Proteins

Made of amino acids Amino acids are the

building blocks of protein- they are organic acids

Contain nitrogen – sets them apart from lipids and carbohydrates (prefix amine means contains nitrogen).

Each amino acid has side chains that gives it its identity

The 20 Amino AcidsWhat do they have in common?

• All contain Nitrogen

• All have a carboxyl group

Essential / Non-Essential

Essential Nonessential

Histidine Alanine

Isoleucine Arginine

Leucine Aspartic acid

Lysine Cysteine

Methionine Glutamic acid

Phenylalanine Glutamine

Threonine Glycine

Tryptophan Proline

Valine Serine

Tyrosine

Asparagine

Non-Essential – amino acids produced by the body.

Essential – amino acids the body does not produce. Must obtain through diet.

The 20 amino acids are like letters and form different sequences

The number of protein combinations is greater than the number of English words (more than 100,000 unique proteins)

A single human cell may contain 10,000 different proteins

Protein Shape

Proteins are extremely large molecules with complex shapes

Shape determines function

Artist renderings of 6 different protein molecules. Each contains thousands of amino acids.

Protein Uses

Creating DNA Catalyzing reactions in cells Transporting other molecules Structurally supporting cell walls Immune responses (many proteins fight

disease) Red blood cells (hemoglobin) Involved in some way in virtually every

cellular process

Dehydration Synthesis

Removal of water creates a C-N peptide bond. All amino acids are connected via peptide bonds.

Denaturation

Proteins do not dissolve in water The change in a proteins shape

brought on by Heat acids or bases alcohol

They unfold. Necessary to break down into

individual amino acids.

Sources of Protein Complete Proteins (all 20 amino acids)

All meats and animal products- eggs, cheese Fish Legumes - alfalfa, clover, peas, beans, lentils, mesquite,

carob, soybeans (tofu and soy products), peanuts, tamarind

Buckwheat Quinoa

Incomplete proteins Nuts Some grains / rice

Fish vs. Land Animals

Protein structure in fish has less connective tissue and liquefies easily.

More tender and cooks quickly Flakes when cooked

Digestion

Denatured by acid Starts in mouth Continues in stomach by acids Worked on in intestines until broken into

single amino acids where they are then absorbed

Circulated through blood

Some more easily digested than others Animal proteins

complete proteins easy to digest and absorb - 90%

Legumes Also complete but harder to digest - 80%

Grains/ plants Incomplete Vary in ability to digest - 60-90%

Each protein is designated for a special purpose in a particular tissue of a specific kind of animal or plant

Protein breaks down to amino acids and rearranges them into specific human body proteins.

Role of proteins1. Support new tissue growth

2. Hemoglobin – red blood cells

3. Fluid and electrolyte balance – cell transfer

4. Provide energy, when carbs and fat in short supply

5. Hormones to regulate body functions

6. Immune system – large proteins act as antibodies to protect against disease

Protein Deficiency

33,000 children die a day Marasmus- calorie deficiency

disease Kwashiorkor- protein deficiency

disease

Kwashiorkor

Marasmus