Transcript Protein - HCC Learning Web

Module 3.2
Proteins:
from foods to cells in
the body
By Jennifer Turley and Joan Thompson
© 2013 Cengage
Presentation Overview
1.
2.
3.
4.
5.
6.
7.
Denaturation vs. digestion
Synthesis
Character & types
Function
Quality
Needs (recommended intake)
Deficiency vs. excess
Protein Denaturation
 Causes

protein to change shape or conformation
protein & amino acids are still intact
 Can
be caused by heat, alkali or acid treatments,
or metals
 Is
required before the protein can be digested
Protein Denaturation
 The
protein strand is broken and the amino acids
are released.
 Occurs
by the protease enzymes secreted by the
pancreas and GI mucosal cells
 Amino
acids are absorbed, transported to cells and
then used to build proteins
Protein Synthesis
 Eat
protein  denature & digest protein  absorb
and transport amino acids to cells  protein is
made (i.e. synthesized) inside cells according to DNA

Protein is synthesized in a process of converting
DNA to RNA to protein
Gene Encodes Protein
Protein Synthesis inside the cell
Protein Character
 Protein


Character is determined by:
How the 20 amino acids are combined together
The polypeptide strand folding & interacting with itself
Types of Protein
Fibrous
 Uniform in structure
Globular
 Have variation in structure

Either exclusively
helical or sheet
formation

Are part helical, part sheet,
part random, or completely
random

Examples are the
proteins found in hair,
muscle fibers & finger
nails

Examples of globular
proteins include blood,
mucous, milk protein and
egg white
Protein Functions- both low & high quality proteins
1.
Growth & tissue maintenance (replace, repair & possibly
2.
Enzymes (catalysts)
3.
Antibodies, complement proteins, circulating
components of immunity
4.
Fluid & electrolyte balance (free proteins)
5.
Acid - base balance (H donors & acceptors)
6.
Energy (4 Cals/gm, requires N removal)
7.
Protein hormones like insulin & glucagon, secretin &
cholecystokinin
8.
Transportation of nutrients (lipoproteins)
add)
Recommended Intake
Eric weighs 90 Kg and ate 88g of protein and 3000
Calories in one day
 What
is his DRI for protein?
 90Kg x 0.8g/Kg = 72g protein
 What

% of his DRI for protein did he consume?
(88g ÷ 72g) x 100 = 122%
 What
% of Calories in his diet came from protein?
 88 g protein x 4 Cal/gm = 352 Cals from protein
 352 Cals ÷ 3000 Cals x 100 = 11.7%
Protein Deficiency
Protein deficiency is called
Kwashiorkor. The individual has
peripheral edema and may not
look undernourished

Severe deficiency is called Marasmus.
The individual looks undernourished
(skin & bones, starvation)

Kwashiorkor

Both conditions occur primarily in 3rd world countries

In the U.S. individuals who are on starvation diets, poor,
abused, or in hyper-metabolic states can experience
Kwashiorkor or Marasmus
Protein Deficiency
Protein deficiency is called
Kwashiorkor. The individual has
peripheral edema and may not
look undernourished

Severe deficiency is called Marasmus.
The individual looks undernourished
(skin & bones, starvation)

Marasmus

Both conditions occur primarily in 3rd world countries

In the U.S. individuals who are on starvation diets, poor,
abused, or in hyper-metabolic states can experience
Kwashiorkor or Marasmus
Excess Protein
 Most
common in athletes & fad dieters
 Increases






risk of:
Dehydration
Liver & spleen enlargement
Accelerated kidney aging
Metabolic acidosis (with low carbohydrate intake)
Vitamin B6 deficiency, Ca & Zn loss
Heart disease & cancer
Body Builders- Sample Diet

Meal 1: Cooked cereal, 12 egg whites, banana, 1 piece
whole wheat toast, coffee, water, vitamin/mineral &
amino acid supplements

Meal 2 (Pre-workout): Protein powder, carbohydrate
powder, amino acids

Meal 3 (Post-workout): 8oz poultry, rice, sweet potato,
corn, non-starchy vegetable, amino acids

Meal 4: 7oz fish, rice, salad, potato, water, amino acids

Meal 5: 8oz beef, potato, mixed vegetable, water, amino
acids

Meal 6: Cooked cereal, 10 egg whites, amino acids
Body Builders- Sample Diet Analysis
 5500
Calories
 36%
Calories from protein,
49% carbohydrate & 15% fat
 Inadequate
in vitamin E (83% DRI)
and Calcium (75% DRI)
What it takes to build muscle
 One
pound of muscle is: 75% water, 20% protein &
5% other material like fat, glycogen, minerals and
enzymes
 One
pound of muscle equals 105 grams protein
 To
gain one pound muscle in 2 weeks an athlete
would need an extra 7-8g protein/day intake
 1oz
meat, 1 cup milk, 3 slices bread
Summary
 Dietary
protein is denatured then digested
 The
amino acids from dietary intake are used by
cells to make proteins by converting DNA to RNA
to protein
 Protein
character is determined by amino acid
sequence
 Proteins
types: fibrous & globular
 Proteins
have many functions in the body
Summary
 Protein
deficiency is called kwashiorkor
 Protein
excess can led to negative health affects
References for this presentation are the same as those for this topic found in module 3 of the textbook