NUCLEIC ACIDS

Question 1

isolated what he called nucleinfrom the nuclei of pus cells

Answer 1

Friedrich Miescher

Question 2

The source of genetic information in chromosomes

Answer 2

nucleic acids

Question 3

DNA is found in

Answer 3

Nucleus, mitochondria, chloroplasts

Question 4

Nucleotides have 3 parts

Answer 4

5-carbon sugar (pentose)
nitrogen containing base (CHN)
Phosphate group

Question 5

double ringed structure

Answer 5

purine
(adenine and guanine)

Question 6

single ring

Answer 6

pyramidine
(cytosine and thymine)

Question 7

no O atom on carbon 2’.

Answer 7

DNA

Question 8

Nucleoside=

Answer 8

Nucleoside= N base + 5-C sugar

Question 9

nitrogen base linked by a glycosidic bond to C1’ of a sugar (ribose or deoxyribose).

Answer 9

nucleoside

Question 10

named by changing the nitrogen base ending to
___ purines
____ pyramidines

Answer 10

-osine
-idine

Question 11

−OH on C5’ of a sugar bonds to phosphoric acid

Answer 11

nucleotide

Question 12

Nucleotide =

Answer 12

nucleoside + phosphate

Question 13

a nucleoside that forms a phosphate ester with the C5’ –OH group of a sugar (ribose or deoxyribose).

Answer 13

nucleotide

Question 14

Raw materials for DNA biosynthesis

Answer 14

dATP, dGTP, dCTP, dUTP

Question 15

Raw materials for RNA biosynthesis

Answer 15

ATP, GTP, CTP, UTP

Question 16

Secondary messengers in hormones action.

Answer 16

cAMP, cGMP

Question 17

nucleotides are joined by

Answer 17

phosphodiester bonds

Question 18

secondary structure of RNA

Answer 18

cloverleaf tRNA

Question 19

What are the four loops in secondary structure

Answer 19

D loop
Anticodon loop
variable loop
T ¥ C

Question 20

What are the four arms of secondary structure

Answer 20

amino acid arm
D arm
T¥ C arm

Question 21

Arrange according to their percentage
tRNA
rRNA
mRNA

Answer 21

rRNA (75)
tRNA (10-15)
mRNA (5-10)

Question 22

Ribosomes consists of
rRNA-
Proteins-

Answer 22

65
35

Question 23

The base chain is written in the _____ direction

Answer 23

5–>3

Question 24

A=T
G=C

what rule

Answer 24

chargaff’s rule

Question 25

X-ray Diffraction Refined Structure

Answer 25

Franklin, Wilkins

Question 26

Adenine is alwayslinked by ____ bonds with Thymine

Answer 26

two H bonds

Question 27

Guanine is always linked by ____^hydrogen with Cytosine

Answer 27

three

Question 28

proposed by Watson & Crick; standardDNA structure

Answer 28

right handed helix

Question 29

atlow humidity,the DNA molecule will take the

Answer 29

A form

Question 30

the minimum functional unit in DNA

Answer 30

gene

Question 31

short coding sequences

Answer 31

exons

Question 32

a longer intervening noncoding sequence

Answer 32

introns

Question 33

Between replications, the DNA is stored in a compact ball called wrapped around the protein called to form

Answer 33

chromatin histones nucleosomes

Question 34

DNA & RNA specific absorption at max =

Answer 34

260 nm

Question 35

The more G-C content, the ___ Tm value.

Answer 35

higher

Question 36

Characteristics of DNA replication

Answer 36

semi conservative bidirectional semi-discontinuous synthesis

Question 37

each daughter duplex contains one strand from the parent duplex

Answer 37

semi conservative

Question 38

is first made as short chains

Answer 38

lagging strand (Okazaki fragments)

Question 39

precursors of DNA replication

Answer 39

dNTPs

Question 40

Unwinds DNAdouble helix

Answer 40

helicase

Question 41

Catalyzessynthesis of RNA primers

Answer 41

Primase

Question 42

Catalyzeschain elongation

Answer 42

DNA polymerase III

Question 43

Involvedin the excision of primers and filling up of gaps

Answer 43

DNA polymerase I

Question 44

Catalyzesthe formation of a phosphodiester linkage between a 3’hydroxyl at the end of one DNA strand and a 5’ phosphate at the end of another strand

Answer 44

DNA ligase

Question 45

replicates DNA only 5’ to 3’

Answer 45

DNA polymerase III

Question 46

one of the major post-replicative reactions.

Answer 46

methylation

Question 47

Site of methylation of eukaryotic DNA is always on

Answer 47

cytosine

Question 48

Transcription has 3 stages

Answer 48

Initiation Elongation Termination

Question 49

stretch of 6 nucleotides

Answer 49

Pribnow box

Question 50

a 2ndnucleotide sequence, TTGACA, located about 35 bases to the left of the transcription start site

Answer 50

-35 sequence

Question 51

the promoter region has been recognized by the

Answer 51

holoenzyme

Question 52

+ supercoil (ahead of the transcription site) –relaxed by

Answer 52

gyrase

Question 53

➢-supercoil (behind) –relaxed by

Answer 53

topoisomerase

Question 54

linkage of 7-methylguanosine to the 5’ terminal residue.

Answer 54

capping

Question 55

attachment of an adennylate polymer (poly A, 20~250 nucleotides) at the 3’ terminal.

Answer 55

tailing

Question 56

While the mRNA is still in the nucleus, the ___ are removed from the pre-RNA

Answer 56

introns

Question 57

Inprokaryotes(bacteria and archebacteria), transcription of proteins is regulated by an ___

Answer 57

operon

Question 58

consists of a control siteand the genes that produce mRNA for lactose enzymes

Answer 58

lactose operon

Question 59

When there is no lactose in the cell, a ____ produces a _____ protein prevents the synthesis of lactose enzymes

Answer 59

regulatory gene repressor

Question 60

Translation Five Stages

Answer 60

Activation of amino acids Initiation of translation Elongation Termination and ribosome recycling Folding and post-translational processing

Question 61

Enzymatic synthesis of aminoacyl tRNA molecules

Answer 61

activation of amino acids

Question 62

Binding of mRNA and N-formylmethionineto ribosome

Answer 62

initiation of translation

Question 63

Binding of aminoacyl tRNAs to ribosome formation of peptide bonds

Answer 63

elongation

Question 64

an adapter molecule, which recognizes an amino acid on one end and its corresponding codon on the other, is required for translation. This adapter molecule is

Answer 64

tRNA

Question 65

have self-checking functions to prevent incorrectly paired amino acyl tRNAs from forming.

Answer 65

Aminoacyl tRNA synthetases

Question 66

a sequence of amino acids in a mRNA that determine the amino acid order for the protein.

Answer 66

genetic code

Question 67

3 stop codons

Answer 67

UUA UAG UGA

Question 68

There are how many triplets of amino acids

Answer 68

61

Question 69

First amino acid is

Answer 69

methionine

Question 70

The addition of a.a to the carboxyl end of the growing polypeptide chain.

Answer 70

elongation

Question 71

By each cycle the polypeptide has grown by one residue and consumed

Answer 71

two GTP

Question 72

Two types of mutation

Answer 72

point mutation base deletion or insertion

Question 73

Changing a single nucleotide base on the m-RNA chain

Answer 73

point mutation

Question 74

The codon containing the changed base codes for the same amino acid

Answer 74

silent mutation

Question 75

The change results in a new different amino acid

Answer 75

missense

Question 76

The change leads to premature termination if the codon containing the changed base become a termination codon.

Answer 76

non-sense mutation

Question 77

Insertion or deletion of one or two bases will alter the reading frame and this cause extensive change in the translated protein

Answer 77

frame shift mutation

Question 78

What are the different mutagens?

Answer 78

radiation chemical mutagens

Question 79

Disrupt DNA and RNA replication

Answer 79

nucleotide analogs

Question 80

Result in base-pair substitutions and missense mutations

Answer 80

nucleotide-altering chemicals

Question 81

Result in nonsense mutations

Answer 81

frameshift mutagens