Discovery of DNA

Which of the following best describes why Rosalind Franklin was not part of the 'winning' team of researchers for the Nobel Prize in the discovery of DNA?

• Her work was not directly related to the discovery of the DNA structure.

• She passed away before the Nobel Prize was awarded.

• Her contributions were not recognized by the Nobel Committee at the time.

• She declined participation in the Nobel Prize nomination.

Watson and Crick are credited with discovering the structure of DNA. The most important result of their discovery was:

• Identification of the double helix model

• Understanding the chemical composition of DNA

• Providing a mechanism for the replication of DNA

• Discovering the function of RNA in protein synthesis

Which of the following best summarizes Chargaff's results and their explanation in terms of the structure of DNA?

• Chargaff's rules indicate that DNA from any cell of all organisms should have a 1:1 ratio (base Pair Rule) of pyrimidine and purine bases and, more specifically, that the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine.

• Chargaff discovered that DNA molecules are double-stranded helices.

• Chargaff's results were inconclusive regarding the structure of DNA.

• Chargaff found that RNA sequences are more variable than DNA.

How does Chargaff's ratio explain the uniform diameter of DNA?

• By ensuring an equal proportion of A to T and G to C, maintaining structural consistency

• Through the replication process of DNA

• By influencing the helical twist of DNA

• None of the above

An analogy to the directionality of a single DNA sequence can be found in these two sentences. "The sun was hot but the old man did not get his hat" and "Tah sith teg ton did nam dlo eht tub toh saw nus ehs". Why is the message the same even though the second sentence appears to be nonsense? Second sentence reads correctly in 5' to 3' direction.

• Because the second sentence is the reverse of the first, mimicking the anti-parallel structure of DNA strands.

• Due to a typographical error in the second sentence.

• The second sentence is in a different language.

• It's a coded message unrelated to DNA.

Look at the following sequences of DNA found in a segment of a double helix. Comparing the strands of DNA written in the correct direction, we observe that the two sides of the DNA molecule have completely different sequences, EVEN THOUGH they have complementary pairing! If one strand of a DNA double helix has the sequence 5'-TTC CGG ATA-3', which of the following is the correct complement strand?

• The complement strand is 5'-TTC CGG ATA-3'

• The complement strand is 3'-AAG GCC TAT-5'

• The complement strand is 3'-TAT CCG GAA-5'

• The complement strand is 3'-ATC CGG AAT-5'

• The complement strand is 3'-TTC CGG ATA-5'

Circle the identical strands of DNA.

Tags

NGSS.HS-LS1-1

Which test tube shows only N15 DNA?

• A

• B

• C

• D

• E

Which test tube shows only N15 and N14 DNA?

• A

• B

• C

• D

• E

Which test tube shows the hybrid DNA and N14 DNA?

• A

• B

• C

• D

• E