1) Use the following information to answer the next two questions.
Some Discoveries about DNA
A) DNA is made of deoxyribose sugar, phosphate, and four nucleotides (A, G, C, and T).
B) DNA was originally isolated from white blood cells.
C) X-ray diffraction of the DNA molecules shows that it is a helical structure.
D) Adenine pairs with thymine and guanine pairs with cytosine in any sample of DNA.
E) DNA, not proteins, carries genetic information.
Match the following scientists with their discoveries listed above.
Discovery: Answer Answer Answer Answer
Scientist: Franklin Chargaff Levene Hershey and Chase
2) Identify three discoveries listed above that were essential in determining the structure of the DNA molecule by Watson and Crick?
Record your answer in descending (highest to lowest) order.
Answer Answer Answer
3) What observation led Hershey and Chase to the conclusion that DNA, not the protein coat, carried the genetic information needed to make new virus or phage particles?
a. The cell membrane of the bacteria infected with a virus tagged with radioactive phosphorus exhibited radioactivity after it’s initial cell division.
b. Bacterial cells infected with viruses tagged with radioactive sulfur were radioactive, indicating viral protein entered the host cell.
c. The cell was vigorously shaken, causing the protein coats to detach from the cell membrane of the bacteria. The protein coats contain genetic information.
d. Bacterial cells infected with viruses tagged with radioactive phosphorus were radioactive, indicating viral DNA entered the host cell.
4) Match the following terms with their correct definition.
1) The structure of double-standed DNA
2) Hold the base pairs together and make up the rungs of the DNA double helix
3) One strand of nucleotides running in the opposite direction of the other strand
4) Consists of a phosphate, a sugar backbone, and a nitrogen base
5) A-T and C-G base pairs
6) Five-carbon sugar found in DNA
Answer Complementary base pairs
Answer Double helix
Answer Antiparallel
Answer Nucleotide
Answer Hydrogen bonds
Answer Deoxyribose sugar
5) Which of the following is NOT true of the structure of DNA?
a. It contains all of the genetic information for an individual.
b. The backbone is made up of alternating sugars and phosphates.
c. Nitrogenous bases A and C bond together, and bases T and G bond together.
d. The molecule has the shape of a coiled ladder.
6) Nucleic acids such as DNA are polymers of nucleotides. Each nucleotide consists of a five-carbon sugar bonded to a nitrogen base and a phosphate molecule. Each carbon on the sugar is numbered with primes according to chemical convention.
Which of the following correctly identifies the hydrogen bonds between nitrogenous bases in a double-stranded DNA molecule?
a. Number of Hydrogen Bonds Nitrogenous Bases
3 C and G
b. Number of Hydrogen Bonds Nitrogenous Bases
2 U and T
c. Number of Hydrogen Bonds Nitrogenous Bases
3 A and T
d. Number of Hydrogen Bonds Nitrogenous Bases
2 C and G
7) Use the following information to answer the next question.
A small segment of DNA has the following sequence:
A – A – T – C – T – C – G – T – A
The sequence of the complementary DNA strand is
a. T – T – A – G – A – G – C – A – T
b. G – G – C – T – C – T – A – C – G
c. A – A – T – C – T – C – G – T – A
d. C – C – G – A – G – A – T – G – C
8) The DNA molecule is replicating. Below are four DNA fragments.
DNA Fragments:
1) CGATCT
2) TCACGA
3) AGCTGC
4) GGCTAA
5) ATGCTG
6) GTACCA
Select the correct fragments from the above list that complement the DNA fragments below.
DNA Fragments: Answer Answer Answer Answer
Complementary DNA: AGTGCT CCGATT GCTAGA TACGAC
9) If the nitrogen-based molecules present in the DNA of an animal are found to be 13.2% adenine molecules, what percentage of guanine would be present in the animal’s DNA?
a. 13.2%
b. 26.4%
c. 73.6%
d. 36.8%
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