CH. 5 PHOTOSYNTHESIS

What is the balanced equation for photosynthesis?

6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂

Where is chlorophyll located in a chloroplast, and what is its function?

Chlorophyll is located in the thylakoid membrane. It absorbs light energy for photosynthesis.

What happens in the light-dependent reactions?

They occur in the thylakoid membrane and use light energy to produce ATP, NADPH, and O₂ from water and sunlight.

What happens in the light-independent reactions (Calvin Cycle)?

They occur in the stroma and use CO₂, ATP, and NADPH to synthesize glucose.

What are the reactants and products of the light-dependent reactions?

Reactants = H₂O, light; Products = O₂, ATP, NADPH.

What are the reactants and products of the light-independent reactions?

Reactants = CO₂, ATP, NADPH; Products = Glucose.

Where do light-dependent reactions occur?

Thylakoid membrane.

Where do light-independent reactions (Calvin cycle) occur?

Stroma.

What are C4 and CAM plants?

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.

What is chemiosmotic phosphorylation?

The process where ATP synthase uses a proton gradient to produce ATP during the light-dependent reactions.

What is photorespiration?

A process where RuBisCO binds to oxygen instead of CO₂, reducing photosynthetic efficiency.

What are autotrophs?

Organisms that make their own food, like plants.

What are heterotrophs?

Organisms that obtain energy by consuming other organisms.

What are photons?

Particles of light energy.

What is wavelength?

The distance between peaks of light waves, determining color.

What are pigments?

Molecules that absorb specific wavelengths of light.

What is a photosystem? What is the reaction center?

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

What is chlorophyll a?

The primary pigment in photosynthesis that absorbs blue-violet and red light.

What are accessory (antenna) pigments?

Pigments that absorb additional light wavelengths and transfer energy to chlorophyll a.

What are the parts of the chloroplast?

Thylakoid (membrane-bound sacs), stroma (fluid inside chloroplast).

What are the parts of a leaf cell?

Mesophyll (photosynthetic tissue), stomata (pores for gas exchange), bundle sheath cells (surround vascular bundles, important in C4 plants).