Lecture 14 Flashcards
Define free energy (state it’s equation symbol) and relate it to exergonic and endergonic reactions.
Free Energy: Delta G
Exergonic reactions have a negative DeltaG value
Endergonic reactions have a positive Delta G value
Relate free energy to ATP breakdown.
Free energy being released when ATP is broken down into ADP is what makes it an exergonic reaction
Know how galactose and glucose enter the pathway of glycolysis.
Galactose goes to galactose-1-phosphate then glucose-1-phosphate then glucose-6-phosphate
ATP is used to create galactose-1-phosphate from galactose
ATP is used to create fructose-6-phosphate from fructose
The above sugars, once they have been phosphorylated, will then undergo glycolysis (glycolysis begins as fructos-6-phophate so glucose-6-phosphate and galatose-6-phosphate must be converted into fructose-6-phosphate)
Describe the 2 methods used to conduct the uptake of glucose.
Via active Na-glucose co-transport (occurs in the GI tract and renal tubules)
Via facilitated transport: occurs in most tissues
State the end products of glycolysis.
begins with glucose
Begins with: Glucose (then gets converted to fructose-6-phosphate)
2 pyruvic acid molecules
4 Hydrogens (whose release is catalyzed by a dehydrogenase
2 ATP molecules
State the end products of the conversion of pyruvic acid to acetyl-CoA.
(begins with Pyruvic Acid)
Begins with: Pyruvic Acid (O2 present)
2 Acetyl-CoA molecules
4 Hydrogens (whose release is catalyzed by a dehydrogenase)
2 CO2 molecules
What is the fate of pyruvate when oxygen is not present?
pyruvate becomes lactic acid
State where in the cell the citric acid cycle occurs. Also list the end products of the citric acid cycle. (begins with Citric acid)
It occurs in the mitochondrial matrix
(Begins with: Citric Acid)
16 (8x2) Hydrogens (release is catalyzed by a dehydrogenase)
2 ATP molecules
4 (2x2) CO2 molecules
Define oxidative phosphorylation. Where does this occur?
Oxidative phosphorylation: basically the process that moves the hydrogen atoms from the previous metabolic cycles, through the electron transport chain in order to produce 34 ATPs (per 1 molecule of glucose)
Occurs in the Mitochondrial Cristae
Describe the fate of the hydrogen atoms and the electrons generated during glycolysis and the citric acid cycle. Name and compare the hydrogen ion carriers.
Hydrogens are removed in pairs, one member of the pair becomes a ion while the other pair creates NADH (by bonding to NAD+)
All hydrogen items still enter the ETC
All Electrons also enter the ETC
List, in sequence, the components of the electron transport chain. (4 things to name)
Flavoprotein
Several ion sulfide proteins
Ubiquinone (Q)
Cytochrome A3 (cytochrome oxidase)
Describe the chemiosmotic mechanism.
Energy is used to pump H+ ions from the inner chamber of the mito, across the inner membrane in order to create a large negative potential in the inner chamber (where they H+ ions were pumped out of)
The H+ ions then travel back across the inner membrane through the ATPase, which is a membrane protein that creates ATP from ADP as H+ ions donate energy to it as they re-enter the inner chamber of the mito (similar to a turbine)
(for each pair of electrons that pass through the electron transport chain, there are up to 3 molecules of ATP created)
Describe the pentose phosphate pathway and explain what it is primarily used for.
The pentose phosphate pathway is a cyclical pathway in which 1 glucose molecule is metabolized
This pathway is mostly involved in the synthesis of fats
Describe the transport mechanism for hydrogen ions in the pentose phosphate pathway.
Hydrogens generated from the pentose phosphate pathway ware bound to NADP+ instead of NAD+ in order to synthesize fats from carbohydrates
Describe how triglycerides are synthesized from glucose.
Glucose is preferentially stored as glycogen in the muscles and liver BUT
When those areas are saturated, it is converted to be stored as triglycerides (fats)
