chapter 17 protein functions in the body (4:02)
TRANSCRIPT
Chapter 17
Protein Functions in the Body (4:02) http://www.youtube.com/watch?v=T500B5yTy58
What is a protein?Large and complex molecules
Made of hydrogen, carbon, oxygen, nitrogen
Often called macromolecules because of their large size containing many atoms.
Nitrogen is a crucial part of protein, gives proteins their variety and versatility
What is a protein? Continued
Human body contains 10,000 to 50,000 different proteins
Made from chemical compounds called amino acids
There are 22 amino acids
Our bodies make all but 9 of them
Structure of Protein Made from chains of amino acidsAmino acids consists of two groups
Carboxyl group, carbon bonded to oxygen by a double covalent bond, and to a hydroxyl group with a single bond (-COOH)
Amine group, two atoms of hydrogen and one atom of nitrogen (-NH2)
Glycine – simplest amino acid
Structure of Protein ContinuedPeptide Bonds, bonds
between nitrogen of one amino acid and the carbon of a second amino acid
Polypeptide, a single protein molecule containing ten or more amino acids linked in peptide chains
Structure and Function Shape determines the proteins function.
Fibrous protein form rope-like fibers, this structure strengthens them to serve as connective tissue in the body such as collagen, hair, skin and nails.
Globular proteins form a rounded shape, this structure makes them convenient carriers such as hemoglobin.
Structure and Function Continued
Protein Denaturation (3:44)http://www.youtube.com/watch?v=v2-iY7ZoDOc
Denaturation is a process of changing the shape of a protein molecule without breaking its peptide bonds.
Coagulation changes a liquid into a soft, semisolid clot or solid mass.
Means of DenaturationHeat – most common
Freezing, pressure, sound waves and addition of certain compounds
Mechanical treatment (beating eggs, kneading dough)
How to Knead Dough (2:45)http://www.youtube.com/watch?v=ySOj0fFWo1U
Very high or very low pH (adding lemon juice)
Metal ions, (Sodium, potassium, copper and iron)
Protein in FoodsEggs – contain almost every vitamin and mineral you need
Meat – contains fibrous proteins called actin and myosin. These proteins form bundles of fibers, which are held together by connective tissue made of collagen and elastin, two proteins with long, strong molecules. Cooking meat is more complex due to variations in fat and types of muscle fibers and connective tissue.
Fish – contain shorter, segmented muscle fibers that are layered between thin sheets of connective tissue. Takes less time to cook.
Nuts and Legumes – carry lots of nutrients, cholesterol free but fat content ranges from zero to very high.
Soybean proteins are equal to that in foods from animals.
Protein in CookingoEmulsifiers – keep foods blended together. Ex:
salad dressing, mayonnaise
oFoams – air bubbles incorporated and trapped in a protein film by whipping. Foam adds volume and lightness to a recipe
oGelatin – animal protein used to set desserts and thicken meat sauces
oGluten – an elastic substance formed by mixing water with the proteins found in wheat, gives baked goods their structure and shape.
Function of Body Proteins1 Structural protein is needed for every cell in
the body. Collagen helps build bones, the ligaments that bind them, the tendons that connect them to muscles, and the muscles themselves.
2 New Growth – replace and repair cells3 Enzymes and hormones that are responsible
for body processes. (hormones aid in growth, balance fluid, regulate metabolism)
4 Transports nutrients in cells. (lipoproteins, oxygen)
5 Antibody proteins help ward off disease6 Stabilize pH levels7 Supply energy if needed
9 Essential Amino Acids Essential Amino Acids you
need to eat every day.
They come from animals source.
Soybeans are the only plant source that provides them
• Unfortunately these contain saturated fat and cholesterol
Two Types of Proteins
Complete Protein – supplies all 9 “essential” amino acids› Meat› Fish› Poultry› Dairy (milk, cheese,
yogurt)
› Eggs › Soy
Incomplete Protein – lacking one or more essential amino acids› Plant sources, must
be eaten in greater variety Rice with beans Legumes Nuts Seeds Grains vegetables
Different Types of Proteins ( 3:07) http://www.youtube.com/watch?v=DRHCVQEIAwc
How much protein do you need?
Depends on…› Age
GenderBody sizeActivity level
Children, pregnant women, and nursing mothers need higher levels
Age 15-18
Multiply your weight by 0.36 to estimate how many grams of protein do you need each day?
Example if you are 130 lbs. You would need 47 grams (130 X 0.36 =46.8)
Food Grams of protein per serving
Tuna (3 ounces) 22
Hamburger (3 ounces) 21
Chicken (3 ounces) 21
Shrimp (3 ounces) 18
Tempeh (½ cup) 15
Yogurt (1 cup) 11
Tofu (½ cup) 9
Lentils, cooked (½ cup) 9
Cow's milk (1 cup) 8
Peanut butter (2 tbsp) 8
Kidney beans, cooked (½ cup)
8
Cheese (1 ounce) 7
Egg, cooked (3 ounces) 7
Soy milk (1 cup) 6
Hummus (1/3 cup) 6
Miso (2 tbsp) 4
Quinoa (½ cup) 4
Bulgur, kasha, oats, cooked (½ cup)
3
Protein Deficiencies
Growth Failure
Loss of Muscle Mass
Decreased Immunity
Weakening of the Heart & Respiratory System
Protein Excesses To much protein
will mainly cause dehydration
Loss in calcium and vitamin B
Which can lead to other mental and physical conditions