Lecture 16 & 17 Study Guide

Question 1

Recall the basic structure of the nucleotide.

Answer 1

• phosphate group
• pentose
• nitrogenous base

Question 2

To what number carbon is the phosphate group attached?

Answer 2

5’ C

Question 3

To what number carbon is the nitrogenous base attached?

Answer 3

1’ C

Question 4

List three important differences between DNA and RNA: structure, function, location.

Answer 4

DNA: deoxyribose, double stranded, has thymine; codes for replication and transcription of RNA; found in chromosomes
RNA: ribose, single stranded, has uracil; codes for protein synthesis, rough ER or throughout cytoplasm

Question 5

Many have suggested that Rosalind Franklin deserved part of the Nobel prize for the discovery of DNA. Discuss and explain why she is not part of the ‘winning’ team of researchers.

Answer 5

she was a woman, and she passed away before the Nobel prize was awarded to them

Question 6

How does Chargoff’s ratio explain the uniform diameter of DNA?

Answer 6

it explains that the % of adenine is approximately equal to the % of thymine and % of cytosine is approximately equal to the % of guanine; all together = 100%

Question 7

State the function of DNA replication.

Answer 7

to create identical chromatids for cell division

Question 8

Helicase

Answer 8

splits DNA strands

Question 9

Single-stranded binding protein

Answer 9

keeps strands from coming back together

Question 10

Topoisomerase

Answer 10

enzymes that participate in the overwinding or underwinding of DNA

Question 11

Primase

Answer 11

adds RNA

Question 12

DNA polymerase III

Answer 12

takes off RNA

Question 13

DNA polymerase I

Answer 13

replaces RNA with DNA

Question 14

DNA ligase

Answer 14

brings together leading and lagging strands

Question 15

Why does DNA replication require primase?

Answer 15

RNA came first