Lecture 3: Nucleic Acids

Question 1

tribasic

Answer 1

• acid having 3 H atoms (3 acid groups) which are easily replacable by basic atoms or groups

Question 2

ester

Answer 2

• chemical compound derived from an acid where 1 OH group is replaced by an O alykyl group

Question 3

ribose; can you explain the linkage of each carbon? can you draw it?

Answer 3

5 carbon sugar

• 1’ linked to base
• 2’ linked to OH (ribose) or H (deoxyribose)
• 3’ linked to a free hydroxy group
• 5’ linked to a phosphate group

Question 4

pyrimidines and examples

Answer 4

single ring nitrogenous base

- cytosine, uracil (in RNA), and thymine (in DNA)

Question 5

purine and examples

Answer 5

• double ring nitrogenous base

- guanine and adenine

Question 6

describe the following monomers/ give their full names

• nucleosides
• ATP
• AMP
• nucleic acids

Answer 6

• base + sugar (adenosine, guanosine, cytidine, thymidine, uridine)
• adenosine triphosphate (energy currency for cells)
• adenosine monophosphate
• polymers of nucleosides

Question 7

can you draw a nucleotide?

Answer 7

see notes

Question 8

explain the reaction of 2 nucleotides

Answer 8

• 2 nucleotides form a dinucleotide and a water molecule through a condensation reaction

Question 9

why are bases stacked inside the dna structure?

Answer 9

• hydrophobic and don’t want to be exposed to wet environment

Question 10

major grove vs minor grove

Answer 10

• describes the indentations on a DNA molecule

Question 11

• describe the secondary DNA structure (shape, length and width)
• how many nucleotides are there per turn?
• where are nucleotides added?

Answer 11

• 2 antiparallel strands make a very stable double helix
• 2nm by 3.4nm
• 10/turn
• 3’ end only

Question 12

Explain the secondary RNA structure (shape, nucleotide connections, describe)

Answer 12

• hairpin structure with a loop stem
• A+U and G+C
• base pairing with H bonds

Question 13

histones

Answer 13

very basic proteins

Question 14

review the DNA vs RNA structure summary from your notes. Describe the differences between both in the primary, secondary, and tertiary stages

Answer 14

see notes

Question 15

How are nucleic acids synthesized?

Answer 15

• 5’–> 3’
• an energy rich nucleotide triphosphate is added to a free 3’ OH
• 2/3 phosphates are released to provide energy
• enzymes catalyze reaction (RNA polymerase or DNA polymerase)

Question 16

Explain DNA replication

• how many strands (1 or 2) can be used as a template
• how do the new daughter strands form
• what is required?
• what enzyme is involved?

Answer 16

• each DNA strand can be duplicated
• complementary nucleotides align with strands (this is catalyzed by enzymes)
• requires a primer
• DNA polymerase

Question 17

polymerization

Answer 17

monomer + monomer = polymer

Question 18

Explain the Polymerase Chain Reaction (PCR) and at what temperature each stage requires/ occurs at

Answer 18

• denaturation: 95 degrees
• annealing: 55 degrees
• polymerization 72 degrees
• DNAS made: 2, 4, 8 (pyramid with every gen)