Homework – Surface Area : Volume
1Look at the words in the box.
carbon dioxide glucose mineral ions
oxygen urea water
aCircle two common waste substances that the human body needs to remove.
bUse a different colour to circle two substances taken in by plant roots.
cUse another colour to circle two substances needed for aerobic respiration in plants and animals.
The surface area : volume (SA : V) ratio is the surface area of something divided by its volume. The higher the SA : V ratio, the more quickly a cell can supply all of its parts with useful substances (and remove wastes).
Some cells have shapes that increase their SA : V ratios. For example, neurones (nerve cells) are long and thin, and this gives them a high SA : V ratio.
2The diagram on the right shows some cells in a root. Label the diagram to:aindicate the cell that has the highest SA : V ratio, and explain how you
can tell /
bexplain what this cell does
cexplain how its shape
helps it do its job.
3The diagram on the right shows an alveolus.
aLabel the diagram to show the overall movements of the two gases that are exchanged.bState how alveoli increase the SA : V ratio of the lungs.
______
______
______
cExplain why an increase in the SA : V ratio is necessary.
______
______
dExplain one other adaptation of alveoli that helps to speed up gas exchange.
______
______
1Look at the words in the box.
carbon dioxide glucose mineral ions
oxygen urea water
aCircle two common waste substances that the human body needs to remove.
bUse a different colour to circle two substances taken in by plant roots.
cUse another colour to circle two substances needed for aerobic respiration in plants and animals.
The surface area : volume (SA : V) ratio is the surface area of something divided by its volume. The higher the SA : V ratio, the more quickly a cell can supply all of its parts with useful substances (and remove wastes).
Some cells have shapes that increase their SA : V ratios. For example, neurones (nerve cells) are long and thin, and this gives them a high SA : V ratio.
2The diagram on the right shows some cells in a root. Label the diagram to:aindicate the cell that has the highest SA : V ratio, and explain how you
can tell /
bexplain what this cell does
cexplain how its shape
helps it do its job.
3The diagram on the right shows an alveolus.
aLabel the diagram to show the overall movements of the two gases that are exchanged.bState how alveoli increase the SA : V ratio of the lungs.
______
______
______
cExplain why an increase in the SA : V ratio is necessary.
______
______
dExplain one other adaptation of alveoli that helps to speed up gas exchange.
______
______