1

Protein•Definition

•Functions

•Incomplete vs. Complete

•Sources

Introductory Video

2

Functions• Grows and repairs tissues

• Regulates body functions

• Transports nutrients and oxygen

• Supplies energy when carbohydrates and fats don’t supply adequate amounts

McGill Video

StructureStructure of Amino Acids:

McGill Video

3

Structure

4

Amino Acids•The main component of every cell in the human body

•Amino Acids are the building blocks of Protein

• 20 Amino Acids

• 9 are Essential McGill Video

Methionine Tryptophan Threonine

Valine Isoleucine Leucine

Proline Histidine Lysine

Arginine Semi-essential – needed for children

5

SourcesEssential/CompleteEssential Amino Acids are required by animals but can only be

supplied by the diet (not synthesized in the body) Animal sources• Supply all 9 essential Amino Acids•Examples: Chicken, Fish, Milk, Eggs *Soy*

IncompletePlant sources•Supply only a few essential Amino Acids•Examples: Peanut Butter, Legumes, Rice

Review the bar graphs below that represent the proportion of amino acids in corn and rice.

These two food sources are considered to be incomplete proteins because:

7

Combinations

You can combine two incomplete sources of protein to make it complete.

• Peanut Butter and Bread

• Beans and Rice

• Hummus and Pita Chips

McGill Video

8

Amounts

Too Much Protein in the Diet

Too Little Protein in the Diet

• Increases workload of the digestive system• Strains the liver and kidneys

Ketosis – body burns fat instead of glucose for energy- causes organs to fail, gout, bad breath

• Causes malnutrition, increased risk of infection• Could possibly cause early death

Kwashiorkor – bloated stomach

9

RDA

Recommended Dietary Allowance for Protein

Grams/Day

Children ages 1 – 3 13Children ages 4 – 8 19Children ages 9 – 13 34Girls ages 14 – 18 46Boys ages 14 – 18 52

Women ages 19 – 70+ 46

Men ages 19 – 70+ 56

Examples of Protein:

1 egg = 6 g

1 c. milk = 8 g

8 oz. yogurt – 11 g

1 c. beans = 16 g

3 oz. meat = 21 g

10

Calories per gram

Protein =4 calories/gram

So how many estimated calories from protein does an egg contain?

6 grams x 4 calories = 24 calories

11

Calories per gram

Protein =4 calories/gram

How many calories from protein are in a cup of milk?

12

Eggs – The “Perfect” Protein

Why are Eggs considered the “perfect” protein?

•Highest Quality Protein•Contain ALL 20 Amino Acids•Helps you feel full•Possesses many nutrients

Benefit of Eggs Video

13

Parts of an Egg

Parts of a Chicken Egg Description of Each Part

Shell The hard coating of an egg, made of calcium carbonate. Gas can exchange but nothing else can enter.

Inner and Outer Membrane Outer – shell is built around this and prevents dirt and bacteria from entering.Inner – Surrounds the white and the yolk.

Air Sac Empty space located at the large end of the egg; the larger the air sac, the older the egg.

Albumen The white part of an egg. There is no fat in the white.

Germinal Spot/Disc A white spot on the yolk. This is where the sperm enter the egg and contains the egg’s DNA. “Nucleus”

Yolk Contains all the fat and cholesterol of an egg and essential nutrients.

Chalaza Twisted strands of fibers. Holds the yolk in the center of the egg.

14

Parts of an Egg

How well do you know the parts of an egg?

Test your knowledge:

Parts of an Egg Board Activity

15

Parts of an Egg

GROUP ACTIVITY:

Carefully break a raw egg into a custard cup or bowl.

Inspect the yolk and white and feel both with your fingers.

Answer the questions on the study sheet provided.