Module 10

Question 1

Components of Nuceotides

Answer 1

Ribose sugar
Nitrogenous base
Phosphate

Question 2

Difference between Ribose and deoxyribose

Answer 2

For DNA 2’ carbon of the ribose is in deoxy form

Question 3

Pyramidines

Answer 3

Single Ring: Adenine Guanine

Question 4

purine

Answer 4

Duble Ring: Cytosine, Uracil, Thymine

Question 5

Nitrogenous Bases

Answer 5

Nitrogenous bases link to ribose through N - Glycosidic bonds
All nitrogenous bases link to C1’ of the sugar
In purines N - Glycosidic bond is to N9 of a nitrogenous Base
In pyramiding to N1 of a nitrogenous base

Question 6

How do nucleotides and nucleosides differ

Answer 6

Whether they are phosphorylated at C5’ position
Nucleosides are phosphorolated nucleotides

Question 7

Physiological Roles of nucleotides

Answer 7

Energy Transfer
Signal Transduction

Question 8

Energy Transfer

Answer 8

Anhydride linages in ATP are high energy bonds
The energy released from hydrolysis of these bonds drives many biochemical reactions

Question 9

Signal Transduction

Answer 9

Cyclic AMP, formed from ATP in a reaction. catalyzed by adenylyl cyclase
Common intracellular messenger produced in response to Harmones

Question 10

Phosphodiester bonds

Answer 10

Nucleotides form linear nucleic trans through 3’-5’ phophodiester linkages
Linages are identical in DNA and RNA

Question 11

Direction of Nucleic Acid strands

Answer 11

5’ - 3’

Question 12

RNA

Answer 12

contains ribose
contains uracil
Single Stranded

Question 13

rRNA

Answer 13

An integral part of ribosomes, - 80% of RNA in cells

Question 14

tRNA

Answer 14

Carry activated amino acids to ribosomes for protein synthesis

Question 15

mRNA

Answer 15

Code for proteins, contains triplet codons

Question 16

Double Helix

Answer 16

Two helical DNA strands coiled around a common axis forming a right handed double helix
The strands run in opposite directions
Strands are complementary to each other
Sugar Phosphate groups outside
Nitrogenous bases are inside

Question 17

weak forces

Answer 17

Stabilize the double helix

Question 18

hydrophobic effects

Answer 18

Burying purine and pyrimidine rings in the interior of the helix

Question 19

Stacking interactions

Answer 19

Stacked base pairs form Van Der Waals interactions

Question 20

hydrogen bonds

Answer 20

Hydrogen bonding between base pairs

Question 21

Charge - charge interactions

Answer 21

Electrostatic repulsion of negatively charged phosphate is decreased by cations

Question 22

Restriction Endonucleases

Answer 22

Restriction ends nucleases recognize and cleave specific DNA sequences
Bacterial defence mechanism against viral invasion
Host cells protect their DNA by covalent modification of bases at the restriction site

Question 23

Restriction enzymes cut at

Answer 23

Palindrome

Question 24

Complimentary Strands in Duplex DNA

Answer 24

Duplex DNA contains two complimentary, anti parallel strands

Question 25

Denaturation of DNA

Answer 25

Complete separation of double stranded DNA by heat or chemical agents
Is a cooperative process

Question 26

Synthesis of Nucleic Acids

Answer 26

DNA and RNA polymerases are the primary enzymes for synthesizing nucleic acids in the 5’ - 3’ direction
Incoming residues are added to the 3’ end of the growing strand

Question 27

PCR

Answer 27

PCR takes advantage of the ability for each DNA strand to serve as a template for production of a complementary strand
Use heat stable enzymes to make new DNA
Allows for exponential; amplification of short regions of DNA vey quickly

Question 28

Histones

Answer 28

DNA packaging proteins
Highly conserved and positively charges
H1 binds the region pop liner DNA

Question 29

Bacterial Genome

Answer 29

Millions of base pairs
Closed, Circular Genome
No introns