amino acids, pep and proteins

Question 1

amino acids

Answer 1

molecules that contain two functional groups, and amino group and a carboxyl group. for an alpha Amino acid, to the alpha carbon, there are two other groups attached to it, a hydrogen atom and a side chain/R group.

Question 2

proteinogenic amino acids

Answer 2

20 alpha amino acids encoded by the human genetic code

Question 3

amphoteric species

Answer 3

AAs for example,

can either accept a proton or donate a proton, spends on the pH of their environment

Question 4

zwitterions

Answer 4

dipolar ions

has both a positive chg and neg chg

the charges neutralize one another

exist in water as internal salts

Question 5

peptides

Answer 5

composed to aa subunits, which are sometimes called residues

Question 6

dipeptides

Answer 6

consist of two animo and residues

Question 7

tripeptides

Answer 7

consists of three amino acid

Question 8

oligopeptide

Answer 8

relatively small peptides (up to about 20 peptides)

longer chains are called polypeptides

Question 9

peptide bond

Answer 9

residues in peptides are joined together thru this, which is a specialized form of an amide bond that forms between the coo- group of one AA and the nh3+ grp of another aa

Question 10

sequencing

Answer 10

laboratory technique that can determine the primary structure of a protein using the dna that coded for hat protein, although it can also be done from the proton itself

Question 11

alpha-helices

Answer 11

rodlike structure in which the peptide chain coils clockwise around a central axis and is stabilized by INTRAMOLECULAR H BONDS BTWN CARBONYL O AND AMIDE H 4 RESIDUES DOWN THE CHAIN

important component in the structure of keratin (fibrous structural protein found in human hair, skin, nail)

Question 12

beta-pleated sheets

Answer 12

parallel or anti-parallel

the peptide chains lie alongside one another, forming rows or strands held together by INTRAMOLECULAR H BONDS WTN CARBONYL O ON ONE CHAIN AND AMIDE H ON ADJACENT chain

to accommodate as many h bonds as possible, they are pleated or rippled

fibroin, primary protein component of silk fibers

Question 13

due to its __ __ structure, ___ will introduce a kink in the peptide chain when it is found in the middle of an alpha helix, so they are rarely found in them, except in ones that cross the membrane. also rare in middle of pleated sheets, so it is found in the turns between chains in beta sheet and start of alpha helix

Answer 13

rigid cyclic

proline!

Question 14

fibrous proteins

Answer 14

collagen

structures that resemble sheets or long strands

Question 15

globular proteins

Answer 15

myoglobin

tend to be spherical

Question 16

disulfide bonds

Answer 16

bond that forms when two cysteine molecules become oxidized to form cystine

create loops in protein chain

the more there are, the curlier your hair is!!

requires the loss of two protons and two electrons (oxidation)

Question 17

molten globules

Answer 17

intermediate states in protein folding, where basically the secondary structures form first, then hydrophobic interaction and H bonds cause the proton to “collapse” into its proper form

Question 18

denaturation

Answer 18

when a proton loses its tertiary structure, so it loses its function

Question 19

solvation layer

Answer 19

formed by the solvent molecules when a solute dissolves in a solvent around that solute

Question 20

more disorder means that it is un/favorable (?) and a __ (non/spontaneous? process)

Answer 20

unfavorable

non spontaneous

Question 21

role of the formation of quaternary structures

Answer 21

more stable by further reducing the surface area of the protein complex

can reduce the amt of DNA needed to encode the protein complex

can bring catalytic sites close together, allowing intermediates from one reaction to be directly shuttled to a second reaction

can induce COOPERATIVITY, OR ALLOSTERIC EFFECTS

Question 22

why do hydrophobic residues tend to occupy the interior of a protein while hydrophilic residues tend to accumulate on the exterior portions

Answer 22

increases entropy by allowing water molecules on the surface of the proton to have more possible positions and configurations. the positive delta S makes delta G <0, stabilizing the protein

Question 23

conjugated proteins

Answer 23

derived part of their function from covalently attached molecules called prosthetic groups (which can be organic molecules or metals)

Question 24

lipoproteins

Answer 24

proteins with lipid prosthetic groups

Question 25

glycoproteins

Answer 25

proteins with carbohydrate prosthetic groups

Question 26

nucleoproteins

Answer 26

proteins with nucleic acid prosthetic groups

Question 27

heme

Answer 27

a prosthetic group that is in each of hemoglobins subunits (as well as myoglobin)

Question 28

denaturation

Answer 28

a proton loses its 3D structure, although sometimes reversible, often irreversible.

two main causes: heat and solutes