Protein Flashcards
Composed of C, H, O, N, and sometimes S
Protein
Only nutrient that can make new cells and rebuild tissue.
Protein
Basic material of every body cell.
Protein
Composed of amino acids linked by peptide bonds.
Protein
Greek word that means “holding first place” and term coined by Mulder (Dutch Scientist) in 1840.
Protein
Molecule w/ a central carbon to which an amino group, a carboxyl group and a functional group are attached.
Amino acid
How many amino acid are needed by the human body?
20
How many from the 20 AA are considered essential, which must be supplied by the diet?
10
General structure of AA
central carbon, amino group, a carboxyl group and a functional group
AA classification
Functional groups, Pathway of catabolism, essentiality
Functional groups
Basic, acidic, neutral
Basic Functional group AA
lysine, arginine, histidine
acidic Functional group AA
aspartic acid, glutamic acid
neutral Functional group AA
glycine, serine, threonine, etc
2 pathway of catabolism
glucogenic, ketogenic
AA that can be catabolized to produce glucose (gluconeogenesis)
glucogenic
AA that can be catabolized to produce acetyl-CoA (-> ketone bodies) and ipids
ketogenic
3 classifications of Essentiality of AA
essential, nonessential, conditionally essential
Indespensable AA
Essential
Dispensable
Nonessential
Indispensable at certain life stages
Conditionally essential
Essential AA
(PVTTIMHALL) Phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, histidine, arginine, leucine, lysine
Conditionally essential
Proline, serine, tyrosine, cysteine, taurine, glycine
Nonessential
Glutamate, alanine, aspartate, glutamine
Protein classification
structure, shape, composition
4 levels of protein structure
primary structure, secondary structure, tertiary structure, quaternary structure
Classification of protein by shapes
fibrous, globular, membrane
Proteins which are long coiled or folded chains of AA bound in parallel line and insoluble in water and dilute salt solutions; serve in structural roles
Fibrous
Protein which are coiled, tightly wound structure & roughly spherical; relatively water soluble; constitute most of the soluble proteins in the cell
Globular
Proteins associated with various membrane systems; insoluble in aqueous solutions; more hydrophobic AA
Membrane
Example of Fibrous protein
keratin
Example of globular protein
hemoglobin
Example of membrane protein
phospholipid membrane
Protein classification by composition
simple, conjugated, derived
Protein which are primary components are AA
simple
Proteins which are composed of AA and other components
conjugated
Proteins which are products of partial hydrolysis
derived
Examples of simple proteins
albumin (egg white), globulins (egg yolk), glutenins or glutelins (wheat, rice), prolamines (wheat, corn) scleroproteins (bones, connective tissues)
protein source with amino acid score: 100%
animal origin
Biological functions of protein
Enzymes - to accelerate rates of biological reactions
Regulation of body processes - to assist in the ability of other proteins to carry out their functions (hormones)
Storage - to provide reservoir like hemoglobin
contraction and motility - for muscles
structure - to provide strength like collagen and keratin
protection - to enhance immunity like immunoglobulins
amino acid score of animal origin
100%
Examples of conjugated proteins
glycoproteins, lipoproteins, nucleoproteins, phosphoproteins, metalloproteins, hemoproteins, flavoproteins, mucoproteins
General functions of protein
- body building or structural
- essential for growth
- source of energy (secondary)
- regulator of body processes
- transport of certain substances
Examples of derived proteins
Primary - edestan, myosan, metaproteins, coagulated proteins
Secondary - proteoses, peptones, and peptides
protein source with true digestibility: 95-98%
animal origin
true digestibility of animal origin
95-98%
protein source which concentrations increase after cooking
animal origin
protein source which includes pulses, cereal & cereal products
plant origin
protein source with amino acid present, could be 1 or more limiting amino acids
plant origin
plant origin examples
pulses, cereal & cereal products
how many limiting amino acid present in a plant origin?
one or more limiting amino acids
protein source with true digestibility in natural foods: 70-85%
plant origin
true digestibility of plant origin
70-85%
bioavailability of protein in pulses
20-25%
bioavailability of protein in flour
7-12%
meat alternative made from soy protein and other ingredients to simulate various kinds of meat
meat analogues
textured vegetable protein (TVP) and tofu
meat analogues examples
Capacity of food proteins to provide nitrogen and essential AA for human growth and functions
Protein quality
- checks AA content & efficiency of digestion
- lower protein quality means more intake of protein