Protein

Question 1

Overview of Protein

Answer 1

• Body is made up of thousands of protein
  substances
• Contains atoms called nitrogen
• Regulates and maintains body functions– Eg. Enzymes, hormone

Question 2

Amino Acid composition

Answer 2

R group- R

Amino Group- H-C-NH2

                 O
                 || Acid group- C----- OH

Question 3

Amino Acid Description

Answer 3

• Building block of proteins
• Most basic unit of proteins
• R group differentiates amino acid

Question 4

Protein Organization

Answer 4

• Peptide bond = connection between amino acids
• Dipeptide = 2 connected (bonded) amino acids
• Tripeptide = 3 connected (bonded) amino acids
• Polypeptide ≥ 50 amino acids bonded together

Question 5

Essential AA

Answer 5

Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine

Question 6

Nonessential AA

Answer 6

Alanine
Arginine
Asparagine
Aspartic Acid
Cysteine
Glutamic acid
Glutamine
Glycine
Proline
Serine
Tyrosine

Question 7

Types of Dietary Protein

Answer 7

High Quality
- Complete

Low Quality
- Incomplete

Question 8

All or none principle in protein synthesis

Answer 8

Need all essential AA present or protein cannot be made

Question 9

Limiting Amino Acid

Answer 9

This refers to the essential AA that is missing but required for protein synthesis

Question 10

Complementary protein

Answer 10

Two food protein sources that make up for each other’s in
adequate supply of specific essential amino
acids

Question 11

Conditionally Essential AA

Answer 11

amino acids which
are only essential in times of
stress or injury. Otherwise, they
are nonessential.

Question 12

Complementary Protein

Answer 12

Grains + Veggies
Nuts/Seeds + Beans
Nuts/Seeds + Veggies

Question 13

Soy

Answer 13

• Soy protein is similar to animal protein (used in school lunches)
• High in linoleic acid and alpha-linolenic
  acid
• Calcium source and bone health
• Isoflavones – phytochemicals– Heart disease– Cancer

Question 14

Protein Turnover

Answer 14

Protein undergo breakdown and synthesis

• Protein balance = protein equilibrium
• Positive protein balance = dietary protein
  intake exceeds protein lost
• Negative protein balance = dietary protein
  intake is less than protein lost
• Responds to chang

Question 15

Denaturation of Proteins

Answer 15

Heat/acid/alkaline/enzymes

Results in alteration of the protein’s three-dimensional structure

Question 16

Protein Content in Food

Answer 16

Fat, Oils and sweets- Low

Milk, yogurt, cheese- High

Vegetables- Medium
Bread, cereal, rice, pasta- medium

Fruit- Low

Question 17

Plant Protein

Answer 17

• Provide protein, minerals, and dietary fiber
• Contain no cholesterol
• Limited saturated fats
• Allow a few weeks for the GI tract to adjust
  to the higher fiber

Availability of Beano®

Question 18

Digestion of Protein

Answer 18

• Proteins are denatured by cooking and acid in the stomach
• Gastrin stimulates the release of acid and pepsin
• Pepsin is activated and breaks down proteins to
  smaller amino acid chains
• Hydrolysis = breaking down of peptide bonds by enzymes

Question 19

Digestion of Protein in the Small
Intestine

Answer 19

• Pancreas release the protein splitting
  enzymes: trypsin, chymotrypsin, and
  carboxypeptidase into the duodenum
• The enzymes will break peptide bonds
  forming smaller peptides and amino acids
• Peptides and amino acids are ready for
  absorption

Question 20

Protein Absorption

Answer 20

• Absorbed across the intestinal walls into
  blood capillaries
• Amino acids are sent to the liver via portal
  vein

Question 21

Functions of Proteins

Answer 21

• Building blocks of body components
• Maintain fluid balance– Edema
• Contribute to acid/base balance – Buffer

Question 22

Functions of Proteins

Answer 22

• Building blocks for hormones and enzymes
• Immune function
• Gluconeogenesis: glucose synthesis from
  lipids or protein
• Energy yielding

Question 23

Is a High-Protein Diet Harmful?

Answer 23

• Low in plant foods (fiber), vitamins,
  phytochemicals
• High intake of animal protein increases risk for
  heart disease (high in saturated fat)
• Excessive intake of red meat is linked with colon
  cancer
• Burden on the kidney
• Increase calcium loss

Question 24

Individual Amino Acid
Supplement

Answer 24

Supplement may cause imbalances and
toxicities
* Body is designed to handle whole proteins
* Supplement can overwhelm the absorptive
mechanism
* Excess of one AA can hamper absorption of
other AAs

Question 25

Malnutrition

Answer 25

Protein-Energy Malnutrition
– Consuming insufficient amounts of protein & energy
– Hospitalization
– Diet
– Marasmus, Kwashiorkor:
* Especially persons who already have a disease e.g.
Infection
* Primarily in children

Question 26

Kwashiorkor

Answer 26

• Moderate energy deficit & severe protein deficit
• “Disease that the first child
  gets”
• Signs and symptoms:– Apathy, listlessness, failure
  to grow, poor weight gain,
  change in hair color,
  nutrient deficiency, flaky
  skin, fatty infiltration in the
  liver, massive edema in the
  abdomen and legs

Question 27

Marasmus

Answer 27

• Severe protein and energy
  deficit
• Starving to death
• “skin and bones” appearance
• Little or no subcutaneous fat
• Reduce brain growth