Proteins

Question 1

Functions of proteins

Answer 1

Antibodies, enzymes, messenger molecules, receptor molecules, structural components (collagen) and transport/storage molecules such as hemoglobin or albumin.

Question 2

What does each amino acid contain

Answer 2

1. Amino functional group (N terminus group) H2N which is to the left of the alpha carbon. Base.
2. Hydrogen (above alpha carbon)
3. R chain (radical= varying) which is below the alpha carbon
4. Carboxyl functional group COOH (C terminus group) to the right of the alpha carbon. Acid.

Question 3

Amino group structure and property

Answer 3

R- NH2
Polar accepts H+ to form NH3

BASE ACCEPTS

Question 4

Carbonyl structure and property

Answer 4

O
||
R-C-R(or H)

Polar

Question 5

Carboxyl structure and property

Answer 5

O
||
R-C-O-H

Polar, ionizes to release H+

ACID RELEASES

Question 6

A base ___ H+ and an acid ___ H+

Answer 6

a base accepts and an acid releases

Question 7

Hydroxyl structure and property

Answer 7

R-O-H

Polar

Question 8

Methyl structure and property

Answer 8

CH3 Nonpolar

Question 9

Phosphate structure and property

Answer 9

R- PO3H2

Polar, ionizes to release H+ (Acid)

Question 10

Sulfhydryl

Answer 10

R-S-H Polar, forms disulfide bonds

Question 11

What functional groups indicate an acid

Answer 11

Anything that is ok with releasing an H+.

Carboxyl group and phosphate group
(Aspartic acid and glutamic acid)

both are also polar

Question 12

What functional groups indicate bases

Answer 12

Anything that wants to accept an H+.

Amino group (R-NH2)

Also polar

Question 13

Condensation reactions

Answer 13

one of two reactions that occur in order to form long chains of amino acids. Either the joining of 2 molecules by dehydration (loss of water)

or the splitting of 2 molecules by hydrolysis (gain of water)

Question 14

Where do peptide bonds form on amino acids

Answer 14

They form between a carboxyl group on one and the amino group on another by dehydration reaction

Question 15

Primary structure bonds

Answer 15

Peptide, covalent

Question 16

Secondary structure bonds and examples

Answer 16

H bonds between alpha helix backbone and beta sheet backbone (parallel or antiparallel)

Question 17

Tertiary structure bonds

Answer 17

• H bones
• Ionic bonds
• Van der waals
• hydrophobic interactions (clustering of hydrophobic molecules away from water)
• disulfide bridges

Gives an overall 3D shape

Question 18

Quaternary structures

Answer 18

Multi-subunit proteins such as dimers (2 polypeptides) or tetramers (4 polypeptides)

Question 19

Based on the tertiary/quaternary structure, proteins are grouped in 2 general classes

Answer 19

Fibrous and globular

Fibrous proteins are elongated, insoluble in water, tend to have structural roles such as collagen or elastin

Globular proteins are compact and spherical, are amphipathic, tend to have roles other than structural such as enzyme, Antibodies, hemoglobin

Question 20

Characteristics and roles of fibrous tertiary/quaternary proteins

Answer 20

Fibrous proteins are elongated, insoluble in water, tend to have structural roles such as collagen or elastin

Question 21

Characteristics and roles of globular tertiary/quaternary proteins

Answer 21

Globular proteins are compact and spherical, are amphipathic (hydrophilic on outside and hydrophobic on inside AKA insoluble in water), tend to have roles other than structural such as enzyme, Antibodies, hemoglobin