8 1 transport in animals

False. Unicellular organisms do not require specialised exchange surfaces due to their large surface area to volume ratio.

An exchange surface is a specialised area in multicellular organisms that maximises the exchange of materials by increasing the efficiency of transport processes.

The three transport processes used by living organisms for exchange are diffusion, osmosis, and active transport.

Alveoli are exchange surfaces in animals used for gas exchange in the lungs.

Villi are exchange surfaces in animals found in the small intestines for absorption of digested food.

False. Large multicellular organisms have relatively small surface areas compared to their volumes.

The primary function of the blood and circulatory system in animals is to carry necessary substances around the body.

Two properties of exchange surfaces that maximise material exchange are having a large surface area and a thin barrier to provide a short diffusion path.

Two examples of exchange surfaces in plants are leaves and roots.

Surface area to volume ratio is the surface area of an object in relation to its volume.

As cell size increases the surface area to volume ratio decreases.

Diffusion distance is the distance molecules have to travel when they diffuse from one region to another.

As diffusion distance decreases, the rate of diffusion increases.

False. As temperature increases, the rate of diffusion also increases. Molecules move around faster at higher temperatures, resulting in faster diffusion.

At higher temperatures particles move around faster; this is because they have more kinetic energy.

True. As the concentration gradient increases, the rate of diffusion also increases.

Fick's law is used to calculate the rate of diffusion.

The rate of diffusion can be described using Fick's law, which is: Rate of diffusion ∝ (surface area x concentration gradient) ÷ diffusion distance "∝" means proportional to.