SURFACE AREA TO VOLUME RATIO AND DIFFUSION - Please help!

[chanelledt]

I really, urgently need to have answered these questions as a part of my assignment tomorrow.

1. What processes use diffusion to move materials in the human body
2. What happens to the surfeace area to volume ratio as an object gets bigger
3. How does the surfae area to volume ratio as affect the rate of diffusion
4. List factors that affect rate of diffusion

Please help,

[JackBean]

did you look into your books? I don't think so.

2. what is the formula for a surface of a square? What is the formula for volume of a cube?

3. how is the rate of diffusion affected by distance and area?

4. pretty easy one. Imagine you put some sugar into glass of water. What factors will affect the speed of diffusion?

BTW most of these questions were already asked on this forum, so all you have to do is search a little...

[chanelledt]

okkk well, if i write a paragraph will you please check that its ok cause i write well, i just dont actually know what im writing about?

[chanelledt]

Diffusion describes the spread of particles through random motion from regions of higher concentration to regions of lower concentration. It is dependent on the motion of the molecules and continues until the reaches a state of equilibrium, which is when the molecules are randomly distributed throughout the system. Diffusion is an important process for bodily function. Important substances, such as oxygen and carbon dioxide need to diffuse within a particular fluid volume as well from one bodily compartment. Throughout the body different processes use diffusion to move materials, including the gas exchanges at the alveoli in the lungs and at the capillaries for respiration, the transfer of transmitter substance and the absorption of mineral nutrients by roots and nutrients by the alimentary canal.

Is that right? :/

[JackBean]

I don't think humans have roots, but otherwise it seems OK. However, you didn't responde the last three questions

[chanelledt]

Hahaha i didnt realise that lol no, im pretty sure they dont have roots, thanks for that one.

And yeah im still looking for the answers :/

[chanelledt]

As an object gets bigger, the volume increases more rapidly than surface area. Cells are more efficient if they're smaller because if a cell gets too large, the inner workings don't function as well. It's more difficult to perform transport within the cell and the food and waste needed to be taken in and expelled is more difficult when the cell is too large. Most cells are no longer than 1mm in diameter as small cells enable nutrients and oxygen to diffuse into the cell quickly and allow waste to diffuse out of the cell quickly. If the cells were any bigger than this then it would take too long for the nutrients and oxygen to diffuse into the cell so the cell would probably not survive.

Is that the answer to question 2?

[chanelledt]

A small organism, like an amoeba, has a large surface area to volume ratio, and so it can achieve all the exchanges it needs by simple diffusion across its body surface. However, a large organism, like a mammal, has a much smaller surface area to volume ratio, so it cannot carry out all the exchanges it needs in this way. These larger organisms need special respiratory organs such as lungs for taking in oxygen and removing carbon dioxide.

[chanelledt]

Some factors affecting the rate of diffusion include shape, size, concentration, charge, lipid solubility, state of matter, size of particle, nature of matter and temperature, among various other factors.

THE END
haha

[Paula78]

Molecules, atoms, and ions normally move about in an irregular fashion called Brownian motion. As the particles move about, they collide with one another producing a random zig-zag movement

Larger particles move slower, due to their larger mass and may be influenced by numerous collisions with many nearby smaller particles. Smaller particles move faster. The overall energy of movement is proportional to the square root of the temperature. Hotter particles move faster because they have more energy.
The rate of diffusion increases as temperature increases because the particles move faster. As temperature increases, the collisions among particles become more energetic, causing particles to move from areas of higher concentration to lower concentration at a faster rate.