Proteins Flashcards
Describe how the chemical make up of proteins differs from that of carbohydrates and fats.
Proteins contain nitrogen (along with carbon, hydrogen and oxygen like carbs and fats). The side groups on the central carbon vary from one amino acid to the next making them more complex.
Why are some, but not all amino acids, essential?
The body can make all nonessential amino acids, given nitrogen to form the amino group and fragments from carbohydrate or fat to form the rest of the structure. The essential nine amino acids must be supplied by the diet. Sometimes a nonessential amino acid becomes essential under special circumstances.
What are the consequences should an essential amino acid be lacking from the diet?
impaired protein synthesis, negative nitrogen balance, metabolic disruptions and impaired immune function
How and where are proteins digested?
mouth (chewing foods and mix with saliva to swallow), stomach (hydrochloric acid HCI uncoils protein strands, activating stomach enzymes), small intestine and pancreas (enzymes split polypeptides which are then hydrolyzed and absorbed in the small intestinal cells)
What is the fate of amino acids once they are digested and absorbed?
Amino acids may be used for energy or to synthesize needed compounds. Those not needed in the intestinal cells are transported across the membrane to the liver
What are the major functions of protein in the body?
- act as structural materials (muscles, blood, skin, collagen)
- act as enzymes (break/build substances like bone)
- act as hormones
- as regulators of fluid balance
- as acid-base regulators
- as transporters
- as antibodies
- as source of energy/glucose
How can the plant-based foods in a vegetarian diet be combined to make complementary (complete) proteins?
Complementary proteins: two or more dietary proteins whose amino acid assortments complement each other in such a way that the essential amino acids missing from one are supplied by the other.
What are the 2 major forms of protein malnutrition.
Marasmus and kwashiorkor
What are the reasons why consuming too much protein is not recommended?
Excess protein consumed is usually stored as fat, while the surplus of amino acids is excreted. This can lead to weight gain over time, especially if you consume too many calories while trying to increase your protein intake.
