Deck 2: The Chemical Basis of Life

Question 1

X-rays can be used to view bones because

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

Answer 1

A

Question 2

Subatomic particles located around the nucleus of an atom are

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

Answer 2

A

Question 3

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

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

Answer 3

E

Question 4

The mass number of an atom is the number of

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

Question 5

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

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

Question 6

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 7

The amount of matter in an object is its

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

Question 8

The amount of matter in an object is its

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

Question 9

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

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

Question 10

In an x-ray film of the skeletal system, the dense tissue areas appear ______ because they ______ the x-rays; and 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) dark, do not absorb; light, do absorb
D) light, do not absorb; dark, aborb

Question 11

Isotopes of the same element have

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

Question 12

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 13

The four most abundant elements in the human body are

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

Question 14

Electrons

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

Question 15

A neutral atom will become a cation if it

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

Question 16

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 17

Covalent bonds form when

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

Question 18

In ionic bonding,

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

Question 19

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

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

Question 20

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 21

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 22

Sodium chloride is considered a(n)

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

Question 23

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

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

Question 24

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 25

Which of the following pairs is mismatched?

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

Question 26

An electrolyte is

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

Question 27

A cation is

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

Question 28

A molecule is

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

Question 29

An anion is

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

Question 30

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

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

Question 31

Electrolytes are substances that

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

Question 32

Carbon dioxide is considered a(n)

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

Question 33

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

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

Question 34

All of the synthesis reactions in the body are called

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

Question 35

Cations and anions that dissociate in water are sometimes called

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

Question 36

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

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

Question 37

Intermolecular forces

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

Question 38

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

Question 39

When ionic compounds dissolve in water, their ions

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

Question 40

Which of the following is a synthesis reaction?

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

Question 41

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

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

Question 42

Kinetic energy is

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

Question 43

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 44

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

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

Question 45

Enzymes are proteins that increase the rate of chemical reactions by

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

Question 46

Potential energy stored in bonds of molecules is _____ energy.

A) mechanical
B) thermal
C) chemical
D) molecular
E) None of the above

Question 47

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 these occur with cyanide poisoning.

Question 48

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

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

Question 49

In the reversible reaction, CO₂ + H₂O $\harr$ H₂CO₃ $\harr$ 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 decrease.
B) H⁺ will increase.
C) H⁺ will be unchanged.

Question 50

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

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

Question 51

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 these choices are correct.

Question 52

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

A) synthesis reactions.
B) decomposition reactions.
C) exchange reactions.
D) reversible reactions.
E) net reaction rates.

Question 53

Potential energy is

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

Question 54

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

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

Question 55

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 56

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

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

Question 57

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 58

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

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

Question 59

Heat energy is

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

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) the chemical reaction equalizes the potential energy levels.
C) energy is not a factor in the reaction.
D) energy has not been gained or lost.
E) energy is released by the reaction.

Question 61

Solution A increases its acidity. This means that the

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

Question 62

Large carbohydrates are formed from smaller units called

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

Question 63

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

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

Question 64

A base is a proton

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

Question 65

Normal blood pH is maintained within a range of

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

Question 66

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

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

Question 67

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 68

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 69

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

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

Question 70

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 71

A buffer will

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

Question 72

The pH value

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

Question 73

Which of the following statements is false?

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

Question 74

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

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

Question 75

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.

Question 76

Which of the following is a proton donor?

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

Question 77

Substances dissolved in the liquid portion of a solution are called

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

Question 78

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

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

Question 79

A group of water molecules are held together by

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

Question 80

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.