CHAPTER 5 PROTEINS (FINAL) Flashcards
what are the functions of proteins in the body (5)?
- structural proteins
- enzymes
- signalling compounds
- transport proteins
- immune system proteins
what 3 things do proteins for in the body?
- growth
- development
- maintenance
what are the 4 protein structures that all proteins have?
- a central carbon
- carboxylate group
- an amino group (NH3+)
- R group
- how are R group structures different?
- how are R groups classified?
- size
- shape
- polarity
- polar, non-polar, charged
- how many amino acids are there?
- how many are essential amino acids?
- how many are non-essential amino acids?
- what are conditional indispensable amino acids?
- 20
- 9/20
- 11/20
- these are amino acids that are not made enough of when there is stress that occurs.
what are the different types of peptides?
- dipeptides (2 AA)
- oligopeptides (30-50 AA)
- tripeptides (3 AA)
what are the preferred sources for for energy?
- fats and CHO
not proteins.
what happens with protein and digestion and where are they digested?
- they are digested in the small intestine, in order for them to be digested they go to the stomach were the protein gets broken down by stomach acid in order for enzymes to target the proteins.
what are BV, PDCAAS, DIAAS?
BV
- the analysis of nitrogen and how much comes in and how much comes out.
PDCAAS
- looks at the amount of amino acids in food and in stool.
DIAAS
- looks at how many amino acids remain.
what is the difference between complete and incomplete proteins?
COMPLETE
- have EAAs in correct quantities / ratios
for human metabolic requirements
INCOMPLETE
Many plant proteins are incomplete (for human protein requirements)
– lysine, methionine
–overcome by complementary plant proteins
– Grains: Lysine-deficient
-Beans: Methionine-deficient
- what denatures proteins?
- HCL activates what?
- Hydrochloric acid
- pepsin
what is positive and negative nitrogen balance?
POSITIVE NITROGEN BALANCE
* Mainly during phases of growth & development (new tissues forming) so
nitrogen is retained
* In adults: mainly occurs during skeletal muscle synthesis
NEGATIVE NITROGEN BALANCE
* Usually undesirable – indicates protein use for energy, or redirected for other
purposes (injury, infection, stressors)
* Can still occur with high protein intake if overall energy intake is too low
with chronic supplementation, what happens to the other amino acids?
- other amino acids become imbalanced.
how are amino acids absorbed into the liver?
portal vein
what is the function of the liver with amino acids?
- the liver functions as regulator for supply and circulation of free amino acids.
under starvation conditions, protein will be catabolized in two
phases?
short term
- a labile protein reserve (in visceral tissues – mainly liver, provides a limited AA supply; skeletal muscle is more protected
long term
- skeletal muscle catabolized to protect visceral organs
name the 3 BCAA?
(think ine)
- leucine
- isoleucine
- valine
how many AA are catabolized for gluconeogenesis?
- 18/20
- what is the RDA for sedentary people and athletes for protein intake?
- what is the UL for protein intake?
- SED
- 0.8g/kg/d - ATH
- 1.2-2.0g/kg/d - 2.5g/kg
how much more protein does a vegetarian athlete need to consume than a non-vegaterian athlete?
~10% more.
how much protein is recommended per meal?
- fast and slow absorbing protein.
- 25-30g per meal
what is the recommended amount of protein intake after exercise?
- 0.25-0.30g/kg after. (~15-25g) within 2 hours.
immune system has what affect with peptides?
- peptides attack forge in bodies when they enter the body
what is food intolerance?
- caused by inability to digest or absorb certain substances (e.g. lactose, fructose)
- May involve pharmacological reactions (i.e. “side effects”) to certain chemicals found in food
