Chapter 5

Amino acids

Building blocks of protein composed of carbon, hydrogen, oxygen, and nitrogen atoms.

Essential amino acids

Amino acids that the body cannot synthesize in sufficient amounts to meet physiological needs.

Nonessential amino acids

Amino acids that the body can synthesize naturally.

Conditionally essential amino acids

Amino acids that are normally nonessential but must be supplied by the diet in certain circumstances when needed in greater amounts.

R group

The side group of an amino acid that distinguishes one amino acid from another. same side as group

Functions of protein

Make, maintain, and repair cells; build structures; produce enzymes, lubricants, and clotting compounds; transport substances; make antibodies and hormones; maintain fluid and acid-base balance; provide energy.

pH

Potential of Hydrogen; a measure of the acidity of a solution.

Antibodies

Large proteins produced in response to foreign molecules (antigens) that invade the body.

Wasting

A form of malnutrition characterized by thinness for height, indicating recent rapid weight loss.

Marasmus

Severe malnutrition characterized by poor growth, dramatic weight loss, and loss of body fat and muscle.

Kwashiorkor

Severe malnutrition characterized by failure to grow and develop, edema, and changes in pigmentation.

Marasmic kwashiorkor

A severe form of malnutrition where lean tissue loss is masked by edema.

HCl in protein digestion

Hydrochloric acid converts pepsinogen into pepsin, which breaks down proteins.

RDA for protein

Recommended Dietary Allowance of 0.8 g/kg of body weight.

AMDR for protein

Acceptable Macronutrient Distribution Range: 10-35% of total energy intake.

Vegetarianism dangers

Risks include low energy and deficiency in high-quality proteins.

Vitamins lacking in vegetarian diets

Vitamin B12, D, and riboflavin.

Minerals lacking in vegetarian diets

Minerals like zinc, iron, and calcium.

Semivegetarian

Diet that includes eggs, fish, and dairy while generally avoiding meat.

High-quality protein sources

Include meat, fish, poultry, eggs, milk, and milk products.

Lipoproteins

Molecules that carry fats in the bloodstream.

Transferrin

Protein that carries iron in the blood.

Acids

Compounds that release hydrogen ions in a solution.

Bases

Compounds that accept hydrogen ions in a solution.

Protein as a buffer

Proteins can help maintain acid-base balance in the blood.

Complementary proteins

Two or more proteins that provide all essential amino acids when consumed together.

Lacto-vegetarian

A vegetarian who includes dairy products in their diet but does not consume meat or eggs.

Ovo-vegetarian

A vegetarian who includes eggs in their diet but does not consume meat or dairy products.

Lacto-ovo vegetarian

A vegetarian who includes both dairy products and eggs in their diet but avoids meat.

Pescatarian

A person who follows a diet that includes fish but excludes other meats.

Flexitarian

A mostly vegetarian diet that occasionally includes meat or fish.

Vegan

A person who does not consume any animal products, including meat, dairy, and eggs.

Protein as a buffer

Proteins can help maintain acid-base balance in the blood.

Antibodies

Proteins that help the body maintain its resistance to disease.

Carbohydrate consumption and protein preservation

Adequate carbohydrate consumption can prevent proteins from breaking down to make glucose.

HCl in protein digestion

Hydrochloric acid breaks down protein structure (denaturation) and activates pepsin.

Protein Digestion Begins

Protein digestion begins in the stomach with pepsin, an enzyme that breaks down proteins into short polypeptides and amino acids.

Complementary proteins

Two or more proteins whose amino acid assortments complement each other, supplying essential amino acids missing from one with the other.