Human Physiology Chapter 2 Part 2

D

A component of an important buffer in the human body is A) NaCl. B) H+. C) HCl. D) HCO3-. E) H2

d

A nucleotide consists of a A) five-carbon sugar and phosphate group. B) five-carbon sugar and a nitrogenous base. C) phosphate group and a nitrogenous base. D) five-carbon sugar, a nitrogenous base, and a phosphate group. E) five-carbon sugar and an amino acid.

e

According to the rules of complementary base pairing, a nucleotide containing the base cytosine would only pair with a nucleotide containing the base A) thymine. B) adenine. C) uracil. D) cytosine. E) guanine.

C

An ion has gained or lost A) a proton(s). B) a neutron(s). C) an electron(s). D) a carbon atom(s). E) a double bond.

D

Cholesterol is a A) precursor to steroid hormones. B) structural component of cell membranes. C) dangerous fat that is absent from a healthy body. D) precursor to steroid hormones and a structural component of cell membranes. E) precursor to steroid hormones, a structural component of cell membranes, and a dangerous fat that is absent from a healthy body.

d

Each amino acid differs from others in the A) number of central carbon atoms. B) size of the amino group. C) number of carboxyl groups. D) chemical structure of the R group. E) number of peptide bonds in the molecule.

B

Which of the following substances is most alkaline? A) lemon juice, pH = 2 B) urine, pH = 6 C) tomato juice, pH = 4 D) white wine, pH = 3 E) stomach secretions, pH = 1

B

If a substance has a pH that is less than 7, it is considered A) neutral. B) acidic. C) alkaline. D) a buffer. E) a salt.

b

In regard to lipids, the term unsaturated refers to A) the lack of double bonds between adjacent carbon atoms in a fatty acid. B) the presence of double bonds between adjacent carbon atoms in a fatty acid. C) the ring structure of steroids. D) glycerol, which acts as an anchor for joined fatty acids. E) fats, such as butter and lard, which come from animal sources.

d

Interactions between different globular or fibrous polypeptide chains result in which type of structure? A) primary B) secondary C) tertiary D) quaternary E) pentagonal

B

Isotopes of the same element differ by having different numbers of A) protons. B) neutrons. C) electrons. D) carbon atoms. E) double bonds.

e

Nucleic acids are polymers of units called A) amino acids. B) fatty acids. C) bases. D) ribose. E) nucleotides.

A

Polymers are a typical formation of ________ molecules. A) organic B) inorganic C) either organic or inorganic

C

Protein specificity is the A) activation of a specific protein that is needed to perform a particular function. B) degree to which a protein is attracted to a ligand. C) ability of a protein to bind a certain ligand or a group of related ligands. D) degree to which a protein-ligand complex initiates a response. E) degree to which a protein is attracted to a ligand and the ability of a protein to bind a certain ligand or a group of related ligands.

b

The alpha-helix and pleated sheet are examples of the ________ structure of a protein. A) primary B) secondary C) tertiary D) quaternary E) pentanary

d

The concentration of a solution expresses the amount of A) solvent per volume of solute. B) solute per volume of solvent. C) solvent per volume of solution. D) solute per volume of solution. E) None of the answers are correct.

A

The identity of an element can be determined by the number of A) protons. B) neutrons. C) electrons. D) carbon atoms. E) double bonds.

d

The most important energy-transferring compound in cells is a nucleotide known as A) glucose. B) fructose. C) protein. D) adenosine triphosphate. E) deoxyribonucleic acid.

D

Which bases below are purines? adenine cytosine guanine thymine uracil A) 1 and 2 B) 2 and 3 C) 1, 3, and 5 D) 1 and 3 E) 2, 4, and 5

B

Which of the following is a common feature of soluble proteins? A) structural support B) noncovalent interaction C) receptor binding D) chemical modulation E) All of the answers are correct.