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43 Cards in this Set

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Metabolism
chemistry of life
i.e. biochemistry
Metabolic Roles
1 - generation of energy (ATP)
2 - generation of biosynthetic precursors (AA, sugars, fatty acids)
3 - synthesis of macromolecules(proteins, nucleic acids, lipids)
4 - synthesis/degradation of special products (steroids)
autotrophs
use CO2 from the atmosphere as their sole source of carbon
heterotrophs
cannot use CO2 from atmosphere and must obtain carbon from their environment in complex organic molecules such as glucose
catabolism
breakdown of complex molecules to form energy

ADP to ATP
anabolism
aka biosynthesis

small simple precursors synthesized into larger, complex molecules

ATP to ADP
carbs, fats, proteins to CO2, H2O, NH3
catabolism
AAs, FAs, sugars, nucleotides to proteins, nucleic acids, polysaccharides, lipids
anabolism
"Unity" principle
Biochemistry of life is essentially the same in all organisms

relevance=underscores the need for very careful regulation of metabolism
Modes of metabolic regulation
1-compartmentalization
2-org. of rxns into stepwise pathway (end product inhibits "feedback" inhibition
3-regulation of expression of imp. metabolic genes (hormonal control, transcript/translat. control)
compartmentalization
defined rxns occur in specific cellular compartments

cytosol=54%
mitochondria=22%
rough ER=9%
smooth ER/Golgi=6%
nucleus/nucleolus=6%
microbodies/peroxisomes=1%
lysomes-1%
endosomes-1%
Concept of "energy change"
conceived by Daniel Atkinson
in 1970s (e.coli)

ATP +.5ADP/(ADP+ATP+AMP)

ATP=1
AMP=0 for all EC
What is the EC of organisms?
all organisms maintain an EC of approximately 0.9 (.82-.95)
endonucleotides
primarily ATP
Daniel Atkinson
concept of energy change
cell fractionation
1-mix sucrose homogenate with teflong pestle
2-strain/vacuum filtrate out homogenate
3-centrifuge 600gx10min. to get supernatant 1 (nuclei/unbroken cells)
4-centrifuge 15000gx5min. to get supernatant 2 (mitochondria, lysosomes, and microbodies)
5-centrifuge 3rd time 100,000gx60min. to get supernatant 3 (fraction of cytoplasm, ER/Golgi/plasma membrane)
glycolysis
"ancient" pathway
Louis Pasteur
studied "fermentations-anaerobic degradation of glucose" in the making of wine finding that microrganisms(yeast) were involved
fermentation
an energy producing pathway with no net oxidation fo reactants or products ex.=fruit juice into ethanol
Pasteur effect
oxygen inhibits fermentation
O2 present=less glucose
Buchner
studied under Fisher (fisher projections)

credited for finding that fermentation can occur in "cell free" yeast extracts
Harden and Young
1900s
young was harden's student

inorganic phosphate stimulates fermentation in cell free systems
five people responsible for elucidation of entire glycolytic pathway
Embden, Meryerhof, Warburg, Parnas, and con Euler-Chelpin
The glycolytic pathway is also commonly called the...
Embden-Meyerhof pathway
Otto Warburg
worked under Fischer
1883-1970
credited along with von Euler-Chelpin for elucidation of the whole pathway in yeast
Embden and Meyerhof
credited for whole pathway in muscle
How many nobel prizes have been awarded for work on or related to the glycolytic pathway?
5!!!
equation for glycolysis
glucose + 2NAD+ + 2ADP + 2 Pi ---- 2 pyruvate + 2NADH + 2H+ + 2 ATP + 2H2O
the conversion of glucose to pyruvate is exergonic or endergonic?
exergonic
the conversion of ATP from ADP and Pi is exergonic or endergonic?
endergonic
importance of phosphorylated intermediates
9 intermediates from glucose to pyruvate are phosphorylated

1-plasma membrane lacks transporters for phosphorylated sugars forcing it to stay in the cell saving energy to keep it in
2-essential in conservation of metabolic energy
3-binding of phosphate groups to active sites of enzymes lowers activation energy/increases specificity of enzymatic rxns
What is the role of Mg2+ in the degradation of ATP to ADP?
shields negative charges of phosphoryl groups in ATP, making the terminal phosphorus atom an easier taget for nucleophilic attack by an -OH of glucose
isozymes
two enzymes that catalyze the same rxn but are encoded in different genes
catalyst of step 1 glycolysis
hexokinase
catalyst of step 2 glycolysis
phosphohexose isomerase
or
phosphoglucose isomerase
catalyst of step 3 glycolysis
phosphofructokinase-1 (PFK-1)
catalyst of step 4 glyclosis
fructose 1,6-biphosphate aldolase
catalyst of step 5 glycolysis
triose phosphate isomerase
catalyst of step 6 glycolysis
glyceraldehyde 3-phosphate dehydrgenase
catalyst of step 7 glycolysis
phosphoglycerate kinase
catalyst of step 8 glycolysis
phosphoglycerate mutase
catalyst of step 9 glycolysis
enolase
catalyst of step 10 glycolysis
pyruvate kinase