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CHEM 102: Exam 3
Metabolism
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set of all chemical reactions used in a living organism to convert food into: energy, molecules body needs, waste products
digestion (trypsine)
absorption (steroids)
transport
utilization in cells
-energy production
-growth and maintenance
-other uses of that energy
elimination of waste products
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Catabolism
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reactions that break molecules apart
degrade compounds (oxidative process)
NAD
glucose ----> CO2, H2O, and energy
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Anabolism`
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reactions that build up compounds
biosynthesize compounds (AA + ATP --> ADP + proteins)
NADP
energy + simple compound ----> complex compound
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Metabolism Pathway
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A--E1--> B --E2--> C --E3--> D
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Pathways
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stepwise series of reactions
taking in food, breathing food out
glucose + 6 O2 ---> 6 CO2 + 6 H2O
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Central
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very important for energy production
interconnected (lipids, nucleotides, etc.)
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Energy
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oxidize glucose (CO2; burn!)
harness energy to make ATP, NADH + H+ and FADH2
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ATP
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high energy carrying molecule
(a lot of negative charges right next to each other)
"energy currency" of cell
interchangeable in many reactions
rapidly recycled
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NADH
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electron carrying molecule
reduced form
equal to 3 ATP
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Central Energy Pathways
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Goal: oxidize glucose, harness energy to make ATP and high energy molecules
(C6H12O6) + 6 O2 ---> 6 CO2 + 6 H2O
Includes: glycolysis, TCA cycle, Ox Phos
Trend always toward increased oxidation of glucose
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Enzymes
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globular proteins
catalysts for reactions in living things
reactant in an enzyme-catalyzed reaction is substrate
catalyzes a specific reaction
enhancers, not consumed (lower activation energy)
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Importance of Enzymes
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understanding metabolism
measurement of enzymes in body fluids
i.e. lactate dehydrogenase - myocardial infarction
used as reagents to measure concentrations of other components of body fluids
i.e. glucose oxidase (measure glucose in blood and urine)
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Dehydrogenases
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oxidation-reduction reactions using NAD or FAD as oxidizing agents
get 1 NADH
i.e. Glyceraldehyde-3-phosophate dehydrogenase
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Isomerases
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convert a molecule into an isomer
i.e. hexosephosphate isomerase
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Mutases
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move a phosphate ester (functional groups) within a molecule
i.e. phosophoglycerate mutase
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Kinases
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add a phosphate ester to a molecule using ATP (phosphate donor)
get 1 ATP
i.e. pyruvate kinase, hexokinase
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Glycolysis
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10 steps
glucose ---> 2 Pyretic acid
overall: 2 ATP and 2 NADH
Anaerobic Reaction
in cytoplasm
goes to form lactic acid
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Aerobic Glycolysis
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pyruvic acid is further oxidized
can recycle NAD using Ox Phos (requires oxygen)
10 NADH ---> 30 ATP
2 FADH2 ---> 4 ATP ------->TOTAL 38 ATP
4 ATP
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TCA Cycle
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TOTAL FOR 1 PYRUVATE (15 ATP, *30 ATP)
4 NADH *8 NADH
1 ATP *2 ATP
1 FADH2 *2 FADH2
*need to do this twice for glycolysis
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Electron Transport and Oxidative Phosphorylation
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Purposes:
1) recycle NADH (reoxidize NAD)
2) recycle FADH2 (reoxidize FAD)
3) while deoxidizing NADH and FADH2, harness the energy to make more ATP
takes place in mitochondria
Process:
1)electrons are passed from NADH or FADH2 to other molecules down a chain of electors carriers
2) transport of electrons from one carrier to the next is linked to pumping hydrogen ions out of mitochondrion
3) pumping of hydrogen ions out of mitochondrial matrix creates hydrogen ion (chemicoelectro) gradient
4) mitochondrial ATPase uses energy (hydroelectric power) from letting hydrogen ions flow bak in to make ATP from ADP + Pi
5) net production of ATP
from 1 NADH: 3 ADP + 3 Pi ---> 3 ATP
from 1 FADH2: 2 ADP + 2 Pi ---> 2 ATP
*more hydrogens, the more ATP made
recycle NADH and FADH2
movement of H+ ions out of mitochondria
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Gluconeogenesis
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synthesis of glucose from pyruvic acid, lactic acid, or amino acids
very energy favorable reaction
replace enzymes, pull off phosphate (phosphotase)
amino acids can be used for energy
most amino acids are broken down to pyruvic acid or oxaloacetic acid
i.e. liver
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Pentose Shunt
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synthesis of Ribose-5-P and NADPH from Glucose-6-P
make ribose for DNA, RNA, and other molecules
make NADPH as reducing agent for biosynthesis reactions
oxidative----> decarboxylation
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Glycogen Synthesis
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starts with Glucose-6-P
stores glucose in the form of glycogen
forward and reverse reaction
i.e. liver (stores glucose for keeping blood glucose levels constant)
muscles (store glucose for later energy needs)
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Glycogenolysis
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breaks down glycogen to get stored glucose and use it for energy needs
i.e. liver (maintain levels)
muscle (use energy, no enzyme because it doesn't need to be modified)
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"Glucogenic"
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amino acids that can be used to synthesize glucose
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Fatty Acid Beta-Oxidation
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Fatty acid --B-oxidation---> Acetyl CoA ----> TCA cycle
NADH NADH
FADH2 FADH2
ATP
B a
R-CH2-CH2-CH2-CH2-COOH
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Fatty Acid Catabolism
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takes place in mitochondria
CoA carries fat acid chain as it is degraded
NADH, FADH2 produced
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Fatty Acid Synthesis
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takes place in cytoplasm
Acyl Carrier Protein (ACP) carries fatty acid chain as it grows
NADPH is used
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Catabolism of Amino Acids for Energy
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1) transaminase reaction
2) a-keto acid feeds into glycolysis or TCA cycle
3) remove amino group from glutamic acid to regenerate a-ketogultaric acid + NH4+
4) get rid of NH4+ via Urea Cycle
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Ketosis
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disturbance of metabolism
when shortage of carbohydrates and lots of fats are being catabolized: starvation, prolonged fasting, diabetes
excess of Acetyl CoA due from B-oxidation of fatty acids
shortage of oxaloacetic acid (being used in gluconeogenesis)
not all acetyl CoA can feed into TCA cycle
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Ketone Bodies
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acetoacetate (3-ketobutanoate)
3-hydroxybutanoate
acetone
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Glucogenic Amino Acids
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amino acids that are broken down to pyruvate, oxaloacetate, or other TCA cycle intermediates
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Ketogenic Amino Acids
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amino acids that are broken down to Acetyl CoA
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Insulin
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produced in and secreted from B-ells of pancreas
sign of "well-fed state", blood glucose is high
signals liver to take up and store glucose
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Glucogen
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produced in and secreted from the a-cells of pancreas
sign that blood glucose is low
signals liver to break down glycogen and release glucose to blood stream
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Type 1 Diabetes
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"insulin dependent"
pancreas doesn't produce insulin
B-cells of pancreas have been destroyed or made non-functional
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Type 2 Diabetes
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"insulin independent"
deficiency in insulin receptors on liver cells
liver doesn't get insulin signal due to lack of insulin receptors
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Body Fluids
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blood (clinically most important)
lymph
CSF
Urine
saliva
sweat
milk
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Hemoglobin
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in red blood cells
globin folds
alpha helices
oxygen and CO2 exchange
oxygen carrying protein
cooperative
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Erythrocytes
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red blood cells
45% of total blood
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Plasma
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55% of total blood
can be stored frozen
whole blood minus "formed elements"
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Whole Blood
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stored cold, not frozen (would rupture cells)
taken directly from patient
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Buffy Coat
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leukocytes and platelets
less than 1% of total blood
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Serum
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allowed to clot then spun in centrifuge
supernatant
whole blood minus cells, platelets and clotting proteins
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"Formed Elements"
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platelets
red blood cells (erythrocytes)
white blood cells (immune system)
components surrounded by lipid bilayer membrane
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Small Molecules
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nutrients (carbs, lipids, amino acids, glucose)
waste products (urea)
other organics (hormones, vitamins)
metabolic intermediates (lactate)
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Electrolytes
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Na+
K+
Ca2+
Mg2+
Cl-
HCO3-
HPO42-
ATP pumps
organic and inorganic substances
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Immunoglobulins
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4 polypeptide chains
2 antigen-binding sites
quaternary structure
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Urea Cycle
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NH4+ converted into urea and then secreted
starts when ammonium ion, bicarbonate, and ATP react to form carbamoyl phosphate (1 nitrogen ion, other from aspartic acid)
transaminase reaction to produce aspartic acid from oxaloacetic acid
catabolism of amino acids
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"Clotting Cascade"
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stop from bleeding
punches a hole in membrane of an invading bacterium and kills it
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Respiratory Acidosis
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caused by hypoventilation
CO2 retained so blood becomes more acidic
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Respiratory Alkalosis
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caused by hyperventilation
CO2 lost so blood becomes alkaline
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Metabolic Acidosis
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too much acid is produced (build up of Acetyl CoA)
body tries to lose CO2--> hyperventilation
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Metabolic Alkalosis
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too much acid lost (prolonged vommitting)
body tries to retain CO2---> hypoventilation
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Kidneys
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get rid of end-products of metabolism (waste products, urea)
control concentration of some components of body fluids
-electrolytes (Na+)
-H+ (helps control blood pH)
-total fluid (water) content and hence osmotic pressure
simple dialysis
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Milk
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produced in mammary tissue of mammals as food for young
high levels of protein, carbs, lipids
necessary for growth and development
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Cerebrospinal Fluid
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around most central nervous tissue
composition similar to plasma
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Lymph
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in lymphatic ducts
transport of macromolecules (proteins)
lipid transport
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Digestive Fluids
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saliva and bile
digestive enzymes, lubricants, detergents, buffers
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Globular Proteins in Blood
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soluble
albumin
globulins (antibodies)
complement proteins
fibrinogen and other clotting proteins
lipoproteins
enzymes
protein hormones
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Serum Albumin
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binds fatty acids, metal ions, drug molecules
regulates osmotic pressure
60% of soluble protein in plasma
loss of it can cause edema
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Osmotic Pressure
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water rushes to the side of the membrane with higher concentration of solutes
two substances that are separated
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Complete Proteins
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help immune system kill invading bacteria
way to get rid of bacteria in blood
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Fibrinogen and other clotting proteins
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inactive enzymes
protease
if active the blood wouldn't pump
produce clotting when circulatory system is broken
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Lipoproteins
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throughout body
transport lipids and cholesterol
protein
triglycerides (cholesterol)
phospholipid
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Protein Hormones
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insulin
human growth hormone
follicle stimulating hormone (FSH)
present in small amounts (trauma can increase)
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Immune System
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protects body from infection by recognizing and destroying foreign molecules
-cells (various white blood cells)
-antibodies (immunoglobins)
-complement
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Antigen
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foreign molecule that IgG "recognizes"
anything that isn't cells or your body
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Antibody
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react with antigenic determinants
on B-cell surface
crosslink and immobilize antigens
water-soluble
circulate in blood stream and other body fluids
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Cooperative
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one of the subunits can help all other subunits bind to oxygen
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Complement
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series of proteins in blood that take part in killing invading cells
use a gradient of H+ ion concentration across membranes to generate ATP
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