Metabolism, Cellular Respiration, etc. Flashcards
includes basic definitions, glycolysis, kreb cycle, pyruvate oxidation, electron transport chain, etc.
what is metabolism
the sum of the biochemical reactions in a living system
what is catabolism
the process of breaking down compounds into smaller molecules to release energy
eg. breakdown of glucose to make ATP
what is anabolism
the process of using energy to build large molecules
eg. making proteins
what are metabolic pathways
step-by-step sequences where one or more substrates form a product that becomes the substrate for the next step; each reaction is catalyzed by an enzyme
What is ATP
adenosine triphosphate
~ the energy that drives and links certain reactions
What is substrate level phosphorylation?
phosphate group is transferred from one molecule to another
ex. when a phosphate group is transferred from a substrate to ADP to form ATP
what are redox rxns
- the transfer of electrons between two species or compounds
LEO lion says GER
~ Loss of Electrons is Oxidation
~ Gain of Electrons is Reduction
What are the “Substrates”/molecules involved in the Kreb cycle
1 molecule of glucose → 2 pyruvate → 2 acetyl coA
CIKSSFMO
Acetyl CoA → citrate → isocitrate → alpha ketoglutarate → succinyl CoA → succinate → fumarate → malate → oxaloacetate
What are the enzymes that catalyze the molecules/substrates of the Kreb Cycle?
(1) Citrate → citrate synthetase
(2 & 3) Citrate to isocitrate → aconitase
(4) Isocitrate to alpha ketoglutarate → isocitrate dehydrogenase
* FIRST REDOX RXN
* PRODUCES CO2
* REDUCES NAD+ INTO NADH + H+
(5) Alpha ketoglutarate to succinyl CoA → dehydrogenase
* 2ND REDOX RXN
* NAD+ IS REDUCED TO NADH + H+
* PRODUCES CO2
(6) Succinyl CoA to succinate → succinyl CoA synthetase
* ONLY ENZYME THAT PRODUCES ATP THROUGH SUBSTRATE LVL PHOSPHORYLATION
* PHOSPHATE GROUP REPLACES THE COA WHICH IS THEN ADDED TO A MOLECULE OF GTP WHICH TRANSFERS IT OFF TO ADP TO PRODUCE ATP
(7) Succinate to fumarate → succinate dehydrogenase
* REDOX RXN #3
* REDUCTION OF FAD TO FORM FADH2
(8) Fumarate to malate → fumarase
(9) Malate to oxaloacetate → malate dehydrogenase
* REDOX RXN #4
* REDUCES NAD+ INTO NADH + H+
THE CYCLE REPEATS!
How many carbons are present in each part of the kreb cycle
glycolysis → 6C
pyruvate → 3C
acetyl CoA → 2C
citrate → 6C
isocitrate → 6C
alpha ketoglutarate → 5C
succinyl CoA → 4C
succinate → 4C
fumarate → 4C
malate → 4C
oxaloacetate → 4C
What are the products of the kreb cycle
FOR EACH PYRUVATE:
1 ATP
3 NADH
1 FADH2
2 CO2
FOR EACH GLUCOSE:
2 ATP
6 NADH
2 FADH2
4 CO2
Where does the krebs cycle occur?
occurs in the mitochondrial matrix when oxygen is present
in terms of pyruvate oxidation under aerobic conditions, what does 1 GLUCOSE yield
2 Acetyl CoA molecules
2 NADH
2 CO2
how to calculate ATP yield for carbohydrates
Depends on the cell type:
~ PROKARYOTIC (no membrane) = 38 ATP/glucose
~ EUKARYOTIC (membrane) = 36 ATP/glucose
~ *** heart liver and kidney = 38 ATP/glucose
1) first determine how many glucose are produced (both fructose and galactose yield the same # of ATP as glucose)
2) multiply by the number of ATP depending on the description (ex. prokaryotic, eukaryotic, in the heart, liver or kidney)
What is glycolysis? where does it occur?
glycolysis is the conversion of glucose (6C) into pyruvate (3C); occurs in the cytoplasm and no oxygen is required
What is a dehydrogenase enzyme
A dehydrogenase enzyme oxidizes the substrate by removing hydrogens and associated electrons and transferring them to an electron acceptor (ex. NAD+ to NADH + H+).
What are kinases
enzymes that chemically add a phosphate group to a substrate molecule
(eg. ADP → ATP; phosphorylation)
What are isomerases
enzymes that catalyze a structural rearrangement of a molecule
eg. (DHAP → G3P; ketone to aldehyde)
For every glucose that goes through glycolysis, how much ATP is made
2 molecules of ATP
What are electron carriers? specify examples
electron carriers are compounds that pick up electrons and donate them to low-energy compounds
eg. NAD+ to NADH
eg. FAD+ to FADH2
What are the 10 steps of glycolysis? include the names of the substrate, enzyme, and where ATP is used.
- Glucose → Glucose-6-Phosphate: Hexokinase
~ ATP TURNS TO ADP - Glucose-6-Phosphate → Fructose-6-Phosphate: Isomerase
~ aldehyde to ketone - Fructose-6-Phosphate → Fructose 1,6 Bisphosphate: Kinase
~ ATP TURNS TO ADP - Fructose 1,6 Bisphosphate → Dihydroxyacetone phosphate (DHAP): Aldolase
~ where 6C chain breaks to 3C - Dihydroxyacetone phosphate (DHAP) → Glyceraldehyde-3-Phosphate (G3P): Isomerase
~ also a 3C
~ can go to DHAP to G3P or the other way around - Glyceraldehyde-3-phosphate to 1,3 Bis Phosphoglycerate (1,3 BPG) → G3P dehydrogenase
~ THIS STEP HAPPENS TWICE
~ NAD+ BECOMES NADH (REDOX RXN) - 1,3 Bis Phosphoglycerate (1,3 BPG) → 3-Phosphoglycerate: Kinase
~ ADP TURNS TO ATP - 3-Phosphoglycerate → 2-Phosphoglycerate: Mutase
~ Phosphate goes from C3 to C2 - 2-Phosphoglycerate → Phosphoenol Pyruvate: Enolase
- Phosphoenol pyruvate → pyruvate: Kinase
~ ADP TURNS TO ATP
~ 3C
~ TWO PYRUVATES ARE FORMED
what is oxidative phosphorylation
oxygen is the final electron acceptor
Where does pyruvate oxidation occur
the mitochondrial matrix
What are the steps of pyruvate oxidation? Whats the enzyme that catalyzes this reaction
- pyruvate is broken down to acetate
- CO2 is produced
- Remainder binds to coenzyme A to produce acetyl-CoA
- NAD+ is reduced to form NADH
the enzyme that catalyzes this rxn is pyruvate dehydrogenase complex (3 enzymes)
