Proteins

Question 1

What are the components of a protein? What is different about the structure than CHO or fat?

Answer 1

Components of Protein:
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
o Some also contain sulfur atoms

• Role that proteins play in the body are far more varied than CHO or Fat
• More complex: Arranged as strands of Amino Acids

Question 2

What structures make up an amino acid? How many are there? What are essential AA? Do not memorize the names of the individual amino acids.

Answer 2

• Amino acids are the building blocks of proteins
• Amino means “nitrogen containing”

Each contains the following components:
* Amine group (nitrogen-containing group)
* Acid group (COOH)
* Chemical side chain
* 20 amino acids with 20 different side chains make up most of the proteins of living tissues!

• What makes some of the amino acids essential (body can’t produce it)???
• The body cannot make them.
• ~9 amino acids are essential

Question 3

How are proteins made? What type of bonds forms? What happens to protein production when an AA is missing?

Answer 3

Protein Synthesis: an OH group from the acid end and an H atom from the amino group of another join to form water where a peptide bond forms and creates a dipeptide (2 amino acids), tripeptide (3 amino acids), polypeptide (4+ amino acids)

If essential AA, protein synthesis will stop and the unfinished chain will be broken down into individual AA’s. if nonessential AA, then it can be made or obtained from the liver.
Name and describe the functions of body proteins.

Question 4

Name and describe the functions of body proteins.

Answer 4

1.) growth & maintenance
2. enzymes
3. hormones
4. antibodies
5. fluid balance
6. acid-base balance
7. transport proteins
8. energy source

Question 5

Digestion: where it takes place, enzymes, what happens to the protein along the way (Figure 6-7).

Answer 5

Denaturation: change in shape of protein brought on by heat, alcohol, acids, bases, salts, or other agents
1st step in protein breakdown1.
Enzymes: ALL enzymes are proteins!
* Work as catalysts to help chemical reactions take place - “biological spark plugs”
* Surface of the enzyme is contoured so that it can only recognize the substance it works on
* Mouth (No digestion here) -> stomach(pepsin: enzyme in stomach)-> small intestine(proteases: enzymes from pancreas and small intestine)(peptidases: enzymes on surface of small intestine)-> large intestine
Look at pg. 13 NTDT Exam 2 Review

Question 6

Recommended intakes – be able to calculate the RDA for protein!

Answer 6

• 2 recommendations: % of total calories or as an absolute number (grams per day)
• DRI Committee: 10-35% total calories
• Recommended protein allowance (RDA): 0.8g/kg of desirable body wt per day
• Uses desirable vs. actual because it is proportional to lean body mass

Calculate RDA for Protein:
* Find the desirable weight for a person your height. Assume this weight is appropriate for you.
* Change pounds to kg (divide by 2.2)
* Multiply kg by 0.8 g/kg!

Example:
* Example (for 5’8” male)
* Desirable wt: ~150 lbs*

150lb/2.2= 68

Desirable weight:
68 times 0.8= 54g protein