Deck 2: The Chemical Basis of Life

Question 1

Subatomic particles located around the nucleus of an atom are ________.

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

Answer 1

B

Question 2

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

A) 19
B) 20
C) 39
D) 58

Answer 2

B

Question 3

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.

Answer 3

B

Question 4

In an x-ray film of the skeletal system, the dense tissue areas appear ________ because they ________ the x-rays; the less dense tissues appear ________ because they ________ the x-rays.

A) light; absorb; dark; do not absorb
B) dark; absorb; light; do not absorb
C) light; do not absorb; dark; absorb
D) dark; do not absorb; light; absorb

Question 5

The amount of matter in an object is its ________.

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

Question 6

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 7

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 8

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 9

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 the choices are correct.

Question 10

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.

Question 11

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 12

The three forms of matter are

A) air, water, and solids.
B) solids, liquids, and gases.
C) blood, bone, and air.
D) vapor, water, and solid.

Question 13

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 14

The smallest particle of an element that still exhibits the chemical characteristics of that element is a/an ________.

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

Question 15

The amount of matter in an object is its ________.

A) mass
B) weight
C) atomic number
D) element
E) ionic charge

Question 16

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

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

Question 17

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 18

X-rays can be used to view bones because

A) x-rays pass through bone.
B) x-rays react with bone.
C) x-rays cannot pass through bone.
D) bones are less dense than soft tissue.

Question 19

Which of the following is not a use of x-ray imaging?

A) Breast cancer screening in mammography
B) Upper digestive tract abnormalities following barium ingestion
C) Brain tumor progression
D) Vertebrae fractures

Question 20

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 the choices are correct.

Question 21

When the hydrogen bonds that maintain a protein's three-dimensional shape are broken, the protein becomes nonfunctional, and is said to be ________.

A) essential
B) denatured
C) structural
D) unsaturated
E) saturated

Question 22

Molecules that form when electrons are shared unequally between atoms are called ________ molecules.

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

Question 23

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 24

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 25

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 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

A substance composed of two or more different types of atoms is a/an ________.

A) compound
B) element
C) ion
D) molecule
E) Both compound and molecule are correct.

Question 28

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 29

Carbon dioxide is considered a/an ________.

A) molecule
B) compound
C) Both molecule and compound are correct.
D) element
E) ion

Question 30

Sodium chloride is considered a/an ________.

A) molecule
B) compound
C) Both molecule and compound are correct.
D) element
E) ion

Question 31

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 32

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 33

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 34

Hydrogen bonds form between molecules containing ________ bonds; the hydrogen bond is between a hydrogen atom of one molecule and a partially ________ charged atom of another.

A) polar covalent; negatively
B) polar covalent; positively
C) nonpolar covalent; positively
D) nonpolar covalent; negatively
E) ionic; positively

Question 35

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 36

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

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

Question 37

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 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

An individual hydrogen bond in a sample of water would be described as

A) strong and intramolecular.
B) strong and intermolecular.
C) weak and intramolecular.
D) weak and intermolecular.

Question 40

All of the synthesis reactions in the body are called ________.

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

Question 41

In a reversible reaction, when the rate of product formation is equal to the rate of reactant formation, the reaction is

A) stopped.
B) at equilibrium.
C) in danger of exploding.
D) a net decomposition reaction.
E) a net synthesis reaction.

Question 42

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 43

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

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

Question 44

The conversion between different states of energy (e.g. potential energy to kinetic energy)

A) is not 100% efficient.
B) is 100% efficient.
C) typically generates heat.
D) is not possible; energy cannot change its state.
E) is not 100% efficient and typically generates heat.

Question 45

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 46

In the reversible reaction, CO₂ + H₂O ↔ H₂CO₃ ↔ 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

Which of the following is an organic compound?

A) Hydrochloric acid (HCl)
B) Salt (NaCl)
C) Sucrose (C₁₂H₂₂O₁₁)
D) Water (H₂O)
E) None of the choices are correct.

Question 48

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 49

If the products of a chemical reaction contain less potential energy than the reactants,

A) energy has been stored in the molecular bonds of the product.
B) energy has been released by the breaking of molecular bonds.
C) the reaction will be reversible without additional energy input.
D) a synthesis reaction is likely to have occurred.
E) All of the choices are correct.

Question 50

Potential energy stored in bonds of molecules is ________ energy.

A) mechanical
B) thermal
C) chemical
D) molecular
E) None of the choices are correct.

Question 51

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 52

Why are cyanide compounds lethal to humans?

A) They interfere with protein synthesis.
B) They interfere with nerve impulses.
C) They interfere with the production of ATP.
D) They interfere with muscle contraction.
E) All of the choices are correct.

Question 53

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 54

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

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

Question 55

Chemical reactions with the property of being able to proceed from reactants to products and from products to reactants are called ________ reactions.

A) exchange
B) synthesis
C) decomposition
D) reversible
E) mirrored

Question 56

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

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

Question 57

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 58

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

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

Question 59

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 60

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 61

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 the choices are correct.

Question 62

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 the choices are correct.

Question 63

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

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

Question 64

Which of the following is a proton donor?

A) An acid
B) A base
C) A salt
D) Glucose
E) A neutral substance

Question 65

Substances dissolved in the liquid portion of a solution are called ________.

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

Question 66

The pH value

A) increases with acidity.
B) is measured on a scale from 0 to 10.
C) is determined by the concentration of H⁺ in a solution.
D) reflects the Na⁺ content of body fluids.
E) decreases with alkalinity.

Question 67

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 the choices are correct.

Question 68

Two solutions, A and B, have the same osmolality. What does that mean?

A) Solution A has more solute particles than solution B.
B) Solution B has more solute particles than solution A.
C) Both solutions have the same number of solute particles.
D) Solution A is water and sugar; solution B is water and salt.
E) Solution A is pure water, and solution B is water and salt.

Question 69

Sam adjusts solution A to increase 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 in the solution has decreased.
E) number of hydrogen ions in the solution has increased.

Question 70

Solution A has a pH of 10, and solution B has a pH of 2. Which of the following statements about these solutions is true?

A) Solution A and solution B are both basic.
B) Solution B is basic.
C) Solution A is acidic.
D) Solution B has a higher H⁺ concentration than solution A.
E) Solution A has a higher H⁺ concentration than solution B.

Question 71

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 72

Hyperventilation causes the loss of large amounts of CO₂ from the body, decreasing the amount of H⁺ 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 are correct.

Question 73

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 74

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

A) Buffer
B) Conjugate acid
C) Salt
D) Conjugate base

Question 75

A group of water molecules are held together by ________ bonds.

A) savings
B) hydrogen
C) ionic
D) nonpolar covalent
E) polar covalent

Question 76

A base is a proton ________.

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

Question 77

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 the choices are correct.

Question 78

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 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

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.