SFM Quiz 1 Flashcards
the body’s inability to easily digest Lactose due to genetic deficiency of lactase, with an age-dependent decrease in production of the enzyme (infant possess sufficient quantities). Results in gas, belly pain, and bloating within 2 hours of consuming lactose.
lactose intolerance
- Nutritional reservoir of carbs in plants
Polysaccharide of glucose - Found in fruits and vegetables
Disaccharide of glucose and fructose - Plant origin
- Major dietary carbohydrates of animal origin
Disaccharide of glucose and galactose
- Starch
- Sucrose
- Dietary fiber
- Lactose
Monosaccharides
Glucose, fructose, galactose, ribose
Disaccharides
Maltose (alpha 1,4)
lactose (beta 1,4)
sucrose (alpha 1, beta 2)
Oligosaccharides
Glycolipids and glycoproteins
Polysaccharides
Glycogen: alpha 1,4 alpha 1,6
starch: amylose (alpha 1,4) amylopectin (alpha 1,4 alpha 1,6)
Cellulose: beta 1,4
The ___ stores lipid-emulsifying bile. Nonideal bile composition including too much cholesterol and too little bile salts cause formation of crystalline ___ in the ___. Continued disturbances in metabolism can lead to malabsorption (____) and fat-soluble vitamin deficiencies. Oral chenodeoxycholic acid can help dissolve ____.
Gall bladder
Gall stones
Gall bladder
steatorrhia
omega 3
omega 6
Linolenic acid
Linoleic and Arachidonic acids
exergonic
ΔG < 0, spontaneous (energy producing)
endergonic
ΔG > 0, non-spontaneous (energy consuming)
Mass action (Le Chatelier’s principle)
Sign of ΔG dependent on Keq
↑ [reactants], ↓ [products]
decrease pH
decrease CO2
decrease bicarb
hyperventilation
Metabolic acidosis
decrease pH
increase CO2
increase bicarb
increase renal bicarb reabsorption
Respiratory acidosis
increase pH
increase CO2
increase bicarb
hypoventilation
Metabolic alkalosis
increase pH
decrease CO2
decrease bicarb
decrease renal bicarb reabsorption
Respiratory alkalosis
Enzymes
Biological catalysts Lower activation energy (Ea) Increase reaction rate No effect on ΔG Facilitate reaction occurring by binding substrates and converting to products
Catalytic triad
acidic, basic, nucleophilic
Found in the parietal cells that line the gastric lumen.
Pump H+ into the lumen where it combines with Cl- to form HCl.
Conditions like ulcers, indigestion, heartburn require decrease in ___ thus _____ are prescribed (Omeprazole, lansoprazole, esomeprazole).
Reduced ___ production causes _____ which can reduce absorption of nutrients, increase in sensitivity to food poisoning, reduction in gastric enzyme efficiency, particularly pepsin, gastric amylase, gastric lipase.
Gastric acid
proton pump inhibitors
HCl
hypochlorhydria
No effect on Vmax
Increase in Km
Larger substrate concentration needed to achieve ½ Vmax
Competitive inhibitors
substrate binding
Examples of Competitive inhibitors
Malonate=succinate dehydrogenase sulfanilamide=dihydropteronate synthetase methotrexate=dihydrofolate dehydrogenase captopril=angiotensin-converting enzyme allopurinol=xanthanine oxidase
Decrease in Vmax
Unchanged Km
Inhibitor effects cannot be overcome by increase in substrate concentration
Noncompetitive inhibitors
binds to E and ES
Examples of Noncompetitive inhibitors
Physostigmine=acetylcholinesterase
allopurinol=xanthine oxidase
oxypurinol=xanthine oxidase
Examples of Uncompetitive inhibitors
Lithium=inositol monophosphate
Examples of Uncompetitive inhibitors
Lithium=inositol monophosphate
Decrease in Vmax
Unchanged Km (no affect on affinity)
Only overcome by synthesis of new enzymes
Enzyme inactivation
Destruction or covalent modification of key amino acid’s functional groups
Examples of Enzyme inactivation
Organophosphates=acetylcholinesterase
cyanide/sulfides=cytochrome c oxidase (complex IV)
aspirin=Prostaglandin synthase (COX1/2)
abdominal pain, sideroblastic anemia, irritability, headaches, impaired nervous system development, encephalopathy
Pb inhibits ALA dehydratase and ferrochelatase.
Ferrochelatase= involved in heme synthesis; coenzyme of hemoglobin
Administration of Ca-EDTA: Pb has a higher affinity for EDTA than Ca
Pb-EDTA excreted in urine
A 66 year-old female is seen in the ED in the late evening. She reports she has had “pressure” on her chest for the last few hours but denies overt chest pain; jaw, neck, shoulder or arm pain; shortness of breath (dyspnea); and sweating (diaphoresis). The pressure does not increase with exertion. History shows hyperlipidemia treated with diet and drugs and no familial history of heart disease. Heart rate and respiratory rates are elevated. Blood is drawn and sublingual nitroglycerin is given. An EKG is performed and the results are characteristic of ___. Cardiac biomarker assay reveals____, ____ (found in heart muscle) to__ ratio and ____.
MI
elevated CK
CK-MB to CK ratio
cTnI
Enzymes useful for diagnosis of disease
bone disease=alkaline phosphatase obstructive liver disease=sorbitol dehydrogenase/lactate dehydrogenase prostatic cancer=acid phosphatase acute pancreatitis=amylase muscular dystrophy=aldolase/ASH liver disorder=CK-MM
Protein Carbs Fats Alcohol N-6 PUFA N-3 PUFA
4kcal/g, 10-35% 4kcal/g, 45-65% 9kcal/g, 20-35% 7kcal/g 5-10% .6-1.2%
Fiber
Plant polysaccharides – cellulose, gums, hemicellulose, & pectin
Not completely (if at all) by humans, “Does not contribute to caloric intake” (i.e., net carbs)
Soluble & insoluble
Slows gastric emptying, reduces glycemic index/load, makes food bulky/satiety, influences absorption and motility along GI tract.
20-35 g/day recommended
Conditional essential fatty acids
EPA, DHA
Digested products are absorbed into hepatic portal system
Conditions and diseases involving absorption
Steatorrhia
Crohn’s disease
Caused by deficiency in the activity of an enzyme called Acid Sphingomyelinase (A-SMase).
A-SMase is a lysosomal enzyme which breaks down sphingomyelin (SM) into ceramide and phosphorylcholine.
Defective A-SMase leads to the accumulation of SM in lysosomes of liver, spleen, CNS, and bone marrow.
Leads to:
Enlargement of liver (hepatomegaly)
Enlargement of spleen (splenomegaly)
Causes neurological damage.
Hallmark “cherry red spot” in the eye.
Fatality – Type A, 85%, by 18 months of age.
Niemann-Pick disease
Outer sheet membrane lipids
Phosphatidylcholine
Sphingomyelin
Glycolipids
Inner sheet membrane lipids
Phosphatidylinositol
Phosphatidylserine (flips to outside, marker for apoptosis)
Phosphatidylethanolamine
Blood type O
H antigen
anti-A/B antibodies
*universal donor
Blood type A
A antigen
anti-B antibodies
Blood type B
B antigen
anti-A antibodies
Blood type AB
A,B antigens
no antibodies
*universal acceptor
disease in which there is incompatibility between blood of mother and fetus.
When mom is Rh- and fetus is Rh+, the mom produces antibodies during pregnancy. These cross placenta and attack the fetus. Risk is greater in subsequent pregnancies
Erythroblastosis fetalis
Hemolytic disease of the newborn
Associated with beta lipoproteinemia and advanced stages of alcoholic liver cirrhosis.
Chronic liver dysfunction impairs cholesterol metabolism by the liver, resulting in excess free cholesterol.
Elevated levels of cholesterol bound to rbc membrane.
Decreases fluidity and flexibility of membrane.
Creates rough thorny projections on the rbcs.
Such cells called acanthocytes.
Impaired deformability of rbcs.
Cause rbcs to break their membranes (lyse) as they pass through capillaries of spleen.
Spur cell anemia
Cholesterol + rigid membrane=
Cholesterol + fluid membrane=
increase fluidity
decrease fluidity
Autosomal recessive disorder.
Caused by defect in the transporter responsible for uptake of dimeric amino acid Cystine and other dibasic amino acids such as Arginine, Lysine, and Ornithine.
Results in formation of Cystine crystals or stones in the kidney (identified via a positive nitroprusside test).
Patients present with renal cholic (abdominal pain that comes in waves and is linked to kidney stones).
Cystinuria
Autosomal recessive disorder.
Caused by a defect in a transporter for non-polar or neutral amino acids (e.g., alanine, valine, threonine, leucine, tryptophan etc).
Transporter found primarily in kidneys and intestine.
Manifests in infancy as failure to thrive.
Clinical findings – intermittent cerebellar ataxia (lack of muscle coordination), nystagmus (rapid and repetitive eye movement), tremor, photodermatitis and photosensitivity.
Also known as pellagra-like dermatosis.
Triggered by sunlight, fever, drugs, or emotional or physical stress.
Period of poor nutrition almost always precedes an attack.
Hartnup disorder
Inhibit the Na+/K+-ATPase in cardiac myocytes.
Leads to increase in intracellular Na+
This impairs the activity of the secondary transporter called Sodium Calcium Exchanger (NCX) as NCX is coupled to the Na/K-ATPase.
Impairment of NCX leads to a secondary increase in Ca2+ in the sarco-endoplasmic reticulum.
Therapeutic use - congestive heart failure (CHF), atrial fibrillation, dysrhythmias.
Cardiac glycosides are extremely potent.
_____ slowly reduces the resting potential of neurons to zero
Common side effects: disturbed vision, confusion, and delirium
Cardiac glycosides souabain and the lipophilic drug digoxin act as cardiotonic (contraction-inducing) drugs.
Digitoxigenin
Autosomal recessive disorder.
Caused by mutation in Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene.
Results in defective CFTR protein which is misfolded and does not leave the ER after translation.
CFTR protein is a chloride ion channel that mediates the active transport of Cl- from inside cells to the outside in airways and sweat ducts
Thicker mucous and leaves the airways susceptible to bacterial infections.
Cystic Fibrosis
Ubiquitous but high expression in RBCs and brain
High affinity
GLUT 1
Km=1
Main transporter in liver
Low affinity
GLUT 2
Km=10
Main transporter in neurons
- High affinity
GLUT 3
Km=1
Present in skeletal muscle, heart, adipose tissue
- Insulin dependent
GLUT 4
Km=5
Exercise-induced muscle cramps and weakness
Hemolytic anemia
High bilirubin and jaundice
Symptoms can be mild; true incidence may be higher due to lack of recognition and diagnosis
Tauri disease
Deficiency in PFK-1
Since rbcs lack mitochondria, glycolysis is only mechanism for producing ATP.
Failure of glycolysis results in ATP deficiency.
Leads to disruption of ion gradients powered by ATP.
Causes reduced cell viability
Hemolytic anemia
Disorders that lead to hemolytic anemia
Phosphoglucose isomerase= autosomal recessive
Aldolase A= deletion
Triose phosphate isomerase=autosomal recessive
Pyruvate kinase=erythrocyte mutation
Brain during extreme starvation
ketone body utilization= beta-hydroxybutyrate
Diabetes Type I
Diabetes Type II
Type I: loss of pancreatic beta cells
Type II: loss of Beta cell function
Diabetes causes
mutations in GK and mitochondrial tRNAleu genes
aberrant conversion of proinsulin to mature insulin
defective insulin receptor
pancreatitis
trauma
infection
pancreatic carcinoma.
Autosomal recessive disorder.
Caused by mutation in GLUT 2 transporter (located in liver, pancreatic β cell, enterocytes and renal tubular cells).
Unable to take up glucose, fructose and galactose
Symptoms – failure to thrive, hepatomegaly, tubular nephropathy, abdominal bloating, and resistant rickets.
Fasting hypoglycemia, and postprandial hyperglycemia.
Treatment – vitamin D and phosphate, and uncooked corn starch (prevents spikes in blood sugar and provides sustained release of glucose).
Fanconi-Bickel syndrome
Links the lactate produced from anaerobic glycolysis in RBC and exercising muscle to gluconeogenesis in liver
Glucose produced in liver transported back to RBC and muscle
Prevents lactate accumulation
Regenerates glucose
Cori cycle