Protein and alcohol Flashcards
What macronutrients is comprised of a unique sequence patten of amino acids and contain nitrogen
protein
What proteins provides tissue support?
elastin
collagen
What proteins provide muscular structure and function?
myosin
actin
troponin
tropomyosin
What proteins transport substances throughout the body?
apoproteins
hemoglobin
albumin
What protein is responsible for blood clotting?
fibrin
what protein is responsible for blood thinning?
plasmin
How are proteins used for fluid balance?
when protein concentration in the blood are low, fluid “leaks” out of the blood into the interstitial space and causes swelling
What elements are amino acids composed of?
Carbon
Hydrogen
Oxygen
Nitrogen
What defines the protein in the molecular structure?
the unique side chain
what proteins contain sulfur in the side chains?
Cysteine and Methionine
Of the 140 AA found in nature, how many are used to make proteins?
20
What is the general molecule structure of AA?
a central Carbon
one carboxyl group (COOH)
at least one amine group (NH2)
a hydrogen atom
a unique side chain
How many essential amino acids must be consumed in the diet?
9
How many nonessential AA are there?
11
What type of bond is formed when the carbon of the acid group of one AA joins with the nitrogen atom of the amine group of a second AA
peptide bond
What reaction forms peptide bonds?
condensation
What reaction breaks peptide bonds?
hydrolysis
two AA joined together
dipeptide
3 AA joined together
tripeptide
4-9 AA joined together
oligopeptide
10+ AA joined together
polypeptide
The genetic information from DNA’s base sequence is copied to the base sequence in mRNA.
Transcription
single strand of nucleotides, with nitrogenous bases AGC, and U (uracil); also contains pentose sugar ribose instead of deoxyribose
RNA
the genetic information in RNA is converted into the AA sequence of a protein
Translation
What structure is the sequential order of the AA?
primary structure
What structure is the initial folding caused by interactions of the positively charged AA and negatively charged carboxylic acid groups?
secondary structure
What structure is the complex folding due to interactions among R-groups (with sulfur bonds being strongest)?
tertiary structure
what structure is two or more polypeptide chains bond together?
(not all proteins)
quaternary structure
What term describes the alteration of the protein’s shape (therefore, functions) through the use of heat, acids/bases, salts, mechanical agitation?
Denaturation of proteins
What structure of the protein is unchanged by denaturing?
primary structure
Where are proteins found in our diet?
animal meats, dairy products, and legumes
-excludes butter/sour cream/cream cheese
What digestion of protein occurs in the mouth?
none
What hormone stimulates the release of gastric juice?
gastrin
What does gastric juice contain that starts to denature proteins?
Hydrochloric acid (HCl)
What does the denaturing process from HCL do for digestive enzymes?
allows digestive enzymes access to the proteins
What bond is not affected by Hydrochloric acid (HCl) in the stomach?
peptide bonds
What enters the small intestine in the digestion process of proteins?
partially digested proteins
polypeptides
What stimulates the release of pancreatic juice?
cholecystokinin
CCK
What is pancreatic juice rich in?
proteases
inactive enzymes (zymogens or proenzymes)
within the small intestines, what are activated into functional proteases?
zymogens
What is located at the surface of the microvilli in the intestinal mucosal cells and yield individual AA (and some di and tripeptides)?
aminopeptidases
In the absorption process, What dictates the transporter used for AA?
features of the specific amino acid
-mass
-electrical charge
-side chain
etc.
in the absorption process, What do all AA transporters have in common?
carrier-mediated mechanism
energy in form of ATP is required
After absorption into the enterocyte, where do AA enter and travel too?
AA enter the portal circulation and travel to the liver, then other tissues
Do peptides absorb differently than AA?
yes
How do peptides absorb?
PEPT1 (for all di- and try-peptides)
once within enterocyte, peptides are hydrolyzed by cytosolic peptidases to generate free AA
What is the primary site for AA uptake following a protein-containing meal?
the liver
Do AA go through anabolic or catabolic processes in metabolization?
either anabolic or catabolic depending on the needs of the body
Anabolic or Catabolic?
Synthesis of a non-protein compound that contain nitrogen, including creatinine and serotonin
Anabolic
Anabolic or Catabolic?
Synthesis of body proteins, such as enzymes, antibodies, and various components of cells
anabolic
Anabolic or Catabolic?
synthesis of fat from amino acid carbon skeletons; this can be stored as adipose tissue
anabolic
Anabolic or Catabolic?
synthesis of glucose from amino acid carbon skeletons; this can be used for energy
catabolic
Anabolic or Catabolic?
energy produced form amino acid carbon skeleton
catabolic
What is a resource of all ‘free’ intra- and extracellular AA in the body?
Amino Acid pool
How are AA in the pool used?
taken up by tissues and are used to meet the energy needs of various tissues
How is the AA pool comprised?
arise from exogenous protein, degradation of endogenous protein, and synthesis of new amino acids
AA intermingle to form pool of about 150g
What are the 3 anabolic fates of AA?
- building blocks for proteins
- building block for other nitrogen containing compounds
- conversion to fat for storage
What hormone promotes protein synthesis?
insulin
what stimulates protein synthesis?
periods of energy excess, but occurs continously because of the diverse functions
what is:
-synthesized from glycine, cysteine and glutamate
-found in cytoplasm of cells in reduced (GSH) or oxidized form (GSSG)
-acts as an antioxidant
Glutathione
the ratio of GSH:GSSG in cells is >10:1; a decrease in the GSH:GSSG is indicative of oxidatitive stress. Why?
The oxidized form (GSSG) increases
What is:
-synthesized from lysine in the liver and kidneys and found in meat products
-needed for the transport of long chain fatty acids across the inner mitochondrial membrane for oxidation
carnitine
what is:
- found in meat and fish and synthesized from arginine and glycine
- approx 95% in muscle, found in free and phosphorylated form
- replenish ATP during rapid contraction at the very onset of exercise
-damage to the heart causes enzyme to ‘leak’ out of heart; thus an elevated plasma level is used to diagnose a heart attack
creatine
What is:
- synthesized from AA serine and found in eggs, meat, fish
- needed as a methyl donor, converts homocysteine to methionine; in the secretion of VLDL from the liver; and to form neurotransmitter acetylcholine
- deficient diets used in research to develop fatty liver in animals and may be associated with liver and heart disease in humans
choline
What are the two main catabolic fates of AA?
- conversion to glucose for energy use
- oxidation of the carbon skeletons
True or false:
proteins are being broken down and rebuilt continuously, irrespective of energy status
True
What is the first step in AA catabolism and occurs by transamination and/or deamination?
removal of the amine group
What process involves the transfer of an amino group from one AA to an a-keto acid (ie an AA carbon skeleton)
Transamination
what catalyzes the AA in catabolism?
amino transferases aka transaminases
what reaction involves only the removal of the amino group, with no transfer to another compound?
Deamination reaction
What enzyme facilitates a deamination reaction?
deaminase/dehydratase enzymes
what is produced from a deamination reaction?
a-keto acid and ammonium
What is created from deamination reactions is very toxic and must be removed from the body?
ammonia
what is the primary means of disposing ammonia?
urea cycle
where does the urea cycle occur at?
in the liver and kidneys
Where urea is formed, then transported to the kidneys, how is it excreted?
through the urine
when urea created in the urea cycle travels in the blood from the liver to the kidney and is excreted, what can be measured and an indicator of renal health?
Blood Urea Nitrogen
BUN
What BUN measurement can be signs of acute or chronic kidney dysfunction/failure?
> 20 mg/dL
What two amino acids are completely ketogenic AA?
leucine and lysine because they do not make glucose
from a metabolic standpoint, AA can be consider either:
- glucogenic
- ketogenic
What type of AA are those that can be degraded to pyruvate, oxaloacetate, a-ketoglutarate, succinate, or fumarate and therefore can be converted into glucose through gluconeogenesis?
glucogenic AA
what type of AA are those that can be converted into ketone bodies through ketogenesis?
ketogenic AA
what is produced in the liver and transported to other tissues where they are reconverted to acetyl-CoA to produce energy via the TCA cycle and are used for fuel for the brain, heart, skeletal muscle, etc.
ketones
What are the three essential branched chain AAs that are found in dairy and red meat, and often used to enhance performance, reduce muscle soreness, and faciliate muscle growth?
- isoleucine
- leucine
- valine
what type of chain consists of a carbon atom bound to more than two other carbon atoms
side chain
what enzymes are on skeletal muscle, heart, kidneys, and adipose tissue and can transaminate all three BCAA (branched chain amino acids)?
branched-chain aminotransferases
What cycle describes:
- a removal of nitrogen from muscle (proteolysis)
- transfers the carbon structure of pyruvate liver where it can be converted to glucose
- synthesized glucose transports back to muscle and used for energy
Glucose alanine cycle
How do we determine nitrogen balance?
N balance is calculated as the difference between nitrogen intake and nitrogen excretion.
2 week diet with specific nitrogen content given
amount of N collected in urine/feces
It’s easier to estimate (protein x 0.16)
How are dietary proteins divided?
- complete (high quality)
- incomplete (low quality)
What does the quality of protein depend on?
- digestibility
- its essential AA composition
What protein category contains all the essential AA in the approximate amounts need?
complete protein
milk, yogurt, cheese, eggs, meat, fish, poultry
What protein category has too little of one or more particular essential AA?
incomplete protein
legumes, vegetables, cereals, plan foods
the essential AA that is present in the lowest quantity in the food
limiting AA
What factors influence protein requirements?
- quality of protein
- body size
- physiologic state
- growth
- level of energy intake
- level/type of physical activity
What Protein calorie Malnutrition?
-inadequate protein with sufficient kcal. generally the result of a diet high in grains and deficient in protein
-symptoms: edema of belly, legs
- seen in developing countries, burn patients, following major surgery
- prone to infection, rapid heart rate, excess fluid in lungs, pneumonia, septicemia, and water and electrolyte imbalances
Kwashiorkor
What Protein calorie Malnutrition?
-severe deficiency in kcal
- symptoms: wasting
-misnomer: deficiency of all nutrients
-body temp and blood pressure are low
-prone to dehydration, infections, and unnecessary blood clotting
marasmus
what factors compose metabolic wasting?
increased use of protein for energy
decreased synthesis of hair/skin pigments
decreased immunoglobin synthesis
decreased synthesis of transport proteins
Age-associated loss of muscle mass
approx .5%/yr between ages 30-50 and 1-2% after
reduced muscle function results in increased risk of falls, disability, frailty
causes: age-related loss of moto neuron input to muscle; oxidative stress; reduced testosterone; reduced dietary protein intake
-effects mitigated by adequate protein intake and physical activity
sarcopenia
what are some risks to a high protein diet?
dehydration
renal damage (with pre-existing conditions
what are some benefits to a high protein diet?
muscle growth (with resistance exercising)
possible weight loss
A group of organic chemicals in which one or more hydroxyl (OH) groups are attached to the carbon atoms in place of the hydrogen atoms
alcohol
ethyl alcohol; found in alcoholic beverages
- considered safe for consumption
- excess can be toxic, can damage the body, and can be lethal
ethanol
sugar alcohol; found in food and in the body as part of the triglyceride molecule
glycerol
alcohol found in antifreeze
- poisonous
methanol
alcohol found in rubbing alcohol
- poisonous
isopropanol
metabolic process that converts sugar in grains and fruit (e.g., glucose, maltose, fructose) to acids, gases, and/or alcohol by the action of yeast and bacterias
Fermentation
forms liquors
-fermented liquid is heated and ethanol vaporizes
-vapors are collected and form liquor
- alcohol content is indicated by its proof
Distillation
how much average alcohol does the body produce via fermentation per day?
approx 3 g of ethanol
Does alcohol require digestion?
No
How is alcohol absorbed?
simple diffusion
Where is most of the alcohol absorbed?
small intestine
Where is alcohol metabolized?
some in the stomach
most transported via blood stream to liver
What are the three metabolic pathways alcohol primarily metabolizes through?
- Alcohol Dehydrogenase (ADH) pathway
- The microsomal ethanol oxidizing system (MEOS)
- Catalase System
What alcohol metabolic pathway does this describe?
-present in stomach and liver
- metabolizes large majority of alcohol consumed
- converts alcohol to acetyl CoA
*used to produce energy in TCA cycle
*converted into fatty acids and stored as a triglyceride
Alcohol dehydrogenase pathway (ADH)
In the ADH pathway, What enzyme converts ethanol to acetaldehyde and located in the liver?
alcohol dehydrogenase
In the ADH pathway, what enzyme transforms acetaldehyde into acetate?
acetaldehyde dehydrogenase
In the ADH pathway, What is the final step in the metabolism of ethanol?
to convert acetate into acetyl CoA
What does the buildup of NADH from drinking too much alcohol result in?
the formation of fatty acids and ketones
What alcohol metabolic pathway does this describe?
- used when there is too much alcohol and ADH cannot keep up; and/or with chronic alcohol consumption
- metabolize alcohol to acetaldehyde via an oxidase enzyme (CYP2E1, part of the cytochrome P450 family)
- occurs in liver and extra-hepatic tissues, including the brain
- used to metabolize drugs and other foreign compounds, but alcohol takes precedence over drugs, thus consumed together can cause lethal doses of drugs in the blood (e.g. acetaminophen)
The Microsomal ethanol Oxidizing System
(MEOS)
What system is activated with chronic alcohol consumption, resulting in enhanced alcohol tolerance?
The Microsomal ethanol Oxidizing System
(MEOS)
What alcohol metabolic pathway does this describe?
- metabolizes alcohol into acetaldehyde
- hydrogen peroxide is necessary
- quantitatively, this system is considered a minor pathway of alcohol oxidation, but may play a large role in alcohol metabolism in the brain
Catalase System
about how many drinks can the liver metabolize in an hour?
1 but this rate varies by up to 3 fold
What happens to excess alcohol that is not metabolized via “first pass”?
circulates throughout the body and raises blood alcohol concentration (BAC)
True or False
amount of alcohol expelled throughout the lungs correlates with the amount of alcohol in the blood
True
Full stomach reduces alcohol absorption speed and can reduce BAC by up to __%
50%
Females have __% less ADH than males
20-30%
Lower ADH =
lower alcohol tolerance
Lower ALDH =
severe hangovers
