Chapter 18- Amino acids and proteins

Question 1

Secondary structure

Answer 1

regular folding patterns seen in localized regions of polypeptide backbone

a and B helix

Question 2

Tertiary structure

Answer 2

Overall shape of protein molecule produced by overall bedding and folding of a protein chain

3

Non covalent interactions and disulfide covalent bonds

A helix and B helix, loops connect

Question 3

Quaternary structure

Answer 3

Overall structure of proteins composed of more than one polypeptide

Question 4

Enzymes

Answer 4

Catalyze biochemical reactions

Ex. Amylase begins digestion of carbohydrates by hydrolysis

Question 5

Hormones

Answer 5

Regulate body functions by carrying messages to receptors

Ex. Insulin facilitates use of glucose for energy generation

Question 6

Storage proteins

Answer 6

Make essential substances available when needed

Ex. Myoglobin stores oxygen in muscles

Question 7

Transport proteins

Answer 7

Carry substances through body fluids

Ex. Serum albumin carries fatty acids in blood
Fatty acids can not easily go through blood because non polar

Question 8

Structural proteins

Answer 8

Provide mechanical shape and support

Example. Collagen provides structure to tendons and cartilage

Question 9

Protective proteins

Answer 9

Defend body against foreign matter

Ex. Immunoglobulin AIDS in destruction of invading bacteria

Question 10

Contractile proteins

Answer 10

Do mechanical work

Ex. Myosin and actin govern muscle movement

Question 11

Zwitterion

Answer 11

Neutral ion with one positive charge and one negative charge

Very soluble

High melting point

Question 12

Isoelectric point

Answer 12

pH at which sample of an amino acid has equal numbers of + and - charges

Net charge= 0

Question 13

Enantiomers /optical isomers

Answer 13

Two mirror -image forms of chiral molecule like alanine

Type of stereoisomers have same formula and atoms with diff connections

Only L in proteins

Question 14

Primary structure

Answer 14

Order

Sequence of amino acids in protein chain connected by peptide bonds

along backbone of protein chain is alternating peptide bonds and a-carbon atoms

DETERMINES PROTEIN SHAPE

Question 15

Globular protein

Answer 15

Water soluble chain is folded in a compact shape with hydrophilic groups

Many are enzymes

Overall shape is tertiary

Question 16

Fibrous proteins

Answer 16

INSOLUBLE

Keratin

Collagen

Elastin

Myosin

Fibrin

Question 17

Keratin

Answer 17

Found in skin, wool, feather, hooves, fingernails

Fibrous

Question 18

Collagens

Answer 18

Animal hide, tendons, bone, eye cornea, other CT

Fibrous

Question 19

Elastins

Answer 19

Blood vessels, ligaments

Fibrous

Question 20

Myosins

Answer 20

Muscle tissue

Fibrous

Question 21

Fibrin

Answer 21

Found in blood clots

Fibrous

Question 22

Globular proteins

Answer 22

SOLUBLE , hydrophilic groups on outside

insulin

Ribonuclease

Immuglobulins

Hemoglobin

Albumins

Question 23

Insulin

Answer 23

Control glucose metabolism

Globular

Question 24

Ribonuclease

Answer 24

Enzyme that catalyzes RNA hydrolysis

Globular

Question 25

Immunoglobulins

Answer 25

Involved in immune response Globular

Question 26

Hemoglobin

Answer 26

Oxygen transport Globular

Question 27

Albumins

Answer 27

Perform many transport function in blood; protein in egg white Globular

Question 28

Native protein

Answer 28

Shape in which it functions in living systems

Question 29

Simple protein

Answer 29

Protein composed of only amino acid residues

Question 30

Conjugated protein

Answer 30

Aided by its function by non-amino acid unit Ex. Myoglobin

Question 31

Edmar degradation

Answer 31

Cleaves N-terminal amino acid of polypeptide chain (left)

Question 32

Chemical properties of proteins

Answer 32

Heat Mechanical agitation Detergents Organic compounds pH change Inorganic salts

Question 33

Denaturation

Answer 33

Loss of secondary, tertiary, or quaternary protein structure leaves primary intact Irreversible

Question 34

Functions of proteins

Answer 34

Transport necessary chemicals Support organs or tissues Protect against foreign substances Storage of energy

Question 35

Saponification reaction used to form soaps can be best describe as

Answer 35

Base hydrolysis

Question 36

Soaps

Answer 36

Salts of carboxylic acids Alkali metal salts of long chain carboxylic acids

Question 37

Basic structure of cell membrane consists of

Answer 37

Phospholipid bilayers studded with proteins

Question 38

Lecithin commonly used as

Answer 38

Emulsifying agent

Question 39

Heat affects

Answer 39

Hydrogen bonds and hydrophobic interactions

Question 40

Acids and bases affect

Answer 40

Hydrogen bonds and salt bridges

Question 41

Agitation affects

Answer 41

Hydrogen bonds and hydrophobic interactions

Question 42

Organic compounds are affected by

Answer 42

Hydrophobic interactions