Deck 2: The Chemical Level of Organization

Question 1

If an element is composed of atoms with an atomic number of 8 and a mass number of 14, then an electrically neutral atom of this element contains

A)6 protons.
B)6 neutrons.
C)6 electrons.
D)14 protons.
E)14 electrons.

Answer 1

B

Question 2

An oxygen atom can have 8, 9, or 10 neutrons in its nucleus. This variation describes

A)atomic number.
B)electric charge.
C)bonding characteristics.
D)isotopes.
E)proton therapy.

Answer 2

D

Question 3

The bond between sodium and chlorine is a(n)________ bond.

A)covalent
B)ionic
C)hydrogen
D)hydrophobic
E)metallic

Answer 3

B

Question 4

The uncharged subatomic particles are called

A)atoms.
B)molecules.
C)protons.
D)neutrons.
E)electrons.

Question 5

Which of the following is sometimes used in diagnostic imaging?

A)a radioisotope
B)a proton
C)an ion
D)an atom
E)an electrolyte

Question 6

An element has 6 electrons, 6 protons, and 6 neutrons. What will be the mass number of that element?

A)6
B)12
C)18
D)36
E)15

Question 7

A molecule containing two atoms of hydrogen and one atom of oxygen in combination is called a(n)

A)oxygen molecule.
B)carbon dioxide molecule.
C)water molecule.
D)hydroxyl molecule.
E)hydroxide molecule.

Question 8

Ions with a negative charge are called

A)cations.
B)anions.
C)radicals.
D)polyatomic ions.
E)None of these is correct.

Question 9

The atomic number of an atom is determined by the

A)number of protons.
B)number of neutrons.
C)number and arrangement of electrons.
D)size of the atom.
E)mass of the atom.

Question 10

A(n)________ contains atoms with the same atomic number.

A)base
B)element
C)cation
D)anion
E)enzyme

Question 11

Combinations of atoms that contain two or more different elements are called

A)molecules.
B)compounds.
C)mixtures.
D)isotopes.
E)None of these is correct.

Question 12

Which is the correct description of a molecule?

A)It is an electrically charged atom.
B)It cannot be broken down physically.
C)It is comprised of two or more elements bonded together.
D)It is the smallest unit of matter.
E)It is comprised of two or more atoms sharing electrons.

Question 13

Which statement is true regarding atomic structure and function?

A)Electrons and protons comprise the nucleus of the atom.
B)An atom is electrically neutral, having the same number of positively charged protons and negatively charged electrons.
C)Neutrons are found in orbits around the atomic nucleus.
D)The charge of an atom depends on where the protons and electrons are located.
E)All shells around the nucleus optimally contain 8 electrons.

Question 14

How many electrons do most atoms need in their second outer shell in order to be stable?

A)two
B)three
C)four
D)six
E)eight

Question 15

Atoms that are of the same element but contain different numbers of neutrons are called

A)isomers.
B)cations.
C)isotopes.
D)anions.
E)None of these is correct.

Question 16

The area around the center of an atom, which contains negatively charged subatomic particles, is called the electron

A)cloud.
B)nucleus.
C)active site.
D)buffering zone.
E)double helix.

Question 17

Covalent bonds are formed when

A)atoms share electrons.
B)cations and anions are held together by their opposite charges.
C)electrons are exchanged between atoms.
D)hydrogen forms bonds with negatively charged atoms in the same or different molecules.
E)two or more atoms lose electrons at the same time.

Question 18

The mass number represents the number of

A)protons in an atom.
B)electrons in an ion.
C)neutrons in an atom.
D)protons and neutrons in an atom.
E)neutrons and electrons in an atom.

Question 19

Which of the following elements is found in all organic molecules?

A)nitrogen
B)oxygen
C)iron
D)carbon
E)copper

Question 20

Which of the following would have a negative charge?

A)an atom
B)a molecule
C)a proton
D)a neutron
E)an electron

Question 21

Which of the following is a weak electrical attraction between molecules?

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

Question 22

The reaction NaOH + HCl → NaCl + H₂O would be an example of a(n)

A)exchange reaction.
B)decomposition reaction.
C)synthesis reaction.
D)enzyme reaction.
E)metabolic reaction.

Question 23

Chemical reactions that release energy are categorized as

A)endergonic.
B)catabolic.
C)anabolic.
D)hydrolytic.
E)exergonic.

Question 24

Reactions that ultimately result in larger molecules formed from smaller ones are called ________ reactions.

A)hydrolysis
B)reversible
C)exergonic
D)dissociation
E)synthesis

Question 25

When two monosaccharides undergo a dehydration synthesis,

A)a new monosaccharide is formed.
B)a starch is formed.
C)a polysaccharide is formed.
D)a condensation reaction occurs.
E)hydrolysis occurs.

Question 26

Which of the following is a characteristic of hydrogen bonds?

A)Hydrogen bonds are strong attractive forces between hydrogen atoms and negatively charged atoms.
B)Hydrogen bonds occur only in water.
C)Hydrogen bonds can form between adjacent molecules.
D)Hydrogen bonds are part of fatty-acid structure.
E)Hydrogen bonds are part of carbohydrate structure.

Question 27

Which of the following is an example of an anion?

A)magnesium
B)potassium
C)calcium
D)chloride
E)sodium

Question 28

Which statement about the reaction H₂ + Cl₂ → 2HCl is correct?

A)H₂ and Cl₂ are the products.
B)HCl is the product.
C)One molecule of hydrogen contains one atom.
D)One molecule of chlorine contains one atom.
E)The reaction is unbalanced.

Question 29

Chlorine atoms have seven electrons in the outermost shell. As a result, one would expect chlorine to form ions with a charge of

A)+1.
B)+2.
C)0.
D)-2.
E)-1.

Question 30

Chemical reactions that occur in the human body are catalyzed by special protein molecules called

A)electrolytes.
B)enzymes.
C)metabolites.
D)steroids.
E)buffers.

Question 31

Hydrolysis is an example of which type of reaction?

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

Question 32

The term that applies to all of the decomposition reactions that occur in metabolism is

A)anabolism.
B)dehydration synthesis.
C)catabolism.
D)ionization.
E)homeostasis.

Question 33

The addition of energy to start a reaction is called the energy of

A)endergonic control.
B)activation.
C)exergonic control.
D)release.
E)equilibrium.

Question 34

Ions with a positive charge are called

A)anions.
B)bases.
C)metabolites.
D)cations.
E)acids.

Question 35

Choose the most accurate definition of chemical reaction.

A)It is a process in which bonds between atoms are formed or broken.
B)It is the energy of motion.
C)It is an increase in random molecular motion.
D)It is movement or a change in the physical structure of matter.
E)It is the capacity to perform work.

Question 36

The symbol ⇌, used in visual chemical reactions, means that

A)the chemical reaction can go in either direction.
B)the concentration of the end products is the same as that of the reactants.
C)the substrates can become reactants and vice versa.
D)there is more end product than reactant.
E)input of energy is required.

Question 37

If two pairs of electrons are shared between two atoms, what type of bond occurs?

A)single covalent bond
B)double covalent bond
C)triple covalent bond
D)polar covalent bond
E)hydrogen bond

Question 38

In a molecule of hydrogen, a pair of electrons is shared equally. Such a bond is called a(n)

A)ionic bond.
B)polar covalent bond.
C)nonpolar covalent bond.
D)oxygen covalent bond.
E)hydrogen bond.

Question 39

Which of these is a molecule but is not considered to be a compound?

A)H₂O
B)CO₂
C)C₆H₁₂O₆
D)H₂
E)CO

Question 40

In an endergonic reaction,

A)large molecules are broken down into smaller ones.
B)small molecules are assembled into larger ones.
C)molecules are rearranged to form new molecules.
D)molecules move from reactants to products and back.
E)energy is consumed during the reaction.

Question 41

________ are compounds that maintain the pH of solutions within given limits.

A)Enzymes
B)Electrolytes
C)Metabolites
D)Isotopes
E)Buffers

Question 42

What is the primary composition of organic compounds?

A)carbon and oxygen atoms
B)oxygen and hydrogen atoms
C)oxygen and nitrogen atoms
D)carbon and hydrogen atoms
E)nitrogen and carbon atoms

Question 43

If a substance resists changes in pH, either by removing or replacing hydrogen ions, it is called

A)neutral.
B)acidic.
C)alkaline.
D)a buffer.
E)a salt.

Question 44

Which of the following substances would be nearest the pH of human blood?

A)milk, pH ≈6.5
B)pure water, pH ≈7
C)tomato juice, pH ≈4
D)wine, pH ≈3
E)stomach secretions, pH ≈1

Question 45

Which of the following constitutes most of the total body weight in humans?

A)water
B)acids
C)bases
D)salts
E)organic molecules

Question 46

Carbon dioxide is produced as a result of

A)metabolic activity.
B)carbon monoxide instability.
C)oxygen synthesis during aerobic respiration.
D)the breakdown of water into oxygen.
E)glucose synthesis.

Question 47

During ionization, water molecules disrupt the ionic bonds of a solute, resulting in a mixture of ions that can conduct an electrical current in solution. These ions are called

A)cations.
B)anions.
C)isotopes.
D)electrolytes.
E)reactants.

Question 48

A buffer

A)removes or replaces hydrogen ions in a solution.
B)is a compound with an extra electron in its outer shell.
C)has an unstable nucleus, making it highly reactive.
D)donates hydrogen ions to a solution.
E)consists of long carbon-carbon chains.

Question 49

The most acidic solution would have a pH of

A)0.
B)7.
C)14.
D)4.
E)10.

Question 50

Why is it important to precisely regulate the pH of blood or other body fluids?

A)Blood functions as an excellent solvent.
B)Blood and other body fluids have a very high heat capacity.
C)Dehydration synthesis of large molecules occurs.
D)Hydrogen ions are extremely reactive.
E)Some organic molecules have polar covalent bonds.

Question 51

A solution containing more hydrogen ions than hydroxide ions is

A)acidic.
B)basic.
C)neutral.
D)alkaline.
E)organic.

Question 52

Which is the mechanism of enzyme functioning?

A)Enzymes raise the activation energy of a reaction.
B)Enzymes remove hydrogen ions.
C)Enzymes lower the activation energy of a reaction.
D)Enzymes replace hydrogen ions.
E)Enzymes promote complementary base-pairing.

Question 53

The best definition of organic material is anything that contains

A)carbon and oxygen covalently bonded.
B)carbon, oxygen, and hydrogen covalently bonded.
C)carbon and hydrogen covalently bonded.
D)hydrogen covalently bonded.
E)carbon, nitrogen, and hydrogen covalently bonded.

Question 54

Which of the following pairs of elements can be classified as inorganic only?

A)sodium and hydrogen
B)carbon and oxygen
C)calcium and carbon
D)hydrogen and carbon
E)sodium and calcium

Question 55

Water is an excellent solvent because

A)it dissolves all solutes.
B)water molecules covalently bond with atoms in other molecules.
C)it has a high heat capacity.
D)it makes up a major part of every cell.
E)water molecules are polar.

Question 56

Which of the following are defined as soluble inorganic compounds whose ions will conduct an electric current in solutions?

A)catalysts
B)electrolytes
C)strong acids
D)buffers
E)steroid hormones

Question 57

Which of the following is an organic compound?

A)CO₂
B)CH₄
C)H₂O
D)CCl₄
E)HCl

Question 58

A mixture of water and a salt would result in breaking down the salt into a mixture of cations and anions. This process is called

A)dehydration synthesis.
B)dissociation.
C)hydrolysis.
D)condensation reaction.
E)equilibrium.

Question 59

Which of the following is inorganic?

A)fatty acid
B)protein
C)DNA
D)sodium
E)glycogen

Question 60

Which of the following is an example of a strong base?

A)NaCl
B)NaOH
C)HCl
D)KF
E)H₂O

Question 61

The most important metabolic fuel molecule in the body is

A)sucrose.
B)starch.
C)protein.
D)vitamin B₁₂.
E)glucose.

Question 62

Which of the following is an example of a disaccharide?

A)starch
B)glycogen
C)sucrose
D)cellulose
E)fructose

Question 63

Figure 2-2 A Molecule
Use Figure 2-2 to answer the following question:
A class of lipids used as chemical messengers, to signal cells to undergo changes, is called

A)polysaccharides.
B)phospholipids.
C)triglycerides.
D)steroids.
E)monoglycerides.

Question 64

Figure 2-3 A Structure
Use Figure 2-3 to answer the following question:
Substrate molecules bind to enzymes at the

A)allosteric sites.
B)modification sites.
C)reaction sites.
D)active sites.
E)ionic sites.

Question 65

Figure 2-3 A Structure
Use Figure 2-3 to answer the following question:
Each amino acid forms bonds by connecting its carboxyl group to the next amino acid's

A)central carbon atom.
B)amino group.
C)carboxyl group.
D)hydroxyl group.
E)hydroxide group.

Question 66

Figure 2-1 A Chemical Reaction
Use Figure 2-1 to answer the following question:
Determine which reaction is shown in the figure and specify its mechanism of action.

A)The addition of a water molecule breaks down a complex molecule.
B)The removal of a water molecule breaks down a complex molecule.
C)Ionic bonds are broken apart as individual ions interact with the positive or negative ends of polar water molecules.
D)The removal of a water molecule facilitates the union of two molecules.
E)The addition of a water molecule facilitates the union of two molecules.

Question 67

Figure 2-3 A Structure
Use Figure 2-3 to answer the following question:
Proteins are composed of units called

A)amino acids.
B)simple sugars.
C)fatty acids.
D)adenosines.
E)nucleotides.

Question 68

Figure 2-2 A Molecule
Use Figure 2-2 to answer the following question:
The group of organic compounds containing mostly carbon and hydrogen with small amounts of oxygen is defined as a

A)carbohydrate.
B)lipid.
C)protein.
D)nucleic acid.
E)fatty acid.

Question 69

Figure 2-2 A Molecule
Use Figure 2-2 to answer the following question:
A fatty acid that contains only single covalent bonds in its carbon chain is said to be

A)saturated.
B)polyunsaturated.
C)monounsaturated.
D)hydrogenated.
E)carboxylated.

Question 70

Figure 2-2 A Molecule
Use Figure 2-2 to answer the following question:
The molecule shown in the figure is considered to be the most important metabolic "fuel" in the body. Choose the best category of molecules to which it belongs.

A)steroid
B)saturated fatty acid
C)monoglyceride
D)cholesterol
E)monosaccharide

Question 71

Figure 2-3 A Structure
Use Figure 2-3 to answer the following question:
Some proteins, like hemoglobin or antibody molecules, require multiple polypeptide chains to come together to act as a single protein. If the association among the different polypeptide chains is blocked, the ________ structure of the protein is destroyed.

A)primary
B)secondary
C)tertiary
D)quaternary
E)binary

Question 72

Figure 2-2 A Molecule
Use Figure 2-2 to answer the following question:
Lipids are used for which of the following?

A)to form essential structural components of cells
B)to provide roughly 10 times as much energy as carbohydrates
C)to help reduce body temperature
D)to help protect the skeleton
E)to carry genetic information

Question 73

Functionally, carbohydrates are most important as

A)storage of glucose molecules.
B)a part of nucleic acid structure.
C)sources of energy.
D)receptors of the cell surface.
E)insulation under the skin.

Question 74

Figure 2-3 A Structure
Use Figure 2-3 to answer the following question:
Indicate the primary function(s)of the structure shown in the figure.

A)structural component of cell membranes
B)storage of glucose molecules
C)energy source
D)structural component of cell membranes, hormones, and digestive secretions in bile
E)energy source, energy storage, and insulation

Question 75

Amino acids contain a central carbon atom adjacent to a(n)________ group and a(n)________ group.

A)carboxyl; phosphate
B)nitrogenous; carboxyl
C)nitrogenous; amino
D)amino; carboxyl
E)amino; phosphate

Question 76

Figure 2-3 A Structure
Use Figure 2-3 to answer the following question:
You are working with a particular protein in your research lab to determine how its properties affect the function of the protein. To determine what consequences there might be on protein function, you decide to change just one amino acid of the entire length of the protein, which consists of a total of 100 amino acids. You have just directly changed the ________ structure of the protein.

A)primary
B)secondary
C)tertiary
D)quaternary
E)binary

Question 77

Figure 2-3 A Structure
Use Figure 2-3 to answer the following question:
Enzymes

A)are lipids.
B)function as biological catalysts.
C)raise the activation energy for a reaction.
D)are carbohydrates.
E)are derived from cholesterol.

Question 78

When placed in solution, an inorganic substance dissociates completely, forming hydrogen ions and anions. This substance would be a

A)strong base.
B)weak base.
C)strong acid.
D)weak acid.
E)salt.

Question 79

Which of the following can be denatured?

A)enzymes
B)ions
C)atoms
D)molecules
E)isotopes

Question 80

Which carbohydrate and example pair are not correctly matched?

A)glycogen - monosaccharide
B)glucose - monosaccharide
C)starch - polysaccharide
D)fructose - monosaccharide
E)sucrose - disaccharide