Water and Nutrition Transport

What is diffusion in the context of solute movement?

Movement of solutes from an area of high concentration to an area of low concentration.

What is the difference between passive and active transport?

Passive transport occurs without energy expenditure, while active transport requires energy to move solutes against a concentration gradient.

What types of molecules can diffuse directly across biological membranes?

Gases (O2, CO2), water (H2O), and small uncharged molecules.

What role do membrane channels play in solute transport?

They are transmembrane proteins that selectively admit certain ions.

What is facilitated diffusion?

A type of passive transport that uses transmembrane proteins to help move solutes across membranes.

What is the function of a proton pump in active transport?

It pumps protons across a membrane against their concentration gradient, requiring ATP.

What is osmosis?

The movement of water to equilibrate concentrations across a membrane.

What happens to plant cells in a hypertonic solution?

They lose water, leading to plasmolysis and potential wilting.

What is root pressure?

The pressure that pushes water up through the xylem from the roots.

How does transpiration contribute to water movement in plants?

It pulls water from the xylem to surrounding leaf cells, creating a negative pressure that draws more water up from the roots.

What adaptations do xerophytic plants have to conserve water?

Minimal leaf surface area, thick epidermis, sunken stomata, and the ability to shed leaves in dry seasons.

What is the Casparian strip and its function?

A layer of waxy suberin in the endodermis that forces water and minerals to cross the plasma membrane into the cytoplasm.

What is turgor pressure?

The pressure of water inside the cell that maintains cell rigidity and structure.

What is the role of root hairs in nutrient uptake?

They increase the surface area for water and nutrient absorption from the soil.

What is water potential (yw)?

A measure that predicts the direction of water movement based on solute concentration.

What occurs during guttation?

The exudation of water from leaf tips, often seen in the morning.

What is the significance of xylem sap movement?

It allows for the transport of water and nutrients from the roots to the rest of the plant.

What is the function of stomata in plants?

They regulate gas exchange and water loss through transpiration.

How do environmental conditions affect stomatal behavior?

In hot and dry environments, stomata may close to conserve water, reducing photosynthesis.

What is the difference between cations and anions?

Cations are positively charged ions, while anions are negatively charged ions.

What is the vascular stele?

The central part of a root or stem that contains the vascular tissue (xylem and phloem).

What are tracheids and vessel elements?

Types of xylem cells that facilitate water transport in plants.

What is the role of the cortex in roots?

It stores nutrients and facilitates the transport of water and minerals to the vascular tissue.

What is girdling in plants?

The removal of a ring of bark, which disrupts the flow of nutrients in the phloem.