Chapter 6 - Proteins

Protein function

1. Contribute to cell growth, repair, and maintenance. 2. Acts as enzymes, and hormones. 3. Maintain fluid and electrolyte balance. 4. Maintain acid-base balance. 5. Help maintain a strong immune system. 6. serve as an energy source.

No, there is no evidence to support supplementation in health active people.

Are protein or amino acid supplements recommended for the general health population?

Acidosis

Blood becomes acidic because excessive hydrogen. Caused by respiratory or metabolic problems

Alkalosis

Blood becomes basic because not enough of hydrogen. Caused by respiratory and metabolic problems

Two or more foods that together contain all nine essential amino acids necessary for a complete protein.

Complementary proteins

Proteins that contain all nine essential amino acids in sufficient quantities for protein synthesis. Proteins from animal sources are complete proteins.

Complete proteins

Amino Acids not produced by the body that must be obtained from food.

Essential Amino Acid

Tyrosine - made from phenylalanine - people with phynlyketonuria (PKU) cannot metabolize phenylalanine meaning that Tyrosine cannot be produced making tyrosine a conditionally essential amino acid needing to be provided by diet.

Give an example of a conditionally essential amino acid?

By eating a variety of different (non-meat) proteins Mutual supplementation

Give an example of how a vegetarian can ensure he or she receives an adequate supply of all the essential amino acids from plant-based protein sources only.

The essential amino acid that is missing or in the smallest supply in the amino acid pool and thus responsible for slowing or halting protein synthesis.

Limiting Amino Acid

Vegan

Rice, pinto beans, acorn squash, soy butter, and almond milk is an example of what type of diet?

False

True or False? Most protein enzymatic digestion occurs in the mouth.

True

True or False? Proteins act as enzymes and hormones

Protein metabolic pathways

1. Transamination 2. deamination 3. Gluconeogenesis 4. Protein turnover/degradation

Wasted and weakened muscles Stunted physical growth low body temperature Stunted brain development Depressed metabolism Deterioration of intestinal lining Anemia Fluid and electrolyte imbalances

A characteristics of Marasmus include...

Marasmus

A form of protein-energy malnutrition that results from grossly inadequate intakes of protein, energy and other nutrients.

Kwashiorkor

A form of protein-enery malnutrition that is typically seen in developing countries in infants and toddlers who are weaned early because of the birth of a subsequent child. Denied breast milk they are fed a cereal diet that provides adequate energy but inadequate protein.

Nitrogen-containing proteins that combine to form proteins.

Amino Acid

Protein shape

Amino Acid bonding and attraction determine...

The process by which an amine group is removed from an amino acid. the nitrogen is then transported to the kidneys for excretion in the urine, while the carbon and other components are metabolized for energy or used to make other compounds.

Deamination

increased risk of heart and kidney diseases

Describe possible health risks associated with excess protein consumption?

protein needs are higher for children adolescents and pregnant/lactating women because more protein is needed during periods of growth and development. Athletes also need higher amounts of protein.

Describe several of the circumstances which would change the recommended daily intake of protein?

combinations of 20 amino acids

Each protein is made from

Sickle cell anemia

Error in DNA results in changes in quaternary structure of the protein, resulting in changes to red blood cell shape. Amino acid change is Valine is in sixth spot as opposed to a second glutamine

Cystic fibrosis

Error in amino acid order alters chloride transporter resulting in thick mucus in digestive and respiratory systems

Essential Amino Acids

Histidine, Isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine

4 kcal/gram

How much energy is provided by Protein?

Proteins that do not contain all of the essential amino acids in sufficient amounts to support growth and health.

Incomplete protein

No.

Is it necessary to eat complementary proteins at the same meal?

Dairy, Eggs, Legumes, Whole Grains, Nuts

List general sources of protein other than meat.

The process of combining two or more incomplete protein sources to make a complete protein.

Mutual supplementation

Make up 17% of body weight Critical components of all tissues of the human body (used to build and maintain body structure) Function in metabolism, immunity, fluid balance, nutrient transport, providing energy.

Name and explain the reasons why we need proteins.

Amino acids that can be manufactured by the body in sufficient quantities and therefore do not need to be consumed regularly in our diet.

Non-essential Amino Acid

No digestion occurs in the large intestine.

Outline protein digestion and absorption in the Large intestine

Mechanical Digestions - proteins are chewed, crushed and moistened with saliva to aid in swallowing and increase surface area. (There is no chemical digestion at that stage)

Outline protein digestion and absorption in the mouth

Polypeptides and amino acids reach the small intestine. Pancreas and small intestine release enzymes (proteases) to digest polypeptides into oligopeptides, tripeptides, dipeptides, and single amino acids. Cells in the wall of the small intestine absorb single amino acids, dipeptineds and tripeptides. Amino acids transported in portal vein to the liver.

Outline protein digestion and absorption in the small intestine

Gastrin (hormone) controls the production of HCL and the release of pepsin. HCL - Denatures (uncoils and untwists) protein strands so that enzymes can break down polypeptides. Converts inactive enzyme pepsinogen into its active form pepsin. Pepsin - an enzyme in the stomach that begins the breakdown of proteins into shorter polypeptide chains and single amino acids.

Outline protein digestion and absorption in the stomach

Unique set of chemical bonds in which the amine group of one amino acid binds to the acid group of another to manufacture dipeptides and all larger peptide molecules.

Peptide bonds

Protein organization

Primary structure, secondary structure, tertiary structure, quaternary

carbon, oxygen, nitrogen and hydrogen

Proteins contain...

The process that occurs when the genetic information carried by messenger RNA is translated into a chain of amino acids at the ribosome.

Translation

Amine group

The portion of an amino acids that contains nitrogen is called the...

mutual supplementation

The process of combining peanut butter and whole-wheat bread to make a complete protein is called..

Protease

The substance the breaks down polypeptides in the small intestine is called...

The process of transferring the amine group from one amino acid to another to manufacture a new amino acid.

Transamination

The process through which the messenger RNA copies genetic information from DNA in the nucleus.

Transcription

Amino acids

What are the building blocks of proteins?

Reduced intake of fat and total calories, which reduces the risk of obesity. Lower BP Reduced risk of heart disease Fewer digestive problems Reduced risk of some cancers Reduced risk of kidney diseases.

What are the possible health benefits of a vegetarian diet?

protein digestibility is potentially lower than in animal based diets. Potential for inadequate intake of certain nutrients.

What are the possible health risks of a vegetarian diet?

Protein synthesis slows to the point at which proteins cannot be generated.

What happens if the diet lacks one or more of the essential amino acids?

a usually non-essental amino acid that cannot be made because the building block is not found in sufficient quantities.

What is a conditionally essential amino acid?

Soybeans

What is considered the only complete plant protein?

0.8 g per Kg of body weight.

What is the recommended daily intake for proteins?

They will compete for the same absorption site an can block the absorption of other amino acids, causing an imbalance of amino acids leading to various amino acid deficiencies.

What occurs if a person consumes a lot of one amino acid?

Lost

When denatured, protein function is