Factors Affecting Material Exchange Flashcards
Cells Make Up The Human Body (11 cards)
Why is the relationship between the surface area of the cell and the volume important?
There is a limit to how big a cell can be.
All requirements/products of a cell must pass across the membrane that surrounds the cell.
Will a small cell have a larger or smaller surface area to volume ratio than a larger cell?
A small cell will have a larger surface-area-to-volume ratio than a large cell.
What happens as a cell grows?
As a cell grows, its ability to exchange enough materials to support its increasing volume is diminished because the volume increases at a greater rate than the surface area.
Why do large cells transport inefficiently?
A large cell could not support itself because it would not have enough surface to absorb the nutrients required, and remove the wastes produced, for its large volume.
To function effectively, most cells have to be microscopic.
What is a concentration gradient?
The difference in concentration that brings about diffusion
In what direction do substances move?
Substances move down the concentration gradient, meaning from an area of higher concentration to an area of lower concentration
Why and how does movement along a concentration gradient happen?
This movement occurs spontaneously and is driven by the natural kinetic energy of molecules.
How does a greater difference in concentration affect diffusion?
The greater the difference in concentrations, the ‘steeper’ the diffusion gradient and the faster the rate of diffusion.
What is the role of concentration gradients on simple diffusion?
Oxygen diffuses into cells from a high concentration (outside the cell) to a lower concentration (inside the cell).
What is the role of concentration gradients on facilitated diffusion?
Glucose or ions move down their concentration gradient through protein channels or carriers in the membrane.
What is the role of concentration gradients on osmosis?
Water moves across a semi-permeable membrane from a region of high-water concentration (low solute) to a region of low water concentration (high solute).
