List four base triplets that are clearly responsible for punctuation (initiation,
termination).
A fundamental property of DNA’s nitrogenous bases that is necessary for the
double-stranded nature of its structure is ________.
Assume that a dihybrid F2 ratio, resulting from epistasis, was 15:1. If a double
heterozygote was crossed with the fully recessive type, what phenotypic ratio is
expected among the offspring?
List three organisms that provide examples of organelle heredity.
“Breaking the genetic code” has been referred to as one of the most significant scientific
achievements in modern times. Describe (in outline or brief statement form) the
procedures used to break the code.
Huntington disease is inherited in humans as an autosomal dominant gene. Affected
individuals show progressive brain deterioration from cell death in the cerebral cortex.
Onset of the disease usually occurs between ages 30 and 50. Give two possible reasons
for the observed variation in the age of onset of this disease.
What might be a reasonable function of restriction endonucleases in a bacterium,
distinct from their use by molecular biologists?
How would the use of a large series of monozygotic and dizygotic twins enhance
studies on the genetic basis of human behavior?
Give a brief definition of the term genetic equilibrium.
Present the general structural features of a plasmid and give an example.
Describe a convenient method for determining gene order from three-point cross
results.
Nutritional mutants in Neurospora can be “cured” by treating the medium with
substances in the defective metabolic pathway. What determines whether the mutant
strain (auxotroph) is “cured” by a particular substance?
What is the role of the F factor in bacterial recombination?
Molecular/structural orientations (gradients) in an egg are thought to play a significant
role in development. What is the origin of such gradients? What evidence indicates that
the maternal genotype is involved in providing such gradients?
Describe the maternal age effect associated with Down syndrome.
Given the accompanying diagram, assume that a G1 chromosome (left) underwent one
round of replication in 3H-thymidine and the metaphase chromosome (right) had both
chromatids labeled. Which of the following replicative models (conservative,
dispersive, semiconservative) could be eliminated by this observation?
Sidney Brenner argued that the code was nonoverlapping because he considered that
coding restrictions would occur if it were overlapping. A second major argument
against an overlapping code involved the effect of a single nucleotide change. In an
overlapping code, how many adjacent amino acids would be affected by a point
mutation? In a nonoverlapping code, how many amino acid(s) would be affected?