L9: Nucleic Acids

Question 1

How do nucleic acids relate to our unique hereditary information?

Answer 1

They store it in DNA and RNA

Question 2

Nucleic acids, such as DNA and RNA, are polymers of what?

Answer 2

Nucleotides

Question 3

What are the three building blocks of a nucleotide?

Answer 3

1. Sugar (ribose or 2-deoxyribose)
2. Nitrogenous base
3. Phosphate group(s)

Question 4

True or false: a nitrogenous base is a nucleobase

Answer 4

True

Question 5

What do you call a nucleobase + sugar?

Answer 5

Nucleoside

Question 6

What do you call a nucleoside + phosphate?

Answer 6

Nucleotide

Question 7

True or false: Nucleotides can be cyclic

Answer 7

True

Question 8

True or false: In a nucleoside, the sugar and nucleobase are joined by a phosphodiester bond

Answer 8

False. The nucleobase and sugar are linked by a b-N-glycosidic link

Question 9

What are the two classifications of nucleobases?

Answer 9

1. Pyrimidines

2. Purines

Question 10

What is the difference between a pyrimidine and a purine?

Answer 10

Pyrimidines consist of a pyrimidine ring. Purines consist of a pyrimidine ring fused to an imidazole ring.

Question 11

What are the three pyrimidine nucleobases?

Answer 11

1. Cytosine
2. Uracil
3. Thymine

Question 12

What are the two purine nucleobases?

Answer 12

1. Adenine

2. Guanine

Question 13

Fill in the gap:

ATP and GTP are examples of _____________ nucleotides

Answer 13

multiphosphorylated

Question 14

Cyclic adenosine monophosphate (ATP with one phosphate group) is produced by which enzyme?

Answer 14

Adenylate cyclase

Question 15

True or false:

cAMP is an important molecule in protein synthesis

Answer 15

False. It is an important cell-signalling molecule

Question 16

How does caffeine relate to cAMP?

Answer 16

Caffeine prevents the breakdown of cAMP, thus improving cell signalling

Question 17

True or false: GTP is similar to ATP

Answer 17

True. It is an important molecule in protein synthesis and cell signalling

Question 18

Fill in the gaps:

DNA’s sugar-phosphate backbone is made by linking a ______(1)______ group on one nucleotide to the _______(2)________ sugar on the next, using a _______(3)_______ bond.

Answer 18

(1) Phosphate
(2) 2-deoxy ribose
(3) Phosphodiester

Question 19

The nitrogenous bases are joined to the sugar-phosphate backbone by what bond?

Answer 19

beta-N-glycosidic link

Question 20

How many hydrogen bonds form between adenosine and thymine?

Answer 20

2

Question 21

How many hydrogen bonds form between guanine and cytosine?

Answer 21

3

Question 22

Which of the following methods is commonly used for forensic use?

A) ‘Fingerprint’ analysis
B) DNA sequencing
C) Somatic gene therapy
D) Genetic engineering

Answer 22

A) ‘Fingerprint’ analysis

Question 23

In genetic engineering, a human gene can be inserted into a bacterium to make it produce insulin, for example. Into which specific part of the bacterium is the gene inserted?

Answer 23

The plasmid

Question 24

What is the ‘central dogma’?

Answer 24

“Once (sequential) information has passed into protein it cannot get out again” (Crick, 1958)

Question 25

What type of bond joins an amino acid to tRNA?

Answer 25

Ester bond

Question 26

The 3’ end of tRNA always ends with which bases?

Answer 26

CCA