Quiz 1-3 Flashcards
The difference between a nucleotide and a nucleoside is the presence of which of the following?
a phosphate group
Which of the following is not true of nucleic acid and protein structure?
When several nucleic acids are joined together, a polypeptide is formed.
Which of the following describes a feature of amino acid structure?
The R groups of amino acids will vary in structure, size, electrical charge, and hydrophobicity.
Which of the following is true about the geometry of a chemical bond?
Single bonds permit free rotation around the bond resulting in more geometric possibilities.
Biological molecules with dipole moments:
are typically called polar molecules.
What kind of bond holds NaCl molecules together
ionic bond
Which of the following interactions is not considered to be a weak chemical bond?
covalent bonds
Hydrophobic interactions:
arise from the tendency of nonpolar molecules to exclude water in solution.
Which of the following atoms cannot participate in biological hydrogen bonds?
carbon
Which of the following molecules are biologically active?
L - amino acids
An acidic solution:
will have a H3O+ concentration higher than its OH- concentration.
What is the hydronium ion (H3O+) concentration in a solution at pH 5?
1 × 10^-5 M
The overall rate of a reaction is dependent on which of the following?
the rate of the slowest or rate-limiting step of the reaction
What was one of the keys that determined Mendel’s success in formulating his laws?
Mendel focused on individual traits of the plant rather than on the overall appearance.
The child of a mother with IAIA blood and father with IAIB blood will have:
50% chance of being IAIA.
Tetrads are:
composed of two pairs of sister chromatids.
The pair of sister-chromatids, formed by replication of a chromosome, are held together at a specific region of the chromosome called the:
centromere.
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:
telophase I
The wild-type allele of a gene is:
found at the greatest frequency in a population.
The requirements of a living system include:
raw materials and energy.
catalysis of reactions.
a selective barrier.
biological information
What observation by Thomas Hunt Morgan led to the understanding that genes were on chromosomes?
The inheritance of the white-eyed trait in fruit flies followed the same pattern of inheritance as that of the X chromosome.
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?
The F1 progeny were mostly the red-eyed males and white-eyed females expected.
Why is it likely that the first self-replicating molecule was very similar to a modern RNA?
because, unlike DNA, RNA is based on ribose and the extra -OH group provides structural flexibility to RNAs
The chromosomal abnormality Calvin Bridges observed as a characteristic of “primary exceptionals” is a result of:
nondisjunction
The RNA World hypothesis is directly supported by all the following except:
micelle to vesicle formation.
LUCA, the last universal common ancestor, is:
a cell from which all organisms descended.
Which of the following amino acids has an aromatic R group?
tyrosine
Which of the following amino acids is/are negatively charged at physiological pH?
aspartate and gluatamate
A Ramachandran plot shows the sterically limited rotational domains
of an R group with respect to the polypeptide backbone
A polypeptide has 115 amino acid residues. What is its predicted length if it is an α helix?
173 Å
Which of the following is not true of the α helix?
Amino acid R groups point toward the helical axis
An α helix is formed by hydrogen bonds between:
the carbonyl oxygen and the amide nitrogen of every fourth amino acid
A beta turn consists of ______________ amino acid(s).
4
Approximately one-third of a polypeptide chain consists of reverse turns because:
turns allow a polypeptide to assume a globular configuration
The supersecondary structure (motif) most likely to contain a heptad (or leucine) repeat would be:
a coiled-coil
Intrinsically unstructured proteins:
are capable of binding to several different sites on different partners
The molten globule model of protein folding suggests:
hydrophobic residues coalesce to form intermediate structures
Positive cooperativity would most likely be observed when a protein is:
comprised of subunits A and B, where ligand binding to A facilitates ligand binding to B