ch 5- proteins Flashcards
basic structure of an amino acid
- amino group
- carboxyl group
- side chain
dispensable amino acid
can be manufactured in the liver
indispensable amino acid
- cannot be made by the body
- aka essential amino acids
conditionally indispensable amino acids
- cannot be made by the body during periods of physiological stress
- 6 of the dispensable AAs
branched chain amino acids, muscles can use as an energy source during prolonged endurance exercise when muscle glycogen stores are low
- isoleucine
- leucine
- ## valine
non glucogenic AAs
- leucine
- lysine
proteins as components of enzymes
enzymes are specialized proteins that speed up chemical rxns in cells
proteins as components of hormones and signaling proteins
hormones, many of which are protein based, regulate metabolic processes; signaling proteins are known as growth factors and can bind to the surface of a cell and influence its cellular processes; some AAs stimulate signaling proteins necessary for skeletal muscle protein synthesis
structural proteins
component of muscle, connective tissue, skin, hair, and nails
transport proteins
part of molecules that allow compounds to be transported, such as oxygen, co2, iron, and fats
immune system proteins
fundamental component of the immune system
acid base regulator
AAs have both acid and basic groups, which help the body to achieve acid base balance and optimal pH
fluid regulator
proteins, esp those found in the blood, help to maintain fluid balance
sources of energy
under normal conditions, a minor energy source, under temp stressful conditions, a small but important source of energy; under sever or prolonged stress, such as starvation, a major source of energy but to the detriment of health
mucosal cells shed in GI tract
endogenous protein
branched chain AA supplement
exogenous protein
hard boiled egg
exogenous protein
ezymes
endogenous protein
Dietary proteins and large polypeptides are broken down into smaller polypeptides and amino acids by
strong acids and digestive enzymes
Amino acids are absorbed via
energy-dependent active transport in the presence of sodium Na1 and hydrogen ions (H1)
amino acids leave the cell by
various passive carriers and enter the blood
AA pool: average of how many g of AAs? how much is glutamine?
150 g total; 80 g is glutamine
the amino acid pool is always in flux bc of
protein turnover
most of the AAs in the AA pool come from
the breakdown of body tissues, including skeletal muscle tissue
anabolic
building complex molecules
catabolic
breaking down of complex molecules
transamination
- amino group is transferred to another carbon skeleton
- liver manufactures dispensable amino acids
deamination
- removal of the amino group
- leaves an alpha keto acid or carbo skeleton
The amino acid pool in muscle tissue is derived from
amino acids taken up from the blood, those synthesized in the muscle (de novo synthesis), or those from the breakdown of muscle protein.
AA from the amino acid pool can be used to
synthesize muscle proteins, metabolized for energy via oxidative phosphorylation, or released into the blood for distribution to other tissues in the body.
glucose alanine cycle
pyruvate -> alanine -> liver -> pyruvate -> gluconeogeneis
positive nitrogen balance
- growth
- ex: pregnancy, hypertrophy
rec athlete protein recommendation
0.8 to 1.0 g/kg/d
middle distance runner protein recommendation
1.2 to 1.5 g/kg/d
athlete in an active muscle building phase protein recommendation
2.0 g/kg/d
Athlete returning to a muscle-maintenance phase after an increase in skeletal muscle mass protein recommendation
1.5 g/kg/d for muscle maintenance
ultraendurance athlete protein recommendation
: Adjust protein intake to reflect rest, low volume, and high-volume endurance training phases
post-exercise protein consumption should be
be 0.25 to 0.3 g/kg, with a focus on leucine-containing and whey protein sources.
T or F Protein supplements are neither more nor less effective than food proteins for skeletal muscle growth.
true
The primary structure of the protein determines its:
function
The amino acids that are most rapidly absorbed from the intestine are:
indispensable amino acids
Absorption of food proteins takes place primarily in the:
small intestine
Which athlete would use protein as an energy source to the greatest extent?
ultraendurance athlete
What is the amino acid pool?
amino acids circulating in the blood or fluid between cells
The amount of protein recommended daily for athletes in training on a kg of body weight basis is:
1.0 to 1.8 g
Which of the following is (are) recommended for postexercise intake?
- low-fat chocolate milk
- fruit-in-the-bottom yogurt
- turkey sandwich
Why do athletes who restrict their energy intake need more protein?
More protein will be burned for energy.
Which of the following systems is highly dependent on protein because of rapid cell turnover?
immune
How do whey and casein differ?
Each is comprised of different amino acids.
Which of the following is NOT an example of complementary proteins or mutual supplementation?
tofu and rice
The amino acid considered conditionally indispensable in long distance runners is:
glutamine
What is the mechanism for beta-alanine supplementation?
helps to buffer muscle pH in high-intensity exercise
