DNA Structure Quiz
1. In the classic experiment by Griffith, evidence of the action of a hereditary biomolecule was identified by:
TRANSFORMATION (PHENOTYPIC CHANGE) OF THE “R STRAIN” BY “S STRAIN” BIOMOLECULES
2. Several early experiments aimed at identifying the genetic material of cells relied on "genetic transformation" assays (see Q1 and Griffiths Figure 7-2). In one experiment, carried out by Avery and colleagues, the scientists HYPOTHESIZED that the hereditary material was protein. To test this idea they treated extracts of virulent heat-killed bacterial cells with proteases (enzymes that destroy proteins) and then mixed these extracts with living bacteria that were not virulent. They then assayed the living cells for their ability to kill mice. Imagine for a moment that their hypothesis was correct, and protein was the genetic material. What result would you PREDICT they would have observed?
BACTERIA MIXED WITH THE PROTEASE-TREATED CELL EXTRACTS DID NOT BECOME VIRULENT, AND DID NOT KILL THE MICE
3. Nucleotides in DNA are connected to one another in the polynucleotide chain by __ bonds between ___
COVALENT; A SUGAR AND A PHOSPHATE GROUP
4. Why is DNA with a higher G + C content more stable at high temperatures than DNA with a high A + T content?
G AND C PAIRS FORM THREE HYDROGEN BONDS, WHEREAS A AND T PAIRS FORM JUST TWO HYDROGEN BONDS
5. Which of the diagrams above best illustrates the relative orientation of two DNA strands in a double helix?
6. What term best describes the orientation of the DNA strands in your answer to Question 5?
7. Which is the sequence of the complementary strand of RNA made from this template sequence? 5’-AGC TTC GCT GAA GCT CGG-3’
3’-UCG AAG CGA CUU CGA GCC-5’
8. Which of the following statements about folded RNA molecules is true?
WIDELY SEPARATED PARTS OF THE MOLECULE CAN BE BROUGHT TOGETHER
9. DNA denaturation, also called DNA melting:
IS THE PROCESS BY WHICH DOUBLE-STRANDED DNA MOLECULE UNWINDS AND SEPARATES INTO SINGLE-STRANDED STRANDS, INVOLVES THE DISRUPTION OF H-BONDS BETWEEN COMPLEMENTARY BASE PAIRS, CAN BE INDUCED BY HEATING THE DNA SAMPLE TO HIGH TEMPERATURES