Cellular energetics Flashcards
what is anabolism?
uses energy to build complex molecules e.g. amino acids to proteins
what is catabolism?
releases energy through molecule breakdown e.g. glucose in glycolysis
exergonic
energy released
endergonic
energy required
when does ATP release energy?
when outermost Pi is cleaved off, yields ADP
Q: What is chemiosmosis and where does it occur?
A:
Chemiosmosis is the process by which ATP is produced using the energy of a proton (H⁺) gradient across a membrane. Protons flow through ATP synthase, which uses this energy to convert ADP + Pi into ATP.
It occurs in the inner mitochondrial membrane during cellular respiration, and in the thylakoid membrane during photosynthesis.
Q: What is free energy and entropy in biological systems?
A:
Free energy (G): Energy available to do work.
Entropy (S): A measure of disorder/randomness.
In biology, spontaneous processes increase entropy and occur when ΔG is negative (free energy is released).
Q: What is the role of ATP in coupling energy-releasing and energy-requiring processes?
A:
ATP acts as an energy shuttle. It captures energy from exergonic reactions and donates it to endergonic reactions via phosphate transfer, enabling cellular work.
Q: What is the importance of redox reactions in energy generation?
A:
Redox reactions transfer electrons between molecules, releasing energy used to form ATP. Electron carriers like NAD⁺ and FAD get reduced and carry electrons to the electron transport chain.
Q: What are the purposes of glycolysis, Krebs cycle, ETC, chemiosmosis, oxidative phosphorylation, and cellular respiration?
A:
Glycolysis: Breaks glucose into pyruvate; makes some ATP/NADH
Krebs Cycle: Generates NADH, FADH₂, CO₂, and a bit of ATP
ETC: Passes electrons to O₂; pumps protons
Chemiosmosis: Uses proton gradient to drive ATP synthesis
Oxidative Phosphorylation: Combines ETC + chemiosmosis to make most ATP
Cellular Respiration: Entire process of extracting energy from glucose
Q: Where do the major ATP-generating pathways occur under aerobic and anaerobic conditions?
A:
Aerobic:
Glycolysis → Cytoplasm
Krebs Cycle → Mitochondrial matrix
ETC & Chemiosmosis → Inner mitochondrial membrane
Anaerobic:
Only glycolysis occurs (cytoplasm); followed by fermentation
Q: How does ATP couple energy-releasing and energy-requiring processes?
A:
ATP couples energy-releasing and energy-requiring processes by temporarily storing energy from exergonic reactions and then releasing it exactly when and where it’s needed to power endergonic reactions.
