Botany Lecture on Leaves and Photosynthesis

These flashcards cover essential vocabulary and concepts related to botany, particularly focusing on leaf structure, functions, and processes related to photosynthesis and transpiration.

Cuticle

A waxy, waterproof layer that reduces water loss from the leaves.

Upper epidermis

Transparent layer of cells that lets light through.

Palisade mesophyll

The main site of photosynthesis, characterized by a high density of chloroplasts.

Spongy mesophyll

Layer with air spaces that allows for gas diffusion in leaves.

Stomata

Pores found on the leaf surface that facilitate gas exchange.

Guard cells

Cells that control the opening and closing of stomata.

Transpiration

The loss of water vapor from leaves through stomata.

Cohesion

The property of water molecules sticking to each other.

Adhesion

The property of water molecules sticking to the walls of xylem.

Xylem

Tissue responsible for water transport in one direction from roots to leaves.

Phloem

Tissue responsible for sugar transport, moving in both directions.

Pressure flow mechanism

The process by which sucrose is actively loaded into phloem, followed by water entering by osmosis, creating pressure that pushes sap to sinks.

Light independent reactions

Reactions in the Calvin cycle that use CO2, ATP, and NADPH to produce triose phosphate.

Limiting factors of photosynthesis

Only one environmental factor (light intensity, CO2 concentration, or temperature) limits the rate of photosynthesis at a time.

Stomatal control

Mechanism by which guard cells regulate stomatal opening due to light presence and low CO2 levels.

Adaptations of leaves

Features such as large surface area and thin structure that maximize light absorption and facilitate gas exchange.