HUBI 2002 - Section 7

Protein

A three dimensional polymer made of amino acids.

20

How many amino acids are in a protein?

9

How many amino acids are essential, i.e. they are not synthesized in the body?

20

How many amino acids must be present at the same time for protein synthesis?

Side chain (R group)

What differs between each amino acid?

Peptide bond

Single amino acids with different side chains can bond to form what?

As their sidechains variously attract and repel each other

Why do protein strands coil?

Forms a functional shape

Purpose of a protein coil foling

- Used to build proteins

- Converted to other small, nitrogen containing compounds (e.g. thyroid hormone)

- Converted to other amino acids

- Once the nitrogen is removed, it's converted to glucose, burned as fuel and converted to fat

What happens to amino acids once they are absorbed?

Acid-base balance

Proteins help to maintain the acid-base balance of body fluids by acting as buffers

Antibodies

Proteins form the immune system molecules that fight diseases.

Blood clotting

Proteins provide the netting on which blood clots are built

Energy

Proteins provide some fuel for the body's needs

Enzymes

Proteins facilitate needed chemical reactions

Fluid and electrolyte balance

Proteins help maintain the water and mineral composition of various body fluids

Growth and maintenance

Proteins form integral parts of most body tissues and serve as building materials for growth and repair of body tissues, such as skin, connective tissues, muscles, organs, and bone.

Hormones

Proteins regulate body processes.

Transportation

Proteins help transport needed substances, such as lipids, minerals, and oxygen, around the body

Vision

Various proteins called opsins are important for both colour and night ___________.

Dietary protein

It is nutritionally essential to provide amino acids and nitrogen for the synthesis of body proteins and other nitrogen-containing molecules.

Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine

List the essential amino acids

- Pattern of essential amino acids

- Digestibility (generally, animal > plant and cooked > raw)

How well does a dietary protein supply the essential amino acids? This is determined by:

High-quality protein

Has all the essential AA in amounts needed by humans and is mostly of animal origins.

Soy (high lys) and gelatin (low trp)

Exception for high-quality proteins (not animal origin)

Low-quality protein

Plant foods (legumes, vegetables, cereals, grains) and limiting AA

First limiting amino acid

The essential amino acid that first become deficient in the diet

Complete protein

A protein that contains all the essential amino acids

Mutual supplementation

The process of combining two or more incomplete protein sources to make a complete protein

Red meats, poultry, total dairy, eggs, pulses, and nuts

Major sources of protein in the Canadian diet

Animal > plant, cooked > raw

Digestibility rating

Animal > plant

Quality rating

0.8 g protein / kg body weight

How much protein do you NEED (for "normal" adults)?

Protein

If you're eating enough calories, you're eating enough _______________.

Growth/repair, inadequate energy, pregnancy/lactation, and high intensity exercise

What situations would cause a need for an increase in protein intake?

Extreme diets, wasting diseases, elderly, and food insecurity

What can cause protein undernutrition?

46 g/day

How much protein is a woman recommended to eat per day?

56 g/day

How much protein is a man recommended to eat per day?

Plant-based protein, because is low in saturated fat but high in fibre.

What protein source should you eat if you're mindful of your heart health, and why?

10%-15%

What percentage of our daily calorie intake should consist of protein?

Omnivore

A consumer that eats both plants and animals

Fruitarian

A person who primarily eats fruits, nuts, honey, and vegetable oils

Lacto-ovo vegetarian

Excludes all animal flesh but does include eggs and dairy products such as milk and cheese

Lacto-vegetarian

Includes dairy products, vegetables, grains, legumes, fruits, and nuts; excludes flesh, seafood, and eggs

Macrobiotic diet

A vegan diet that is composed mostly of whole grains, beans, and certain vegetables—taken to extremes, macrobiotic diets can compromise nutrient status.

Ovo-vegetarian

Includes eggs, vegetables, grains, legumes, fruits, and nuts; excludes flesh, seafood, and milk products

Partial vegetarian

A term sometimes used to mean an eating style that includes seafood, poultry, eggs, dairy products, vegetables, grains, legumes, fruits, and nuts; excludes or strictly limits certain meats, such as red meats.

Pesco-vegetarian

Same as partial vegetarian but eliminates poultry

Vegan

Includes only food from plant sources.

Vegetarian

Includes plant based foods and eliminates some or all animal-derived foods