Proteins

Question 1

Proteins

Answer 1

Polymers w/amino acid monomers

Question 2

Protein Functions

Answer 2

• structural roles (eg. keratin and collagen)
• enzymes that speed up chemical reactions
• transport substances within the body
• transport substances across cell membranes

Question 3

Monomer of: Proteins

Answer 3

Amino Acid

Question 4

Functional groups of: Protein

Answer 4

• amino group (H2N is nitrogen group)
• acid group (COOH can disassociate making H+, thus more acid)
• R-group (remainder group; 20 diff kinds)

Question 5

Essential Amino Acids

Answer 5

Must be consumed in our diet since the body cannot produce it (=essential!)

Question 6

Non-essential Amino Acids

Answer 6

Can be made in the body and therefore not essential to consume them in our diet.

Question 7

Structure of Amino Acid

Answer 7

H H
    |  |   
H-N-C-C=O
       |   |
      R  OH

• Amino group H2N
• Acid group COOH
• R-group

-all around central C

Question 8

Dipeptide

Answer 8

Amino acid + amino acid = 1 dipeptide + 1 H2O (peptide bond formed by dehydration reaction)

Question 9

Polymer of proteins

Answer 9

Polypeptide

• a single chain of amino acids w/peptide bonds (dehydration reaction)
• N-C-C-N-C-C-N-C-C

Question 10

Peptide Bonds

Answer 10

• joins 2 amino acids covalently
• Acid group COOH reacts w/amino group of another H2N in a dehydration reaction
• links C to N creating uneven charge distribution (allowing H-bonds = shapes)

Question 11

Levels of Protein Organization

Answer 11

• 4 structures overall
• can be complete @ 3rd or 4th
• shape of protein is very important to its function
• cannot function properly if the shape has been tampered with

Question 12

Primary Structure

Answer 12

Polypeptide chain in linear sequence. They are differentiated from one another by their specific sequence of R-groups in the chain.
-peptide bonds

Question 13

Secondary Structure

Answer 13

Polypeptide chain in primary changed to Alpha (helix) or Beta (pleated sheet)
-H-bonds

-peptide + H-bonds

Question 14

Tertiary Structure

Answer 14

Single Polypeptide chain 3D in shape w/both Alpha and Beta structures in it. Can be complete at this stage.

• disulfide bonds (to condense & twist into 3D shape)
  (eg. Enzymes)

-peptide + H-bonds + disulfide

Question 15

Quaternary Structure

Answer 15

2+ tertiary polypeptide chains that have their own structure and create another when bonded together.
(eg. Hemoglobin)

Question 16

How do Primary structures differ from one another?

Answer 16

By the sequencing of amino acid R-groups (up to 20 diff types not including combinations)

Question 16

Denaturation

Answer 16

Occurs when a protein is exposed to extreme heat or pH so that it undergoes an irreversible change in shape.
Once its original shape is lost it can no longer perform its usual function.
Eg. heat - egg whites coagulating
Eg. pH - milk curdling