BIO Exam PDF

1. Enzymes What are they? Proteins that speed up chemical reactions in the body. How they work: o Substrates (reactants) fit into an enzyme’s active site like a "lock and key." o They lower the energy needed for a reaction. What affects them? o Temperature:...

1. Enzymes What are they? Proteins that speed up chemical reactions in the body. How they work: o Substrates (reactants) fit into an enzyme’s active site like a "lock and key." o They lower the energy needed for a reaction. What affects them? o Temperature: Too hot = enzyme stops working (denatured). o pH: Too acidic or too basic can damage enzymes. o Substrate concentration: More substrate = faster reaction (to a point). 2. Photosynthesis What is it? The process plants use to make food (glucose) using sunlight. Equation: o Carbon dioxide + Water + Light → Glucose + Oxygen o (6CO₂ + 6H₂O + Light → C₆H₁₂O₆ + 6O₂) Steps: o Light-dependent stage (in leaves): Sunlight splits water → Makes energy (ATP) and oxygen. o Calvin Cycle: Uses energy to turn carbon dioxide into glucose. Why is it important? o Gives oxygen to breathe. o Produces food for plants and other organisms. 3. Respiration What is it? The process of breaking down glucose to make energy (ATP). Types: o Aerobic respiration (needs oxygen): ▪ Glucose + Oxygen → Carbon dioxide + Water + Energy o Anaerobic respiration (no oxygen): ▪ In animals: Glucose → Lactic Acid + Energy ▪ In yeast: Glucose → Alcohol + Carbon dioxide + Energy Why is it important? o Provides energy for everything the body does (e.g., moving, growing).