Metabolism + Bioenergetics Flashcards
Metabolic pathways that lead to biosynthesis are ___ while pathways that lead to degradation of complex metabolites are ___
Anabolic, catabolic
Metabolism equation
Metabolism = anabolism + catabolism
Phosphoanhydride bonds
Join the 3 phosphate groups on a nucleotide - cleaving these bonds releases energy due to instability caused by neighbouring negatively charged P groups
Metabolites
Intermediates in metabolic pathways
Glycolysis
Leads to breakdown of glucose into 2 pyruvate molecules (oxidation of glucose to pyruvate is coupled to reduction of NAD+ into NADH + to production of 2 ATP)
TCA cycle
Further oxidation of pyruvate into CO2 occurs during this - inside mitochondria of eukaryotes
What does transport of pyruvate into mitochondria occur via?
Pyruvate translocase
Exergonic vs endergonic
If delta G prime < 0 it’s exergonic and if > 0 it’s endergonic
Oxidizing agent vs reducing agent
Oxidizer receives electrons while reducer donates electrons
Oxidative phosphorylation
Produces further ATP from NADH produced during complete CO2 oxidation from pyruvate in aerobic metabolism
Two stages of glycolysis pathway
1) Preparatory stage to create 2 molecules of glyceraldehyde-3-phosphate - requires investment of 2 ATP
2) Energy production stored as ATP - GAP and DHAP are further phosphorylated using P to create 2 molecules of 1,3-biphosphoglycerate which have higher free energy than glucose + are converted to pyruvate to release energy. Rxns coupled w/production of 2 ATP per 1,3-biphosphoglycerate for total of 4 ATP
Ethanolic fermentation
- NADH is regenerated in anaerobic metabolism by this - allows regeneration of NAD+ needed for further glycolysis rxns
- 1st is decarboxylation of pyruvate to produce acetaldehyde + CO2
- 2nd is reduction of acetaldehyde to ethanol allowing for oxidation of NADH into NAD+
Lactic acid fermentation
NADH is regenerated in anaerobic metabolism by this - pyruvate converted into lactic acid
Homolactic fermentation
Pyruvate converted to lactic acid - catalyzed by lactase dehydrogenase
Heterolactic fermentation
Occurs via pentose phosphate pathway - 1 molecule glucose converted into 1 molecule lactate+ 1 molecule ethanol + 1 molecule CO2