-muscles, organs, and tissue are comprised of significant amounts of protein
What vit/min do animal proteins provide more effectively than plants
Animal products provide an excellent source of B vitamins and minerals such as iron, zinc, and calcium
What role does hydrochloric acid play in protein digestion?
it denatures proteins to make them more accessible to enzyme attack and activates the protein-digesting enzyme pepsin
What sizes of amino acid chains can enter the bloodstream via mucosal cells?
tripeptides, dipeptides, and single amino acids
What are the enzymes used in protein digestion what do they do and where are they found?
-pepsin breaks proteins into polypeptides and amino acids in the stomach.
-trypsin and chymotrypsin break polypeptides into tripeptides, dipeptides, and amino acids in the small intestine
What causes certain amino acids to compete for absorption? What problems can this create?
-Amino acids with similar structures share the same transport system
-if too much of one amino is ingested, other amino's that share the same transport system may not be absorbed causing deficiencies
What is anaphylaxis
An immediate and severe allergic reaction to a substance (e.g., food or drugs). Symptoms include breathing difficulty, loss of consciousness, and a drop in blood pressure and can be fatal.
How do proteins trigger food allergies?
They occur when protein from the diet is absorbed without being completely digested. The first time it happens the immune system is stimulated . The second time the immune system sees it as a foreign substance and attacks.
What can increase a persons chances of developing allergies?
gastrointestinal disease- damaged intestines allow the absorption of incompletely digested proteins
immature gastrointestinal tracts(in infants)- more likely to allow larger polypeptides to be absorbed
what is the amino acid pool?
All of the amino acids in body tissues and fluids that are available for use by the body.
When are amino acids metabolized to provide energy?
When the diet contains protein in excess of needs and when the diet is low in energy.
Under regular circumstances what are amino acids used for?
synthesis of body proteins and other nitrogen-containing compounds
What does "protein turnover" describe
The continuous nature of synthesis and degradation of body proteins.
What is transcription?
The process of copying the information in DNA to a molecule of mRNA, occurs in the nucleus.
What is translation?
The process of translating the mRNA code into the amino acid sequence of a polypeptide chain.
What is deamination
The removal of the amino group from an amino acid.
What is the limiting amino acid
The essential amino acid that is available in the lowest concentration in relation to the body's needs(lowest Amino Acid Score)
What can the carbon of an amino acid be used for after deamination?
-Can be broken down to form 3-carbon compounds and used by the liver to synthesize glucose via gluconeogenesis
-converted into acetyl-CoA or compounds that directly enter the citric-acid cycle to synthesize ATP
How is Ammonia eliminated from the body?
1-it is converted to urea in the liver and sent out into the bloodstream
2- the urea is filtered out of the bloodstream by the kidneys and eliminated from the body in urine
during starvation what percentage of protein loss from the body for energy can be fatal?
What are the 8 types of proteins?
4-Proteins that Provide Protection(antibodies)
7-Proteins that Regulate Fluid Balance(movement in and out of cells)
8-Proteins that Regulate Acid-Base Balance(buffers)
What is kwashiorkor
A form of protein-energy malnutrition in which only protein is deficient.(bloated belly)
What is marasmus
A form of protein-energy malnutrition in which a deficiency of energy in the diet causes severe body wasting.(extreme weight loss)
What effects does excess protein consumtion have on the kidney and bone health?
kineys - more water is needed to excrete amplified amounts of urea (no negative effect on healthy kidney although a diet high in protein and low in fluid may promote kidney stones)
Bones- essentially none because as more calcium is excreted in urine more is absorbed intestinally
What is phenylketonuria (PKU)
An inherited disease in which the body cannot metabolize the amino acid phenylalanine. If the disease is untreated, toxic by-products called phenylketones accumulate in the blood and interfere with brain development.
What is celiac disease?
A disorder that causes Autoimmune damage to the intestines when the protein gluten is eaten
what is the differency between a food allergy and a food intolerance?
A food intolerance is not an immune response to the ingested protein. The negative effects stem from how a certain protein acts in the body when ingested.(can include autoimmune responses such as celiac disease)
What is nitrogen balance?
The amount of nitrogen(protein) consumed in the diet compared with the amount excreted by the body over a given period
how is Nitrogen loss or output measured?
by totalling the amounts of nitrogen excreted in urine and feces and that is lost from skin, sweat, hair, and nails
What is the Rda for protein in adults?
0.8 g/kg of body weight per day
What can increase protein breakdown in the body?
Extreme stresses on the body such as infections, fevers, burns, or surgery
What is complete dietary protein?
Protein that provides essential amino acids in the proportions needed to support protein synthesis such as that found in animals
What is incomplete dietary protein?
Protein that is deficient in one or more essential amino acids relative to body needs such as those found in plants.
What is protein quality?
A measure of how efficiently a protein in the diet can be used to make body proteins.
What is a chemical or amino acid score?
A measure of protein quality determined by comparing the essential amino acid content of the protein in a food with that in a reference protein. The lowest amino acid ratio calculated is the chemical score