Nucleoproteins Flashcards
Histone are positively charged at physiologic pH due to high content of __ & ___
Lysine and arginine
Protein combined with DNA is often ___ or ___
Histone or protamine
5 classes of histones
H1 H2A H2B H3 H4
structural core of __is composed of 2 molecules each of H2A,H2B,H3,H4
Nucleosome
Neighboring nucleosomes joined by “linker” DNA approx __base pairs long
50
Her images suggested that DNA had spiral shape.
Rosalind Franklin
In purines, base of nucleotide is joined covalently at__
N9
A nucleoside consists of a N-base linked by a ___ to C1 of a ribose or deoxyribose
glycosidic bond
Nucleotide: nucleoside that forms ___ with C5 OH group of ribose or deoxyribose
phosphate ester
All bonds are in ribonucleotides except:
a) O-glycosidic bond
b) ester bond
c) anhydride bond
a)O-glycosidic bond
In the sugar-phosphate backbone of nucleic acids, the phosphate group joins the ____ of one sugar to the ___ of the sugar next in line.
3rd carbon
5th carbon
The sugar-phosphate backbone is hydrophobic, true or false?
False. Hydrophilic siya.
In test tube, RNA is hydrolyzed fast at ___ condition
a. acidic
b. basic
c. neutral
d. all
e. none
b. basic
Free purines and pyrimidines are weakly ____ compounds and may exist in two or more tautomeric forms, dep on pH
a. acidic
b. basic
b. basic
All nucleotide bases absorb UV light. true or false?
true
Purine and pyrimidine bases are hydrophilic at near-neutral cell pH, true or false?
false. hydrophobic dapat
[Nucleic Acid Structure] Find the mismatched pair/s a. secondary structure: covalent structure and nucleotide sequence b. tertiary structure: super coiling c. primary structure: double helix d.none of the above e. all are mismatched
a. secondary structure: covalent structure and nucleotide sequence
AND
c. primary structure: double helix
baliktad sila :)
According to Chargaff, which N-bases have equal percentages in DNA?
A. adenine-guanine, cytosine-thymine
B. adenine-cytosine, thymine-guanine
C. guanine-cytosine, adenine-thymine
D. All of them have equal percentages with each other.
C. guanine-cytosine, adenine-thymine
False about DNA
a. 2 strands run in the same direction
b. sugar-phosphate backbone outside, N–bases inside
c. DNA melts at 85-90 degrees Celsius
d. DNA releases UV light at melting point
a. 2 strands run in the same direction
opposite direction dapat
Which is the most stable DNA form under physiological conditions?
a. A form
b. B form
c. Z form
d. all of them are equally stable under physiological conditions
b. B form
True or false: DNA is organized into chromosomes even if the cell isn’t replicating.
False. DNA is only organized into chromosomes when the cell is replicating.
Explain semi-conservative replication of DNA
one strand of each daughter DNA comes from parent DNA and the other strand is new
energy of DNA synthesis comes from hydrolysis of phosphate bonds as ___ form between bases
phosphodiester bonds
To start DNA replication, this enzyme unwinds several sections of parent DNA
Helicase
