Deck 2: The Chemistry of Life

Question 1

The mass number of an atom is defined as:

A)The total number of protons, neutrons, and electrons of an atom
B)The total number of protons and electrons of an atom
C)The total number of protons and neutrons of an atom
D)The total number of neutrons and electrons of an atom
E)The total number of protons of an atom

Answer 1

C

Question 2

A base:

A)Has a value of 7 on the pH scale
B)Is a chemical that adds hydrogen ions to a solution
C)Is a chemical that absorbs hydrogen ions from a solution
D)Has a value below 7 on the pH scale

Answer 2

C

Question 3

In a chemical equation:

A)The reactants are on the right of the yields arrow
B)Reactants and products are on both sides of the yields arrow
C)The products are on the left of the yields arrow
D)The reactants are on the left of the yields arrow
E)The number of atoms of each element may be different on the two sides of the yields arrow

Answer 3

D

Question 4

The second energy shell of an atom contains a maximum of:

A)Eight electrons
B)Two electrons
C)Four electrons
D)One electron
E)Sixteen electrons

Question 5

Ice floats on water because:

A)The molecules are closer together in ice than in water
B)The molecules are farther apart in ice than in water
C)Ice is more dense than water

Question 6

Evaporation is:

A)The conversion of a liquid into a vapor
B)The conversion of a solid into a vapor
C)The conversion of a vapor into a liquid
D)The conversion of a vapor into a solid
E)All are correct

Question 7

If an atom has a valence shell that is full it:

A)Is highly reactive
B)Is not chemically stable
C)Is highly likely to combine with other atoms
D)Is not inert
E)Is chemically stable

Question 8

The first energy shell of an atom contains a maximum of:

A)One electron
B)Two electrons
C)Four electrons
D)Eight electrons
E)Sixteen electrons

Question 9

The atomic number of an atom or element is:

A)The number of neutrons in the nucleus
B)The number of electrons in the nucleus
C)The number of protons in the nucleus
D)The number of neutrons in the orbitals
E)The number of protons in the orbitals

Question 10

In the example of ionic bond formation between sodium and chlorine,which of the following is not a true statement?

A)Na is the chemical symbol for sodium
B)Chlorine donates an electron
C)Sodium donates an electron
D)Sodium becomes positively charged
E)The bond that is formed is a strong bond

Question 11

In a covalent bond:

A)Atoms share electrons
B)Atoms of opposite charges attract each other
C)Atoms share a proton

Question 12

The primary elements making up living organisms are:

A)Carbon, hydrogen, oxygen, calcium, iron, and iodine
B)Carbon, oxygen, iron, chlorine, sulfur, and phosphorous
C)Carbon, hydrogen, iron, sulfur, sodium, and calcium
D)Carbon, hydrogen, oxygen, sulfur, nitrogen, and phosphorous
E)Carbon, oxygen, sulfur, calcium, iron, and phosphorous

Question 13

If a covalent bond is polar:

A)Electrons are not shared by atoms
B)Protons are shared by atoms
C)The bond is not important to living cells
D)One of the atoms has a partial negative charge
E)The bond is not a strong bond

Question 14

Isotopes of the same element are different from one another in that:

A)They have a different number of protons
B)They have a different number of neutrons
C)They have a different number of electrons

Question 15

In the example of ionic bond formation between sodium and chlorine:

A)Na is the chemical symbol for chlorine
B)Sodium accepts an electron
C)Chlorine accepts an electron
D)Chlorine becomes positively charged
E)Both sodium accepts an electron and chlorine becomes positively charged are correct

Question 16

An ionic bond is a bond in which:

A)Atoms share electrons
B)Atoms share a proton
C)Atoms of opposite charges attract each other

Question 17

A hydrogen bond:

A)Is a strong bond
B)Does not occur within a molecule
C)May occur between molecules
D)Is not important to living cells
E)Usually has a hydrogen atom with a partial negative charge

Question 18

An acid:

A)Has a value above seven on the pH scale
B)Is a chemical that takes hydrogen ions from a solution
C)Has a value of seven on the pH scale
D)Is a chemical that adds hydrogen ions to a solution
E)All are correct

Question 19

An ion is:

A)An atom that has gained electrons
B)An atom that has a positive charge
C)An atom that has lost electrons
D)An atom that has a negative charge
E)All are correct

Question 20

Which of the following is not a true statement?

A)Nitric oxide consists of one atom of nitrogen and one atom of oxygen
B)Nitric oxide is a gas
C)Nitric oxide passes freely into and out of cells
D)Nitric oxide is a harmful substance found in smog and acid rain
E)Nitric oxide has no true function in living organisms

Question 21

The four major groups of organic compounds are:

A)Fats, waxes, carbohydrates, and amino acids
B)Carbohydrates, lipids, steroids, and monosaccharides
C)Lipids, fats, waxes, and steroids
D)Carbohydrates, lipids, proteins, and nucleic acids
E)Carbohydrates, proteins, amino acids, and nucleic acids

Question 22

Individual water molecules bind to each other through:

A)Covalent bonds
B)Ionic bonds
C)Hydrogen bonds
D)Hydrophobic bonds
E)Non-polar bonds

Question 23

A substance having a pH of 13 would best be described as:

A)A weak acid
B)A weak base
C)Neutral
D)A strong acid
E)A strong base

Question 24

A substance having a pH of 6 would best be described as:

A)A weak acid
B)Neutral
C)A weak base
D)A strong acid
E)A strong base

Question 25

Water is best described as which of the following?

A)An ion
B)A non-polar molecule
C)An atom
D)A polar molecule
E)An element

Question 26

Organic molecules are defined as chemical compounds that contain:

A)Carbon
B)Carbon and oxygen
C)Carbon and nitrogen
D)Carbon, hydrogen, and nitrogen
E)Carbon and hydrogen

Question 27

A substance having a pH of 2 would best be described as:

A)Neutral
B)A weak acid
C)A weak base
D)A strong base
E)A strong acid

Question 28

A process by which cells break polymers down into smaller units is:

A)Hydrolysis
B)Condensation
C)Reproduction
D)All are correct

Question 29

A substance having a pH of 8 would best be described as:

A)Neutral
B)A weak base
C)A weak acid
D)A strong acid
E)A strong base

Question 30

A peptide bond:

A)Is an ionic bond in proteins
B)Is a covalent bond in carbohydrates
C)Is a covalent bond in proteins
D)Is an ionic bond in carbohydrates

Question 31

A process by which cells build large molecules from monomers is:

A)Hydrolysis
B)Reproduction
C)Condensation
D)All are correct

Question 32

Which is not a lipid?

A)A triglyceride
B)A phospholipid
C)A wax
D)A sterol
E)A starch molecule

Question 33

An amino acid contains:

A)Nitrogen
B)Nitrogen and carbon
C)Carbon
D)Phosphorous
E)Carbon and phosphorous

Question 34

The four nitrogen bases found in RNA are:

A)Adenine, thymine, guanine, and uracil
B)Adenine, cytosine, guanine, and uracil
C)Adenine, thymine, cytosine, and uracil
D)Thymine, cytosine, guanine, and uracil
E)None of these are correct

Question 35

The primary building block (monomer)of nucleic acids is:

A)A nucleotide
B)A glucose molecule
C)A fatty acid
D)An amino acid
E)Four interconnected rings

Question 36

Examples of monosaccharides are:

A)Glucose, maltose, and cellulose
B)Glucose, lactose, and maltose
C)Glucose, galactose, and fructose
D)Glucose, lactose, and cellulose
E)None of these are correct

Question 37

Within a single molecule of water,____ bonds are formed between oxygen and hydrogen?

A)Ionic bonds
B)Covalent bonds
C)Hydrogen bonds
D)Hydrophobic bonds
E)Nuclear bonds

Question 38

A substance having a pH of 7 would best be described as:

A)A weak acid
B)A weak base
C)Neutral
D)A strong acid
E)A strong base

Question 39

The three major components in a nucleotide are:

A)Glucose, a nitrogen base, and a phosphate group
B)Glucose, a fatty acid, and glycerol
C)A nitrogen base, a six carbon sugar, and a phosphate group
D)A nitrogen base, a five carbon sugar, and a phosphate group
E)A carboxyl group, an R group, and an amino group

Question 40

The primary building block (monomer)of proteins is:

A)A glucose molecule
B)A fatty acid
C)A nucleotide
D)An amino acid
E)Four interconnected rings

Question 41

Many digestive enzymes are hydrolases.What do these enzymes have in common?

A)They use water to form bonds between monomers
B)They use water to break bonds in monomers
C)They use water to break bonds in polymers
D)They use water to form bonds between polymers
E)They release water in forming bonds between monomers

Question 42

Saturated fats have long straight tails of fatty acids,while unsaturated fats have kinks in their tails due to double bonds.These kinks prevent the fats from packing together as tightly.Animals that are ectothermic (cold blooded)need to keep their membranes fluid at cooler temperature and thus use ______ in their membranes.

A)Mostly unsaturated fats
B)Mostly saturated fats
C)Equal amounts of saturated and unsaturated fats
D)Carbohydrates
E)Proteins

Question 43

The term pH refers to:

A)[H⁺]²
B)[H⁺]
C)-log[H⁺]
D)-[H⁺]
E)log[H⁺]

Question 44

The most common isotope of carbon is ¹²C.¹⁴C will have ____ than ¹²C.

A)More protons
B)More neutrons
C)Fewer neutrons
D)Fewer protons
E)More electrons

Question 45

If a fossil has only 25% of its ¹⁴C remaining,how old is it?

A)5,730 years
B)2,865 years
C)1,432.5 years
D)22,920 years
E)11,460 years

Question 46

How are the monomers in nucleic acids joined?

A)Peptide bonds between carbohydrates
B)Peptide bonds between amino acids
C)Phosphodiester bonds between amino acids
D)Peptide bonds between nucleotides
E)Phosphodiester bonds between nucleotides

Question 47

Blood pH is closely maintained at a pH of 7.4.A patient whose blood pH drops below 7.35 is suffering from metabolic acidosis and can go into a coma.What happens to the concentration of H⁺ ions in a patient with a blood pH of 6.4?

A)H⁺ concentration is decreased 10-fold
B)H⁺ concentration is decreased 2-fold
C)H⁺ concentration is increased 2-fold
D)H⁺ concentration is decreased 4-fold
E)H⁺ concentration is increased 10-fold

Question 48

Which question can evolution not explain?

A)The diversity of species on Earth
B)The common ancestry of all species on Earth
C)How life started on Earth
D)The same types of molecules are found in all organisms
E)The origin of new species

Question 49

¹⁴C and ¹⁴N have the same:

A)Atomic number
B)Number of protons
C)Atomic mass
D)Number of neutrons
E)Number of electrons

Question 50

In making beer,barley is partially fermented to produce malt.Barley is not sweet,but the malt is.What is the best explanation for this observation?

A)Fermentation allows the barley to make simple sugars from sunlight and carbon dioxide
B)Fermentation releases sugars stored in organelles in the barley
C)Fermentation causes the starch in the barley to taste sweet
D)The fermentation breaks starch in the barley down into simple sugars in the malt
E)Fermentation breaks down the simple sugars in the barley

Question 51

Saturated fats have long straight tails of fatty acids,while unsaturated fats from vegetables have kinks in their tails due to double bonds.These kinks prevent the fats from packing together as tightly.Hydrogenated vegetable oils have hydrogens added back to the double bonds and thus behave like ____.

A)Unsaturated fats
B)Waxes
C)Carbohydrates
D)Protein
E)Saturated fats

Question 52

How are the monomers in proteins joined?

A)Phosphodiester bonds between amino acids
B)Peptide bonds between amino acids
C)Peptide bonds between nucleotides
D)Phosphodiester bonds between nucleotides
E)Peptide bonds between carbohydrates

Question 53

A nucleotide contains which of the following?

A)Amino acid
B)Sugar
C)Sugar and nitrogenous base
D)Nitrogenous base
E)Nitrogenous base and amino acid

Question 54

The polymers with the most complex and diverse three-dimensional structure are:

A)Saturated fats
B)Unsaturated fats
C)Proteins
D)Waxes
E)Carbohydrates

Question 55

____ bonds are formed between monomers to form a polymer.

A)Ionic bonds
B)Covalent bonds
C)Hydrogen bonds
D)Hydrophobic bonds
E)Nuclear bonds

Question 56

¹⁴C and ¹⁴N are both:

A)Atoms
B)Molecules
C)Compounds
D)Polymers
E)Ions

Question 57

Trees take up water hundreds of feet away by:

A)Water's high density
B)Cohesion
C)Water's high boiling point
D)Adhesion
E)A neutral pH

Question 58

Sugars (CH₂O)_n dissolve well in water because sugars form ____ bonds with water.

A)Covalent bonds
B)Ionic bonds
C)Hydrogen bonds
D)Hydrophobic bonds
E)Non-polar bonds

Question 59

You can painlessly wade into a pool,but doing a belly flop off of the high diving board hurts because of ____ in water.

A)Water's high density
B)Adhesion
C)Water's high boiling point
D)A neutral pH
E)Cohesion

Question 60

When ¹⁴C decays to ¹⁴N the number of protons ____ and the number of neutrons ___.

A)Decreases by 1; increases by 1
B)Stays the same; increases by 1
C)Increases by 1; stays the same
D)Increases by 1; decreases by 1
E)Decreases by 1; stays the same

Question 61

What essential function would lipids play in the origin of life?

A)The formation of membranes
B)Storage of information
C)Catalysis of reactions
D)Formation of a cytoskeleton
E)Anaerobic fermentation

Question 62

If ice were more dense than water,then during the winter most organisms living in ponds and lakes in colder climates would become entrapped in ice and freeze.

Question 63

Proteins store the genetic information of the cell and transmit it to the next generation.

Question 64

Cohesion is a property of water in which water molecules tend to stick together.

Question 65

How did the scientists determine if an organic molecule was extraterrestrial?

A)By looking for a decrease in ¹³C and ¹⁵N in the meteorite
B)By measuring the amount of amino acids in the meteorite
C)By measuring the amount of nucleotides in the meteorite
D)By looking for an increase in ¹³C and ¹⁵N in the meteorite
E)By measuring the total amount of carbon and nitrogen in the meteorite

Question 66

In Table 2.7 why were amino acids analyzed for ¹⁵N?

A)Nitrogen is not present in nucleotides or carbohydrates
B)Nitrogen is not present in nucleotides or lipids
C)Nitrogen is not present in carbohydrates or lipids
D)Nitrogen is not present in amino acids or carbohydrates
E)Nitrogen is not present in nucleotides or amino acids

Question 67

What hypothesis were the scientists testing?

A)Can organic molecules be made on Earth?
B)Can extraterrestrial life be detected on meteorites?
C)Can life be created from a mixture of organic molecules?
D)What conditions existed on Earth when life first began?
E)Were organic molecules found on meteorites extraterrestrial?

Question 68

The primary function of hemoglobin is to regulate the level of sugar in the blood.

Question 69

How are ¹³C and ¹⁵N different from the more abundant isotopes ¹²C and ¹⁴N?

A)¹³C and ¹⁵N each have one more neutron than ¹²C and ¹⁴N
B)¹³C and ¹⁵N each have one more proton than ¹²C and ¹⁴N
C)¹³C and ¹⁵N each have one less neutron than ¹²C and ¹⁴N
D)¹³C and ¹⁵N each have one less proton than ¹²C and ¹⁴N
E)¹³C and ¹⁵N each have one less electron than ¹²C and ¹⁴N

Question 70

An essential amino acid is an amino acid that is found in all types of foods.

Question 71

A substance in which other substances dissolve is called a solute.

Question 72

If a protein is denatured,its structure has been changed enough to make the protein nonfunctional.

Question 73

Which of the following conclusions can be made from Table 2.7?

A)Glycine is a more abundant amino acid in the meteorite than in terrestrial samples
B)¹⁵N is more abundant in amino acids from the meteorite than from terrestrial samples
C)Amino acids in the meteorite contain more nitrogen than amino acids from terrestrial samples
D)¹³C is more abundant in amino acids from the meteorite than from terrestrial samples
E)Uracil is a more abundant amino acid in the meteorite than in terrestrial samples

Question 74

A fatty acid is unsaturated if there is at least one double bond between the carbon atoms in that fatty acid.

Question 75

A peptide bond is a covalent bond formed between the amino group of one amino acid and the R group of another amino acid.

Question 76

What is significant about detecting uracil in meteorites?

A)Uracil is found in DNA which is thought to be the original genetic material
B)Uracil is a precursor for many other biological molecules including DNA and proteins
C)Uracil is a very complex molecule that can only be made in living cells, thus confirming that extraterrestrial life exists
D)Uracil is found in RNA which is thought to be the original genetic material
E)Uracil can catalyze reactions