SEMIS: ISOLATION, HYDROLYSIS, & QUALITATIVE ANALYSIS OF RNA

Question 1

are macrobiopolymers of high molecular weight with mononucleotide as the repeating unit

Answer 1

nucleic acids

Question 2

what are the two structural kinds of nucleic acids

Answer 2

DNA (deoxyribonucleic acid)
RNA (ribonucleic acid)

Question 3

DNA and RNA are made up of

Answer 3

nitrogenous bases
sugar
phosphate group

Question 4

what are the 5 nitrogenous bases

Answer 4

cytosine
thymine
uracil
adenine
guanine

Question 5

what are the bases of pyrimidine

Answer 5

cytosine
thymine
uracil

Question 6

what are the bases of purine

Answer 6

adenine
guanine

Question 7

what is the base pair of cytosine

Answer 7

guanine (DNA and RNA)

Question 8

what is the base pair of adenine

Answer 8

thymine (DNA)
uracil (RNA)

Question 9

major components of all cells

Answer 9

5-15% of their dry weight

Question 10

3 types of interactions responsible for the rigid molecular configuration of nucleic acids

Answer 10

phosphodiester bonds
hydrogen bonds
van der Waal’s forces

Question 11

interaction that join the nucleotides in each chain

Answer 11

phosphodiester bonds

Question 12

interactions that join the bases

Answer 12

hydrogen bonds

Question 13

interactions between stacked bases

Answer 13

van der Waal’s forces

Question 14

general procedure for isolation of nucleic acids

Answer 14

• disruption of the cell membrane to release nucleic acids
• treatment with a solution causing dissociation of nucleoprotein and denaturation of proteins
• purification of nucleic acids

Question 15

scientific name of baker’s yeast

Answer 15

saccharomyces cerevisiae

Question 16

a unicellular fungus

Answer 16

yeast or saccharomyces cerevisiae

Question 17

yeast contains __% RNA by weight

Answer 17

4%

Question 18

the isolation of RNA from yeast involves

Answer 18

heating with alkali (NaOH)

Question 19

the nucleic acid is then separated from associated protein and other interfering substances by

Answer 19

acid extraction at pH 4-5

Question 20

heating with alkali extracts

Answer 20

nucleic acids and water soluble proteins

Question 21

treatment with __ can precipitate the RNA

Answer 21

alcohol and conc HCl

Question 22

repeated washings with __ and __ or __ can remove lipids

Answer 22

alcohol and ether or organic solvents

Question 23

what are the bases after hydrolysis

Answer 23

purine
pyrimidine

Question 24

ribose and base

Answer 24

nucleoside

Question 25

base, sugar, and phosphate

Answer 25

nucleotide

Question 26

hydrolysis of nucleic acid by either chemical or enzymatic methods yields

Answer 26

bases (purine and pyrimidine)
oligonucleotides <20 mononucleotides (containing up to 20 residues)
nucleosides (base + sugar)
ribose or D- ribose
phosphate

Question 27

more resistant to acid hydrolysis

Answer 27

pyrimidine

Question 28

is susceptible to acid hydrolysis

Answer 28

purine-N-glycosyl bond

Question 29

what qualitative tests were done

Answer 29

benedicts test
orcinol
test for purine bases
test for inorganic phosphate

Question 30

result of benedicts test

Answer 30

H- brick red precipitate
U- blue solution (no visible reaction)

Question 31

result of orcinol test

Answer 31

H- blue green sol’n
U- blue green sol’n

Question 32

result of test for purine bases

Answer 32

H- whitish precipitate or flocculent ppt.
U- grayish white precipitate

Question 33

result for inorganic phosphate

Answer 33

H- clear solution with yellow precipitate
U- yellow solution with yellow precipitate

Question 34

test for reducing sugars ; cupric reduced to cuprous

Answer 34

benedicts test

Question 35

test for pentoses

Answer 35

orcinol test