Unit 15 Flashcards
(34 cards)
What is protein made out of?
Amino Acids
Major function of protein
construction, maintenance, and repair of protein tissues
Protein synthesis proceeds only when…
ALL amino acids are available
Chains of amino acids create?
Protein
the body can and cannot produce what amino acids?
CAN –> non-essential amino acids
CANNOT –> essential amino acids
How many essential amino acids
9
How many non-essential amino acids
11
Protein digestion in the GI tract
Mouth -> stomach -> Small Intestine
Protein Digestion in GI Tract: Mouth
moisten and mechanical crushing
Protein Digestion in GI Tract: Stomach
HCl denatures protein, then it converts the pepsinogen into pepsin
Pepsin
acts to cleave large polypeptides into smaller polypeptides (makes them smaller and smaller)
Protein Digestion in GI Tract: Small Intestine
Trypsin and Chymotrypsin break down polypeptides smaller.
Carboxypeptidases and
aminopeptidases “chew” along from
the ends to release amino acids.
this happens in walls of SI
free amino acids absorbed into blood system
Protein Function in body (detailed)
- construction
- enzymes
- hormones
- fluid balance
- transport (liporoteins)
- acid-base regulation *picks up H ions
- antibodies
- energy
How much energy does protein provide
4 kcal/g
What does protein contain that fat and carbs do not?
Nitrogen
can be used for muscle/components, excess comes out at urea
Glucose, fat and protein are stored as
Glucose –> Glycogen
Fat –> Triglycerides
PROTEIN CONSUMED IN EXCESS CANNOT BE STORED
What can be converted to glucose if need be?
amino acids
Fat cannot be converted
Dietary Proteins
Animal (digested easier)
>90% digested
Plants (harder to digest)
legume 80%
grains and other plants 60-90%
can a protein be built without the proper amino acids
no, synthesis would stop completely
Complete VS Incomplete Protein Quality
Complete: all essential amino acids present for protein formation (i.e. meat)
Incomplete: missing some essential amino acids (i.e. plants)
What is missing for incomplete Protein
Lysine (grains) and methonine (legumes)
if both are eaten together then all essential amino acids are present and it is a complete protein
Dietary Protein Requirements (3)
Postive nitrogen balance
Nitrogen Equlibrium
Negative nitrogen balance
Positive Nitrogen Balance
retain more protein than excrete
- growing children, muscle, pregnancy
Nitrogen Equilibrium
normal healthy
