Exchange and Transport

These flashcards cover essential vocabulary and concepts related to exchange and transport mechanisms in biological systems.

Surface Area to Volume Ratio

The ratio that describes the relationship between the surface area and volume of an organism, affecting its efficiency in exchanging materials.

High SA:V

Organisms with a high surface area to volume ratio can efficiently exchange materials directly through their body surface.

Low SA:V

Organisms with a low surface area to volume ratio require specialized systems for gas exchange and transport.

Phospholipid Bilayer

A double layer of phospholipids that makes up the plasma membrane, with hydrophilic heads facing outward and hydrophobic tails facing inward.

Hydrophilic

Water-attracting; describes the heads of phospholipids that are attracted to water.

Hydrophobic

Water-repelling; describes the tails of phospholipids that avoid water.

Fluid Mosaic Model

Description of the plasma membrane structure, indicating that it is flexible (fluid) and consists of various proteins embedded (mosaic) within the phospholipid bilayer.

Diffusion

The passive movement of particles from an area of high concentration to an area of low concentration.

Active Transport

The movement of particles against a concentration gradient, requiring energy from ATP.

Osmosis

The movement of water molecules from an area of high water concentration to an area of low water concentration through a semi-permeable membrane.

Turgor Pressure

The pressure of the cell contents against the cell wall in plant cells, created by water moving into the cell by osmosis.

Xylem

Plant tissue responsible for the transport of water and minerals.

Phloem

Plant tissue that transports sugars and other metabolites.

Endocytosis

The process of transporting large molecules into a cell via vesicle formation.

Exocytosis

The process of transporting large molecules out of a cell through vesicle fusion with the plasma membrane.

Counter Current System

A mechanism in fish gills maintaining the concentration gradient for oxygen exchange, where water flows opposite to blood flow in gill capillaries.

Cardiac Cycle

The sequence of events in one heartbeat, including contraction and relaxation of the heart chambers.

Haemoglobin

A protein in red blood cells that binds to oxygen for transport throughout the body.

Bohr Effect

The phenomenon where increased carbon dioxide levels lower the affinity of haemoglobin for oxygen, facilitating oxygen release in tissues.

Mass Flow Hypothesis

The theory explaining the movement of sucrose in the phloem, where the pressure gradient drives the flow from source to sink.

Guard Cells

Specialized cells flanking the stomata that control their opening and closing depending on water potential.