Question

Please answer #1-4 & clearly explain your reasoning and indicate which # you are answering. Thank you so much!

(Q1-4) The following compounds are usually found as a structural component of DNA and RNA.

a. ribose          b. deoxyribose            c. phosphate    d. guanine       e. cytosine

f. uracil            g. phosphodiester

1. A nucleotide is made of _________.

A.        a+b+c

B.        b+c+d

C.        c+d+e

D.        e+f+g

E.         none of the above

2. A nucleoside is made of _________.

A.        b+c

B.        b+d

C.        c+d

D.        b+g

E.         a+g

3. Which one(s) are found only in RNA?

A.        a and c

B.        a and d

C.        a and e

D.        a and f

E.         a and g          

4. Which experiment used isotopes to demonstrate DNA as a genetic material?

A. Fredrick Griffith's experiments

B. Oswald Avery's experiments

C. Hershey and Chase's experiments

D. all of the above

E. None of the above

Answer 1

1. The answer is option - B - b+c+d

A nucleotide is made of base + phosphate + sugar. Hence in this question, base = guanine (d), sugar = deoxyribose ( b) , phosphate (c).

2. The answer is option - B

Guanine + deoxyribose as nucleoside = base + sugar

3. The option is D - a and f

Ribose and uracil are the exclusive components of RNA which are not found in DNA or in any other macromolecule.

4. The option is C - Hershey and Chae experiments

Hershey and Chase had done experiment to confirm DNA as a genetic material and not protein by radioactively labelled phosphates and sulphates. Since proteins contain sulphate and not phosphate, they used radioactive labelled sulphates for protein experiments and as DNA consists of phosphate, they used radioactively labelled phosphate.

Answer 2

1) B - b+c+d nucleotide is made of ribose/deoxyribose, sugar and phosphate

2) B - b+d nucleoside is made of ribose/deoxyribose and sugar

3) D - a and f RNA contains ribose, adenine, Guanine, Cytosine and Uracil

4) C - Hershey and Chase's experiments