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What percentage of the human body is protein
- -about 15%
- -muscles, organs, and tissue are comprised of significant amounts of protein
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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
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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
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What sizes of amino acid chains can enter the bloodstream via mucosal cells?
tripeptides, dipeptides, and single amino acids
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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
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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
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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.
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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.
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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
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what is the amino acid pool?
All of the amino acids in body tissues and fluids that are available for use by the body.
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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.
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Under regular circumstances what are amino acids used for?
synthesis of body proteins and other nitrogen-containing compounds
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What does "protein turnover" describe
The continuous nature of synthesis and degradation of body proteins.
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What is transcription?
The process of copying the information in DNA to a molecule of mRNA, occurs in the nucleus.
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What is translation?
The process of translating the mRNA code into the amino acid sequence of a polypeptide chain.
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What is deamination
The removal of the amino group from an amino acid.
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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)
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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
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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
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during starvation what percentage of protein loss from the body for energy can be fatal?
30%
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What are the 8 types of proteins?
- 1-Structural Proteins
- 2-Enzyme Proteins
- 3-Transport Proteins
- 4-Proteins that Provide Protection(antibodies)
- 5-Contractile Proteins(muscles)
- 6-Protein Hormones
- 7-Proteins that Regulate Fluid Balance(movement in and out of cells)
- 8-Proteins that Regulate Acid-Base Balance(buffers)
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What is kwashiorkor
A form of protein-energy malnutrition in which only protein is deficient.(bloated belly)
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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)
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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
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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.
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What is celiac disease?
A disorder that causes Autoimmune damage to the intestines when the protein gluten is eaten
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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)
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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
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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
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What is the Rda for protein in adults?
0.8 g/kg of body weight per day
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What can increase protein breakdown in the body?
Extreme stresses on the body such as infections, fevers, burns, or surgery
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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
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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.
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What is protein quality?
A measure of how efficiently a protein in the diet can be used to make body proteins.
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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
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What are the 4 classes of vegetarianism?
- Vegan - Grain with legumes, seeds and nuts
- Lacto vegetarian - + milk
- Lacto-Ovo Vegetarian - +eggs
- Pesco Vegetarian - +fish
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