Enzyme
What do enzymes do to the activation energy of a reaction?
Lower it.
What happens to most enzymes at very high temperatures?
They denature
What molecule is known as the “energy currency” of the cell?
ATP
What are the main reactants and products of photosynthesis?
CO₂ + H₂O + light → glucose + O₂
What are the three main stages of aerobic respiration?
Glycolysis, Krebs cycle, and ETC
What type of biological macromolecule are enzymes?
Proteins
What environmental factor besides temperature can denature enzymes?
pH
What happens to an organism if energy input is less than energy loss?
It loses order and may die
Where in the chloroplast does the Calvin cycle occur?
Stroma
Where does glycolysis occur in the cell?
Cytosol
What is formed when a substrate binds to an enzyme’s active site?
Enzyme-substrate complex
What is the term for molecules that block the active site of an enzyme?
Competitive inhibitors.
What law states that energy cannot be created or destroyed?
The first law of thermodynamics
What structure in the chloroplast contains the photosystems and Electron Transport Chain (ETC)?
Thylakoid membranes
What gas is the final electron acceptor in aerobic respiration?
Oxygen
Why is enzyme structure important for its function?
The shape and charge of the active site must match the substrate
Can denaturation ever be reversed?
Sometimes, if the primary structure isn’t destroyed
How do living organisms maintain order without violating thermodynamic laws?
They use constant energy input to counter entropy
What process creates ATP in the light reactions?
Photophosphorylation via chemiosmosis
What process generates ATP using a proton gradient across the inner mitochondrial membrane?
Oxidative phosphorylation
What would happen if a mutation changed an enzyme’s active site shape?
The enzyme may no longer bind the substrate or function properly
How does substrate concentration affect enzyme activity?
Increases reaction rate until enzymes become saturated
What is meant by coupling reactions in cells?
Energy-releasing reactions drive energy-requiring ones
What is the role of photosystems I and II?
They capture light energy and transfer electrons through the ETC
What is the main difference between aerobic respiration and fermentation?
Fermentation occurs without oxygen and produces less ATP