Deck 28: Chemistry of the Living State

Question 1

Enantiomers are non-superimposable mirror images,

Answer 1

True

Question 2

Enantiomers have the same chemical and physical properties.

Answer 2

True

Question 3

Choose the INCORRECT statement.

A) Tissues are the fundamental unit of all life.
B) Tissues group into organs.
C) Organs combine into organisms.
D) A nucleus, mitochondria, and chloroplasts are components of cells.
E) Living tissue is synthesized from simple precursors: N₂, H₂O, CO₂.

Answer 3

Tissues are the fundamental unit of all life.

Question 4

Diastereomers have the same chemical and physical properties.

Question 5

Choose the INCORRECT statement.

A) Fats become rancid when they hydrolyze and cleave at the double bonds by oxidation.
B) Antioxidants retard fat rancidity.
C) Medical studies correlate a high intake of saturated fats and coronary heart disease.
D) Healthy diets called for unsaturated fatty acids.
E) In general, mammal fats are unsaturated.

Question 6

Guanine always pairs with cytosine.

Question 7

Choose the INCORRECT statement.

A) When the long chain monocarboxylic acids are removed from a triglyceride they are called fatty acids.
B) Saturated fatty acids have multiple double bonds.
C) Glycerides can be hydrolyzed in alkaline solution to glycerol and salts of fatty acids.
D) Salts of fatty acids are called soaps.
E) The hydrolysis of triglycerides is called saponification.

Question 8

The fundamental agents involved in energy transfer are adenosine diphosphate (ADP) and adenosine triphosphate(ATP).

Question 9

Triglycerides are composed of which two compounds linked through an ester functionality?

A) glycerol and long chain monoalcohols
B) glycine and carboxylic acids
C) glycerol and long-chain monocarboxylic acids
D) lauric acid and glucose
E) ethylene glycol and dicarboxylic acids

Question 10

Choose the INCORRECT statement.

A) About 50 elements occur in measurable concentrations in living matter.
B) About 25 elements have functions that are definitely known.
C) Oxygen, carbon, hydrogen and nitrogen account for 96% of human body mass.
D) Water is the most abundant compound in most living organisms.
E) Mitochondria make up the nucleus of a cell.

Question 11

Choose the INCORRECT statement.

A) Triglycerides are glyceryl esters.
B) Fats and oils are glyceryl esters.
C) Oils have predominately saturated acid components.
D) Oils are liquid at room temperature.
E) Pure fats and oils are colorless, odorless and tasteless.

Question 12

Fats and oils differ in the nature of the acid components in the triglycerides.

Question 13

The cell is the fundamental unit of all life.

Question 14

All of the known elements occur in measurable amounts in the human body.

Question 15

Proteins are made of 40 amino acids.

Question 16

Choose the INCORRECT statement.

A) Lipids are hydrocarbons with basic properties.
B) The acyl groups of triglycerides are fatty acids.
C) A mixed triglyceride has different acyl groups.
D) Lipids are constituents of plant and animal tissues that are soluble in solvents of low polarity.
E) Triglycerides are esters of glycerol with long-chain monocarboxylic acids.

Question 17

A glycerol ester of unsaturated fatty acids best describes a(n):

A) vegetable oil
B) vegetable starch
C) animal fat
D) lipid
E) wax

Question 18

Metabolic reactions in which substances are broken down are referred to as anabolism.

Question 19

DNA contains the sugar ribose.

Question 20

Lipids are those constituents of plant and animal tissue that are soluble in very polar solvents.

Question 21

Choose the INCORRECT statement.

A) A levorotatory isomer rotates plane polarized light to the left.
B) A chiral atom is said to be asymmetric.
C) The absolute configuration is the arrangement of atoms as determined by x-ray studies.
D) Molecules that are optically active isomers but not mirror images are diastereomers.
E) Enantiomer properties differ only in the direction they rotate plane polarized light.

Question 22

Choose the INCORRECT statement.

A) Glycogen is the main structural material of plants.
B) Carbohydrates are produced in plants by the photosynthesis reaction.
C) Oligosaccharides contain 2 to 10 saccharide units.
D) Polysaccharides contain more than 10 saccharide units.
E) Monosaccharides contain one saccharide unit.

Question 23

Which of the following is a polysaccharide?

A) ribose
B) fructose
C) glucose
D) glycogen
E) pentose

Question 24

Choose the correct statement.

A) Fructose is a pentose.
B) All sugars have oxygen and are good oxidizing agents
C) Reducing sugars don't open into the straight chain form.
D) Sucrose is a disaccharide.
E) Ribose and deoxyribose are hexoses.

Question 25

Which of the following contains less than six carbon atoms?

A) deoxyribose
B) glucose
C) aldohexose
D) methylcyclopentane
E) benzene

Question 26

A typical E. coli bacterium is a cylindrical cell about 2 μm long and 1 μm in diameter, weighing about 1.8 × 10^-12 g and containing 80% water by volume. Calculate the number of lipid molecules present, assuming their average molecular weight is 688 and the lipid content is 1.9%.

A) 8.3 × 10¹⁰
B) 2.1 × 10¹⁰
C) 2.4 × 10⁷
D) 1.6 × 10⁹
E) 3.0 × 10⁷

Question 27

Enantiomers ALWAYS:

A) have an asymmetric carbon
B) have different physical properties
C) change the color of light
D) rotate polarized light
E) have different chemical properties

Question 28

Choose the INCORRECT statement.

A) Two molecules that are nonsuperimposable mirror images of one another are optical isomers.
B) Enantiomers are molecules that are mirror images of one another which are superimposable.
C) A dextrorotatory isomer rotates plane polarized light to the right.
D) Optical isomers generally have one carbon with 4 different groups attached to it.
E) A carbon atom with 4 different groups attached to it is called a chiral center.

Question 29

Choose the INCORRECT statement.

A) A 50/50 mixture of two enantiomers is a racemic mixture.
B) A racemic mixture will not rotate plane polarized light.
C) Separating the optical isomers is called resolution.
D) Dextrorotatory optical isomers are designated -.
E) Molecules that will rotate plane polarized light are optically active.

Question 30

Which molecule is optically active?

A) 2-chlorobutane
B) 1-chlorobutane
C) trans-propene
D) cis-propene

Question 31

Which of the following readily dissolve in nonpolar solvents?

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

Question 32

Saponification of 1 mole of glyceryl dibutyrooleate with excess potassium hydroxide would yield which of the following products?

A) 2 moles of potassium butyrate, 1 mole of potassium oleate
B) 1 mole of glycerol, 1 mole of potassium oleate, 2 moles of potassium butyrate
C) 2 moles of potassium butyrate
D) 1 mole of glycerol, 2 moles of butyraldehyde, 1 mole of olealdehyde
E) 1 mole of glycerol, 1 mole of potassium decanoate, 2 moles of potassium butyrate

Question 33

Which of the following fatty acids is unsaturated?

A) palmitic acid
B) oleic acid
C) myristic acid
D) stearic acid

Question 34

Choose the INCORRECT statement.

A) The simplest carbohydrates are the oligosaccharides.
B) Mono- and oligosaccharides are called sugars.
C) Polysaccharides contain more than 10 monosaccharide units.
D) Starch and cellulose are polysaccharides.
E) The general term for all carbohydrates is glycoses.

Question 35

Choose the INCORRECT statement.

A) Glucose, galactose and mannose exist in straight-chain and in ring structures.
B) Two monosaccharides combine by losing a water molecule to form a disaccharide.
C) The important natural disaccharides are maltose, cellobiose, lactose and sucrose.
D) Glycogen is the reserve carbohydrate of animals.
E) Glycogen cannot be broken down by human digestion.

Question 36

Compounds which are optical isomers of one another but differ in physical and chemical properties are known as what?

A) geometric isomers
B) enantiomers
C) racemic compounds
D) allotropes
E) diastereomers

Question 37

Which of the following do humans have difficulty digesting?

A) cellulose
B) proteins
C) vegetable oils
D) vegetable starch
E) animal fats

Question 38

Choose the molecule which may display optical isomerism.

A) CH₂OH-CH(OH)-CH₂OH
B) CH₃CH₂CH(OH)CH₃
C) NH₃CH₂COOH
D) O CH₃(CH2)16COH
E) O HOCH₂CH₂CH

Question 39

Choose the INCORRECT statement.

A) Unsaturation in a fat or oil can be removed by hydrogenation.
B) Unsaturation can be removed by the catalytic addition of hydrogen.
C) Removing unsaturation raises the melting point of the fat or oil.
D) Margarines are oils, fortified with color.
E) Fats and oils become rancid when exposed to heat, air, and light.

Question 40

Which of the following is a monosaccharide?

A) glycogen
B) animal fat
C) cellulose
D) starch
E) sucrose

Question 41

Salt linkages:

A) occur between acidic and basic R groups
B) join two halves of cysteine
C) occur between purine and pyrimidine bases
D) occur in sugars
E) connect the cell with the environment

Question 42

Which of the following is an aromatic amino acid?

A) leucine
B) tryptophan
C) arginine
D) cysteine
E) alanine

Question 43

The R group CH₂SH belongs to which amino acid?

A) aspartic acid
B) phenylalamine
C) cysteine
D) tyrosine
E) arginine

Question 44

Which of the following examples of protein structure would be classified as the tertiary structure of a protein?

A) β-pleated sheet
B) gly-leu-trp-lys-lys-arg-met
C) three identical subunits
D) an elongated α-helix between two β-pleated sheets
E) amorphous, globular peptide

Question 45

Choose the INCORRECT statement.

A) Peptides are amino acids joined by a peptide bond.
B) A tripeptide has three peptide bonds.
C) A protein is hydrolyzed to a mixture of α-amino acids.
D) An α-amino acid is a carboxylic acid with an amine group on the α carbon.
E) Proteins are a polymer of amino acid units.

Question 46

Cellulose and starch are both polymers of glucose units, but most animals can only use starch as a source of carbohydrate in their diets. Why are most animals incapable of digesting cellulose?

A) Starch contains α linkages between carbons 1 and 4, where as cellulose contains β linkages between carbons 1 and 2.
B) This statement is incorrect. Most animals can digest cellulose.
C) The polymer of cellulose is simply too long to be completely digested by animals.
D) Most animals do not produce enzymes which are capable of hydrolyzing β linkages between glycoses.
E) The glucose units of cellulose are in the open chain form and cannot be hydrolyzed by the cyclic-sugar specific enzymes of animals.

Question 47

Which of the following is unimportant for tertiary structure of the proteins?

A) peptide bonds
B) salt linkages
C) hydrogen bonding
D) disulfide linkages

Question 48

Glycine is a(n):

A) nucleic acid
B) optically active compound
C) carbohydrate
D) amino acid
E) lipid

Question 49

Which of the following is a basic amino acid?

A) alanine
B) cysteine
C) lysine
D) aspartic acid
E) glycine

Question 50

Amino acids are joined into proteins by:

A) a 3'-5' linkage
B) a beta 1-4 linkage
C) DNA
D) an ester
E) peptide bonds

Question 51

The R group CH₂C₆H₅ belongs to which amino acid?

A) aspartic acid
B) phenylalamine
C) cysteine
D) tyrosine
E) arginine

Question 52

Choose the INCORRECT statement.

A) The bond between amino acids is called a peptide bond.
B) There are four levels of structure in a protein.
C) Primary structure is the order of the amino acids in the chain.
D) Secondary structure is the bonding of more than one protein together.
E) Enzymes are biological catalysts that contain protein.

Question 53

The R group -CH₃ belongs to which amino acid?

A) glycine
B) lysine
C) proline
D) alanine
E) histidine

Question 54

Choose the INCORRECT statement.

A) Proteins make up the bulk of the body's nonskeletal structure.
B) Enzymes are carbohydrates which speed up reactions.
C) Except glycine, naturally occurring amino acids are optically active.
D) Essential amino acids are necessary for proper health and growth.
E) Essential amino acids must be ingested through foods because the body is unable to synthesize them.

Question 55

Which of the following are unimportant for tertiary structure of the proteins?

A) salt linkage
B) disulfide bonds
C) hydrophobic interactions
D) van der Waals forces
E) hydrogen bonding

Question 56

What is the common name of the following glycose shown in Fischer notation?

A) D-glyceraldehyde
B) L-glyceraldehyde
C) s-glyceraldehyde
D) (-)-glyceraldehyde
E) D-erythrose

Question 57

At the isoelectric point, an amino acid has what charges?

A) + and -
B) none
C) + only
D) - only
E) multiple charges

Question 58

Choose the INCORRECT statement.

A) Amino acids can exist as dipolar ions.
B) Dipolar ions are also called zwitterion.
C) Isoelectric point is the pH at which an amino acid becomes a cation.
D) Two amino acids joined by the elimination of a water molecule is a dipeptide.
E) A large polypeptide of more than 10,000 U is called a protein.

Question 59

Choose the INCORRECT prediction. By careful inspection of the formula of lactic acid, CH₃CH(OH)COOH, one would predict:

A) Molecules should have two forms. These forms are mirror images of one another.
B) Molecule should show cis and trans isomerism.
C) Molecule should have a chiral carbon atom.
D) Molecule should show optical isomerism.
E) Molecule should show acidic properties.

Question 60

Which of the following compounds may display the property of optical isomerism?

A) 3-pentanol
B) 2-pentene
C) 2-bromopropane
D) 2-bromobutane
E) acetone

Question 61

What is the correct structure for glyceryltrilinolenate?

A)CH₂-OOC(CH₂)₇(CH=CHCH₂)3CH₃ ∣
CH₂-OOC(CH₂)₇(CH=CHCH₂)3CH₃
∣
CH₂-OOC(CH₂)₇(CH=CHCH₂)₃CH₃
B)CH₂-OOC(CH₂)16CH₃ ∣
CH₂-OOC(CH₂)₁₆CH₃
∣
CH₂-OOC(CH2)16CH₃
C) CH₂OH ∣
CHOH
∣
CH₂OH
D) CH₂-OOC(CH2)14CH₃ ∣
CH₂-OOC(CH₂)₁₄CH₃
∣
CH₂-OOC(CH₂)₁₄CH₃
E) OHOC(CH₂)₂CH₃

Question 62

What is the common name of the following triglyceride?

A) glyceryl myristolaurolinoleneate
B) glyceryl palmitostearooleate
C) glycero laurostearooleate
D) glycero palmitostearooleate
E) glyco stearooleolaurate

Question 63

Which of the following is correct with respect to the purine and pyrimidine bases in nucleic acids?

A) G + A = C + T
B) A = C
C) G = T
D) T = C

Question 64

Apart from bringing the reactants close together, how does the binding of substrates in the active site of the enzyme serve to catalyze a reaction?

A) Binding lowers the activation energy of the reaction.
B) Enzymes provide energy upon substrate binding to drive the reaction.
C) Binding of the substrate maintains the optimal temperature for the reaction.
D) Binding maintains the optimal pH for enzyme activity.
E) Binding lowers the energy of the products increasing the reaction rate.

Question 65

Many insecticides contain compounds which inhibit the enzyme acetylcholine esterase which is essential for respiration and other vital functions in insects. These compounds exert their inhibitory effects by covalently bonding to active site amino acid side chains. What would be the most likely explanation for the inhibitory effects of these compounds?

A) Bonding of these compounds denatures the enzyme disrupting its secondary and tertiary structure.
B) Bonding changes the primary structure of the enzyme profoundly affecting the activity of the enzyme.
C) These compounds compete for the active site of the enzyme where they bind covalently and block the subsequent binding of substrate molecules.
D) Covalent bonding of these compounds changes the pI of the enzyme which causes it to become less soluble and precipitate.
E) Bonding of these compounds raises the activation energy of the reaction catalyzed by the enzyme.

Question 66

β-D-N-Acetylglucosamine (shown below) is a glycose found in many glycoproteins which are an integral part of cell membranes. One chair conformation of this glycose is shown below. How many of the hydroxyl groups on the six-membered ring occupy equatorial positions?

A) 2
B) 4
C) 0
D) 3
E) 1

Question 67

Which of the following represents an INCORRECT breakdown sequence for that food?

A) carbohydrates - polysaccharides - coenzyme A
B) starch - maltose and dextrins - maltose - glucose
C) protein - polypeptides - small peptides - amino acids
D) fats and oils - glycerol, glycerides, and fatty acids - fatty acids to CO2 and water
E) fats and oils - glycerol, glycerides, and fatty acids - glycerol to triose phosphate

Question 68

Living cells are unable to convert glucose-6P i into which of the following?

A) glycogen
B) glucose
C) coenzyme A
D) polysaccharide stored in liver
E) it may be metabolized

Question 69

Find a mismatch enzyme - substrate pair.

A) amylases - starch
B) amylase - polysaccharides
C) lipase - fats and oils
D) pepsin - diglycerides
E) trypsin and chymotripsin - polypeptides

Question 70

Which of the following is a minor component of a cell?

A) amino acids
B) carbohydrates
C) proteins
D) nucleic acids
E) hormones

Question 71

Which of the following is a pyrimidine?

A) thymine
B) adenine
C) glycine
D) arginine
E) pyridine

Question 72

Choose the INCORRECT statement about metabolism.

A) Catabolism is when substances are broken down.
B) Anabolism is the derivation of energy from substances.
C) Metabolites are substances involved in metabolism.
D) Endergonic reactions are nonspontaneous.
E) Metabolism is the totality of an organism deriving energy from matter and excreting excess.

Question 73

The molecule on which an enzyme acts is commonly referred to as:

A) reactant
B) substrate
C) hydrolate
D) active site
E) actor

Question 74

Find a mismatch in the following body part - food metabolism pairs:

A) mouth - starch
B) small intestine - polysaccharides
C) small intestine - fats and oils
D) stomach - proteins
E) stomach - polypeptides

Question 75

Which of the following structural elements cannot be found in DNA?

A) purine
B) pentose
C) phosphate
D) heme
E) pyrimidine

Question 76

Choose the INCORRECT statement.

A) The nucleus of the cell contains chromosomes that cause replication from one generation to the next.
B) Genes are portions of the chromosome that carry specific traits.
C) The usual form for DNA is a double helix.
D) Nucleic acids are made up of heterocyclic amines, a 5-carbon sugar and phosphate groups.
E) The bases in the two chains of the double helix are randomly paired.

Question 77

Which of the following combinations make up the nucleic acid, RNA?

A) ribose and the bases A, G, U, C
B) ribose and the bases A, G, T, C
C) deoxyribose and the bases A, G, T, C
D) deoxyribose and the bases A, G, U, C

Question 78

Below is a double stranded DNA composed of one strand containing 15N atoms and the other strand containing 14N atoms. If the cell which contains this DNA is grown for one generation (replication) on 15N medium and then transferred to 14N media for a second generation, what would the resulting double stranded DNA molecules look like?

A) Four molecules; each containing one 14N strand and one 15N strand.
B) Two molecules; one with a 15N and a 14N strand, the other with two 14N strands.
C) Four molecules; three containing one 14N strand and one 15N strand and one molecule with two 14N strands.
D) Four molecules; one with two 15N strands, two molecules with two 14N strands, and one molecule with one 14N and one 15N strands.
E) Four molecules; all molecules have 14N strands.

Question 79

What four elements make up approximately 96% of the total human body mass?

A) C, N, O, P
B) C, O, Ca, N
C) Mg, Cu, Fe, N
D) C, O, N, H2O
E) C, H, N, O

Question 80

By definition, exergonic reaction has:

A) ΔG= positive value
B) ΔG= negative value
C) ΔH= positive value
D) ΔH= negative value
E) ΔS = positive value