Diffusion and Cell Size

Question 1

Diffusion

Answer 1

the movement of substances from an area of high concentration to low concentration

Question 2

Key Idea

Answer 2

Diffusion is less efficient in cells with a small surface area relative to their volume than in cells with a large surface area relative to their volume

Question 3

How do larger organisms overcome the physical limit to growing?

Answer 3

By becoming multicellular

Question 4

Object Size

Answer 4

When an object is small, it has a large surface area in comparison to its volume. As an object gets larger, its surface area compared to its volume is smaller.

Question 5

Single celled organisms

Answer 5

As they are small, they have a large surface area relative to the volume, The requirements are met by diffusion or active transports of materials in and out of the cells.

Question 6

Multicellular organisms

Answer 6

As they are quite large, they have a small surface area compared to their volume. They need specialized systems to transport the materials they need to and from the cells and tissues in their body.

Question 7

Surface Area to Volume Ratio

Answer 7

A measure of the critical balance between the surface area available for substance exchange and the volume of the cell.

Question 8

Cells may increase their SA:V by

Answer 8

• Having a long thin shape/elongated shape
• Folding the surface of the object
• Having thin, flat cells
• Plant cells have a large vacuole that pushes organelles to the edge where they get regular access to resources.

Question 9

How do cells transport products and how do we know how well it is done?

Answer 9

Through the cell membrane, and how well this is done depends on how much surface area there is to its volume

Question 10

Surface Area’s Key Role

Answer 10

The amount of surface area must be sufficient and enough to supply to materials inside the volume.

Question 11

What happens when the volume increases

Answer 11

When the volume increases, the metabolic needs also increases meaning that more materials have to be transported in and out

Question 12

SA and V Increasing

Answer 12

Both the SA and V increases but they both increase at a different rate. The volume increases at a faster rate..

Question 13

How does the SA and V increasing put a limit to how much a cell can grow

Answer 13

By growing at a different rate, the volume continues to grow meaning more materials have to be transported, however the SA may not be able to supply its needs