Deck 2: The Chemical Basis of Life

Question 1

The smallest particle of an element that still exhibits the chemical characteristics of that element is a(n)

A) electron.
B) atom.
C) chemical bond.
D) orbital.
E) proton.

Answer 1

B

Question 2

Sodium chloride is considered a(n)

A) molecule.
B) compound.
C) molecule and a compound.
D) element.
E) ion.

Answer 2

B

Question 3

The four most abundant elements in the human body are

A) carbon, hydrogen, oxygen, and iron.
B) carbon, hydrogen, oxygen, and nitrogen.
C) calcium, hydrogen, sodium, and potassium.
D) carbon, oxygen, magnesium, and zinc.
E) carbon, sulfur, calcium, and potassium.

Answer 3

B

Question 4

Molecules that form when electrons are shared unequally between atoms are called

A) salt molecules.
B) polar molecules.
C) nonpolar molecules.
D) lopsided molecules.
E) None of these choices are correct.

Question 5

An atom of chlorine has 17 protons and 18 neutrons. Which of the following statements is true?

A) Chlorine atoms have 18 electrons.
B) Chlorine has a mass number of 35.
C) Chlorine has an atomic number of 18.
D) Chlorine has 35 electrons.
E) Chlorine has an atomic number of 35.

Question 6

The amount of matter in an object is its

A) mass.
B) weight.
C) density.
D) volume.
E) size.

Question 7

Isotopes of the same element have

A) the same number of neutrons but different numbers of protons.
B) different numbers of protons and electrons.
C) the same mass number.
D) the same atomic number but differ in their mass numbers.
E) no mass number.

Question 8

Which of the following best describes a proton?

A) one negative charge, no mass, found in orbitals
B) no charge, mass of one, found in nucleus
C) one positive charge, mass of one, found in nucleus
D) subatomic particle with no electric charge
E) None of these choices is correct.

Question 9

Carbon dioxide is considered a(n)

A) molecule.
B) compound.
C) molecule and a compound.
D) element.
E) ion.

Question 10

The number of atoms in exactly 12 grams of carbon-12 is called

A) Dalton's number.
B) Socrates's number.
C) Avogadro's number.
D) Pasteur's number.
E) Le Chatelier's number.

Question 11

Covalent bonds form when

A) atomic nuclei fuse.
B) molecules become ionized.
C) neutrons are transferred from one atom to another.
D) protons are lost from atoms.
E) electrons are shared between two atoms.

Question 12

When ionic compounds dissolve in water, their ions

A) cling tightly together.
B) dissociate or separate from one another.
C) lose their charge.
D) get lost in the solvent.
E) settle to the bottom of the container.

Question 13

A substance composed of two or more different types of atoms is a(n)

A) compound.
B) element.
C) ion.
D) molecule.
E) compound and a molecule.

Question 14

Electrons

A) comprise the majority of the mass of an atom.
B) are located in the nucleus of an atom.
C) have a positive charge of one.
D) are the subatomic particles most involved in bonding behavior of atoms.
E) do not participate in the bonding of atoms.

Question 15

A neutral atom will become a cation if it

A) gains electrons.
B) gains protons.
C) loses electrons.
D) loses protons.
E) gains neutrons.

Question 16

An atom has an atomic number of 19 and a mass number of 39. This atom will have

A) 19 neutrons.
B) 20 neutrons.
C) 39 neutrons.
D) 58 neutrons.
E) 20 electrons.

Question 17

Subatomic particles located around the nucleus of an atom are

A) protons.
B) electrons.
C) neutrons.
D) neutrinos.
E) photons.

Question 18

A neutral atom contains

A) more protons than electrons.
B) more electrons than protons.
C) the same number of electrons and protons.
D) only neutrons.
E) None of these choices is correct.

Question 19

In ionic bonding,

A) only non-polar molecules are involved.
B) a "sea of electrons" forms.
C) electrons are transferred from one atom to another.
D) two hydrogen atoms share one pair of electrons.
E) the charge of the ion does not play a role in the bond.

Question 20

The mass number of an atom is the number of

A) protons in the atom.
B) neutrons in the atom.
C) protons plus electrons in the atom.
D) electrons plus neutrons in the atom.
E) neutrons plus protons in the atom.

Question 21

Which of the following is a synthesis reaction?

A) Two amino acids are bonded together to form a dipeptide.
B) Sucrose is chemically separated to form one molecule of glucose and one molecule of fructose.
C) Sodium chloride is dissolved in water.
D) Several dipeptide chains are formed from digestion of a long polypeptide chain.
E) ATP is converted to ADP.

Question 22

Chemical substances that dissolve in water or react with water to release ions are known as

A) buffers.
B) enzymes.
C) bases.
D) inorganic compounds.
E) electrolytes.

Question 23

Which of the following factors will influence the rate of chemical reactions?

A) temperature
B) concentration of reactants
C) presence of catalysts
D) presence of enzymes
E) All of these factors will influence the rate of chemical reactions.

Question 24

Which of the following pairs is mismatched?

A) synthesis reaction - two reactants combine to form a larger product
B) decomposition reaction - large reactant broken into smaller products
C) oxidation - gain of electrons
D) dehydration reaction - water is a product of the reaction
E) hydrolysis - water is used in decomposition reaction

Question 25

Potential energy is

A) the form of energy that actually does work.
B) movement of ions or electrons.
C) energy that flows between objects with different temperatures.
D) stored energy that could do work but is not doing so.
E) energy that moves in waves.

Question 26

Cations and anions that dissociate in water are sometimes called

A) nonelectrolytes, because they do not conduct an electrical current.
B) molecules
C) electrolytes, because they can conduct an electrical current.
D) nonelectrolytes and solutes.
E) molecules and electrolytes.

Question 27

An electrolyte is

A) a combination of atoms held together by chemical bonds.
B) a positively charged ion.
C) a negatively charged ion.
D) a substance that conducts electricity when placed in solution.
E) the alteration in the three-dimensional structure of a protein.

Question 28

The energy stored in ATP is a form of ________ energy.

A) mechanical
B) chemical
C) kinetic
D) heat
E) electrical

Question 29

The minimum amount of energy that reactants must have to start a chemical reaction is called

A) kinetic energy.
B) mechanical energy.
C) activation energy.
D) electromagnetic energy.
E) potential energy.

Question 30

Electrolytes are substances that

A) form covalent bonds with water.
B) conduct electricity when dissolved in water.
C) cannot conduct electricity in solution.
D) are NOT found in the human body in any appreciable amounts.
E) are NOT charged particles.

Question 31

A cation is

A) a combination of atoms held together by chemical bonds.
B) a positively charged ion.
C) a negatively charged ion.
D) a molecule that conducts electricity when placed in solution.
E) an alteration in the three-dimensional structure of a protein.

Question 32

Chemical energy

A) moves matter.
B) results from the position or movement of objects.
C) is a form of potential energy within chemical bonds.
D) comes from the sun.
E) is not important in physiological processes.

Question 33

Kinetic energy is

A) the form of energy that actually does work.
B) movement of ions or electrons.
C) energy that flows between objects with different temperatures.
D) stored energy that could do work but is not doing so.
E) energy that moves in waves.

Question 34

Solubility refers to the ability of one substance to ___________ in another.

A) react
B) dissolve
C) precipitate
D) conduct
E) None of these choices are correct.

Question 35

Intermolecular forces

A) form dissociated ions.
B) are electrostatic attractions between different molecules.
C) evenly distribute electrical charge among all atoms in a sample.
D) separate atoms and ions from one another.
E) are found within molecules.

Question 36

If the potential energy in the chemical bonds of the reactants is greater than the potential energy in the chemical bonds of the product,

A) energy must be supplied for the reaction to occur.
B) energy is released by the reaction.
C) the chemical reaction equalizes the potential energy levels.
D) energy has not been gained or lost.
E) energy is not a factor in the reaction.

Question 37

Heat energy is

A) the form of energy that actually does work.
B) movement of ions or electrons.
C) energy that flows between objects with different temperatures.
D) stored energy that could do work but is not doing so.
E) energy that moves in waves.

Question 38

An anion is

A) a combination of atoms held together by chemical bonds.
B) a positively charged ion.
C) a negatively charged ion.
D) a molecule that conducts electricity when placed in solution.
E) an alteration in the three-dimensional structure of a protein.

Question 39

A molecule is

A) a combination of atoms held together by chemical bonds.
B) a positively charged ion.
C) a negatively charged ion.
D) a substance that conducts electricity when placed in solution.
E) an alteration in the three-dimensional structure of a protein.

Question 40

Energy

A) has mass.
B) is the capacity to do work.
C) has weight.
D) takes up space.
E) cannot be stored.

Question 41

Reactions that use water to split molecules apart are called _______ reactions.

A) dehydration
B) synthesis
C) hydrolysis
D) reversible
E) oxidation

Question 42

The hydrogen and oxygen atoms in a molecule of water are held together by

A) ionic bonds.
B) peptide bonds.
C) savings bonds.
D) polar covalent bonds.
E) nonpolar bonds.

Question 43

Why is water involved in most metabolic reactions in the human body?

A) It can dissolve many chemical compounds.
B) It can absorb and release heat without changing temperature very much.
C) It has a high surface tension.
D) Its bonds are nonpolar.
E) It is a solute.

Question 44

The pH value

A) increases with acidity.
B) is measured on a scale from 0 to 10.
C) is determined by the concentration of hydrogen ions.
D) reflects the sodium content of body fluids.
E) decreases with alkalinity.

Question 45

For most chemical reactions, an increase in temperature will cause the reaction rate to

A) increase.
B) decrease.
C) remain unchanged.

Question 46

In the reversible reaction, CO₂ + H₂O $\longleftrightarrow$ H₂CO₃ $\longleftrightarrow$ H⁺ + HCO₃- , a decrease in respiration rate will increase the concentration of CO₂ in the blood. What will this do to the amount of H⁺ in the blood?

A) H⁺ will increase.
B) H⁺ will decrease.
C) H⁺ will be unchanged.

Question 47

All of the synthesis reactions in the body are called

A) catabolism.
B) hydrolysis.
C) oxidation-reduction.
D) anabolism.
E) dissociation.

Question 48

Hyperventilation causes the loss of large amounts of carbon dioxide from the body, decreasing the amount of hydrogen ions in solution. As a result,

A) the pH of body fluids will rise.
B) the pH of body fluids will fall.
C) the pH of body fluids will become neutral.
D) the pH of body fluids will not be affected.
E) None of these choices is correct.

Question 49

Enzymes are proteins that increase the rate of chemical reactions by

A) increasing the activation energy of the reaction.
B) decreasing the activation energy of the reaction.
C) adjusting the temperature of the reaction.
D) increasing the concentration of the reactants.

Question 50

A buffer will

A) enhance changes in the pH of the solutions.
B) resist drastic changes in the pH of the solutions.
C) have no effect on the pH of the solutions.
D) make a solution more acidic.
E) make a solution more basic.

Question 51

Solution A increases its acidity. This means that the

A) solution is closer to neutrality.
B) pH of the solution has increased.
C) solution will now accept more protons.
D) number of hydrogen ions has decreased.
E) number of hydrogen ions has increased.

Question 52

A base is a proton

A) donor.
B) converter.
C) acceptor.
D) creator.
E) Both acceptor and creator.

Question 53

Which of the following statements is false?

A) Water allows the body to resist sudden temperature changes.
B) Water transports nutrients in the body.
C) Water serves as an effective lubricant in our bodies.
D) Water evaporation cools the body.
E) Water evaporation heats the body.

Question 54

A solution that contains one osmole of solute in one kilogram (kg) of water is called a

A) 1% solution.
B) 1 molar solution.
C) 10% solution.
D) 1 osmolal solution.
E) None of these choices are correct.

Question 55

A group of water molecules are held together by

A) salt.
B) hydrogen bonds.
C) ionic bonds.
D) double covalent bonds.
E) polar covalent bonds.

Question 56

Substances dissolved in the liquid portion of a solution are called

A) solutes.
B) solvents.
C) catalysts.
D) osmoles.
E) insoluble.

Question 57

The presence of water in our bodies allows us to

A) cool the body with sweat.
B) maintain a fairly constant body temperature.
C) provide an environment for chemical reactions.
D) keep tissues moist and reduce friction.
E) All of these choices are correct.

Question 58

The molecular formula H₂O means

A) 1 hydrogen atom and 2 oxygen atoms.
B) 1 hydrogen atom and 1 oxygen atom.
C) 2 hydrogen atoms and 1 oxygen atom.
D) 2 hydrogen atoms and 2 oxygen atoms.
E) None of these choices is correct.

Question 59

Which of the following is a proton donor?

A) an acid
B) a base
C) a salt
D) glucose
E) a neutral substance

Question 60

A substance that will increase the rate of a chemical reaction without being permanently changed is called a/an

A) solute.
B) catalyst.
C) oxidator.
D) reducing agent.

Question 61

What particle is formed when an acid loses a proton (H+)?

A) buffer
B) conjugate acid
C) salt
D) conjugate base

Question 62

What molecule is produced as a waste product of the metabolism of glucose by cells?

A) water
B) oxygen
C) carbon dioxide
D) carbon monoxide
E) nitrogen

Question 63

Which of the following lists includes only monosaccharides that are isomers of one another?

A) glycogen, glucose, sucrose
B) starch, glycogen, cellulose
C) glucose, fructose, galactose
D) ribose, glycogen, glucose
E) deoxyribose, glycogen, starch

Question 64

Which of the following is an organic compound?

A) hydrochloric acid (HCl)
B) salt (NaCl)
C) sucrose (C₁₂H₂₂O₁₁)
D) water (H₂O)
E) None of these choices are correct.

Question 65

Which of the following is NOT a function of carbohydrates in the body?

A) structural component of DNA
B) protection
C) bulk in feces
D) energy
E) structural component of RNA

Question 66

Glucose is the

A) storage carbohydrate in animals.
B) storage carbohydrate in plants.
C) nondigestible plant polysaccharide.
D) major nutrient for most body cells.
E) sugar found in RNA.

Question 67

Consider the following five terms. Which term does not belong with the other four terms?

A) disaccharide
B) sucrose
C) lactose
D) maltose
E) glucose

Question 68

Deoxyribose is a sugar found in

A) glycogen.
B) starch.
C) DNA.
D) RNA.
E) ATP.

Question 69

The molecule used most frequently by cells as a fuel belongs to which of the following groups?

A) prostaglandins
B) carbohydrates
C) nucleic acids
D) steroids
E) phospholipids

Question 70

Normal blood pH is maintained within a range of

A) 7.35 - 8.5.
B) 7.35 - 7.45.
C) 4.5 - 5.5.
D) 1.0 - 14.0.
E) 6.5 - 9.5.

Question 71

Which of the following is a carbohydrate?

A) triglyceride
B) hemoglobin
C) cholesterol
D) animal fat
E) sucrose

Question 72

Ribose is the

A) storage carbohydrate in animals.
B) storage carbohydrate in plants.
C) nondigestible plant polysaccharide.
D) major nutrient for most body cells.
E) sugar found in RNA and ATP.

Question 73

Polysaccharides

A) are formed when sucrose and glucose combine.
B) are the smallest carbohydrates.
C) contain carbon, hydrogen, and phosphate atoms.
D) contain long chains of monosaccharides.
E) are not found in plants.

Question 74

Starch is the

A) storage carbohydrate in animals.
B) storage carbohydrate in plants.
C) nondigestible plant polysaccharide.
D) major nutrient for most body cells.
E) sugar found in RNA.

Question 75

Large carbohydrates are formed from smaller units called

A) phosphate groups.
B) monosaccharides.
C) amino acids.
D) steroids.
E) lipids.

Question 76

Cellulose is the

A) storage carbohydrate in animals.
B) storage carbohydrate in plants.
C) nondigestible plant polysaccharide.
D) major nutrient for most body cells.
E) sugar found in RNA.

Question 77

Lipids

A) are subunits of carbohydrates.
B) serve as buffers.
C) are an important component of cell membranes.
D) tend to be water soluble.
E) are polarized.

Question 78

Glycogen is the

A) storage carbohydrate in animals.
B) storage carbohydrate in plants.
C) nondigestible plant polysaccharide.
D) major nutrient for most body cells.
E) sugar found in RNA.

Question 79

Normal pH range for blood is 7.35 to 7.45. If blood pH falls below 7.35,

A) an imbalance called alkalosis results.
B) nothing happens as this is an acceptable deviation.
C) an imbalance called acidosis results.
D) the blood becomes saltier.
E) the number of red blood cells decreases.

Question 80

Normal pH for blood is 7.35 to 7.45. Maintenance of the pH in this range is

A) critical because enzymes work best within narrow ranges of pH.
B) not critical because extreme pH values do not affect enzyme function.
C) called denaturation.
D) not required.
E) None of these choices is correct.