Quiz 1-3

Question 1

The difference between a nucleotide and a nucleoside is the presence of which of the following?

Answer 1

a phosphate group

Question 2

Which of the following is not true of nucleic acid and protein structure?

Answer 2

When several nucleic acids are joined together, a polypeptide is formed.

Question 3

Which of the following describes a feature of amino acid structure?

Answer 3

The R groups of amino acids will vary in structure, size, electrical charge, and hydrophobicity.

Question 4

Which of the following is true about the geometry of a chemical bond?

Answer 4

Single bonds permit free rotation around the bond resulting in more geometric possibilities.

Question 5

Biological molecules with dipole moments:

Answer 5

are typically called polar molecules.

Question 6

What kind of bond holds NaCl molecules together

Answer 6

ionic bond

Question 7

Which of the following interactions is not considered to be a weak chemical bond?

Answer 7

covalent bonds

Question 8

Hydrophobic interactions:

Answer 8

arise from the tendency of nonpolar molecules to exclude water in solution.

Question 9

Which of the following atoms cannot participate in biological hydrogen bonds?

Answer 9

carbon

Question 10

Which of the following molecules are biologically active?

Answer 10

L - amino acids

Question 11

An acidic solution:

Answer 11

will have a H3O+ concentration higher than its OH- concentration.

Question 12

What is the hydronium ion (H3O+) concentration in a solution at pH 5?

Answer 12

1 × 10^-5 M

Question 13

The overall rate of a reaction is dependent on which of the following?

Answer 13

the rate of the slowest or rate-limiting step of the reaction

Question 14

What was one of the keys that determined Mendel’s success in formulating his laws?

Answer 14

Mendel focused on individual traits of the plant rather than on the overall appearance.

Question 15

The child of a mother with IAIA blood and father with IAIB blood will have:

Answer 15

50% chance of being IAIA.

Question 16

Tetrads are:

Answer 16

composed of two pairs of sister chromatids.

Question 17

The pair of sister-chromatids, formed by replication of a chromosome, are held together at a specific region of the chromosome called the:

Answer 17

centromere.

Question 18

In meiosis, the complexity of DNA (amount of information encoded) per cell is essentially halved as compared to the original cell. This reduction in information occurs immediately after:

Answer 18

telophase I

Question 19

The wild-type allele of a gene is:

Answer 19

found at the greatest frequency in a population.

Question 20

The requirements of a living system include:

Answer 20

raw materials and energy.
catalysis of reactions.
a selective barrier.
biological information

Question 21

What observation by Thomas Hunt Morgan led to the understanding that genes were on chromosomes?

Answer 21

The inheritance of the white-eyed trait in fruit flies followed the same pattern of inheritance as that of the X chromosome.

Question 22

Calvin Bridges, an associate of Thomas Hunt Morgan’s, found further evidence that genes were located on chromosomes. Which of the following is not a component of his study?

Answer 22

The F1 progeny were mostly the red-eyed males and white-eyed females expected.

Question 23

Why is it likely that the first self-replicating molecule was very similar to a modern RNA?

Answer 23

because, unlike DNA, RNA is based on ribose and the extra -OH group provides structural flexibility to RNAs

Question 24

The chromosomal abnormality Calvin Bridges observed as a characteristic of “primary exceptionals” is a result of:

Answer 24

nondisjunction

Question 25

The RNA World hypothesis is directly supported by all the following except:

Answer 25

micelle to vesicle formation.

Question 26

LUCA, the last universal common ancestor, is:

Answer 26

a cell from which all organisms descended.

Question 27

Which of the following amino acids has an aromatic R group?

Answer 27

tyrosine

Question 28

Which of the following amino acids is/are negatively charged at physiological pH?

Answer 28

aspartate and gluatamate

Question 29

A Ramachandran plot shows the sterically limited rotational domains

Answer 29

of an R group with respect to the polypeptide backbone

Question 30

A polypeptide has 115 amino acid residues. What is its predicted length if it is an α helix?

Answer 30

173 Å

Question 31

Which of the following is not true of the α helix?

Answer 31

Amino acid R groups point toward the helical axis

Question 32

An α helix is formed by hydrogen bonds between:

Answer 32

the carbonyl oxygen and the amide nitrogen of every fourth amino acid

Question 33

A beta turn consists of ______________ amino acid(s).

Answer 33

4

Question 34

Approximately one-third of a polypeptide chain consists of reverse turns because:

Answer 34

turns allow a polypeptide to assume a globular configuration

Question 35

The supersecondary structure (motif) most likely to contain a heptad (or leucine) repeat would be:

Answer 35

a coiled-coil

Question 36

Intrinsically unstructured proteins:

Answer 36

are capable of binding to several different sites on different partners

Question 37

The molten globule model of protein folding suggests:

Answer 37

hydrophobic residues coalesce to form intermediate structures

Question 38

Positive cooperativity would most likely be observed when a protein is:

Answer 38

comprised of subunits A and B, where ligand binding to A facilitates ligand binding to B