Module 1 Section 1

Question 1

mRNA features

Answer 1

• transient molecule
• following transcription, mRNA carries DNA message out of nucleus into cytosol
• one gene can encode several mRNA
• one mRNA can encode several proteins

Question 2

rRNA features

Answer 2

• RNA component of ribosome
• most abundant type of RNA in cell
• several strands of rRNA combine with ribosomal proteins to form ribosome complex

Question 3

tRNA features

Answer 3

• act as an adaptor between nucleic acids and protein
• transfer individual amino acids from cytoplasm to ribosome
• anticodon on tRNA is complementary to codon on mRNA

Question 4

Building blocks of nucleic acids

Answer 4

• Nitrogenous base
• pentose (5-C) sugar (ribose/deoxyribose)
• at lease one phosphate group
• called nucleoside if lacking one of more phosphate group

Question 5

Groups for Nitrogenous bases

Answer 5

Purines: two rings (adenine, guanine)
Pyrimidines: one ring (uracil, thymine, cytosine)

Question 6

Protein functions

Answer 6

• catalyzing biochemical rxns
• serving structural roles
• recieving + transmitting chemical signals within/among cells
• transporting specific ions + mlc across membranes

Question 7

Bond strength using electronegativity difference

Answer 7

0-0.4 non-polar
0.4-1.7 polar
>1.7 ionic

Question 8

Polarity regions in proteins

Answer 8

• outer regions typically polar (in aqueous cytoplasm)

- cell membrane proteins have nonpolar outer regions to interact with fatty acid chains

Question 9

Ionic interactions in biomlc

Answer 9

• can form salt bridges

- combination of weak interactions: H-bonding + electrostatic interactions

Question 10

Van der Waals Radius

Answer 10

• distance at which attractive and repulsive forces are balanced
• the strongest van der Waals force comes when macromolecule contains surface the precisely fits the shape of the mlc it binds (ie. antibody/antigen)

Question 11

H-bonding in DNA

Answer 11

• complementary stands held together by h-bonding between nucleotide base pairs (results in major/minor grooves)
• each groove has potential h-bond donor/acceptor atoms for protein interactions (major groove =more accessible)

Question 12

H-bonding in proteins

Answer 12

• plays role in folding
• role in interaction between subunits in protein complex
• H-bond donors/acceptors on AA residues in polypeptide interact to cause polypeptide folding