dada

Bond between amino acids is called

peptide bond

The order of amino acids in the polypeptide

chain determines

a protein’s shape/ structure

protein denaturation

the

irreversible change in a

protein’s folded shape

what causes protein denaturation?

heat, agitation, acid,

base, alcohol, soaps, salts

Digestion of Protein

Denatured, pepsin, Pancreatic protease enzyme

Denatured

• By cooking

• By acid in the stomach

pepsin

• Enzyme produced and released by the

stomach.

• Breaks polypeptide into shorter chains of amino acids

Pancreatic protease enzymes

• Released into small intestine

• Continue to break down polypeptides and peptides into

smaller units

Absorbable units

amino acids, di-peptides and

tri-peptides

DNA is the code for

proteins

RNA is the ‘helper’ that translates

DNA’s code

into proteins.

protein synethsis requires..?

energy

RNA converts the

code into protein

gene expression

Gene ‘turned off’

no protein made

Gene ‘turned on

protein made

Protein Turnover

The

continuous breakdown and synthesis of body proteins involving the recycling of amino

acids.

When protein synthesis = protein degradation

Protein equilibrium

When synthesis > degradation

Positive protein balance (gaining protein)

When synthesis < degradation

Negative protein balance (losing protein)

amino acids uses

Amino acids can be used to build proteins, make other substances the body needs, or provide energy

Proteins supply little energy

for a weight- stable person.

how are proteins used for energy

When protein is used for energy, the amino group is removed, and the remaining carbon skeleton is used for energy. The nitrogen waste is converted into urea and removed in urine.

To be used for energy, nitrogen??

must first be removed from amino acids!

Protein provides the highest feeling of

satiety after a meal: No longer a desire to eat; a feeling of

satisfaction.

High-quality protein

Dietary proteins that are

readily digestible and contain all 9 essential amino

acids in the amounts that humans need.

Low-quality protein

lack in one or more of the

essential amino acids

High quality proteins examples

egg, meat, fish, poultry, dairy

low quality proteins exammples

Vegetables, nuts, seeds, grains,

legumes

Complementary proteins

two plant protein sources that are combined because each makes up for the essential amino acids the other one lacks.

Adults:

0.8 g protein / kg body weight / day

Protein Amounts in the New 2025 DGAs

Prioritize protein at every meal.”

• “Protein serving goals: 1.2-1.6 g protein/kg body weight per day

Most Americans exceed the

RDA