Topic 9: DNA structure

Question 1

what do DNA and nucleic acid (DNA and RNA) all have in common

Answer 1

they are polynucleotides

Question 2

what are nucleic acids

Answer 2

DNA and RNA

linar polymers of nucleotides

Question 3

what is the structure of a nucleotide

Answer 3

pentose sugar connected to base and phosphatew

Question 4

what is the structure of a nucleoside

Answer 4

pentose base and sugar

Question 5

what are the two types of pentose sugar and where are they found

Answer 5

ribose in RNA, deoxyribose in DNA

Question 6

how does structure of types of pentose sugar differ

Answer 6

in ribose - c2 is hydroxyl, in deoxyribsose on C2 just as hydrogen

Question 7

what are the two types of nitrogenous base

Answer 7

purine and pyrimidine

Question 8

what bases are purines

Answer 8

guanine

adenine (AG)

Question 9

what bases are pyrmidines

Answer 9

cytosine, uracil, thymine (CUT)

Question 10

what is the difference between purines and pyrmidines

Answer 10

purines are 2 rings, pyrmidines one ring

Question 11

where is thymine found

Answer 11

only in dna

Question 12

where is uracil found

Answer 12

only in RNA

Question 13

what are the two types of nucleoside

Answer 13

nucleoside (RNA) and deoxyribonucleoside (DNA)

Question 14

what can nucleosides be used for

Answer 14

precursors for nucleotides

phosphorylated to form them (C5 = phosphate)

Question 15

if the base of a nucleoside was adenosine what would the nucleoside be called

Answer 15

deoxyadenosine monophosphate

Question 16

what are the bases

Answer 16

A, T, C, G, U

Question 17

what are the nucleosides

Answer 17

adenosine, guanosine, uridine, cytidine (RNA)

deoxyadenosine, deoxyguanosine, deoxythymidine, deoxycytidine (DNA)

Question 18

what are the nucleotides

Answer 18

AMP, GMP, UMP, CMP (RNA)

dAMP, dGMP, dTMP, dCMP (DNA)

Question 19

what are the monomers of polynucleotides

Answer 19

nucleotides

Question 20

how are nucleotides bonded together

Answer 20

phosphodiester bond
chain has a 5 to 3 prime polarity
5 prime end = phosphate, 3 prime end = hydroxyl groups

Question 21

how does base pairing work

Answer 21

NH3 - delta positive, C=O = delta negative on O which attract each other to form hydroge bonds

Question 22

how many Hydrogen bonds in G-C

Answer 22

3

Question 23

how many hydrogen bonds in A-U

Answer 23

2

Question 24

what is base pairing between

Answer 24

between pyrimindine and purine

Question 25

how many hydrogen bonds in A-T

Answer 25

2

Question 26

how is a secondary structure formed

Answer 26

one in 5-3 prime end from top to bottom
one in 3-5 prime end from bottom to top
antiparallel strands bring complementary base together

Question 27

what is secondary structure

Answer 27

double stranded

Question 28

how are sugars and phosphates held together in single strand of DNA

Answer 28

covalent bonds

Question 29

how are complementary base pairs held together

Answer 29

hydrogen bonds and london forces as tightly stacked

Question 30

what is the tertiary structure of DNA

Answer 30

right handed double helix with anti parallel strands
major groove - bases accessible
minor groove - bases hidden in helix

Question 31

what is the quarternary structure of DNA

Answer 31

from double helix to nucelosomes

nucleosomes to hetero and euchromatin

Question 32

how is a single stranded nucleic acid depicted

Answer 32

5 end sugar, phosphate, S, P, S, P 3 end

5 prime ACCT 3 prime

Question 33

5 prime end is on the

Answer 33

left

Question 34

how is a duplex sequence depicted

Answer 34

double strand antiparallel so
5 prime ACCTCG 3 prime
3 prime TGGAGC 5 prime
(may only be top strand as know what bottom strand will be)