Midterm Section 3.3 - Protein/Body Comp Flashcards
(32 cards)
main functions of protein/AA
maintenance and regulation of body functions
growth
repair and response to injury
energy (converted to glucose, converted to fat or burned as fuel)
thyroid hormone requires which amino acid precursor?
tyrosine
definition of an essential nutrient
performs an identifiable biological function
abnormality results from lack of consumption
body cannot make it, or cannot make enough to satisfy demand
insulin peptides are held together with
disulfide bonds
enzymes and chemicals that break down proteins
HCl denatures protein structures
activated pepsin hydrolyzes peptide bonds
pancreatic bicarbonate denatures pepsin
pancreatic peptidases hydrolyze peptide bonds
dipeptidases on brush border
SNP
single nucleotide polymorphisms - single change of an amino acid in sequence can create disease state, such as sickle cell anemia
heterozygous genes for sickle cell have resistance to malaria
PKU
phenylketonuria - change of phenylalanine hydroxylase, needed to create enzyme to break down phenylalanine
nutritional genomics categories
nutritional genomics - interactions of food and genes, includes:
nutrigenetics - examines how genes influence activities of nutrients
nutrigenomics - include epigenetics, examines how nutrients affect expression of genes
how nutrients can affect gene expression
nutrients can turn on or off genes, or interacting with intermediates
protein synthesis up or down regulated which directly affects disease progression or prevention
protein turnover in a healthy adult
is in equilibrium: same amount synthesized, same amount broken down
does increased protein intake alone drive increase muscle mass?
no, requires weight training or increased protein requirements due to illness/injury/stage of life/poor absorption
30g in one sitting required to trigger protein synthesis
percent nitrogen in protein and nitrogen balance equation
16%
Nitrogen balance = N intake - N fecan - N urinary
how ammonia is never free in the body
it is toxic, transferred from one amino acid to another in intermediate keto acid form
delivered to liver for urea cycle
AA required for urea cycle
arginine, required for ammonia detoxification into urea
nephron definition and numbers
working unit of the kidney
more than 1 million nephrons in one kidney
nephron anatomy
blood flows into the glomerulus where fluid and substances are absorbed in the tubule
reabsorption of nutrients and fluid along the descending tubule
adequacy of dietary protein (3)
- adequate energy intake, otherwise amino acids will be catabolized
- protein quantity: official RDA is .8g per kg/day, AMDR 10-35%
- quality - having all EAA in relative amounts similar to need
usual intake of protein vs. RDA
athletes recommendation
unofficial recommendation
100g/day vs .8g per kg/day (~56g)
1.2-2 g per kg/day, 1.7g per kg/day for female athletes
unofficial recommendation is 1.2g per kg/day
what is a limiting amino acid
AA present in the lowest amount, relative to the body’s need for it
all others are comparatively present in excess and must be degraded
DIAAS
Digestible Indispensable Amino Acid Score
expressed as a percent of dietary requirement relative to .66g (EAR protein) of the test protein
test protein is lowest DIAAS score
above 100 is considered excellent
homeostasis defition
dynamic processes maintain constant internal environment despite changing external environment (often relies on negative feedback)
in energy production pathways, which intermediates have a one way arrow between them? meaning?
pyruvate to acetyl coA, ketogenic amino acids to acetyl coA
this means that ketogenic amino acids cannot produce glucose and an excess of acetyl coA will become ketone bodies
cellular respiration pathway (basic)
glucogenic AA pathway for energy
glucose (or glycogen) –> pyruvate by pyruvate decarboxylase –> acetyl coA –> krebs cycle and ATP
AA –> pyruvate –> lactase to leave cell –> back to liver to convert into glucose
postprandial
fed state
