Plant Biology: Gravitropism, Phototropism, Vascular Tissue, and Cell Organization

These flashcards cover key vocabulary and concepts related to plant biology, including their responses to gravity and light, vascular tissue, and levels of cellular organization.

Gravitropism

A plant control system that responds to the gravity of the Earth.

Positive Gravitropism

Growth in the same direction as gravity, such as roots growing downward.

Negative Gravitropism

Growth in the opposite direction to gravity, such as stems growing upward.

Phototropism

A plant control system that responds to light.

Positive Phototropism

Growth towards sunlight, such as stems.

Negative Phototropism

Growth away from sunlight, such as roots.

Auxins

A plant growth hormone found in the tips of plants that regulates growth in response to light.

Osmosis

The movement of water across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Xylem Sap

A solution of water and minerals that travels through xylem vessels from roots to leaves.

Cohesion

The tendency of water molecules to stick to other water molecules.

Adhesion

The tendency of water molecules to stick to other surfaces, such as the walls of the xylem vessels.

Transpiration

The evaporation of water from the leaves of a plant.

Stomata

Small openings on the underside of leaves that allow for gas exchange.

Guard Cells

Cells that control the opening and closing of stomata to regulate gas exchange and water loss.

Phloem

Vascular tissue that carries sugars produced in the leaves to different parts of the plant.

Xylem

Vascular tissue that carries water and minerals from the roots to the leaves.

Epidermal Cells

Cells that protect the leaf, located on the upper and lower surfaces.

Palisade Mesophyll

Layer of cells beneath the upper epidermis of a leaf, where most photosynthesis occurs.

Spongy Mesophyll

Loosely packed layer of cells in a leaf involved in gas exchange.

Cuticle

Waxy substance on the surface of leaves that prevents water evaporation.

Multicellular Organism

An organism made up of more than one cell, which often has specialized cells for different functions.

Tissue Level

A group of similar cells that work together to perform a specific function.

Organ Level

Two or more types of tissues that work together to complete a specific task.

Organ System Level

A group of organs that work together to carry out a generalized set of functions.