biology math question ratios alevel aqa

ileum cell without microvilli has 7.85 μm2 of cell surface in contact with digested substances.
A scientist found an ileum cell with 1000 microvilli. The microvilli cover the entire cell surface in contact with digested substances.
Microvilli are 0.1 μm in diameter and 1 μm in length.
The surface area of a microvillus is calculated using this equation 2 πrl + πr^2 where π is 3.14,r is the radius, l is the length.

Calculate the ratio of the area of the ileum cell surface with microvilli to the area of ileum cell surface without microvilli.Show your working.

answer is 40:1

(edited 5 months ago)

Reply 1

bl0bf1sh

15

Original post by ricecakes1

ileum cell without microvilli has 7.85 μm2 of cell surface in contact with digested substances.
A scientist found an ileum cell with 1000 microvilli. The microvilli cover the entire cell surface in contact with digested substances.
Microvilli are 0.1 μm in diameter and 1 μm in length.
The surface area of a microvillus is calculated using this equation 2 πrl + πr^2 where π is 3.14,r is the radius, l is the length.

Calculate the ratio of the area of the ileum cell surface with microvilli to the area of ileum cell surface without microvilli.Show your working.

answer is 40:1

What are you thinking so far?

Reply 2

ricecakes1

OP

8

Original post by bl0bf1sh

What are you thinking so far?

i got the area of the 1000 microvilli as 322 idk what to do after

Reply 3

bl0bf1sh

15

Original post by ricecakes1

i got the area of the 1000 microvilli as 322 idk what to do after

Ok, so the question is asking for the ratio of (surface area with microvilli) to (surface area without microvilli).

A ratio is usually in the form x : y, where x and y are both integers (whole numbers). Often (but not always) the smaller of the two integers will be 1.
To get this, divide each number (i.e. the areas) by the smallest number (smaller area). If you get a number ("n") reasonably close to a whole number, then n : 1 is your ratio :smile:

If "n" isn't particularly close to a whole number, then you'll need to do some multiplying (both sides of the ratio) until both are integers. e.g. if you got 4.51 : 1, then multiply each side by 2, to get the approximate ratio 9 : 2.

biology math question ratios alevel aqa

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you