BIOC 301 Lecture Exam 1 | Questions with 100%
Correct Answers| Verified-
Pentose nomenclature - ✔✔Use ' to differentiate base numbers
Difference at 2' determines DNA and RNA:
2' OH - RNA
2' H - DNA
Pentose flexibility - ✔✔Not planar, has puckering conformations
5' location determines name:
same side- endo
opposite side- exo
DNA nomenclature - ✔✔When modification is:
On ring- name position and modification type
Exocyclic- identify position and modification type
heritable phenotype - ✔✔Can result from change in chromosome without altering
DNA sequence
Result of environment or inherited
Can change how DNA is read changing development, disease, physiology, and psychiatry
Post-synthesis modification - ✔✔Both DNA and RNA
RNA has more, especially on non coding regions (tRNA, rRNA)
Can have unusual ribose-base connections
, DNA and RNA structure - ✔✔5' and 3' ends
Phosphate makes backbone negative
Sugar and phosphate hydrophilic
Bases hydrophobic
Double helix - ✔✔Two anti parallel, reverse complementary strands linked non
covalently through H bonds G:C A:T
Backbone on outside bases on inside
#A = #T and #G = #C
Helix Structure - ✔✔Bases nearly perpendicular separates by 3.4A
10.5 bases per turn (36A)
One turn is major and minor groove
Major groove used for protein-DNA interactions
Why double strand - ✔✔1. Hydrophobic effect- sugars and phosphates hydrophilic
outside, bases hydrophobic inside
2. Base stacking- bases stack because of numerous van der Waal forces, double strands
stack better, GC better stacking than AT AU
3. Counterions like Mg shield negative charge on backbone to reduce repulsion
DNA flexibility - ✔✔Can bend, exist as circular DNA because of:
Change in sugar puckering
Twisting around phosphodiester bond
Twist of base with respect to sugar
Correct Answers| Verified-
Pentose nomenclature - ✔✔Use ' to differentiate base numbers
Difference at 2' determines DNA and RNA:
2' OH - RNA
2' H - DNA
Pentose flexibility - ✔✔Not planar, has puckering conformations
5' location determines name:
same side- endo
opposite side- exo
DNA nomenclature - ✔✔When modification is:
On ring- name position and modification type
Exocyclic- identify position and modification type
heritable phenotype - ✔✔Can result from change in chromosome without altering
DNA sequence
Result of environment or inherited
Can change how DNA is read changing development, disease, physiology, and psychiatry
Post-synthesis modification - ✔✔Both DNA and RNA
RNA has more, especially on non coding regions (tRNA, rRNA)
Can have unusual ribose-base connections
, DNA and RNA structure - ✔✔5' and 3' ends
Phosphate makes backbone negative
Sugar and phosphate hydrophilic
Bases hydrophobic
Double helix - ✔✔Two anti parallel, reverse complementary strands linked non
covalently through H bonds G:C A:T
Backbone on outside bases on inside
#A = #T and #G = #C
Helix Structure - ✔✔Bases nearly perpendicular separates by 3.4A
10.5 bases per turn (36A)
One turn is major and minor groove
Major groove used for protein-DNA interactions
Why double strand - ✔✔1. Hydrophobic effect- sugars and phosphates hydrophilic
outside, bases hydrophobic inside
2. Base stacking- bases stack because of numerous van der Waal forces, double strands
stack better, GC better stacking than AT AU
3. Counterions like Mg shield negative charge on backbone to reduce repulsion
DNA flexibility - ✔✔Can bend, exist as circular DNA because of:
Change in sugar puckering
Twisting around phosphodiester bond
Twist of base with respect to sugar
