5C. PROTEINS

Proteins

* Sequenced amino-acids joined by %%peptide bonds%% or %%amide groups%%

Monomers of Proteins

Amino acids

What do proteins usually contain?

Carbon, hydrogen, nitrogen, oxygen, usually sulfur, and occasionally other elements (phosphorus or iron)

Functions of Proteins

1. ==Energy Source== - Nutrients for the body
2. @@Transport and Storage of Nutrients@@ - Such as Hemoglobin
3. $Repair and Maintenance$ - Building block of body
4. %%Enzymes%% - Increase the rate of chemical reactions in the body
5. ^^Antibodies^^ - Form antibodies to fight off bad bacteria and viruses
6. ==Hormones== - Formation of hormones like insulin and secretin

How are Proteins formed?

Amino Acids → Peptide → Proteins

Amino Acid Structure

Composed of


1. Alpha (α) carbon (Central C)
2. Carboxyl Group (COOH)
3. Amino Group NH2)
4. Hydrogen Atom
5. Side Chain (R)

Essential Amino Acids

* Can only get from food
* 9 are essential:
* Histidine
* Isoleucine
* Leucine
* Lysine
* Methionine
* Phenylalanine
* Threonine
* Tryptophan
* Valine

Conditionally Essential amino acids

* Can be produced in a healthy state
* Abnormal or stressed states are unable to produce them
* Arginine
* Cysteine
* Glutamine
* Glycine
* Proline
* Tyrosine

Non-essential amino acids

* Our bodies can make them, also obtainable from food
* Alanine
* Asparagine
* Aspartic Acid
* Glutamic Acid
* Serine

What is the R Group?

It determines the identity of the amino acid. Basically, it could be anything.

Peptide bonds

* Connects one amino acid to another
* Carboxyl group of an amino acid reacts with the amino group of another amino acid

ROLE 1 - Structural Proteins

* Strength and shape in the structures of organisms
* collagen and keratin in ligaments, tendons, and cartilage

ROLE 2 - Contractile Proteins

* For strength and movement of muscles
* Actin and myosin

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ROLE 3 - Storage Proteins

* Source of nitrogen for developing embryos
* Ex. ovalbumin; found in eggs

ROLE 4 - Defensive Proteins

* Protects the body against diseases
* Ex. protein antibodies, blood-clotting proteins

ROLE 5 - Transport Proteins

* Transport substances in the body
* Hemoglobin

ROLE 6 - Hormonal proteins

* Help coordinate body activities, usually found in proteins
* Ex. Insulin, glucagon, other hormones

ROLE 7 - Receptor Proteins

* Enables the body cells to respond to chemical stimuli
* Ex. receptors in a nerve’s cell membrane

ROLE 8 - Catalytic Proteins

* A.K.A. Enzymes or catalysts
* Speeds up chemical reactions
* Structure is significant

Enzyme Activity

* Substrate: Molecule that is catalyzed by an enzyme
* Two types of enzyme activity:
* Lock and key model
* Induced fit model

Sickle Cell Anemia

* Change in the @@amino acid composition of hemoglobin@@
* Shape turns into a %%more vulnerable sickle shape%%
* The sixth amino acid is usually replaced ^^from glutamic acid to valine^^
* ==Valine== has ==hydrophobic== properties
* @@Glutamic@@ acid has @@hydrophilic@@ properties