Deck 2: Chemical Composition of the Body and Its Relation to Physiology

Question 1

Compounds A, B, and C have molecular weights of 10, 50, and 100, respectively. If 5 grams of each compound were put into 1 liter of water, which compound will have the greatest molar concentration?

A) Compound A
B) Compound B
C) Compound C
D) All will have the same molar concentration.

Answer 1

A

Question 2

If a sports beverage advertises that it replaces the body's electrolytes, what does the drink contain?

A) sugars that were broken down for energy
B) ionic forms of mineral elements
C) lipids that form the membranes of cells
D) oxygen and gases used by metabolism
E) vitamins

Answer 2

B

Question 3

Which correctly describes the structure of an atom?

A) There are always the same number of protons and neutrons.
B) There are always the same number of protons and electrons.
C) There are always the same number of neutrons and electrons.
D) The number of protons, neutrons, and electrons is always the same
E) There are never the same number of neutrons and protons.

Answer 3

B

Question 4

Carbohydrates:

A) have carbon and oxygen atoms in equal proportions.
B) are the major organic molecules of the body by mass.
C) are nonpolar molecules.
D) are defined by the inclusion of nitrogen in their structure.
E) are composed of only carbon and hydrogen atoms.

Question 5

Which is true about the composition of organic molecules?

A) They always contain oxygen.
B) They always contain carbon.
C) They are always macromolecules.
D) They never contain hydrogen.
E) They never contain oxygen.

Question 6

Of these major ions found in the body, which one carries a negative charge?

A) Chloride
B) Sodium
C) Potassium
D) Hydrogen
E) Calcium

Question 7

What directly determines an atom's identity?

A) the number of electrons
B) the number of neutrons
C) the number of protons
D) the number of bonds it can form
E) the ratio of protons to electrons

Question 8

When magnesium loses electrons to become an ion, what does it become?

A) a covalent molecule
B) a cation
C) an anion
D) a new element
E) a free radical

Question 9

Carbon-12 and carbon-14 are isotopes. How are they different from each other?

A) different numbers of protons
B) different numbers of neutrons
C) different numbers of electrons
D) they can form different numbers of chemical bonds
E) different number of energy shells

Question 10

Ions are

A) electrically neutral.
B) electrically charged.
C) formed by the gain or loss of protons from the nucleus.
D) insoluble in water.
E) nonpolar atoms.

Question 11

Which is a covalent bond?

A) two atoms share inner-orbit electrons with each other
B) a bond between water molecules
C) a bond between two oppositely charged ions
D) a bond between two free radicals
E) two atoms share outer orbit electrons with each other

Question 12

Which best describes a hydrolysis reaction?

A) Molecules are broken down into smaller ones by breaking covalent bonds within water molecules and transferring hydrogen atoms and hydroxyl groups to the smaller ones.
B) Electrically charged molecules separate into ions when they dissolve in water, and then hydrogen ions and hydroxyl groups covalently attach themselves to the oppositely charged ions.
C) Large molecules are assembled from smaller ones by breaking water into hydrogen and hydroxyl ions.
D) Dissolving a large molecule in water reduces it to its individual atoms.
E) The breaking of hydrogen bonds between any two molecules.

Question 13

Which describes a characteristic of free radicals?

A) They rapidly oxidize other atoms by removing an electron.
B) They are inert molecules that don't interact readily with other molecules.
C) They contain two electrons in the outermost orbital.
D) They have extra neutrons in their nuclei.
E) They are found in high quantities in most sports drinks.

Question 14

Most of the body weight of an average young adult male is what substance?

A) Water
B) Protein
C) Minerals
D) Lipids
E) Carbohydrates

Question 15

Which chemical group does glucose best fit into?

A) monosaccharides
B) disaccharides
C) polysaccharides
D) glycoproteins
E) phospholipids

Question 16

Which of the following is not true of a polar chemical bond?

A) It is covalent.
B) It is ionized.
C) It has opposite electrical charge at each end.
D) It has no net electrical charge.

Question 17

Which is true about electrolytes?

A) They are neutral atoms.
B) They conduct electricity when dissolved in water.
C) They are found in pure water.
D) They have equal numbers of protons and electrons.
E) They are insoluble in water.

Question 18

Oil spilled into the ocean does not easily disperse, but rather clumps into an oil slick. Which of the following explains why this occurs?

A) Oil is composed mainly of hydrophilic molecules.
B) Oil is composed mainly of nonpolar molecules.
C) Oil has no hydrogen in its molecular structure, so it can't form hydrogen bonds with water.
D) Water is hydrophobic.
E) Electrons are shared unequally between carbon and hydrogen atoms.

Question 19

The pH of a solution

A) is a measure of the concentration of hydrogen atoms in the solution.
B) is a measure of the concentration of hydrogen ions bound to other molecules in the solution.
C) is a measure of the concentration of free hydrogen ions in the solution.
D) increases as the acidity of the solution increases.
E) increases as the free hydrogen ion concentration in the solution increases.

Question 20

Molecules that have properties of both polar and nonpolar molecules are called

A) hydrophobic.
B) hydrophilic.
C) amphipathic.
D) unipolar.
E) bipolar.

Question 21

Which is a correct description of nucleic acids?

A) They are polymers of subunits containing glucose an an amino acids.
B) They are polymers of subunits containing glucose, a phosphate group, and an amino acid.
C) They are polymers of subunits containing a phosphate group, a sugar, and a purine or pyrimidine base.
D) They are polymers of subunits containing a phosphate group, a sugar, and an amino acid.
E) They are long polymers of amino acids, folded into an alpha helix.

Question 22

Trace elements such as zinc and manganese are found in minute quantities in the body but do not serve any known function.

Question 23

The number of covalent bonds that can be formed by a given atom depends upon the number of electrons present in the outermost orbit.

Question 24

What best describes the main determinant of the secondary structure of a protein?

A) the sequence of the various amino acids that make up a polypeptide chain
B) the total number of amino acids that make up a polypeptide chain, and its overall resulting length
C) the total number of polypeptide chains that combine to determine the overall size of the protein
D) molecular interactions between widely separated regions of a polypeptide, such as disulfide bonds, that stabilize the folded conformation
E) molecular interactions along a polypeptide chain that fold various regions into alpha helices or beta sheets

Question 25

Eicosanoids are an important class of regulatory molecules; what chemical class do they belong to?

A) steroids
B) proteins
C) carbohydrates
D) fatty acids
E) amino acids

Question 26

Twelve grams of C contain the same number of atoms as one gram of H.

Question 27

The mass of an atom is the sum of its protons and electrons.

Question 28

Which of the following is NOT a type of molecular interaction that determines the tertiary structure of a protein?

A) covalent bonds between purines and pyrimidine bases
B) ionic bonds
C) Van der Waals forces
D) covalent bonds between two cysteine amino acids
E) hydrogen bonds

Question 29

Protons and neutrons have roughly the same mass.

Question 30

The four most common elements in the body are hydrogen, carbon, calcium, and oxygen.

Question 31

The atomic number of an element is given by the number of electrons in the atom.

Question 32

The atomic number of an element refers to the number of particles in its atomic nucleus.

Question 33

Which statement is FALSE with regard to proteins?

A) Their roles in the body include acting as enzymes, providing structural support, and signaling between cells.
B) They make up a greater percentage of body mass than carbohydrates do.
C) They are composed of nucleic acids.
D) They are macromolecules with subunits linked by polypeptide bonds.
E) They are polymers made up of amino acids.

Question 34

What are the two main atoms in lipids, and what type of bonds connect them?

A) carbon and oxygen, connected by covalent bonds.
B) carbon and hydrogen, connected by covalent bonds
C) carbon and hydrogen, connected by ionic bonds
D) carbon and hydrogen, connected by hydrogen bonds
E) oxygen and hydrogen, connected by hydrogen bonds

Question 35

Carbohydrates are stored in the liver and muscles in the form of

A) cellulose.
B) starch.
C) triacylglycerol.
D) glycogen.
E) protein.

Question 36

An atom is electrically neutral.

Question 37

An atomic nucleus is electrically neutral.

Question 38

Important mineral elements in the body include Na, Ca, and K.

Question 39

What is the term describing the covalent bond formed between two amino acids?

A) Glycosidic bond
B) Peptide bond
C) Phosphodiester bond
D) Ester bond
E) Hydrolytic bond

Question 40

Which best describes the main role of adenosine triphosphate (ATP)?

A) It is an amino acid that is part of polypeptide chains that serve structural functions within cells.
B) It is a nucleotide that makes up the backbone of DNA and RNA molecules, that harbor the genetic code.
C) It is a carbohydrate molecule that can be stored in large quantities in the liver to energize cellular processes.
D) It is a purine derivative created from the breakdown of fuel molecules, that transfers energy for cellular processes.
E) It is a waste product of aerobic metabolism that is excreted from the body by the kidneys.

Question 41

All of the physiologically important atoms of the body readily form ions.

Question 42

The molarity of a solution is a measure of the concentration of the solute.

Question 43

The shape of a molecule may change as atoms rotate about their covalent bonds.

Question 44

A solution with a pH of 8 is more acidic than one with a pH of 3.

Question 45

Sucrose is called "blood sugar" because it is the most abundant carbohydrate in the blood.

Question 46

Saturated fats contain carbon atoms linked by double bonds.

Question 47

Triacylglycerol is one subclass of lipid molecules.

Question 48

Nitrogen atoms can form a maximum of four covalent bonds with other atoms.

Question 49

Molecules with both polar and nonpolar regions are called ambidextrous.

Question 50

Organic chemistry is the study of oxygen-containing compounds.

Question 51

Cholesterol is a phospholipid.

Question 52

During hydrolysis, hydrogen ions and hydroxyl groups are formed.

Question 53

In general, polar molecules will dissolve in polar solvents, while nonpolar molecules cannot.

Question 54

In a molecule of water, an oxygen atom forms a double bond with each of two hydrogen atoms.

Question 55

NaCl is a molecule formed by the covalent bonding of a sodium atom to a chlorine atom.

Question 56

The carboxyl ion is an anion.

Question 57

All covalent bonds are polar.

Question 58

Solutes that do not dissolve in water are called hydrophilic.

Question 59

Water molecules can form covalent bonds with other water molecules.

Question 60

When multiple repeating simple sugar molecules combine to form a larger molecule, it is called a polysaccharide.

Question 61

A protein may consist of more than one polypeptide chain.

Question 62

The sequence of amino acids in a protein is known as the secondary structure.

Question 63

Glycoproteins are protein molecules with molecules of glycogen attached to the amino acid side chains.

Question 64

Substitution of one amino acid for a different one in a given protein always significantly alters the conformation of that protein.

Question 65

In DNA, thymine binds with adenine and cytosine binds with uracil.