Question

Which of the following shows the correct sequence of events? (1point)
(A) Chargaff's base ratio analysis-> Miescher;s isolation of DNA -> Franklin's X-ray diffraction studies
(B) Griffith's Transformation experiment -> Chargaff's base ratio analysis -> Watson and Crick's model of DNA
(C) Franklin's X-ray diffraction studies -> Hershey-Chase experiment-> Avery's transformation experiment
(D) Miescher's isolation of DNA -> Franklin's X-ray diffraction studies -> Griffith's transformation experiment

What are the roles of covalent bonds and hydrogen bonds in the structure of DNA? short answ

Answer 1

1. The table in Figure 12-3 showes the results of measuring the percentages of the four bases in the DNA of several different organisms. Some of the values are missing from the table. Based on Chargaff's rule, the percentages of guanine bases in chicken DNA should be around _____.
(A) (0 pts) 28.8%
(B) (0 pts) 19.9%
(C) (1 pt) 21.5%
(D) (0 pts) 13.4%
2. Based on Chargaff's rule, the percentage of cytosine in the DNA of the bacterium S. lutea in figure 12-3 should be around _____.
(A) (0 pts) 26.6%
(B) (0 pts) 73.2%
(C) (1 pt) 36.6%
(D) (0 pts) 29.4%
3. What structural problem prevents adenine from pairing with guanine?
(A) (0 pts) The bases are both short
(B) (0 pts) They lack phosphate
(C) (0 pts) They lack the deoxyribose group
(D) (1 pt) The bases are both long
4. Rosalind Franklin contributed to the understanding of DNA by ____
(A) (1 pt) Producing images of DNA molecules using X-rays.
(B) (0 pts) Figuring out that DNA strands form a double helix.
(C) (0 pts) conducting experiments that showed which nucleotides are complementary.
(D) (0 pts) Finding that DNA was nucleic acid make up of a long chain of individual nucleotides.
5. What is true about the base pairs !-T and G-C?
(A) (1 pt) They occupy different widths, which allows the DA molecule to form a helix.
(B) (1 pt) They occupy the same width, which allows the helical radius to remain constant.
(C) (1 pt) They are always present in the same ratios across all species.
(D) (1 pt) They are stabilized by covalent bonds between the bases.
6. Which of the following discoveries provided a critical clue to Watson and Crick in solving the structure of DNA?
(A) (0 pts) the Hershy-Chase experiment
(B) (0 pts) Griffith's Transformation experiment
(C) (1 pt) Chargaff's base ratios
(D) (0 pts) Miescher's isolation of DNA
7. A DNA strand with the sequence A_T_T_G_C-T would be complementary to which of the following?
(A) (0 pts) T_A_T_G_G_A
(B) (1 pt) T-A-A-C-G-A
(C) (0 pts) C-A-A-T-A-G
(D) (0 pts) G-C-C-A-T-C
8. DNA from one species differs from the DNA of another species in its _____.
(A) (1 pt) Base ratios
(B) (0 pts) sugars
(C) (0 pts) Phosphate groups
(D) (0 pts) all of the above
9. which of the following shows the correct sequence of events?
(A) (0 pts) Chargaff's base ratio analysis-> Miescher;s isolation of DNA -> Franklin's X-ray diffraction studies
(B) (1 pt) Griffith's Transformation experiment -> Chargaff's base ratio analysis -> Watson and Crick's model of DNA
(C) (0 pts) Franklin's X-ray diffraction studies -> Hershey-Chase experiment-> Avery's transformation experiment
(D) (0 pts) Miescher's isolation of DNA -> Franklin's X-ray diffraction studies -> Griffith's transformation experiment