Question

biology exam 5

1. the dna double helix model used today is the product of research done by scientists...

a. hershey and chase
b. watson and crick
c. pauling and franklin
d. chargaff and griffith

1. which scientist discovered that dna was the transforming principle in heredity?

a. martha chase
b. oswald avery
c. frederick griffith
d. alfred hershey

1. how did hershey and chases use of radiolabeled bacteriophages to study the genetic material validate averys research?

a. it demonstrated conclusively that the genetic material is not protein.
b. it showed that bacteriophages are not digested by bacterial enzymes.
c. it proved that bacteria will take up phosphorus, but not sulfur.
d. it confirmed that bacteriophages cannot inject radiolabeled dna.
b.h.5: modern genetics

1. what is the full name of dna?

a. ribonucleic acid
b. deoxynucleic acid
c. deoxyribonucleic acid
d. ribodeoxynucleic acid

1. what are genes and where are they located?

a. sequences of rna located on specific sites of ribosomes in the cytoplasm.
b. sequences of dna located on specific sites of chromosomes in the nucleus.
c. sequences of rna located on specific sites of chromosomes in the nucleus.
d. sequences of dna located on specific sites of mitochondria in the cytoplasm.

1. which statement is true of the chromosome shown below?

a. its telomeres have been shortened due to repeated cell division.
b. its left and right halves carry identical genetic information.
c. its sister chromatids have spindle fibers attached.
d. its centromere has been lost during the copying of dna.

Explanation:

1. Watson and Crick are famous for proposing the DNA double - helix model.
2. Oswald Avery's experiments showed that DNA was the transforming principle in heredity.
3. Hershey and Chase's experiment used radiolabeled bacteriophages. Proteins contain sulfur (\(S\)) and DNA contains phosphorus (\(P\)). Bacteria took up phosphorus - labeled DNA (from bacteriophages), but not sulfur - labeled protein, demonstrating that genetic material is not protein.
4. The full name of DNA is Deoxyribonucleic Acid.
5. Genes are sequences of DNA located on specific sites of chromosomes in the nucleus.
6. In a chromosome (before separation of sister chromatids), the left and right halves (sister chromatids) carry identical genetic information.

Answer:

1. b. Watson and Crick
2. b. Oswald Avery
3. a. It demonstrated conclusively that the genetic material is not protein.
4. c. Deoxyribonucleic Acid
5. b. Sequences of DNA located on specific sites of chromosomes in the nucleus.
6. b. Its left and right halves carry identical genetic information.