UNIT 1: Proteins

Question 1

Amino Acids

Answer 1

Molecules that have an amino group and a carboxyl group.

• There are 20
• Each has it’s own unique side chain based on its chemical and physical properties.

Question 2

Sidechains

Answer 2

R groups that branch off of amino acids. Their interaction determines the shape and function of the protein.

• Nonpolar: Hydrophobic carbon based groups that may contain sulfur.
• Polar: Hydrophilic with either oxygen or nitrogen that cause partial charges,
• Charged / Ionic: Hydrophilic and either + or -

Question 3

Amino Acid Structure

Answer 3

All amino acids contain a carboxyl group, hydroxyl group, and a hydrogen on the central carbon.

Question 4

Functions of proteins

Answer 4

• Antibodies: fight / protect from diseases
• Messengers: Transmit signals
• Transportation / Storage: Bind to carry small atoms / molecules through the body
• Enzymes: Carry out chemical reactions or assist in creating new molecules.
• Structural: Provide structure and support.

Question 5

Peptide Bonds

Answer 5

Form when the carboxyl group of one amino acid is positioned next to the amino group of another amino acid and a dehydration reaction combines them.

Question 6

Polypeptides

Answer 6

Many amino acids linked by peptide bonds and determines the 3D shape based on sequence of amino acids.

Question 7

Protein Shape

Answer 7

Determines Function!!!

Question 8

Primary Structure

Answer 8

A linear chain of amino acids determined by genes and which dictates the secondary and tertiary forms.

Question 9

Secondary Structure

Answer 9

When the polypeptide begins to coil and fold due to hydrogen bonding within the backbone.

• Pleated Sheets: Hydrogen bonds between polypeptide chains lying side by side
• Helix: Hydrogen binding between every fourth amino acid.

Question 10

Pleated Sheets

Answer 10

A secondary structure in which Hydrogen bonds between polypeptide chains are lying side by side.

Question 11

Helix

Answer 11

A secondary structure in which Hydrogen binding occurs between every fourth amino acid.

Question 12

Tertiary Structure

Answer 12

3D folding due to interactions between the side chains (R groups) of the amino acid.

Question 13

Disulfide Bridges

Answer 13

When covalent bonds form between the sulfurs in 2 different cystine molecules.

Question 14

Quaternary Structure

Answer 14

When there is an association of two or more polypeptides (proteins).

• Found only in some proteins
• EX: Hemoglobin works with 4 other proteins.