.
D) disaccharides.
E) hexoses.

Question 52

The atoms that make up carbohydrates are

A) C, H, and N.
B) C and H.
C) C, H, and P.
D) C, H, and O.
E) C, H, O, and N.

Question 53

Lactose, or milk sugar, which is composed of one glu­cose unit and one galactose unit, can be classified as a

A) disaccharide.
B) hexose.
C) pentose.
D) polysaccharide.
E) monosaccharide.

Question 54

Why does a starchy food, like bread, become hard and stale when it dries out?

A) Cellulose molecules aggregate in the absence of water.
B) In the absence of water, unbranched starch forms hydrogen bonds between polysaccharides, which then aggregate.
C) The release of carbon dioxide causes the bread to harden.
D) Water and heat cause the polysaccharide chains to bind together.
E) Mold growth interferes with $\alpha$ linkages, causing the bread to harden.

Question 55

Quaternary structure is found in proteins

A) composed of subunits.
B) of membranes.
C) of the quadruple complex.
D) that change over time.
E) None of the above

Question 56

The tertiary structure of a protein is determined by its

A) interactions among R groups.
B) right-handed coil.
C) hydrogen bonding.
D) branching.
E) glycosidic linkages.

Question 57

Glucose and fructose both have the formula C₆H₁₂O₆, but the atoms in these two compounds are arranged differently. Glucose and fructose are therefore

A) isomers.
B) polysaccharides.
C) oligosaccharides.
D) pentoses.
E) steroids.

Question 58

DNA and RNA both include

A) pentoses.
B) hexoses.
C) fructoses.
D) maltoses.
E) amyloses.

Question 59

A $\beta$ pleated sheet organization in a polypeptide chain is an example of _______ structure.

A) primary
B) secondary
C) tertiary
D) quaternary
E) coiled

Question 60

Knowledge that incorrect folding of a protein can be deleterious to cell functioning is being used to design drugs to treat

A) rickets.
B) cancerous tumors.
C) hemophilia.
D) diabetes.
E) high blood pressure.

Question 61

Starch and glycogen are different in that only one of them

A) is a polymer of glucose.
B) contains ribose.
C) is made in plants.
D) is an energy storage molecule.
E) can be digested by humans.

Question 62

You have isolated an unidentified liquid from a sample of beans. You add the liquid to a beaker of water and shake vigorously. After a few minutes, the water and the other liquid separate into two layers. To which class of large biological molecules does the unknown liquid most likely belong?

A) Carbohydrates
B) Lipids
C) Proteins
D) Enzymes
E) Nucleic acids

Question 63

A molecule that has an important role in long-term storage of energy is

A) a steroid.
B) RNA.
C) glycogen.
D) an amino acid.
E) hexose.

Question 64

Which of the following statements about lipids is false?

A) They are readily soluble in water.
B) They help capture light energy.
C) They release large amounts of energy when broken down.
D) They form two layers when mixed with water.
E) They act as an energy storehouse.

Question 65

Lipids are

A) insoluble in water.
B) important for energy storage.
C) hydrophobic.
D) important constituents of biological membranes.
E) All of the above

Question 66

In animals, glucose is stored in the compound

A) cellulose.
B) amylose.
C) glycogen.
D) fructose.
E) cellobiose.

Question 67

Molecules that are both attracted to water and repel water are called

A) hydrophilic.
B) hydrophobic.
C) amphipathic.
D) amphoric.
E) glycosidic.

Question 68

Unsaturated fatty acids do not pack together due to

A) kinks in the hydrocarbon-chain ribozymes.
B) glycosidic linkage proteases.
C) peptide-bond chaperonins.
D) disulfide bridges.
E) van der Waals-force triglycerides.

Question 69

A fat contains fatty acids and

A) glycerol.
B) a base.
C) an amino acid.
D) a phosphate.
E) None of the above

Question 70

A molecule that has an important role in limiting what gets into and out of cells is

A) glucose.
B) maltose.
C) phospholipid.
D) fat.
E) phosphohexose.

Question 71

Lipids form the barriers surrounding various compartments within an organism. Which property of lipids makes them a good barrier?

A) Many biologically important molecules are not soluble in lipids.
B) Lipids are polymers.
C) Lipids store energy.
D) Triglycerides are lipids.
E) Lipids release large amounts of energy when broken down.

Question 72

The portion of a phospholipid that contains the phosphorous group has one or more electric charges. That makes this region of the molecule

A) hydrophobic.
B) hydrophilic.
C) nonpolar.
D) unsaturated.
E) saturated.

Question 73

In a biological membrane, the phospholipids are arranged with the fatty acid chains facing the interior of the membrane. As a result, the interior of the membrane is

A) hydrophobic.
B) hydrophilic.
C) charged.
D) polar.
E) filled with water.

Question 74

Which of the following is not a function in which lipids play an important role?

A) Vision
B) Storing energy
C) Membrane structure
D) Storing genetic information
E) Chemical signaling

Question 75

Chitin is a polymer of

A) galactosamine.
B) glucose.
C) glucosamine.
D) glycine.
E) All of the above

Question 76

Two important polysaccharides made up of glucose monomers are _______ and _______.

A) guanine; cytosine
B) RNA; DNA
C) sucrose; lactose
D) cellulose; starch
E) testosterone; cortisone

Question 77

The main function of cellulose, the most abundant organic compound on Earth, is

A) to store genetic information.
B) as a storage compound for energy in plant cells.
C) as a storage compound for energy in animal cells.
D) as a component of biological membranes.
E) to provide mechanical strength to plant cell walls.

Question 78

Fatty acids are molecules that

A) contain fats bonded to a glycerol.
B) are composed of hydrogen, carbon, and a carboxyl group.
C) are carbohydrates linked to a hydrocarbon chain.
D) contain glycerol and a carboxyl group.
E) are always saturated.

Question 79

Starch and glycogen, which are both polysaccharides, differ in their functions in that starch is _______, whereas glycogen _______.

A) the main component for plant structural support; is an energy source for animals
B) a structural material found in plants and animals; forms external skeletons in animals
C) the principle energy storage compound of plants; is the main energy storage of animals
D) a temporary compound used to store glucose; is a highly stable compound that stores complex lipids
E) is the main energy storage of animals; a temporary compound used to store glucose

Question 80

You look at the label on a container of shortening and see the words "hydrogenated vegetable oil." This means that during processing, the number of carbon-carbon double bonds in the oil was decreased. What is the result of decreasing the number of double bonds?

A) The oil now has a lower melting point.
B) The oil is now solid at room temperature.
C) There are more "kinks" in the fatty acid chains.
D) The oil is now a derivative carbohydrate.
E) The fatty acid is now a triglyceride.