Choose the best answer

1			The flow of genetic material in microbial cells usually proceeds from
			A)	Proteins through RNA to DNA
			B)	RNA through DNA to proteins
			C)	DNA through RNA to proteins
2			A new copy of a DNA molecule is precisely synthesized during a process called
			A)	translation
			B)	transcription
			C)	replication
3			The final step in gene expression is protein synthesis, or
			A)	translation
			B)	transcription
			C)	replication
4			The chromosome of almost all bacteria is in the shape of
			A)	an open circle
			B)	a closed circle
			C)	a linear chromosome
5			The enzyme that catalyzes the synthesis of DNA is called
			A)	helicase
			B)	DNA gyrase
			C)	DNA polymerase
6			The actual process of protein synthesis takes place on ribosomes that serve as workbenches, with _____________ acting as the blueprint or template.
			A)	DNA
			B)	mRNA
			C)	tRNA
7			DNA polymerase catalyzes the synthesis of DNA in the
			A)	3' to 5' direction
			B)	5' to 3' direction
8			The bases of one strand of DNA match-up with the bases of the second strand according to base pairing rules, therefore, the two strands are said to be
			A)	oppositely charged
			B)	complementary
			C)	identical
9			Eucaryotes are able to replicate their chromosomes in a relatively short period of time because
			A)	each chromosome contains multiple replicons
			B)	the eucaryotic replicative machinery is 1000 times faster than the procaryotic replicative machinery
			C)	eucarotic DNA is always single stranded
10			The enzymes that unwind short stretches of DNA helix immediately ahead of a replication fork are
			A)	single-stranded binding proteins
			B)	topoisomerases
			C)	helicases
11			The enzyme that repairs nicked DNA by forming a phosphodiester bond between adjacent nucleotides is
			A)	DNA gyrase
			B)	helicase
			C)	DNA ligase
12			The approximate rate of DNA replications in procaryotes is
			A)	10 bases per second
			B)	1,000 bases per second
			C)	100,000 bases per second
13			Another name for the three stop codons which aid in termination of translation is
			A)	nonsense codons
			B)	missense codons
			C)	pause codons
14			The enzyme that catalyzes the synthesis of RNA from a DNA template is
			A)	DNA gyrase
			B)	DNA ligase
			C)	RNA polymerase
15			Another name for the RNA polymerase recognition/binding site upstream of a gene is the
			A)	promoter
			B)	terminator
			C)	facilitator
16			The ____________ is nontranslated sequence that is located between the transcription start site and the translation start site
			A)	reading frame
			B)	leader sequence
			C)	trailer sequence
17			The Shine-Dalgarno sequence is
			A)	a short sequence that acts as a ribosomal binding site
			B)	another name for a stop codon
			C)	the reading frame of a gene
18			Most procaryotic proteins begin with this modified amino acid
			A)	N-formylleucine
			B)	N-formylmethionine
			C)	N-formylserine
19			Mutations may be characterized by
			A)	changes in genotype
			B)	changes in phenotype
			C)	changes in either genotype or phenotype
20			Mutations that arise without exposure to external agents are called
			A)	induced mutations
			B)	analogous mutations
			C)	spontaneous mutations
21			A mutagen is
			A)	a chemical or physical agent that induces mutations
			B)	an enzyme that repairs mutations
			C)	a molecule which stabilizes DNA thus prevents mutations from occurring
22			A mutation that affects only a single nucleotide is called
			A)	a regional mutation
			B)	a site mutation
			C)	a point mutation
23			A nonsense mutation results in
			A)	an abnormal elongation of a polypeptide
			B)	a premature termination of the synthesis of a polypeptide
			C)	a large deletion within the reading frame of a gene
24			The process by which thymine dimers are directly repaired with the help of visible light is called
			A)	photosynthesis
			B)	excision repair
			C)	photoreactivation
25			DNA repair mechanisms are able to distinguish newly synthesized DNA strands from older strands because
			A)	new strands do not contain cytosine bases
			B)	old strands are methylated while new strands are not
			C)	new strands are methylated while old strands are not
26			The ability of the anticodon of tRNA to interact with multiple codons of mRNA is called
			A)	promiscuity
			B)	wobble
			C)	stagger