Chapter 2 - Nucleic Acids

Question 1

what is a nucleotide?

Answer 1

the monomer that makes up a polynuclotide

Question 2

what are the nitrogen containing bases for DNA?

Answer 2

Adenine, Thymine, Cytosine, Guanine

Question 3

describe DNA

Answer 3

double stranded, codes for proteins, double helix

Question 4

what base is present in RNA, what does it replace?

Answer 4

Uracil replaces Thymine

Question 5

What sugar makes up DNA?

Answer 5

deoxyribose

Question 6

What sugar makes up RNA?

Answer 6

ribose

Question 7

describe RNA

Answer 7

single stranded, short polynucleotides, transfer genetic code form DNA to ribosomes

Question 8

what bonds form between bases in the double helix?

Answer 8

HYDROGEN BONDS - 2 A/T 3 G/C

Question 9

what bond forms between the phosphate and sugar groups?

Answer 9

phosphodiester bonds

Question 10

what does the DNA HELICASE enzyme do?

Answer 10

unwinds the HYDROGEN BONDS between the 2 strands

Question 11

describe SEMI CONSERVATIVE REPLICATION

Answer 11

dna is unwound, both strands act as templates, free nucleotides join by COMPLEMENTARY BASE PAIRING, DNA POLYMERASE joins nucleotides with phophodiester bonds, H BONDS reform,

Question 12

explain why one strand can be replicated in one go and one is done in sections.

Answer 12

DNA is ANTIPARRALEL (the nucleotides are arranged differantly) the ACTIVE SITE of DNA POLYMERASE has a SPECIFIC TERTIARY STRUCTURE, only substrate with a COMPLIMENTARY ORIENTATION can form an ENZYME SUBSTRATE COMPLEX

Question 13

4 reasons why ATP is useful

Answer 13

• releases energy in small manageable amounts
• broken down in a single reaction
• phosphorylation of other molecules increases reactivity
• re synthesises easily

Question 14

What type of reaction is ATP —–> ADP + Pi

what enzyme?

Answer 14

hydrolysis and ATP hydrolase

Question 15

What type of reaction ADP + Pi ——–> ATP?

what enzyme

Answer 15

condensation + ATP synthase