Deck 3: Biological Molecules

Question 1

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

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

Answer 1

B

Question 2

Large biological molecules are synthesized by removing

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

Answer 2

C

Question 3

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

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

Answer 3

B

Question 4

Which of the following reactions is an example of dehydration synthesis?

A) Glucose + galactose -lactose
B) Fat -fatty acids + glycerol
C) Cellulose -glucose
D) Glycogen -glucose subunits
E) Peptide -alanine + glycine

Question 5

An example of a structural polysaccharide is

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

Question 6

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

Question 7

The fiber in your diet is actually

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

Question 8

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

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

Question 9

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

A) Ionization
B) Oxidation
C) Hydrolysis
D) Condensation

Question 10

In dehydration synthesis, the atoms that make up a water molecule come from

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

Question 11

Prions are known to cause

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

Question 12

The carbohydrate in DNA is

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

Question 13

Which of the following is NOT an organic molecule?

A) Carbon monoxide
B) Lipid
C) Protein
D) Monosaccharide
E) Nucleic acid

Question 14

Which molecule is a disaccharide?

A) Glucose
B) Lactose
C) Water
D) Fructose

Question 15

Chitin is an example of a

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

Question 16

Maltose is made from

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

Question 17

Where is glycogen stored in vertebrate animals?

A) Brain and kidneys
B) Teeth and bones
C) Liver and muscles
D) Pancreas and blood
E) Fat cells

Question 18

If digestion is , then synthesis is .

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

Question 19

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

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

Question 20

Hydrolysis may be correctly described as the

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

Question 21

Fats and oils are made of

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

Question 22

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) Enzymes
C) Nucleic acids
D) Lipids
E) Proteins

Question 23

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

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

Question 24

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

Question 25

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

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

Question 26

When 1 gram of each of these food sources is consumed, which yields the greatest amount of energy in calories?

A) Fat
B) Glucose
C) Phenylalanine
D) Sucrose
E) Polypeptide

Question 27

Which of the following categories includes monosaccharide monomers?

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

Question 28

What property of phospholipids makes them important in cell membranes?

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

Question 29

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

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

Question 30

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

Question 31

Which type of lipid is most important in biological membranes?

A) Wax
B) Fat
C) Phospholipid
D) Steroid
E) Oil

Question 32

Cell membranes are an example of a lipid bilayer. In this lipid bilayer, both the outside of the cell and the inside of the cell are in nature.

A) watery
B) charged
C) hydrophobic
D) polar
E) hydrophilic

Question 33

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

Question 34

Which of the following is insoluble in water?

A) Sucrose
B) Olive oil
C) DNA
D) Salt
E) Amino acids

Question 35

All of the following lipids or lipid components are hydrophobic EXCEPT

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

Question 36

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

Question 37

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

A) Glucose and galactose
B) Glycogen
C) Starch
D) Glucose and fructose

Question 38

Cholesterol, testosterone, and estrogen are examples of

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

Question 39

Triglycerides are

A) a main component of cellular membranes.
B) polymers of amino acids.
C) made from glycerol and fatty acids.
D) always composed of carbon rings.
E) hydrophilic.

Question 40

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

A) Glycogen
B) Cellulose
C) Starch
D) Glucose
E) ATP

Question 41

A denatured protein differs from a normal protein because it

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

Question 42

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

A) Tertiary structure
B) Primary structure
C) Secondary structure
D) Quaternary structure

Question 43

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

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

Question 44

A peptide bond forms between which of these groups?

A) Amino and aldehyde
B) Carboxyl and aldehyde
C) Carboxyl and amino
D) Phosphate and hydroxyl
E) Hydroxyl and carboxyl

Question 45

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

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

Question 46

What maintains the secondary structure of a protein?

A) Hydrogen bonds
B) Peptide bonds
C) Disulfide bonds
D) Ionic bonds

Question 47

The bonding of two amino acid molecules to form a larger molecule requires which of the following?

A) Addition of a water molecule
B) Both removal of a water molecule and formation of a hydrogen bond
C) Formation of a hydrogen bond
D) Removal of a water molecule
E) Formation of a glycosidic bond

Question 48

Complex, three- dimensional, tertiary structures of proteins result from

A) hydrogen and disulfide bonds.
B) ionic bonds.
C) disulfide bonds.
D) ionic and hydrogen bonds
E) hydrogen bonds.

Question 49

Proteins are constructed using how many different amino acids?

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

Question 50

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

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

Question 51

Enzymes are specialized _ that catalyze chemical reactions within the body.

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

Question 52

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

A) Protein
B) Carbohydrate
C) Lipid
D) Nucleic acids
E) Water

Question 53

The specific function of a protein is determined by the

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

Question 54

All of the following are polysaccharides EXCEPT

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

Question 55

Which of the following statements about lipids is incorrect?

A) They are used for energy storage.
B) They are primary component of cell membranes.
C) They are large chains of nonpolar hydrocarbons.
D) They are hydrophobic and water insoluble.
E) They are short chains of polar hydrocarbons.

Question 56

Which of the following is an example of a protein?

A) ATP
B) Cellulose
C) Estrogen
D) Keratin

Question 57

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

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

Question 58

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

A) Primary
B) Secondary
C) Tertiary
D) Quaternary

Question 59

Which of the following is TRUE about waxes?

A) They are unsaturated and most similar to proteins.
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 a type of complex carbohydrate.

Question 60

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

A) All are important enzymes that function within the cell.
B) Polymers of these organic molecules form monomers via dehydration synthesis reactions.
C) All are inorganic molecules.
D) Covalent bonding holds these molecules together.

Question 61

How many hydrogen bonds exist between a G- C base pair?

A) 1
B) 2
C) 3
D) 4

Question 62

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

A) Prions are proteins that are denatured more easily than most proteins.
B) Prions are proteins that cause nearby proteins to change shape and become infectious.
C) Prions are noninfectious proteins.
D) Prions are infectious proteins that cannot be denatured by any amount of heat.

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

Question 64

DNA carries genetic information in its

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

Question 65

Important biological molecules that have a carbon backbone bonded to hydrogen atoms are considered to be
.

Question 66

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

Question 67

Adenosine triphosphate (ATP) is an example of a(n)

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

Question 68

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

Question 69

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

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

Question 70

Phospholipids have hydrophilic tail regions and hydrophobic head regions.

Question 71

Which of these biological molecules contain genetic information?

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

Question 72

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

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

Question 73

Many biological molecules are formed by the joining of monomer units in a(n) reaction (removal of water); the reverse process is called _.

Question 74

Which of these is NOT a nucleic acid or nucleotide?

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

Question 75

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

A) DNA; ATP
B) Carbohydrate; polysaccharides
C) Protein; amino acids
D) Hydrocarbon; monosaccharides
E) Lipid; steroids

Question 76

A nucleotide is made of a

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

Question 77

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

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

Question 78

Carbon provides a backbone for a variety of biological molecules. Carbon can typically form covalent bonds.

Question 79

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

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

Question 80

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 chains of carbohydrates, and amino acids are a type of lipid.
D) Proteins are a portion of an amino acid.