Chapter 1

Question 1

What did Johann Miescher publish a paper on in 1871?

Answer 1

Nuclein, the viscous substance extracted from cell nuclei, they had no idea the importance of what they extracted at the time.

Question 2

What is a nucleotide?

Answer 2

A unit of nucleic acid comprised of a phosphorylated ribose sugar and a nitrogen base

Question 3

What is a nucleoside?

Answer 3

unit of nucleic acid comprised of a ribose sugar and nitrogen base

Question 4

What are the four nitrogen bases that make up DNA?

Answer 4

adenine, guanine, thymine, and cytosine

Question 5

What is the bond that forms polymers of nucleotides in DNA?

Answer 5

phosphodiester bonds

Question 6

How are nucleotides converted to nucleosides?

Answer 6

Hydrolysis

Question 7

How do the nitrogen base components of DNA stay together in double stranded DNA?

Answer 7

Hydrogen bonds

Question 8

How many hydrogen bonds does guanine form with cytosine?

Answer 8

3

Question 9

How many hydrogen bonds does adenine form with thymine?

Answer 9

2

Question 10

What are pyrimidines?

Answer 10

Nitrogen bases with a single ring structure - thymine and cytosine

Question 11

What are purines?

Answer 11

Nitrogen bases with a double ring structure- adenine and guanine

Question 12

What is a gene?

Answer 12

An ordered sequence of nucleotides on a chromosome that encodes a specific functional product

Question 13

What way is DNA oriented?

Answer 13

5’ to 3’

Question 14

How do nucleic acid chains grow?

Answer 14

attaching a 5’ phosphate group of an incoming nucleotide to the 3’ hydroxyl group of the last nucleotide on the chain

Question 15

How are the two strands of connected DNA orientated?

Answer 15

Antiparallel, one is 5’ to 3’ while the other is 3’ to 5’

Question 16

What is the open reading frame in DNA?

Answer 16

region of DNA comprised of codons coding for an amino acid sequence

Question 17

What is the promoter region?

Answer 17

DNA sequences that bind RNA polymerase and associated factors

Question 18

What is a regulatory sequence?

Answer 18

part of a gene sequence that binds factors controlling expression of a gene

Question 19

What is a structural sequence?

Answer 19

part of a gene sequence that codes for amino acids

Question 20

In what direction does DNA polymerase read the DNA template?

Answer 20

3’ to 5’

Question 21

What type of DNA replication is used in humans?

Answer 21

semi-conservative replication, each DNA double helix consists of a parent strand and a newly synthesized strand in the other directiob

Question 22

What three codons are stop codons?

Answer 22

UAA, UAG, UGA

Question 23

What are the 4 types of mutations?

Answer 23

Missense, silent, frameshift, and nonsense

Question 24

What does the phosphodiester backbone of DNA cause?

Answer 24

polarity

Question 25

What are the 6 steps of DNA replication?

Answer 25

1. Enzymes (helicase) unwind the parentla double helix.
2. Proteins stabilize the unwound parental DNA
3. The leading strand is synthesized continuously in the 5’ to 3’ direction by DNA polymerase.
4. The lagging strand is synthesized discontinuously (okazaki fragments) RNA polymerase synthesizes a short RNA primer, which is then extended by DNA polymerase.
5. DNA polymerase digests RNA primer and replaces it with DNA
6. DNA ligase joins the discontinuous fragments of the strand