CH. 5 PHOTOSYNTHESIS

CHAPTER 5: PHOTOSYNTHESIS

Q: What is the balanced equation for photosynthesis?
A: 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂

Q: Where is chlorophyll located in a chloroplast, and what is its function?
A: Chlorophyll is located in the thylakoid membrane. It absorbs light energy for photosynthesis.

Q: What happens in the light-dependent reactions?
A: They occur in the thylakoid membrane and use light energy to produce ATP, NADPH, and O₂ from water and sunlight.

Q: What happens in the light-independent reactions (Calvin Cycle)?
A: They occur in the stroma and use CO₂, ATP, and NADPH to synthesize glucose.

Q: What are the reactants and products of each stage of photosynthesis?
A:

• Light-dependent reactions: Reactants = H₂O, light; Products = O₂, ATP, NADPH

• Light-independent reactions: Reactants = CO₂, ATP, NADPH; Products = Glucose

Q: Where does each stage of photosynthesis occur?
A:

• Light-dependent reactions: Thylakoid membrane

• Light-independent reactions (Calvin cycle): Stroma

Q: What are C4 and CAM plants?
A:

• C4 plants (e.g., corn) fix CO₂ into a 4-carbon compound to minimize photorespiration.

• CAM plants (e.g., cacti) open stomata at night to store CO₂ for daytime use, conserving water.

Q: What is chemiosmotic phosphorylation?
A: The process where ATP synthase uses a proton gradient to produce ATP during the light-dependent reactions.

Q: What is photorespiration?
A: A process where RuBisCO binds to oxygen instead of CO₂, reducing photosynthetic efficiency.

TERMINOLOGIES

Q: What are autotrophs?
A: Organisms that make their own food, like plants.

Q: What are heterotrophs?
A: Organisms that obtain energy by consuming other organisms.

Q: What are photons?
A: Particles of light energy.

Q: What is wavelength?
A: The distance between peaks of light waves, determining color.

Q: What are pigments?
A: Molecules that absorb specific wavelengths of light.

Q: What is a photosystem? What is the reaction center?
A: A photosystem is a protein-pigment complex that captures light. The reaction center is where electrons are excited for photosynthesis.

Q: What is chlorophyll a?
A: The primary pigment in photosynthesis that absorbs blue-violet and red light.

Q: What are accessory (antenna) pigments?
A: Pigments that absorb additional light wavelengths and transfer energy to chlorophyll a.

Q: What are the parts of the chloroplast?
A: Thylakoid (membrane-bound sacs), stroma (fluid inside chloroplast).

Q: What are the parts of a leaf cell?
A: Mesophyll (photosynthetic tissue), stomata (pores for gas exchange), bundle sheath cells (surround vascular bundles, important in C4 plants).