Module 10: Nucleic Acids

Question 1

NAD & FAD are…

Answer 1

enzyme co-factors

Question 2

what are nucleotides & what are they made of?

Answer 2

building blocks of nucleic acids
ribose sugar, nitrogenous base & phosphate

Question 3

what is the cycled form of ribose in nucleotides?

Answer 3

beta-D-ribofuranose

Question 4

how many rings do pyrimidines & purines?

Answer 4

pyrimidines: 1 ring
purines: 2 rings

Question 5

what 3 bases are found in both DNA & RNA?

Answer 5

adenine, guanine & cytosine

Question 6

what base is only found in DNA?

Answer 6

Thymine

Question 7

what base is only found in RNA?

Answer 7

Uracil

Question 8

how do nitrogenous bases link to ribose?

Answer 8

though N-glycosidic bonds

Question 9

what carbon do nitrogenous bases link to?

Answer 9

C1

Question 10

in purines, the N-glycosidic bond is to what position on the nitrogenous base?

Answer 10

N9

Question 11

in pyrimidines, the N-glycosidic bond is to what position on the nitrogenous base?

Answer 11

N1

Question 12

how do nucleotides and nucleosides differ?

Answer 12

whether they are phosphorylated at the C5 position

Question 13

what suffix is used for nucleosides?

Answer 13

osine

Question 14

what suffix is used for nucleotides?

Answer 14

late

Question 15

what is AMP formed by?

Answer 15

formed from ATP in a reaction catalyzed by adenylyl cylcase

Question 16

what do phosphodiester bonds do?

Answer 16

join nucleotides in nucleic acids

Question 17

nucleotides form linear nucleic strands through…

Answer 17

3-5 phosphodiester linkages

Question 18

sickle cell anemia is caused by the…

Answer 18

change of 1 nitrogenous base

Question 19

can RNA adopt 3D structures?

Answer 19

yes

Question 20

what percentage of rRNA is found in ribosomes?

Answer 20

80%

Question 21

what does tRNA do?

Answer 21

transport amino acids to ribosomes for protein synthesis

Question 22

what does mRNA do?

Answer 22

code for proteins

Question 23

what does miRNA do?

Answer 23

regulation of gene expression

Question 24

how long are oligonucleotides?

Answer 24

22-24

Question 25

what idea did Watson & Crick develop?

Answer 25

DNA consists of 2 anti-parallel chains in right handed double helical arrangement

Question 26

where are sugar-phosphate backbones and nitrogenous bases on the helix?

Answer 26

sugar-phosphates: outside Nitrogenous bases: inside

Question 27

Adenine pairs with ( )

Answer 27

Thymine

Question 28

Guanine pairs with ( )

Answer 28

Cytosine

Question 29

what is Chargaffs rule?

Answer 29

A + G = T + C

Question 30

In duplex DNA, what the ratio of purines to pyrimidines?

Answer 30

of purines = # of pyrimidines

Question 31

what is the hydrophobic effect of the double helix?

Answer 31

hides purine & pyrimidine rings inside helix

Question 32

what are stacking interactions?

Answer 32

stacked base pairs form van der waals contacts

Question 33

electrostatic repulsion of negatively shared phosphate groups is decreased by...

Answer 33

cations (Mg) & cationic proteins

Question 34

how many grooves does a double helix have?

Answer 34

2 (major & minor)

Question 35

are grooves in double helix the same length?

Answer 35

no

Question 36

what do restriction endonucleases do?

Answer 36

recognize & cleave specific DNA sequences

Question 37

what is methylation?

Answer 37

when host cells protect their own DNA by covalent modification of bases at the restriction site

Question 38

where do restriction enzymes cut?

Answer 38

at palindrome sequences

Question 39

what are restriction enzymes used as?

Answer 39

molecular scissors

Question 40

what does RFLP stand for?

Answer 40

restriction fragment length polymorphisms

Question 41

what is denaturation?

Answer 41

complete separation of double-stranded DNA by heat or chemical agents

Question 42

what is annealing?

Answer 42

reforming the double stranded helix to form single strands

Question 43

what is the melting point? (Tm)

Answer 43

the temperature at which 1/2 DNA has become single stranded

Question 44

what are the substrates for synthesis?

Answer 44

nucleotide triphosphate

Question 45

where are incoming residues added to in DNA?

Answer 45

3' end of the growing strand

Question 46

what is polymerase chain reaction (PCR)?

Answer 46

uses heat-stable enzymes to make new DNA

Question 47

what does PCR allow?

Answer 47

exponential amplification of short regions of DNA very quickly

Question 48

who discovered PCR?

Answer 48

Kary Mullis

Question 49

what is the 1st level of packaging eukaryotic DNA?

Answer 49

involves information of nucleosomes

Question 50

Histones are ( ) packaging proteins

Answer 50

DNA

Question 51

Nucleosome composed of:

Answer 51

2 of each: H2A, H2B, H3, H4 and 146 base pairs of DNA

Question 52

( ) binds to the region of the linked DNA

Answer 52

H1

Question 53

how many nucleotides make a codon?

Answer 53

3

Question 54

what are introns?

Answer 54

non-coding intervening sequences

Question 55

what are plasmids?

Answer 55

non-chromosomal DNA

Question 56

what kind of genome does bacteria have?

Answer 56

closed, circular genome

Question 57

what shape are eukaryotic chromosomes?

Answer 57

linear

Question 58

what are telomeres / where are they found?

Answer 58

repeating sequences at the end of chromosomes

Question 59

what are exons?

Answer 59

cotton protein-coding information

Question 60

what is an advantage of introns?

Answer 60

multiple mRNAs can be generated from 1 gene

Question 61

what modification is used in epigenetics?

Answer 61

methylation of cytosine residues

Question 62

what is epigenetics?

Answer 62

changes to the genome that do not involve a change in nucleotide sequence