Diffusion and Osmosis Flashcards
Define diffusion
The net movement of particles from a region of their higher concentration to a region of their lower concentration downa concentration gradient, as a result of their random movements
Diffusion in cells
Substances move into and out of cells by diffusion
Where does the wnergy for diffusion come from?
The kinetic energy of random movement of molecules and ions
Why does diffusion occur in liquids and gases
Molecules in liquids and gases are constantly moving and bumping into eachother, this means they tend to spread out.
What does osmosis diffuse through?
A partially permeable membrane
Osmosis in cells
Water moves in and out of cells by osmosis through the cell membrane
Define osmosis
The net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution) through a partially permeable membrane
What potential does a solution with many molecules have?
A high water potential
What potential does a solution with few water molecules have?
Low water potential
Carbohydrates
- give us energy
- starch is made from glucose
Proteins
- needed for growth and repair
- made from amino acids
Fats
- an energy store, protecting vital irgans and providing insulation
- made from a glycerol molecule and three fatty acids
Water
- formation of blood
- solvent for transport of nutrients
- enzymes only work in solution
