Metabolism Flashcards
What are the 2 types of reactions in metabolic pathways
Anabolic
Catabolic
Catabolic reactions
Breakdown of large complex organic mol. –> smaller ones.
Release of chem. energy stored in covalent bonds.
Anabolic reactions
Synthesis of larger organic mol. from smaller ones.
Are catabolic reaction exergonic or endergonic?
EXERGONIC
Are anabolic reaction exergonic or endergonic?
ENDERGONIC
ATP
Facilitates energy transfer between catabolic + anabolic reactions by storing chemical energy in its P bonds.
Structure of ATP
Pentose sugar ribose
Nitrogenous base - Adenine
3 Phosphate groups
Apoenzymes
Enzymes that are catalytically inactive.
Once activated, i.e by coenzymes or cofactors, known as – holoenzymes.
Does substrate level phosphorylation require O2?
NO
Where does oxidative phosphorylation occur
ETC
Does oxidative phosphorylation require O2?
YES
Where does the energy req. for oxidative phosphorylation come from?
Generated by transfer of e- from NAD+ + FAD.
What do coenzymes FAD + NAD+ do?
Act as couriers by transferring e- between mol. during oxidation + reduction reactions.
What are REDOX reactions
Chemical reactions involving the transfer of e- between mol.
OXIDATION
Chemical reaction involving LOSS of e- through the loss of Hydrogen or the gain of O2.
REDUCTION
Chemical reaction involving GAIN of e- through gain of hydrogen or loss of O2.
What happens to the potential energy of the mol. when oxidation occurs
Decreases
Hence why they’re called exergonic reactions.
What happens to the potential energy of the mol. when REDUCTION occurs
Increases
Hence why they’re called endergonic reactions.
NAD+
Accepts + donates 2 H atoms:
1 H+ – containing 1 proton + 1 e-
1 Hydride ion – containing 1 proton + 2e-
FAD
Accepts 2 H+ – each containing 1 p + 1 e-.
In which pathways does substrate level phosphorylation occur
Glycolysis (cytoplasm)
Krebs cycle (mit. matrix)
== Yielding 4 mol. of ATP per mol. of glucose.
What are the ways in which glucose can be transported across plasma membranes of a cell?
Secondary AT
FD
Glucose catabolism
Glucose –> Pyruvic acid = Glycolysis
What are the 2 fates of Glucose 6-phosphate
Skeletal muscle
Liver
Control of glycogenolysis
Stimulated by hormone glucagon – secreted from pancreas
+ epinephrine, – secreted from suprarenal medulla.
Define enzyme
A specific protein catalyst that accelerates the forward + reverse rates of chemical reactions w/out being consumed or changed in the reaction.
