Chapter 5 Proteins Flashcards
basic structural component of proteins
amino acids
what distinguishes protein build from carbs, fats, and alcohol
nitrogen
what is the nitrogen content of an amino acid
16 percent
how many amino acids does the body use to make proteins
20
the differences in amino acid ___ play critical roles in the functions of the proteins
structures
how many of the amino acids are considered indispensible
9
why are some amino acids considered indispensible
the body cannot manufacture them
what makes 11 of the amino acids dispensible
they are naturally created by the liver
how many of the 11 amino acids are considered conditionally indispensible
6
why are some amino acids considered conditionally indispensible
because during periods of stress, the body cannot manufacture a sufficient amount
what determines protein quality
the amounts and types of amino acids and the extent to which the amino acids are absorbed
Who determines the current recommendation for protein quality
Food and Agricultural organization of the United Nations
What score determines protein quality
digestible indispensable amino acid score (DIAAS)
indispensable amino acids are found in lower concentration in what form of protein
plant protein
complete proteins- contain all indispensable amino acids
animal proteins
incomplete proteins
plant proteins
greatest concern for indispensable amino acids
lysine, threonine, cyseine and methionine
combining 2 or more incomplete proteins
complementary proteins
two or more amino acids combined
peptide
specifically, two amino acids
dipeptide
three amino acids
tripeptide
four or more amino acids
polypeptide
protein and _____ are use interchangeably
polypeptide
_____ and _____ are terms commonly used when discussing digestion and absorption
dipeptide and tripepetide
polypeptides are synthesized on ___
ribosomes- organelles found in large numbers in the cytoplasm of cells
the ___ strucutre of a polypeptide determines how a protein functions
primary
what structure affects the shape of the protein
secondary- result of bonding of amino acids that are close to each other
The third level of structure (tertiary) is the result of
interactions of amino acids that are located far away from each other
What structure levels creates a loop
third
quaternary level structure involves more than one ____
polypeptide- like insulin
body proteins are classified in ___ major categories
five
what are the 5 major categories of body proteins
enzymes, hormones, structural proteins, transport proteins, and immune system proteins
enzymes are ____
polypeptides
enzymes are needed to ___ reactions
catalyze- speed up
what is the purpose of enzymes
regulate the speed of chemical reactions- like metabolizing nutrients
hormones act as chemical messengers to regulate __ ____
metabolic reactions
____ is the most abundant amino acid in the amino acid pool
glutamine
where is glutamine synthesized
skeletal muscle
sarcopenia
muscle wasting
milk proteins are rich in ___
leucine- stimulator of signaling proteins within skeletal muscle cells
structural proteins include the proteins of ___ and ____ tissue
muscle and connective tissue
proteins of the skin, hair, and nails
structural
hemoglobin
transport protein- carries oxygen and carbon dioxide in the blood
lipoproteins
transport proteins- carry lipids through the body
cells that produce antibodies
lymphocytes
majority of amino acids absorbed with remain where
liver
absorption of amino acids takes place primarily where
middle and lower small intestine
what does teh hydrochloric acid (Hcl) in the gastric jucie do to the protein
denatures it- changes the structure
what does HCl activate that breaks down polypeptides
pepsin- an enzyme
what are the preferred amino acids that peptin breaks down
leucine and tryptophan
how are amino acids absorbed
through energy dependent active transport through the presence of sodium and hydrogen ions
how do amino acids leave the cell
passive transport- will enter the blood through this
where does protein absorption take place
small intestine
two thirds of amino acids are absorbed in what form
dipeptides or tripeptides
____ amino acids are absorbed more frequently
indispensible
what does predigested protein mean
it is hydrolyzed and can be absorbed faster
exogenous
originate from outside the body
endogenous
originating inside the body
amino acids that are not incorporated into cellular proteins will be released into the blood via ___
the portal vein - liver
branched chain amino acids
leucine, isoleucine and valine
where do BCAA go
through the plasma and are taken up by skeletal muscle
what percentage of amino acids will be absorbed in the liver after a meal
50-60 percent
protein turnover
the flux in amino acids in the amino acid pool that changes through exercise food and breaking down/building of muscle tissue
how much energy in the resting metabolism is expended each day synthesizing and degrading proteins
10-25 percent
anabolic
building complex for molecules from simple ones
catabolic
breaking down of complex molecules into simple ones
the use of protein for energy is what kind of process
catabolic
deamination
removal of the amino group from the amino acid
what is the remaining compound after an amino group is removed
alpha-keto acid- carbon skeleton
transamination
transfer of an amino group to another carbon skeleton-amino acid is formed
____ allows the liver to manufacture dispensable amino acids from indispensable amino acids
transamination
albumin
protein that circulates in the blood to help transport nutrients to tissues
a ___ state occurs when the synthesis of proteins is greater than their breakdown
anabolic
what is the kcal/g of protein
4 kcal/g
protein sparing effect
sufficient caloric intake in the form of carbs and fat
how many amino acids are broken down to yield energy from muscle cells
leucine, isoleucine, and valine, aspartate, asparagine, and glutamate
proteolysis
breakdown of muscle
break down of muscle (proteolysis) is stimulated by what stress hormone
cortisol- secreted in the adrenal glands
endurance exercise utilizes what amino acid
leucine
what percentage of total energy comes from amino acids
3-5%
how many amino acids can be converted into glucose
18- leucine and lysine cannot
what is produced as a result of protein catabolism
ammonium
on average an adult body turns over about ___ g of protein a day
300 g- 1-2 percent of total protein is degraded per day
at least __ g of nitrogran is excreted per day
5 g= 30 g of protein
nitrogen balance
difference between total nitrogen (protein intake) and total nitrogen loss ( urine and feces)
in growth state what is the nitrogen balance in the body
positive and positive net protein balance
labile protein reserve
reserve of amino acids in the liver and other organs known as viscerla tissues
DRI for adults for protein is what
.8 grams of protein per kilgram of body weight daily
general recommendation for protein intake in trained athletes is
1.2-2.0 g/kg/day
what are the two assumption made for recommendations of protein intake in trained athletes?
- total energy intake is adequate
- quality of protein is good
protein rec for recreattional athletes training at moderate intensity several times a wekk
1.0 g/kg/d
bodybuilder protein intake
2.5-3.5 g/kg
percent of protein in total calorie intake
10-35%
percent of protein total calorie intake for endurance, strength, and strength with increase muscle mass
endurance- 10-155
strength - 15-20%
strength bulk- 20-30%
anabolic window
1-2 hours after exercise
leucine trheshold
concentration of muslce intracellular leucine that is associated with maximal mps
leucine is high in what
whey products- milk
what is the importance of protein right after workout
reverse catabolic reaction- helps build and support skeletal muscle
max protein synthesis amount after exercise
20-25 g
dehydration can results from excess protein intake why
additional water is needed to metaboliz protein
post protein consumption amount
.25 to .3 g.kg- focus on whey and leucine
