Second Half F24: Lecture Slides 74 - 89

Question 1

What is RNA?

Answer 1

Ribonucleic Acid

Question 2

What is DNA?

Answer 2

Deoxyribonucleic Acid

Question 3

What are Nucleic Acids?

Answer 3

Linear polymers made by connecting nucleotides via phosphodiester bonds.

Question 4

What is the repeating unit called?

Answer 4

Nucleotide

Question 5

What does a nucleotide consist of?

Answer 5

Sugar, Base and a Phosphate Group

Question 6

What are the “sugars” linked together by?

Answer 6

The phosphates from the backbone of nucleic acid - “sugar-phosphate backbone”

Question 7

What does RNA contain?

Answer 7

D-ribose

Question 8

What does DNA contain?

Answer 8

An unusual sugar, D-2 deoxyribose where the -OH of carbon 2 is replaced by -H

Question 9

What form do both sugars occur in?

Answer 9

B-furanose

Question 10

What two parent compounds are the nitrogenous bases derivatives of?

Answer 10

Pyrimidines and Purines

Question 11

Which bases are the Pyrimidines?

Answer 11

Cytosine (C) found in both DNA and RNA

Thymine (T) in DNA and Uracil (U) in RNA

Question 12

What are tautomeric forms?

Answer 12

Isomers that differ by the shift of a H atom and a double bond.

Question 13

What does the OH group undergo?

Answer 13

Keto/Enol Tautomerism

Question 14

What does the NH2 group undergo?

Answer 14

Amino/Imino Tautomerism

Question 15

What are Purines?

Answer 15

A Fused (joined together), bicyclic (two rings) heterocycle

Question 16

What are the Two Purine Bases in RNA and DNA?

Answer 16

Adenine and Guanine

Question 17

What does a Nitrogenous Base and Sugar Produce?

Answer 17

A nucleoside

Question 18

How is a nucleoside formed?

Answer 18

A base is joined to the sugar through a glycosidic bond

Question 19

What is a nucleoside a special type of?

Answer 19

A glycoside found in nucleic acids.

Question 20

What is the glycosidic bond sometimes called?

Answer 20

A glycosidic bond to designate the C-N linkage

Question 21

What links to the anomeric carbon of ribose/deoxyribose?

Answer 21

The NH at position 9 of purines and the NH at position 1 of pyrimidines

Question 22

What are Nucleotides?

Answer 22

A base + sugar + phosphate

Question 23

How does a nucleotide compare to a nucleoside?

Answer 23

A nucleotide is a phosphorylated nucleoside.

Question 24

How is a phosphodiester linkage formed?

Answer 24

A phosphate group bridges between the 5’ OH of one nucleotide unit and the 3’ OH of another

*Same for both DNA and RNA

Question 25

What does each linear nucleic acid strand have?

Answer 25

A specific 5’end (lacks a nucleotide at the 5’ position) and a 3’ end (lacking a nucleotide at the 3’ position)

Question 26

What are the phosphate groups at pH 7?

Answer 26

Completely ionized and negatively charged at ph 7

Question 27

What way are nucleotide sequences written from?

Answer 27

5’ to 3’

Question 28

What does the 2’ hydroxyl of RNA (absent from DNA) act as?

Answer 28

A nucleophile in an intramolecular displacement, breaking the phosphodiester linkage.