Chapter 6.1: Exchange between organisms and their environment

Substances must be transferred from and to the environment. This can be done via

• Diffusion (Both simple and facilitated)

• Active transport

• osmosis

What are examples of products taken in by the environment

• Oxygen

• Nutrients

• Water

What are examples of waste products

• carbon dioxide

• Urea

• Water

What is the relationship between surface area and size

when an object is small it has a large surface area in comparison to its volume

When an object is large it has a small surface area in comparison to its volume

How do smaller organisms intake necessary things from their environment

since they have a large surface area to volume ratio the materials can be moved into and out of the cell by diffusion or active transport

How to larger organisms intake necessary things from their environment

• Since they have a smaller surface area to volume ratio they develop specialised exchange surfaces (e.g the lungs)

How do you calculate the volume of a cuboid

Length x Width x Height

How do you calculate the surface area of a cuboid

(4 x Length x Height) + (2 x Height x Width)

How do you calculate the volume of a cylinder

πr² x Height

How do you calculate the surface are of a cylinder

(2πr x Height) + 2πr²

How do you calculate the volume of a sphere

4/3 x πr³

How do you calculate the surface area of a sphere

4πr²

How do you calculate the surface area to volume ratio

divide the surface area by the volume