Read each question carefully and then select the best answer.

1		The transforming agent was identified as DNA by
			A)	Griffith.
			B)	Avery.
			C)	Hershey and Chase.
			D)	Watson and Crick.
2		If Hershey and Chase had found S35 in progeny phages rather than P32, their experiment would have demonstrated that
			A)	proteins contain phosphorus.
			B)	DNA contains sulfur.
			C)	phage DNA enters the host cell.
			D)	phage protein enters the host cell.
3		If a DNA molecule contains 20% A, approximately what percentage of G is present?
			A)	20%
			B)	40%
			C)	30%
			D)	60%
4		Who was the first to discover than inborn errors of metabolism are due to enzymes?
			A)	Franklin
			B)	Watson and Crick
			C)	Griffith
			D)	Garrod
5		The first group of researchers to demonstrate that proteins are not the hereditary material were __________.
			A)	Watson and Crick
			B)	Garrod and Miescher
			C)	Franklin and Pauling
			D)	Hershey and Chase
6		Identification of DNA as a helical molecule was first done by _____ .
			A)	Watson and Crick
			B)	Chargaff
			C)	Franklin
			D)	Hershey and Chase
7		_____ was the first to identify the chemical differences between DNA and RNA.
			A)	Levene
			B)	Garrod
			C)	Franklin
			D)	Griffith
8		The process of transformation was first identified by _____.
			A)	Watson and Crick
			B)	Griffith
			C)	Avery
			D)	Hershey and Chase
9		Which group of researchers used radioactively labeled viruses to identify the genetic material?
			A)	Watson and Crick
			B)	Avery, MacLeod and McCarty
			C)	Franklin and Pauling
			D)	Hershey and Chase
10		Which strand below would make the sequence 5' AAACGCTT 3' a double stranded DNA molecule?
			A)	5' TTTGCGAA 3'
			B)	5' UUUGCGUU 3'
			C)	5' AAGCGUUU 3'
			D)	5' AAGCGTTT 3'
11		The current model of DNA structure was proposed by
			A)	Griffith.
			B)	Chargaff.
			C)	Avery.
			D)	Watson and Crick.
12		Energy is required to break the hydrogen bonds holding the bases together. Which pair will be the most difficult to separate?
			A)	A - T
			B)	C - G
			C)	A - C
			D)	G - T
13		If a nucleic acid is found to contain 20% A and 20% T, the molecule is probably
			A)	single-stranded DNA.
			B)	double-stranded DNA.
			C)	single-stranded RNA.
			D)	double-stranded RNA.
14		The two strands in a DNA molecule are
			A)	identical.
			B)	complementary.
			C)	antiparallel.
			D)	b and c
15		Which of the following is not a component of chromatin?
			A)	histone proteins
			B)	DNA polymerase
			C)	RNA
			D)	DNA binding proteins
16		______ are the building blocks of DNA
			A)	Histones
			B)	Proteins
			C)	Nucleotides
			D)	Phosphates
17		A______ is a DNA-protein complex.
			A)	histone
			B)	sugar-phosphate backbone
			C)	complementary base pair
			D)	nucleotide
18		Which of the following is found in a nucleotide?
			A)	five carbon sugar
			B)	nitrogenous base
			C)	phosphate group
			D)	All of the above.
19		DNA replication is________.
			A)	semiconservative
			B)	conservative
			C)	dispersive
			D)	semidispersive
20		In the Meselson and Stahl experiment, what percentage of the DNA is labeled with light nitrogen in the third generation?
			A)	25%
			B)	50%
			C)	75%
			D)	100%
21		Enzymes called ____ catalyze the formation of covalent bonds that hold together the sugar-phosphate backbone of the DNA molecule.
			A)	helicases
			B)	primases
			C)	RNA polymerases
			D)	ligases
22		Replication proceeds in a ____ to _____ direction.
			A)	3' to 3'
			B)	3' to 5'
			C)	5' to 3'
			D)	5' to 5'
23		Considering DNA replication along the 5' to 3' template strand, what event takes place first?
			A)	DNA polymerase begins adding RNA nucleotides
			B)	DNA polymerase begins adding DNA nucleotides
			C)	primase adds an RNA primer
			D)	primase removes the 5' phosphate
24		The enzyme primase is required for DNA replication because
			A)	primase breaks the hydrogen bonds holding the two strands together.
			B)	DNA polymerase cannot start a new chain.
			C)	the enzyme binds small pieces of DNA together.
			D)	the primase corrects any errors made by the DNA polymerase.
25		A scientist isolates a cell line characterized by unusual cell division. In these cells, only small fragments of DNA are found. A defective ____ enzyme may be responsible.
			A)	DNA polymerase
			B)	ligase
			C)	primase
			D)	exonuclease
26		If DNA polymerase could add bases in the 3' to 5' direction, there would be no need for
			A)	DNA ligase.
			B)	Okazaki fragments.
			C)	helicase.
			D)	PCR.