Week 9/3

Question 0

Side chain

Answer 0

The atoms of an amino acid which are attached to the alpha carbon of an amino acid and which are not the carbonyl group, amino group, or hydrogen.

Question 1

Residue

Answer 1

The monomeric component of a polymer minus the atoms which were removed to make the chemical linkage

Question 2

Zwitter ion

Answer 2

A molecule which contains both positive and negative charges but is electrically neutral. AA are zwitter ions at their pI

Question 3

Peptide bond

Answer 3

The covalent secondary amide linkage that joins the carbonyl group of one amino acid residue to the amino nitrogen of another in peptides and proteins.

Question 4

Isoelectric point (pI)

Answer 4

The pH at which a molecule is electrically neutral or has zero net charge.

Question 5

Net charge

Answer 5

The algebraic sum of all the charges on a single molecule.

Question 6

Chromatography

Answer 6

A technique of separation and/or analysis which is based on the relative affinity of solutes for a moving and stationary phases.

Question 7

Electrophoresis

Answer 7

A technique of separation based on the movement of charged molecules in the presence of an electric field. This is typically used to separate proteins or nucleic acids and is a very powerful analytic tool.

Question 8

alpha helix

Answer 8

a type of secondary structure commonly found in proteins which his characterized by 3.6 residues per turn and a φ angle of -57 degrees and a Ψ angle of -47 degrees for a right handed helix and a φ angel of 57 degrees and a Ψ angle of 47 degrees for a left handed helix

Question 9

beta sheet

Answer 9

a type of secondary structure commonly found in proteins which is characterized by two linear strands of the polypeptide back bone lying side by side and connected with hydrogen bonds and which is characterized by a φ angle of -119 degrees and a Ψ of +113 degrees for parallel beta sheets and a φ angle of -139 degrees and a Ψ angle of +135 degrees for antiparallel beta sheets.

Question 10

primary structure

Answer 10

the linear sequence of amino acids in a polypeptide or protein

Question 11

proteins

Answer 11

a polymer of alpha-amino acids linked by a peptide (amide) bond.

Question 12

quaternary structure

Answer 12

the association of multiple tertiary structures to form a complex

Question 13

secondary structure

Answer 13

a regular or periodic folding of the primary structure

Question 14

tertiary structure

Answer 14

the irregular or non-repeating folding of the primary and secondary structures

Question 15

domain

Answer 15

a substructure of the tertiary structure that cna evolve, funtion, and exist independetnly of the rest of teh protein chain.

Each domain forms a compact threee-dimensional structure and often can be independently stable and folded. It usually has a singular function such as biding site for substrate or affector.

Question 16

motif

Answer 16

a unique combination or folding of secondary structures.

There is some controversy as to its exact meaning, and it has been used [incorrectly?] interchangeably witht he word domain. Unlike domain, a motif can be composed of non-contiguous primary sequences