U3T1 – Surface Area to Volume Ratio and Adaptations to Exchange

The surface area in biology often refers roughly to how much skin an organism has, or how much cell membrane a cell has. Which of the following will have the biggest surface area, if they are all approximately the same length and width?

A Palisade cell is rectangular, and measures 100 µm by 40 µm. What is its surface area?

What is the volume of the same palisde cell measuring 100 µm by 40 µm?

What is the surface area to volume ratio of a palisade cell with a volume of 120,000 µm ³ and a surface area of 6500 µm²?

If we assume a spongy mesophyll cell is approximately a sphere. Using the formula 4 pi r ² , what is its surface area if its diameter is 80 µm?

What is the volume of the same roughly spherical spongy mesophyll cell with a diameter of 80 µm, using the formula Volume=4/3 pi r ³?

What is the surface area to volume ratio of a spongy mesophyll cell with the surface area of 24,000 µm ², and a volume of 110,000µm ³?

Is it important which way round the numbers go when writing a ratio?

Cresol red is an indicator which goes clear at a low pH. A plate of agar jelly with cresol red added was made, and two blocks were cut out. Block A measured 10mm x 10mm x 10mm. Block B measured 20mm x 7mm x 7mm. Are they a similar volume (within 5% difference)?

Cresol red is an indicator which goes clear at a low pH. A plate of agar jelly with cresol red added was made, and two blocks were cut out. Block A measured 10mm x 10mm x 10mm. Block B measured 20mm x 7mm x 7mm. Are the two agar blocks a similar surface area (within 5% difference)?

Cresol red is an indicator which goes clear at a low pH. A plate of agar jelly with cresol red added was made, and two blocks were cut out. Block A measured 10mm x 10mm x 10mm. Block B measured 20mm x 7mm x 7mm. Which one will decolourise quickest when placed in an acidic solution ?

Cresol red is an indicator which goes clear at a low pH. A plate of agar jelly with cresol red added was made, and two blocks were cut out. Block A measured 10mm x 10mm x 10mm. Block B measured 20mm x 7mm x 7mm. You have chosen one which will decolourise the quickest, why did you choose that block?

Why can single celled organisms exchange many substances by simple diffusion over the plasma membrane?

Multicellular organisms cannot absorb enough substances by diffusion. Why is this?

How have multicellular organisms adapted to not being able to absorb everything via diffusion over their surface?

Some animals are adapted to higher temperatures in their environment. Which of the following is an example of this ?

Some animals are adapted to a lower environmental temperature. Which of the following is an example of this?

Other than surface area to volume ratio, which is an example of a physiological adaptation, which allows an animal to live at colder temperatures?

Other than surface area to volume ratio, which is an example of a physiological adaptation, which allows an animal to live at hotter temperatures?

Which is an example of a behavioural adaptation which allows an animal to live at hotter temperatures?