Deck 3: Biological Molecules

Question 1

The fiber in your diet is actually:

A)protein.
B)ATP.
C)starch.
D)glycogen.
E)cellulose.

Answer 1

E

Question 2

What type of chemical reaction results in the breakdown of organic polymers into their respective subunits?

A)condensation
B)oxidation
C)hydrolysis
D)ionization

Answer 2

C

Question 3

Which of the following BEST explains the molecular complexity of living organisms?

A)The large number of different monomers allows for the construction of many polymers.
B)Each organism has its own unique set of monomers for use in constructing polymers.
C)Condensation reactions can create different polymers because they can combine virtually any molecules in the cell.
D)Although there are not many biological molecules in cells, each one has many different functions.
E)A small number of monomers can be assembled into large polymers with many different sequences.

Answer 3

E

Question 4

Chitin is an example of a:

A)monomer.
B)polysaccharide.
C)nucleic acid.
D)peptide.
E)triglyceride.

Question 5

Which molecule is a disaccharide?

A)glucose
B)water
C)lactose
D)fructose

Question 6

Which of the following reactions requires the removal of water to form a covalent bond?

A)glycogen → glucose subunits
B)peptide → alanine + glycine
C)cellulose → glucose
D)glucose + galactose → lactose
E)fat → fatty acids + glycerol

Question 7

You are telling your friend that organic molecules are all made up of carbon backbones with hydrogens. She doesn't understand how there can be so many different organic molecules if they all are made up of the same basic components. You explain that organic molecules:

A)vary because they possess different isotopes of carbon.
B)vary because they possess different functional groups.
C)actually all have the same structure but differ in the number of electrons.
D)are different because of the different types of hydrogen bonds that form.

Question 8

Prions are known to cause:

A)mad cow disease.
B)the common cold.
C)herpes.
D)sickle cell anemia.

Question 9

In dehydration synthesis, 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 10

Where is glycogen stored in vertebrate animals?

A)liver and muscles
B)brain and kidneys
C)teeth and bones
D)pancreas and blood
E)fat cells

Question 11

An example of a structural polysaccharide is:

A)maltose.
B)chitin.
C)starch.
D)glucose.
E)glycogen.

Question 12

Maltose is made from:

A)two peptides.
B)two glucose molecules.
C)glucose and fructose.
D)glucose and galactose.

Question 13

Dehydration synthesis involves the removal of a hydrogen ion and a hydroxyl ion. What happens next?

A)A large polymer is split apart into small monomers.
B)The hydrogen and hydroxyl ions interact to form water.
C)A polysaccharide is released from a monosaccharide.
D)The hydrogen ion becomes an isotope.

Question 14

Hydrolysis may be correctly described as the:

A)heating of a compound in order to drive off its excess water and to concentrate its volume.
B)breaking of a compound into its subunits by adding water between the subunits.
C)constant removal of hydrogen atoms from a carbohydrate.
D)removal of water from a polymer.

Question 15

If digestion is ________, then synthesis is ________.

A)hydrolysis; dehydration
B)dehydration; hydrolysis
C)organic; inorganic
D)inorganic; organic

Question 16

Which of the following is NOT an organic molecule?

A)protein
B)nucleic acid
C)monosaccharide
D)carbon monoxide
E)lipid

Question 17

Keratin and silk are examples of ________, whereas glucose and maltose are examples of ________.

A)proteins; lipids
B)proteins; carbohydrates
C)carbohydrates; proteins
D)nucleic acids; lipids

Question 18

The carbohydrate in DNA is:

A)ribose.
B)cellulose.
C)glucose.
D)deoxyribose.
E)phosphate.

Question 19

Large biological molecules are synthesized by removing:

A)carbon.
B)covalent bonds.
C)water.
D)oxygen.
E)peptides.

Question 20

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

A)Dehydration reactions assemble polymers, and hydrolysis breaks them down.
B)Hydrolysis creates polysaccharides, and dehydration creates monosaccharides.
C)Dehydration reactions can occur only after hydrolysis.
D)Hydrolysis creates monomers, and dehydration reactions destroy them.
E)Dehydration reactions occur only in animals, and hydrolysis reactions occur only in plants.

Question 21

Imagine that you have isolated a mysterious liquid from a sample of food. 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 biological molecules does the unknown liquid most likely belong?

A)carbohydrates
B)lipids
C)proteins
D)enzymes
E)nucleic acids

Question 22

When the level of glucose in your blood is high, your body is able to store excess glucose in the liver by forming glycogen. When blood glucose levels fall, this stored glucose can be released. Based on this information, which of the following is true?

A)Glucose is a polysaccharide that can join to form the monosaccharide glycogen.
B)Glucose is not an organic molecule, but glycogen is an organic molecule.
C)Glycogen is a polysaccharide formed by joining excess monosaccharides of glucose.
D)Glycogen is a highly branched functional group that forms a larger glucose polymer.

Question 23

Which type of lipid is most important in biological membranes?

A)fats
B)steroids
C)phospholipids
D)oils
E)trans fats

Question 24

In humans, dental cavities form when Streptococcus mutans bacteria in the mouth hydrolyze sucrose. Which of the following is/are released during this reaction?

A)glucose and fructose
B)starch
C)glucose and galactose
D)glycogen

Question 25

Fats and oils are made of:

A)three glycerols and three fatty acids.
B)three fatty acids and one glycerol.
C)one glycogen and two phospholipids.
D)two fatty acids and one carboxyl acid.
E)three amino acids and one glycerol.

Question 26

Which of the following provides long-term energy storage for plants?

A)glucose
B)glycogen
C)starch
D)cellulose
E)ATP

Question 27

Two classes of organic compounds typically provide energy for living systems. Representatives of these two classes are:

A)fats and amino acids.
B)amino acids and glycogen.
C)amino acids and ribose.
D)fats and polysaccharides.
E)nucleic acids and phospholipids.

Question 28

Which of the following include monosaccharide monomers?

A)proteins
B)carbohydrates
C)lipids
D)nucleic acids

Question 29

Lactose is a disaccharide of glucose and galactose, and its digestion requires the actions of the enzyme lactase. If lactose is eaten as part of the diet but is not digested by lactase, this sugar is then metabolized by bacteria in the intestine, leading to the symptoms of lactose intolerance. Lactose intolerance, therefore, results from a(n):

A)lack of hydrolysis of lactose.
B)lack of dehydration synthesis of lactose.
C)low blood lactose level.
D)inability of the body to produce lactose.

Question 30

Cholesterol, testosterone, and estrogen are examples of:

A)fatty acids.
B)proteins.
C)steroids.
D)hormones.
E)waxes.

Question 31

The fat substitute Olestra contains a sucrose backbone with six to eight fatty acids attached. How is this different from a naturally occurring fat?

A)Naturally occurring fats contain a glycerol and three fatty acids.
B)Naturally occurring fats contain a glycerol, two fatty acids, and a phosphate group.
C)Naturally occurring fats contain a sucrose backbone and three fatty acid chains.
D)It isn't; Olestra and natural fats have the same structure, just different tastes.

Question 32

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 33

New government regulations require that foods containing trans fats be labeled appropriately. A trans fat is formed when food manufacturers turn liquid oils into solid fats by adding hydrogen to vegetable oils. This hydrogenation process produces a solid fat because adding the hydrogen:

A)allows fats to form tertiary and quaternary structures.
B)allows the fatty acid chains to pack together more tightly.
C)causes a phospholipid to form.
D)forms a wax molecule.

Question 34

Triglycerides are:

A)polymers of amino acids.
B)always composed of carbon rings.
C)lacking carboxyl groups (COOH).
D)nonpolar and hydrophobic.
E)made from glycerol and nucleic acids.

Question 35

Lard is a solid fat at room temperature. What does this tell you about the triglycerides in lard?

A)The fats in lard are not organic molecules.
B)Lard is composed of saturated fats.
C)The fats in lard are mostly phospholipids.
D)Lard is composed of unsaturated fats.

Question 36

Phospholipids are unusual yet important to cell membrane structure because they:

A)are part of DNA.
B)contain nucleic acids.
C)have a polar end and a nonpolar end.
D)are found only in animals.
E)are an important energy carrier molecule.

Question 37

Which of the following is insoluble in water?

A)olive oil
B)DNA
C)sucrose
D)salt
E)amino acids

Question 38

All of the following lipids or lipid components are hydrophobic EXCEPT:

A)waxes.
B)saturated fats.
C)unsaturated fats.
D)fatty acid "tails."
E)fatty acid "heads."

Question 39

When 1 gram of each of the following is metabolized, which yields the greatest amount of energy?

A)sucrose
B)glucose
C)glycerol
D)polypeptide
E)fat

Question 40

Which of the following can serve as an energy source and as structural support in plant cells?

A)proteins
B)carbohydrates
C)lipids
D)nucleic acids

Question 41

The group of biological molecules that are most diverse in function is:

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

Question 42

Which of the following biological molecules possess large nonpolar regions, making them insoluble in water?

A)proteins
B)carbohydrates
C)lipids
D)nucleic acids

Question 43

What maintains the secondary structure of a protein?

A)peptide bonds
B)disulfide bonds
C)hydrogen bonds
D)ionic bonds

Question 44

All of the following are polypeptides EXCEPT:

A)starch.
B)maltose.
C)glycogen.
D)chitin.

Question 45

A peptide bond forms between which of these groups?

A)amino and aldehyde
B)carboxyl and amino
C)hydroxyl and carboxyl
D)phosphate and hydroxyl
E)carboxyl and aldehyde

Question 46

Which of the following is an example of a protein?

A)casein
B)cellulose
C)estrogen
D)ATP

Question 47

Which of the following is TRUE about waxes?

A)They are a type of complex carbohydrate.
B)They are an important food source, and most animals have enzymes for breaking them down.
C)They are saturated fats and are solid at normal outdoor temperatures.
D)They are unsaturated and most similar to proteins.

Question 48

Organisms contain thousands of different proteins composed of ________ different amino acids.

A)4
B)20
C)100
D)1,000
E)more than 5,000

Question 49

A denatured protein differs from a normal protein because it:

A)does not contain amino acids.
B)has lost its usual secondary and tertiary structures.
C)is composed of nucleotides.
D)contains many disulfide bonds.

Question 50

What type of amino acid side chain 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 51

HDL and LDL are different types of cholesterol found in the blood. These compounds are:

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

Question 52

Enzymes are ________ that orchestrate chemical reactions within the body.

A)proteins
B)carbohydrates
C)lipids
D)nucleic acids

Question 53

Which of the following refers to the amino acid sequence of proteins?

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

Question 54

What do carbohydrates, lipids, and proteins have in common?

A)Polymers of these organic molecules form monomers via condensation reactions.
B)Covalent bonding holds these molecules together.
C)All are inorganic molecules with various functional groups attached.
D)All are important enzymes that function within the cell.

Question 55

Which of the following groups is crucial to the structure and function of the sex hormones estrogen and testosterone?

A)proteins
B)carbohydrates
C)lipids
D)nucleic acids

Question 56

Which type of molecule is most abundant in a typical cell?

A)hydrocarbon
B)protein
C)water
D)lipid
E)carbohydrate

Question 57

Complex, three-dimensional, tertiary structures of globular proteins are characterized by:

A)an absence of hydrophilic amino acids.
B)a helical shape.
C)a lack of cysteines in the amino acid sequence.
D)disulfide bonds.

Question 58

The four polypeptides that are joined together to make hemoglobin represent which level of protein organization?

A)primary structure
B)secondary structure
C)tertiary structure
D)quaternary structure

Question 59

The specific function of a protein is determined by the:

A)exact sequence of amino acids.
B)number of disulfide bonds.
C)hydrophilic "head" attached to the hydrophobic "tail."
D)fatty acids that are joined together in the polypeptide.
E)number of peptide bonds it contains.

Question 60

Which of the following lipids make up about 2% of the human brain?

A)glycogen
B)myosin
C)glycerol
D)cholesterol

Question 61

Which of these is NOT a nucleic acid or nucleotide?

A)RNA
B)DNA
C)ATP
D)LDL

Question 62

Covalent bonds joining two nucleotides within a single strand of DNA form between:

A)a phosphate group and adenine.
B)deoxyribose and a phosphate group.
C)adenine and thymine.
D)the phosphate groups of both.
E)ribose and a base.

Question 63

Suppose you have discovered a new virus and have isolated its nucleic acids. What feature could you look for to determine whether the nucleic acids of this virus are RNA or DNA?

A)If it is RNA, it will contain ribose.
B)If is RNA, it will contain deoxyribose.
C)If it is DNA, the virus will not contain proteins.
D)If it is RNA, there will be no adenine.

Question 64

The "backbone" of a nucleic acid molecule is made of:

A)nitrogenous bases.
B)sugar and phosphate groups.
C)ATP molecules.
D)NAD+ and FAD.
E)amino acids.

Question 65

Your friend is trying to learn about how to kill bacteria. She reads that preservatives such as citric acid are added to foods because the acidic environment kills bacteria by denaturing their proteins. She thinks this sounds like a lot of scientific jargon and asks you what it means. How can you explain it in simpler terms?

A)Denaturing their proteins means that the proteins in bacteria are converted into carbohydrates.
B)The acid causes the cells to swell and burst open, also known as denaturation.
C)Denaturing means that the proteins of the bacteria lose their structure and can't function, so the bacteria die.
D)Denaturing refers to the fact that the bacterial cells divide too quickly and die.

Question 66

Many biological molecules are formed by the connection of monomer units in a(n)________ reaction (removal of water); the reverse process occurs via a(n)________ reaction (addition of water).

Question 67

________ molecules are synthesized from carbon skeletons bonded to hydrogen atoms.

Question 68

Which of the following biological molecules are composed of monomer units containing a sugar, a phosphate group, and a nitrogen-containing base?

A)proteins
B)carbohydrates
C)lipids
D)nucleic acids

Question 69

Which of these biological molecules contain genetic information?

A)proteins
B)carbohydrates
C)lipids
D)nucleic acids

Question 70

Phospholipids have hydrophilic tail regions and hydrophobic head regions.

Question 71

A nucleotide is made of a:

A)phospholipid, sugar, and base.
B)phosphate, protein, and base.
C)phosphate, sugar, and base.
D)phospholipid, sugar, and protein.

Question 72

Carbon provides a versatile backbone for biological molecules. With an atomic number of 6, carbon can form up to ________ different ________ bonds.

Question 73

DNA carries genetic information in its:

A)helical form.
B)sequence of bases.
C)tertiary structure.
D)phosphate groups.
E)sugar groups.

Question 74

Which of the following may possess primary, secondary, tertiary, and quaternary structures?

A)proteins
B)carbohydrates
C)lipids
D)nucleic acids

Question 75

Your classmate is trying to keep all the facts about biological molecules straight. He asks you to explain how amino acids and proteins are related. What do you tell him?

A)Proteins are made up of chains of amino acids.
B)Amino acids are formed by joining together many proteins.
C)Proteins are a portion of an amino acid.
D)Proteins are chains of carbohydrates, and amino acids are a type of lipid.

Question 76

Adenosine triphosphate is an example of a(n):

A)carbohydrate.
B)protein.
C)lipid.
D)nucleotide.
E)inorganic molecule.

Question 77

Scientists consider prions to be "puzzling" proteins. Which of the following is TRUE about prions?

A)Prions are the same as normal proteins but are denatured more easily than typical proteins.
B)Prions are noninfectious proteins.
C)Prions are infectious proteins that cannot be denatured by any amount of heat.
D)Prions are proteins that cause nearby proteins to change shape.

Question 78

Which of the following biological molecules are composed of amino acid subunits?

A)proteins
B)carbohydrates
C)lipids
D)nucleic acids

Question 79

Functional groups determine the characteristics and chemical reactivity of organic molecules.

Question 80

Which of the following correctly matches an organic polymer with its monomers, respectively?

A)protein, amino acids
B)carbohydrate, polysaccharides
C)hydrocarbon, monosaccharides
D)lipid, steroids
E)DNA, ATP