Deck 2: The Chemistry of Life

Question 1

Which of the following statements regarding chemical reactions is false?

A)The products of a chemical reaction always have the same mass as the reactants.
B)During a chemical reaction, molecules are rearranged.
C)During a chemical reaction, atoms of one element can be converted into a different element.
D)There are chemical reactions close to you right now.

Answer 1

C

Question 2

What is a trace element?

A)An element that is very common in nature
B)An element that is evenly distributed on the planet
C)An element that is required in miniscule amounts for life
D)An element that is used to identify the location of other elements

Answer 2

C

Question 3

Why is one side of a single water molecule partially negative while the other side is partially positive?

A)Electron pairs are unevenly shared between the oxygen atom and the two hydrogen atoms.
B)Electron pairs are unevenly shared between the two hydrogen atoms.
C)Oxygen donates its electrons to hydrogen.
D)Hydrogen donates its electrons to oxygen.

Answer 3

A

Question 4

The typical carbon atom is described in the periodic table by the accompanying box.How many protons are in a typical oxygen atom?

A)8
B)12
C)18
D)Not enough information given

Question 5

The 2+ in Cu²⁺ tells us that this atom ________.

A)has two more neutrons than protons
B)has two more protons than electrons
C)has two more electrons than neutrons
D)has two more electrons than protons

Question 6

The bond in which bonded atoms share electrons is called a(n) ________.

A)ionic bond
B)covalent bond
C)hydrogen bond
D)polar bond

Question 7

What is the most common element in your body?

A)Oxygen
B)Water
C)Carbon
D)Sugar

Question 8

Which is not one of the four atoms that make up the bulk of living organisms?

A)Oxygen
B)Nitrogen
C)Calcium
D)Carbon

Question 9

Which of the following bonds is the weakest?

A)The ionic bond
B)The covalent bond
C)The hydrogen bond
D)All three bonds are roughly equal in strength

Question 10

In an atom, the number of neutrons determines most specifically the ________.

A)chemical element
B)isotope
C)ion state
D)chemical properties

Question 11

What is the maximum number of single covalent bonds a carbon atom can form with other elements?

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

Question 12

The atomic number corresponds to the number of ________ in a specific element, while the atomic weight corresponds to the number of ________ in a specific element.

A)protons; neutrons
B)neutrons; protons
C)protons; protons and neutrons
D)protons and neutrons; neutrons

Question 13

The chemical name for table salt is sodium chloride, or simply NaCl.What type of chemical is NaCl?

A)A compound
B)An element
C)A molecule
D)An ion

Question 14

During a chemical reaction, atoms are ________.

A)destroyed
B)created
C)rearranged
D)destroyed and created

Question 15

How many neutrons are in a typical oxygen atom?

A)8
B)12
C)18
D)Not enough information given

Question 16

Which number represents the atomic weight of oxygen?

A)6
B)16
C)18
D)Not enough information given

Question 17

While the maximum number of electrons required to fill the outermost shell of an atom varies depending on the size of the atom, almost all of the smaller atoms (atomic numbers 2-20) are considered stable, and thus nonreactive, when they contain ________ electron(s) in the outermost shell.

A)1
B)2
C)8
D)16

Question 18

Individual water molecules are held to one another by relatively weak ________ bonds.

A)covalent
B)hydrogen
C)ionic
D)nonpolar

Question 19

The number of electrons of an atom determines its ________.

A)chemical element
B)isotope
C)bonding properties
D)all of the above are correct

Question 20

Identify the reactants in the following chemical reaction: C₁₀H₈ + 12 O₂ → 10 CO₂ + 4 H₂O

A)C₁₀H₈ and 10 CO₂
B)12 O₂ and 4 H₂O
C)C₁₀H₈ and 12 O₂
D)10 CO₂ and 4 H₂O

Question 21

When water melts from a solid ice cube to a liquid, its volume ________ and its mass ________.

A)Increases; decreases
B)Decreases; increases
C)Decreases; stays the same
D)Increases; stays the same

Question 22

What are the ecological consequences of acidification of rain and oceans?

A)They damage the health of ecosystems.
B)They do not have any consequences on ecosystems.
C)They improve the health of ecosystems.
D)Acid rain damages ecosystems, but ocean acidification improves the health of oceans.

Question 23

Why is life based on carbon-based molecules?

A)Because carbon is found everywhere
B)Because carbon has unique ionic properties
C)Because a single carbon can bond with up to four other atoms
D)Because a single carbon can bond with up to eight other atoms

Question 24

Water is the least dense when it ________.

A)is frozen
B)is just above freezing
C)is at room temperature
D)is just below boiling

Question 25

Water "beads up" on synthetic fabric such as polyester but binds to cotton.What is the most likely explanation for this?

A)Polyester is not a naturally occurring substance, whereas cotton is a naturally occurring substance.
B)Polyester is more flexible than cotton.
C)Polyester fibers are thinner than cotton fibers.
D)Polyester is nonpolar, whereas cotton is polar.

Question 26

How do buffers minimize change in the pH of biological systems?

A)By absorbing H⁺ ions when there is an excess
B)By donating H⁺ ions when there is a shortage
C)Both of these
D)Neither of these

Question 27

What is an organic compound?

A)A molecule that contains nitrogen bonded to other elements
B)A molecule that contains carbon bonded to other elements
C)A molecule that contains both carbon and nitrogen
D)A molecule that contains a nitrogen skeleton

Question 28

Select the most complete explanation of what the pH scale measures.

A)The acidity of a solvent
B)The alkalinity of a solvent
C)The concentration of hydrogen ions in a solution
D)The concentration of buffers in a solution

Question 29

The breaking of a large organic molecule into smaller, individual subunits involves multiple ________.

A)hydrolysis reactions
B)osmotic reactions
C)dehydration synthesis reactions
D)hydrosynthetic reactions

Question 30

What are the four classes of large organic molecules important to life on Earth?

A)Carbohydrates, lipids, proteins, and enzymes
B)Carbohydrates, lipids, proteins, and sugars
C)Carbohydrates, proteins, nucleic acids, and sugars
D)Carbohydrates, proteins, lipids, and nucleic acids

Question 31

The building of a large organic molecule from small subunits involves multiple ________.

A)hydrolysis reactions
B)osmotic reactions
C)dehydration synthesis reactions
D)hydrosynthetic reactions

Question 32

How can we explain that water is a solvent?

A)Water has a polar nature, and as such its polar molecules will bind to substances that have positive or negative charges.
B)Water is a heavy substance, and as such can disrupt pre-existing bonds.
C)Water is highly cohesive and adhesive, which allows it to bind to different substances as a solvent.
D)Water is very dense in its liquid state, which allows it to bind to different substances as a solvent.

Question 33

Which of the following properties of water molecules has important implications to life?

A)High surface tension
B)The ability to dissolve polar substances
C)The ability of ice to float in water
D)All of the above are true

Question 34

Which of the following accurately describes the pH scale?

A)The pH scale runs from 0 (most basic)to 14 (most acidic), with 7 as a neutral.
B)The pH scale runs from 0 (most acidic)to 14 (most basic), with 7 as a neutral.
C)The pH scale runs from 0 (neutral)to 14 (most acidic), with 7 as an average acidity level.
D)The pH scale runs from 0 (most acidic)to 14 (neutral), with 7 as an average acidity level.

Question 35

Organic compounds are distinguished by molecules that contain ________ bonded to other elements.

A)nitrogen
B)carbon
C)oxygen
D)hydrogen

Question 36

Something with a pH of 5 would be ________.

A)acidic
B)basic
C)neutral
D)alkaline

Question 37

What do we call the sum total of all the chemical reactions that take place in your body?

A)Catabolism
B)Anabolism
C)Embolism
D)Metabolism

Question 38

Which of the following large organic molecules include table sugar?

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

Question 39

A needle can be made to "float" on the surface tension of water.What causes this surface tension to form?

A)The adhesion of water molecules to the needle
B)The cohesion of water molecules to each other
C)The solubility of water
D)The heat capacity of water

Question 40

What are the monomers of proteins?

A)Glucose
B)Nucleic acids
C)Fatty acids
D)Amino acids

Question 41

What kind of bond joins amino acids together to form a protein?

A)Peptide bond
B)Hydrogen bond
C)Polar bond
D)Protein bond

Question 42

Enzymes are a type of ________.

A)carbohydrate
B)protein
C)lipid
D)monomer

Question 43

What will be accomplished by lowering the activation energy of a reaction?

A)The reaction will proceed more slowly.
B)The reaction will proceed more quickly.
C)The reaction will stop completely.
D)The reaction will reverse.

Question 44

What is the basic structure of a triglyceride?

A)A glycerol head and three fatty acid tails
B)A linear chain of fatty acids
C)A branched chain of fatty acids
D)A chain of fatty acid tails

Question 45

Which would have the highest concentration of C-H bonds?

A)Saturated fat
B)Unsaturated fat
C)Trans fat
D)Cholesterol

Question 46

What are inhibitors?

A)Molecules that allow reactions to proceed more quickly
B)Molecules that prevent enzymes from working
C)Molecules that inhibit protein synthesis
D)Molecules that bind to an enzyme to help its reaction

Question 47

To a large extent, a protein's function is dependent upon its shape.What determines a protein's shape?

A)The location of the active site
B)The sequence of amino acids
C)The number of amino acids
D)The number of peptide bonds

Question 48

Which of the following is not made from long chains of glucose?

A)Starch
B)Sucrose
C)Glycogen
D)Cellulose

Question 49

A polypeptide is ________.

A)a long chain of amino acids
B)a long chain of glucose
C)a long chain of fatty acids
D)a long chain of nucleic acids

Question 50

Which of the following represents a simple sugar (also called a monosaccharide)?

A)Lactose
B)Cellulose
C)Glucose
D)Sucrose (table sugar)

Question 51

What might happen if a protein has a change in one amino acid?

A)The amino acid chain folds incorrectly.
B)The protein can no longer function properly.
C)The protein has a new shape.
D)All of these may happen.

Question 52

All lipids are ________.

A)water-loving molecules
B)hydrophilic
C)hydrophobic
D)hydrolytic

Question 53

Which of the following dietary fats is considered to be the least healthy?

A)Saturated fat
B)Trans unsaturated fat
C)Cholesterol
D)All dietary fats are unhealthy

Question 54

Which of the following is a polysaccharide?

A)Glucose
B)Cellulose
C)Fructose
D)Sucrose

Question 55

Which of the following molecules is solid at room temperature?

A)Saturated fats
B)Unsaturated fats
C)Cholesterol
D)Both saturated and unsaturated fats

Question 56

What is another name for the polymers of carbohydrates?

A)Triglycerides
B)Polysaccharides
C)Polypeptides
D)Nucleotides

Question 57

What are isomers?

A)Two molecules that have the same arrangement of atoms
B)Two atoms that have the same ionic properties
C)Two molecules that have the same atoms arranged differently
D)Two elements that can bond with each other

Question 58

Oil hydrogenation can produce a product, such as vegetable shortening or margarine, that is spreadable at room temperature because of an unusual bond that does not occur naturally.What is the name of this category of lipid?

A)Saturated fat
B)Healthy fat
C)Trans fat
D)Cholesterol

Question 59

________ is the polysaccharide most commonly found in highly fibrous foods such as celery.

A)Starch
B)Cellulose
C)Glycogen
D)Chitin

Question 60

Proteins are diverse molecules that perform a wide variety of functions.Which of the following is not a typical function of proteins?

A)Transport
B)Catalyze reactions via enzymes
C)Movement
D)Energy storage

Question 61

The unique chemical qualities of individual amino acids do not directly determine the function of an enzyme.What, then, is the role of the individual amino acid's unique chemical qualities, and what directly determines the function of an enzyme?

Question 62

Which of the three gasses is the easiest to break apart: nitrogen gas (N₂), oxygen gas (O₂), or hydrogen gas (H₂)? Which is the most difficult to break apart? What accounts for the differences?

Question 63

List the different types of macromolecules of life, and for each one, list one of its functions and its main monomer.

Question 64

An old home remedy for anemia was to drink from a jug of water into which was added a handful of iron nails.Why might this have been effective at treating certain forms of anemia?

Question 65

Why does sweating cool your skin on a hot, dry day but make you feel warmer on a hot, humid day?

Question 66

Penicillin is a competitive inhibitor produced by a fungus in order to kill invading bacteria.It does this by mimicking the substrate required by the bacterium to build and repair its cell wall.Describe how mimicking the substrate would result in the death of the bacterium.