Photosynthesis and Plant Resource Transport: BIO 123

What is the overall equation for photosynthesis?

6 CO2 + 12 H2O + Light energy → C6H12O6 + 6 O2 + 6 H2O

Where does photosynthesis occur in plants?

In chloroplasts, specifically in the mesophyll cells of leaves.

What are the two main stages of photosynthesis?

Light reactions and the Calvin Cycle.

What is the function of chlorophyll in photosynthesis?

Chlorophyll absorbs light energy, primarily in the violet, red, and blue wavelengths.

What are the light-dependent reactions of photosynthesis?

They split water, release oxygen, and produce ATP and NADPH.

What is the Calvin Cycle responsible for?

It uses ATP and NADPH to convert CO2 into sugar.

What enzyme catalyzes the carbon fixation in the Calvin Cycle?

RuBisCO (ribulose bisphosphate carboxylase/oxygenase).

What are C4 and CAM plants?

They are types of plants that have adapted different mechanisms for carbon fixation to minimize water loss.

What role do stomata play in photosynthesis?

Stomata allow for the diffusion of CO2 into the leaf while also facilitating water evaporation.

How do roots contribute to a plant's ability to acquire nutrients?

Roots absorb water and minerals from the soil and can adapt to local soil conditions.

What is mycorrhizae?

A mutualistic association between plant roots and fungi that enhances nutrient absorption.

What is the significance of nitrogen-fixing bacteria in legumes?

They provide fixed nitrogen to the plant, enhancing its growth.

What is the role of the xylem in plants?

Xylem transports water and minerals from the roots to the rest of the plant.

What is the process of transpiration?

The evaporation of water from plant leaves, creating a negative pressure that pulls water upward.

What is the pressure flow model in phloem transport?

It explains how sugars move from sources (high pressure) to sinks (low pressure) in the plant.

What are sugar sources and sinks in plants?

Sugar sources are organs that produce sugar, while sinks are organs that consume or store sugar.

What is the role of guard cells?

They regulate the opening and closing of stomata to balance gas exchange and water loss.

What is the significance of the Casparian strip in plant roots?

It acts as a barrier to control the uptake of minerals and prevent toxins.

What is the relationship between water potential and osmosis in plants?

Water moves from areas of higher water potential to lower water potential by osmosis.

What adaptations do leaves have for photosynthesis?

Broad surfaces for light capture and stomata for gas exchange.

How do plants minimize water loss during photosynthesis?

By having adaptations like small leaves or closing stomata during hot conditions.

What is the function of tracheids and vessel elements in xylem?

They facilitate the long-distance transport of water in plants.

What is the role of ATP in the Calvin Cycle?

ATP provides the energy needed for the conversion of CO2 into sugar.

What is the significance of the electron transport chain in light reactions?

It transfers energized electrons to produce NADPH and ATP.

What happens during the reduction phase of the Calvin Cycle?

3-PGA is converted into G3P using ATP and NADPH.

What is the regeneration phase of the Calvin Cycle?

G3P is rearranged to regenerate RuBP, allowing the cycle to continue.

How do plants transport sugars throughout their body?

Through phloem, using a pressure flow mechanism.

What is the role of companion cells in phloem transport?

They assist in loading sugars into sieve tubes and require ATP for active transport.

How do plants adapt their root systems in nutrient-rich vs. nutrient-poor soils?

They may branch extensively in nutrient-rich soils and extend through nutrient-poor soils.

What is the impact of light wavelength on photosynthesis?

Shorter wavelengths have greater energy, which is utilized in photosynthesis.