Midterm 1 Flashcards
(269 cards)
Energy
Chemical energy stored in the sugar is converted to chemical energy of ATp
Stepwise conversion
Each step catalyzed by individual enzymes:: Each step generates distinct metabolic intermediates.
Metabolites
Can also be used for other pathway and biosynthesis
Key enzymes are regulated:
control of metabolic flux
Metabolite concentrations
also control metabolic flux, especially when G is around 1
A metabolic pathway must be
exergonic (ΔG < 0)
May require the input of ATP/NADH
Catabolic vs. Anabolic Pathways:
NOT simply the reverse of each other
Compartmentation
Increased organization and control
Coordinated Regulation of Anabolic and Catabolic pathways
• HormonalRegulation
(eg. Insulin/ Glucagon)
• Allostericcontrolofenzymeactivity
• Committedstepsinapathwayare often tightly regulated
• PreventFutileCycles ADP+Pi
• Long-termregulationbygene ATP expression
Most metabolic reactions are…
The chemistry of carbonyls, They are electrophilic and Carbonyl carbon can enhance the acidity of adjacent carbon-bound protons
What are the 5 main types of metabolic reactions?
Nucleophilic additions, Nucleophilic substitutions, Elimination reactions, Carbonyl condensation reaction, Oxidation and reduction.
Nucleophilic addition
when the nucleophile is a carbon anion -get a new CC bond
nucleophilic substitution
Replace one nucleophile with another. Need good leaving group. Ester and anhydrides, nucleophilic acyl sub reactions, tetrahedral intermediates.
Elimination reactions
need good leaving group
Carbonyl condensation
important for synthesizing CC bonds, can run in reverse
oxidation and reduction
Reversible, EX: hydride transfer from alcohol to form a ketone. Dehydrogenation reaction catalyzed by a dehydrogenase.
overview of metabolic flow
- Lipid Metabolism
- Amino Acid Metabolism
• Integration of Metabolism - Nucleic Acid Metabolism
Nucleophiles
Alkoxide, carboxylate, thiolate, carbanion, amine
electrophiles
Carbonyl, imine, phosphorus atome of phosphate
What are the uses of lipids?
membrane constituents, hormones, fat- soluble vitamins, thermal insulators, signaling molecules
What are used for energy reserves and why?
Fat-
• Fats are an efficient form of stored energy- can be stored without water
• Fats are more reduced than sugars or amino acids, yielding more energy
- Fats have more energy per gm
What are triacylglycerols?
Energy reserves in Adipose and other tissues. Excludes water.
What are lipid droplets?
dynamic organelles filled with Triacylglycerols (TAGs)
and Cholesterol-Esters (CEs). Surrounded by a phospholipid monolayer and associated proteins.
What are the components of triacylglycerols?
Phosopholipid monolayer, storage enzymes, lipid mobilization enzymes, Peripilins (regulatory proteins).