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Terms in this set (70)
What are different cells present in the stomach and what do they produce?
Neck Cells- produce mucus
Parietal (oxyntic) Cells- produce HCL and intrinsic factor
Chief (peptic or zymogenic) cells- produce enzymes needed for fat digestion
Enteroendorcrine cells (G-Cells)- produce gastrin which stimulates parietal and chief cells.
What are the components of the GI tract system?
Small and large intestine
Which accessory organs are involved in digestion?
What is the role of bile?
to break down large fat globules into small fat droplets called micelles(emulsification) which allows pancreatic lipase to hydrolyze bonds with the triacylglycerols in the micelles.
Where is bile produced and stored?
What is biles composition?
What are the different ways glucose can be absorbed in the intestine?
sodium must bind first
Facilitated transport GLUT2
GLUT 4- insulin dependent
muscle, heart, adipose
INTESTIN, BRAIN, SKELETAL MUSCLE, ADIPOSE TISSUE
What happens to the receptor once insulin binds to it?
Insulin binds to the ALPHA SUBUNIT which leads to stimulation of KINASE activity in the BETA SUBUNIT.
Transphosphorylation of tyrosine residues in the BETA subunit occurs
There is activation of kinases in the BETA subunits of the receptor leading to transphosphorylation of tyrosine residues in the BETA subunits.
Which glucose transporter is dependent on insulin?
What are the enzymes involved in glycogenesis?and what do they do?
glucokinase(liver) or hexokinase(muscle)- glucose enters the cell and is converted to G6P
phosphoglucomutase-G6P is converted to G1P
Uridine triphosphate (UTP) seats with G1P to form an activated compound:UDP-glucose
Glycogen synthase- transfers glucose from UDP to glycogenic
Branching enzymes- transfers a chain of 6 to 7 glucose to carbon 6 of a glucose molecule
What are the enzymes involved in glycogenolysis? and what do they do?
Phosphorylase- cleaves alpha 1-4bond
De branching enzyme- cleaves alpha 1-6bond
in the liver glucose 6-phosphatase converts G-6-P into glucose which is released into the blood stream
What is the purpose of glycolysis?
convert glucose to pyruvate
How many ATPs can be produced directly and indirectly from the TCA cycle? Be specific and list the compounds that can be used to produced ATP from the TCA cycle.
1.5 ATP / FADH
What are the major enzymes in gluconeogenesis? Where does it occur?
The liver is the major site, although kidneys become more important under starvation
To make glucose from non-carbohydrates precursors
Substrates: lactate, glucogenic amino acids, glycerol
Enzymes: fructose 1-6 biphosphatase, glucose 6 phosphatase, lactate dehydrogenase
What is the mechanism of action of thiamin
TPP is active form
Thiamin role in energy transformation:
1.Pydruvate dehydrogenase complex
2.Alpha-ketogluterate dehydrogenase complex
-converts alpha-kltogluterate to succinyl Co-A within the TCA cycle
3.Brachned-chain alpha keto acid
- combination of enzymes responsible for the degradation of the BCAA
thiamin involved in the oxidation decarboxylation of pyruvate to make acetyl coA
What is the mechanism of action of niacin
Involved in oxidative decarboxylation of pyruvate to make aceytl CoA
*carb and BCAA
-synthesis of pentode and nicotinamide
What is the mechanism of action of riboflavin
NADH dehydrogenase, lactate dehydrogenase, oxidizes B6 into coenzyme form
FAD- cytochrome reductase, succinate dehydrogenase, acyl coA dehydrogenase, pyruvate dehydrogenase complex
What are the two coenzymes formed from pantothenic acid and what is the role of 4-phosphopantetheine?
Co enzymes are CoA and 4-phosphopantethine
Role of 4-phosphopanthetheine is to synthesis of fatty acid
How is vitamin B6 involved in protein metabolism? List enzymes and their roles.
PMP and PNP oxidase
Needed to synthesize essential amino acids,
convert tryptophan into niacin,
and break down glycogen to release glucose into the blood.
What is the difference between T4 and T3? How are they transported? How do they function?
T3- triiodothyronine-amino acids are needed for synthesis
-is 20-100X more potent than T4 at equal concentrations
- more biologically active
-function is mediated through effects in the nucleus of cell
-plasma concentration is 50-100X greater
-can be de iodinated to T3 by the liver, kidneys, brain, pituitary, and brown adipose tissue
-the enzyme 5'-de iodininase deiodinates T4 and its selenium-depended.
What are the stages of iron deficiency and which indicators characterize each phase?For example, low plasma hemoglobin levels characterize the final stage which is iron deficiency anemia
1. Decrease in iron store
Plasma ferritin less than 12ng/Ml=iron deficiency
2.Decrease in circulating iron
transferrin saturation decreases to less than 16%
3.free protoporphyin concentration in RBC and transferrin receptors rise
-affects the making of hemoglobin
RBC do not have enough iron to make protoporphyrin
increase in serum transferrin receptors
-hemoglobin drops below 12-13g/dl
-hematocrit drops below 37%-40%
How are fatty acids represented via the omega and delta systems?
What are the major enzymes in digestion of triacylglycerols, cholesterol esters, and phospholipids?
TAG- fatty acytl CoA Synthetase
Cholesterol esters- HMG-CoA REDUCTASE
Which type of lipid is transported by VLDL, HDL, LDL and chylomicrons?
Which lipoproteins contain apo C-II and what is the function of this protein?
chylomicrons-Apo C-II stimulates lipoprotein lipase
VLDL-APO C II-activator is LPL
HDL- Apo C II- is present but Apo C I is the main which stimulates the activity of LCAT
Which reaction does acetyl CoA carboxylase catalyze and what are the requirements for this reaction?
Which pathway is stimulated when this enzyme is active?
Regulation of FA translocation/FA synthesis
Fasting state or during exercise
Acetyl Co A carboxylase is phosphorrylated which results in inactivation
-decreased malonyl Coa
-increased transport of FA to mitochondria for oxidation
Acetyl CoA carbonylase is activated by insulin
What is the rate limiting enzyme in cholesterol synthesis?
What is the function of glycerol kinase and where is it located?
Glycerol is phosphorylated into glycerol-3-phosphate (mainly In the liver)
What are the specific roles of CPT1, CPT2, acyl CoA synthetase and carnitine acylcarnitine translocase?
Acyl-CoA synthetase (activates FA before oxidation process begins)
Carnitine palmitoyl transferase 1 (CPT1) - Produces a CoA and Acylcarnitine
Carnitine acylcarnitine translocase (CAT) - shuttles acylcarnitine in the mitochondrial membrane and carnitine out.
Carnitine palmitoyl transferase II (CPTII) - converts Acylcarnitine into acyl-CoA to be oxidized.
Know how many ATPs can be synthesized from different types of fatty acids, monounsaturated and saturated.
#OF carbons/2=acytle coA
#OF acyle CoA
1. #of turns*4ATP=_____ATP
2.# of acetyl CoA *10ATP=______ATP
subtract 1.5 ATP if monounsaturated/ double bond.
What are the enzymes responsible for metabolism of alcohol?
What are the consequences of alcohol abuse?
Acetaldehyde toxicity- damage to liver cells, attachment to proteins forming adducts
High NADH/NAD ratio- increases levels of reducing equivalents
-increases reduction of pyruvate to lactate (lactic acidosis)
-accumulation of citrate which stimulates acetyl CoA carboxylase
-increases activity of glycerophosphate dehydrogenase to make glycerol-3-phosphate, increased TAG
-glutamate dehydrogenase shifts toward production of glutamate from alpha ketoglutarate which impairs gluconeogenesis.
Substrate competition-vitamin A deficiency
Induced metabolic tolerance- inhibition of retinol dehydrogenase which seems to be identical to ADH
-induction of MEOS accelerates oxidation of retinol and hepatic depletion leads to higher needs.
What are the substrates and products of ketogenesis and in which tissues does it occur?
What are the enzymes that digest proteins and where are they produced?
How are peptides absorbed in the intestine?
Peptides are transported into the intestinal cell along with H+
H+ are pumped back into the intestinal lumen in exchange for Na+
A Na+,K+ ATPase pumps Na+ out of the cell in exchange for K+ across the basolateral membrane
What are the pathway by which ammonia can be disposed of?
Urea Cycle occurs in the liver
arginine is the amino acid synthesized in the urea cycle.
Glutamate dehydrogenase: Produces glutamate which uses NADPH, NH4, and alpha ketoglutarate.
Glutamine synthetase: Produces glutamine which uses ATP, Glutamate, and NH4
CPS1 makes carbamoyl-PO in the liver and is excreted by the kidneys which uses CO2, NH4, ATP
What are the main characteristics of the autophagy-lysosomal and ubiquitin-proteasome pathways?
-present in cytoplasm of the cells
-less selective in targeting specific proteins for degradation
-degradation of while cell organelles
activated by E1
-present in nucleus and cytoplasm of cells
-degradation of short lived proteins.
What are the substrates and products of ALT and AST?
ALT: Alanine amitotransferase:transfers the amino group from alanine to an alpha-leto acid. (ALPHA KETO GLUTARATE)
AST: aspartate aminotransferase: transfers an amino group from aspartate to an alpha keto group (found higher in the heart)
What is the role of AMPK?
Stimulates the translocation of GLUT4 for glucose to enter the cell.
STIMULATES CATABOLIC PATHWAY
What is the Cori cycle and when is it activated?
Lactate from anaerobic metabolism of glucose (RBC or MUSCLE) travels to the liver and is converted back to glucose via gluconeogenesis.
activates 20-75s anaerobic activity.
What are the four energy systems utilized to obtain ATP for physical activity?
Lactic acid -Anaerobic
How does exercise intensity affect the type of fuel used to make ATP?
the longer duration of exercise there is a decrease in _____
What types of activities would mostly derive energy from PCr?
High intensity activities lasting 15-25s
What types of activities would mostly derive energy from anaerobic glycolysis?
High intensity activités lasting 20-75s
(sprints 800m, swimming 100-200m)
What is the function of carnitine?
Compound that transports fatty acids from cytosol into mitochondria, where they undero beta-oxidation
What is the function of carnosine?
-present in skeletal, cardiac muscle, brain, kidney, stomach.
-meats are the main food source
-Buffer in the muscle to help increase pH
Caroline provides the first line of defense against muscle change in pH
What is the role of the bacteria in the mouth in nitric oxide production?
Chlorhexidine-based mouth wash inhibits bacterial reduction of nitrates leading to high BP
mouth bacteria reduced it to nitrate via reductase enzymes
What is the function and where are the following hormones/proteins synthesized?
-synthesized in the hypothalamus but stored in and secreted by the posterior pituitary
function: increase permeability of the distal convoluted table to water by stimulating the movement of aqua pores
-increase reabsorption of Na via NA channels.
hormone secreted by the kidney; it raises blood pressure by influencing vasoconstriction
synthesized by the liver
hydrolyzes angiotensinogen into angiotensin 1
synthesized in the lungs
converted into angiotensin 2 by ACE
-interacts with receptors in the adrenal cortical cells resiling in the release of aldosterone
-vasoconstrictor that stimulates the release of ADH and the twist center of the hypothalamus
functions in the distal ascending loop of hence and collecting suits
-inserts addition Na channels into the luminal membrane and Na-K pumps into the basolateral membrane
-Na is reabsorbed and both salt and water are retained.
ANP and BNP
Atrial natriuretic peptide
Brain natriuretic peptide
-stored in the cardiac myocytes of atrium and ventricles
-release triggered by increase BP
-function: promote Na and water excretion, dilation of afferent arteriole and constriction of efferent arterioles
-increase in glomerular pressure leads to increase in GFR and excretion of Na and water
Which type of lipid is transported by VLDL, HDL, LDL and chylomicrons?
Look at slide 22 from the Tools of a Healthy Diet PowerPoint and make sure you know what the recommendations for the different food groups are.
Fruits: 2 cups
Veggie: 2 1/2 CUPS
Dairy- 3 cups
protein 5 1/2 oz
oils- 5 tsp
saturated fat- less than 10%
added sugar- less than 10%
sodium- less than 2300mg
What is the difference between the 2-compartment and the 4-compartment method of body composition assessment?
Fat Mass (FM)
Fat Free Mass(FFM)
Ex: ultrasonography, air displacement, bia, anthropometric, infrared interactance. Total body water, total body potassium.
Total body water
Ex; Dexa, MRI, CAT scan
What is the function of ghrelin? Where is it produced and when is it secreted?
-stimulates hunger and food intake.
-promotes digestion and is a secretagogue for growth hormone.
-ONLY OREXIGENIC HORMONE
-produced in the stomach
-levels increase between meals and decrease after a meal
What is RQ and how can it be used to determine the type of fuel that is being used for energy?
Measures of fuel utilization and exercise intensity
RQ .70- fat
RQ 0.82 protein
AMOUNT OF ENERGY EXPENDED CAN BE CALCULATED FROM RQ
What are some examples of nutrient claims? What does 'reduced' and 'light' mean?
reduced or less: at 25% less KCAL/serving of reference food
light or lit( for KCAL and sodium) 50% less fat or 33% less kcal if less than half of the foods KCAL are from fat
nutrient content claim describes nutrient content and is closely regulated by the FDA. (ex:twirlers: low fat snack)
What are the phases of meal timing and what are their characteristics?
Early phase (catabolic):
cortisol levels are increased
insulin levels are decreased
muscle glycogen is depleted
goal is to increase energy delivery to the muscles via carbs
anabolic phase: (25-min post exercise)
muscle cells are sensitive to insulin
muscle glycogen is depleted
goal is to increase delivery to the muscles via carbs to increase the rate of glycogen synthesis and initiate the recovery process
-muscle glycogen stores are replenished faster within the first house after exercise.
growing/adaptive phase: 18-20HRS post exercise
muscle repair , growth, and strength
-maintain insulin sensitivity to continue to replenish glycogen stores
-consuming a protein and carbohydrate meal within 1-2 HRS after resistance training has a positive effect on protein synthesis.
What are the macronutrient needs of infants?
Protein- 2X greater need/lb
Fat- ~50% of energy from fat
fat should decline to 30% of calories by the age of 5
Carbs gradually increase as fat and protein goes down
What are the recommendations for protein intake based on the dietary guidelines?
5 1/2 oz?____________
What are the energy and protein needs of pregnancy?
-Protein: ~50% above normal requirements
-Calcium and Vitamin D
-Pre-natal vitamin and mineral supplements
What are the health risks of anorexia nervosa and bulimia nervosa?
Anorexia health risk:
Energy and nutrient deficiency
Bulimia nervosa health risk:
Electrolyte imbalance: dehydration, loss of sodium and potassium
What is EDNOS?
eating disorder not otherwise specified
What is the macronutrient composition of a 4:1 and 3:1 ketogenic diet? What do those ratios mean?
classic keto diet is prescribed as a ratio of grams of fat to combined games of carbohydrate and protein
it requires all foods and beverages by carefully calculated and precisely weighed on a gram scale
classic ratios are 4:1 and 3:1
What are the differences between whey and casein?
Whey is a soluble protein and is absorbed more quickly. 11% leucine wt/wt
Casein is absorbed slowly because it clots in the stomach leading to delayed gastric emptying and slower amino acid absorption 8% leucine
plasma appearance of AA is fast and transient
-no change in protein breakdown
plasma appearance of AA is slower, lower, and prolonged
-protein synthesis (slightly increased)
-protein break down
Why would vegetable-based proteins be less effective than animal-based proteins?
Vegetable based proteins contain less leucine than animal based proteins
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