Nucleic Acids

Question 1

What are the functions of nucleotides?

Answer 1

monomers; used for energy metabolism, enzyme cofactors, and signal transduction

Question 2

What are the functions of nucleic acids?

Answer 2

polymers; used for storage of genetic information (DNA), transmission of genetic information (mRNA), processing genetic information (ribosomes), and protein synthesis (tRNA and rRNA)

Question 3

Nucleotide:

Answer 3

N base+pentose+phosphate

Question 4

Nucleoside:

Answer 4

N base+pentose

Question 5

Traits of the phosphate group:

Answer 5

• PO4
• negative (at neutral pH0
• typically attached to 5’ carbon

Question 6

Nucleic acids are build using the 5’ _____ version of the nucleotides (_TP, _TP, _TP, and _TP)

Answer 6

triphosphate/A/C/G/T

Question 7

What happens if the phosphate group isn’t attached to the 5’ C?

Answer 7

It leads to specialized functions

Question 8

Which pentose is used for DNA and which is used for RNA?

Answer 8

Deoxyribose and ribose

Question 9

N bases are either _____ (two rings) or _____ (one ring)

Answer 9

purine/pyrimidine

Question 10

What are the characteristics of the N bases?

Answer 10

heteroaromatic, planar, absorb UV light

Question 11

Which bases are in DNA?

Answer 11

A, T, C, G

Question 12

Which bases are in RNA?

Answer 12

A, U, C, G

Question 13

__, ___, and ___ are pyrimidines, ___ and ___ are purines

Answer 13

C/U/T/A/G

Question 14

Pentose is attaches to N-base via ____ ____ from position N__ (purines) or N__ (pyrimidines), ___ conformation has a bond angle of 0* and ___ conformation has a bond angle of 180*

Answer 14

glycosidic linkage/9/1/syn/anti

Question 15

A ____ _____ is related to bond 4, it limits the angle of torsion for the N-glycosidic bond between the N base and the pentose

Answer 15

Ring pucker

Question 16

Modification is done after DNA synthesis, it makes ____ nucleosides; ____, ____, ____, ____, and ____

Answer 16

• minor

- 5-methylcytosine, N6-methyladenoside, epigenetic markers, inosine, pseudouridine

Question 17

Polynucleotides: formed by ______ bonds (____ linkages) between nucleotides to form a ____-charged backbone that is _____ with ______

Answer 17

covalent/phosphodiester/negatively/linear/directionality

Question 18

Base pairs form between __ + __ and __ + __, there are __ per turn of the helix and the strands are complementary ____.

Answer 18

A/T/C/G/10.5/antiparallel

Question 19

__ is the predominant form of DNA but there is also __ (11bp/turn) and __ (left turn, 12bp/turn).

Answer 19

B/A/Z

Question 20

Steps of DNA replication: (basic outline)

Answer 20

1) strands separate, each is a template for a new strand
2) DNA polymerase catalyzes synthesis
3) new DNA is formed with one daughter and one parent strand

Question 21

mRNA:

Answer 21

messenger RNA

• synthesized using DNA template
• ribose instead of deoxyribose
• uracil instead of thymine
• transfers genetic into into proteins

Question 22

What are the two types of mRNA?

Answer 22

1) monocistronic: only codes for one gene

2) polycistronic: codes for more than one gene

Question 23

RNA hydrolysis occurs in _____ conditions or is catalyzed by ____. The __‘-hydroxyl acts as a _____ in intramolecular displacement, since DNA doesn’t have a __‘-hydroxyl it is unstable under these conditions

Answer 23

alkaline/RNase/2/nucleophile/2

Question 24

_____ cause many problems because they mix up the DNA, problems include hairpins and cruciforms

Answer 24

Palindromes

Question 25

DNA ____: induced by high temperatures or pH changes, can be ______. If the _____ bonds remain intact so does the genetic code, if the __ bonds break the strands split, is the ____ ____ ____ is lost UV absorption increases

Answer 25

denaturation/reversible/covalent/H/base pair stacking

Question 26

Annealing:

Answer 26

reversal of DNA denaturation

Question 27

Midpoint of melting

Answer 27

Tm: depends on the base pair composition (more C/G instates Tm), longer DNA has a higher Tm, more salt increases Tm, more

Question 28

Mechanisms of spontaneous mutagenesis:

Answer 28

1) deamination: removal of NH2, causes slow reactions with a large number of residues, C becomes U 2) depurination: N-glycosidic bonds are hydrolyzed and the purines split

Question 29

Mechanisms of radiation:

Answer 29

1) UV light: induces dimerization (neighbouring pyrimidines join via a dimer) which causes kinks in DNA 2) ionizing radiation: causes rings to open and strands to break

Question 30

Mutations are ___ to fix, accumulating mutations are linked to ___ and ____

Answer 30

hard/ageing/carcinogenesis

Question 31

_____ nucleotide triphosphates provides energy to ___ some enzymatic reactions

Answer 31

Hydrolyzing/catalyze

Question 32

What are some coenzymes that contain adenosine?

Answer 32

Coenzyme A (CoA), FAD

Question 33

Nucleotides act as regulators for cell signalling, an example of this is ___, a second messenger that activates ____ _____ __ activity

Answer 33

cAMP/protein kinase A