Transport in Animals Practice Questions

Complete the table below.

Glucose is a dissolved food molecule that is transported to the cells of the body.

State why cells need glucose.

State what is meant by the term diffusion.

State three factors that affect the rate of diffusion of oxygen into the flatworm.

Calculate the surface area of the cube with sides of length $4\ \text{cm}$.

Surface area = .............................. $\text{cm}^2$

Calculate the surface area : volume ratio of the cube with sides of length $4\ \text{cm}$.

Describe how the surface area : volume ratio changes as the size of the cube increases.

Use the information in the table to explain why large animals need a transport system.

Calculate the surface area : volume ratio of the $15\ \text{mm}$ cube.

Give your answer to one decimal place.

Describe the relationship between the surface area : volume ratio and the time taken for the colour to disappear.

Explain, in terms of diffusion, why the largest cube took the longest time for the colour to disappear.

Give one variable, other than the size of the cube, that the student should have kept the same.

Complete Fick's law by writing the missing words in the spaces.

rate of diffusion $\propto$ $\dfrac{\text{surface area} \times \text{.......................................}}{\text{.......................................}}$

An exchange surface has a surface area of $20$ arbitrary units, a concentration difference across it of $15$ arbitrary units and a thickness of $4$ arbitrary units.

Calculate the relative rate of diffusion across this surface.

The surface area of this exchange surface is then tripled and its thickness is doubled. The concentration difference stays the same.

Calculate the new relative rate of diffusion.

Describe the relationship between the concentration difference and the rate of diffusion.

Predict the rate of diffusion when the concentration difference is $10$ arbitrary units.

Use Fick's law to explain the results shown in the table.

Other than the concentration difference, give one variable that must be kept the same in this investigation.

Calculate the relative rate of diffusion of oxygen across the gills of the fish.

The relative rate of diffusion of oxygen across the frog's skin is $0.045$.

Calculate how many times greater the relative rate of diffusion across the fish gills is than across the frog's skin.

Give your answer to the nearest whole number.

Using the data in the table and Fick's law, explain two features of the fish gills that give them a high rate of diffusion of oxygen.

In dry conditions, the outer layer of the frog's skin becomes twice as thick. Nothing else changes.

State the effect this has on the rate of diffusion of oxygen across the frog's skin.

Explain why a mouse needs specialised exchange surfaces and a transport system, but Amoeba does not.