Unit 4 AP Bio

UNIT 4: RESPIRATION AND PHOTOSYNTHESIS

Cellular Respiration and Fermentation (Ch. 7)

• The general equation for cellular respiration: C6H12O6 (Glucose) + 6 O2 (Oxygen) -> 6C02+ 6H2O+ ATP

• The three main stages of cellular respiration and locations of these stages: Glycolysis in cytosol, Krebs cycle in mitochondrial matrix, electron transport chain in inner mitochondrial membrane

• The general equation for each variation of fermentation: 

• Alcoholic fermentation:  C6H12O6 + 2ADP + 2Pi (Inorganic Phosphate) -> 2 C2H5OH (ethanol) + 2CO2 + ATP, 

• Lactic Acid Fermentation: Glucose + ADP + Pi -> Lactate + Ethanol + CO2 + ATP

• The start and end products of glycolysis: Starts with one glucose molecule, products are 2 pyruvate, 4 ATP, and 2 NADH

• The start and end products of the Krebs cycle: Starts with acetyl COA, products are 2 GTP, 6 NADH, 2 FADH2, and 4 CO2

• The start and end products of the electron transport chain: 

• Reactants: NADH, FADH2, Protons, ADP, and oxygen

• Products: H20, 32-34 ATP

• The roles of components within the ETC, especially electron carriers and ATP synthase

• NADH and FADH2 drop off their electrons at the chain, the electrons then move down the chain and generate energy

• The energy is used in the active transport of H+ ions from the mitochondrial matrix to the intermembrane space

• Oxygen acts as the final electron acceptor, and it turns into water after accepting electrons

• The H+ ions diffuse from intermembrane space back to mitochondrial matrix using the protein ATP synthase, and then ATP is made

Gas Exchange (Ch. 34)

• General path of oxygen through the human circulatory and respiratory systems: Oxygen is breathed in through nose or mouth, travels to lungs, and is transferred to bloodstream at alveoli

• The role of hemoglobin in transporting oxygen, and how to interpret hemoglobin graphs: Hemoglobin is a protein in red blood cells that transports oxygen similar to an enzyme, has 4 subunits which can each bond to one O2 molecule, if hemoglobin has lots of O2 attached it means it does not need to donate it, and if hemoglobin has low O2 attached it has lower affinity meaning it donated more of its oxygen

Photosynthesis (Ch. 8)

• Diets of heterotrophs and autotrophs

• Heterotrophs: Eat other animals or plants

• Autotrophs: Use water, CO2, and sunlight

• The general equation of photosynthesis:  6CO2 + 6H2O -> C6H12O6 + 6O2

• The two main reactions of photosynthesis and their locations: Light reactions in the thylakoid, and dark reactions in the stroma

• The chloroplast structures associated with photosynthesis: Stroma and thylakoid

• How the light reactions and dark reactions are connected to each other: The ATP and NADP+ produced in the dark reactions are then used in the light reactions

• Comparisons between cellular respiration and photosynthesis: Reactants of cellular respiration are products of photosynthesis, and vice versa, photosynthesis makes glucose which is then used in cellular respiration for making ATP, the glucose then transforms back into CO2 which is used for photosynthesis

• The roles of the electron carriers in photosynthesis, and the names of the carriers

• NADP+ acts as final electron acceptor and gets reduced to NADPH after accepting electrons

• Roles of NADPH and ATP in photosynthesis: Convert CO2 into carbohydrates

• The purpose of multiple pigments in plants: So they can absorb energy from multiple wavelengths

• Detailed steps of the light reactions: 

• Light Reactions: Light is absorbed by photosystem II and water breaks into oxygen -> When light is absorbed by PS II it excites electrons in PS II to move down  the transport chain to PS I, the electrons moving down the ETC is exergonic and therefore generating energy, the energy is sued to fuel active transport from lumen (thylakoid interior) to the outside, Light gets absorbed by PS I and excites electrons which get accepted by NADP+, which then reduces to NADPH, the H+ ions pumped across come back through ATP synthase and make ATP, 

• Dark Reactions: Calvin Cycle that takes place in stroma of chloroplasts, CO2 combines with RuBP 

• Alternate mechanisms of mainstream photosynthesis, such as C4 and CAM

• C4 plants prevent photorespiration by storing CO2 in one cell, and performing the Calvin Cycle in another cell 

• CAM plants store CO2 in the night and then store them in vacuoles to be used during photosynthesis in the day, and close stomata in the day to prevent water loss