BackMicrobiology Metabolism Flashcards
04:21
Terms in this set (28)
Metabolism is the sum of all chemical reactions within a living organism.
Catabolism breaks down complex molecules releasing energy (exergonic). Anabolism builds complex molecules requiring energy (endergonic).
ATP is the energy currency of the cell, storing and transferring energy between catabolic and anabolic reactions.
Collision theory explains how molecular motion and energy affect the frequency and success of chemical reactions.
Activation energy is the energy needed to disrupt electron configurations to start a chemical reaction.
Enzymes lower activation energy, speeding up reactions without being consumed.
The active site is the specific region on an enzyme where the substrate binds.
Temperature, pH, and substrate concentration affect enzyme activity by altering enzyme structure or availability.
Competitive inhibitors bind the active site; noncompetitive inhibitors bind elsewhere causing allosteric changes.
Feedback inhibition uses the end product to noncompetitively inhibit an enzyme early in the pathway to prevent excess production.
Ribozymes are RNA molecules with enzymatic activity that catalyze RNA splicing and protein synthesis.
Redox reactions involve coupled oxidation (loss of electrons) and reduction (gain of electrons) processes.
NAD+ accepts electrons and hydrogen atoms to become NADH, storing energy for the cell.
ATP is generated by substrate-level phosphorylation and oxidative phosphorylation.
Glycolysis oxidizes glucose to pyruvic acid, producing ATP and NADH in preparatory and energy-conserving stages.
The Krebs cycle produces 2 ATP, 6 NADH, and 2 FADH2 by oxidizing acetyl CoA to CO2.
The ETC transfers electrons from NADH and FADH2 to generate a proton gradient used by ATP synthase to produce ATP.
In aerobic respiration, oxygen is the final electron acceptor; in anaerobic respiration, other molecules are used.
Fermentation breaks down organic molecules anaerobically without the TCA cycle or ETC, producing small energy amounts.
Lipids are broken down by lipases into glycerol and fatty acids, which enter glycolysis and acetyl CoA pathways.
Proteins are broken down by proteases into amino acids, which are modified to enter glycolysis or the Krebs cycle.
Phototrophs use light energy to generate chemical energy via photosynthesis.
Light reactions generate ATP and NADH; dark reactions use these to fix CO2 into sugars.
ATP yield is reduced due to proton leakage across membranes and diversion of intermediates for biosynthesis.
The pentose phosphate pathway metabolizes 5-carbon sugars and provides precursors for nucleic acids and amino acids.
Bacteria store excess glucose as glycogen by linking glucose-6-phosphate molecules, consuming ATP.
Amino acids are synthesized by adding amine groups to glycolysis or Krebs cycle intermediates via amination or transamination.
Nucleotides are synthesized using intermediates from the pentose phosphate pathway and amino acids like glycine and glutamine.