3 - Transport in Cells Flashcards
What is diffusion?
Diffusion is the net movement of molecules or atoms from a region of high concentration to a region of low concentration
What is osmosis?
Osmosis is the diffusion of water from a dilute solution where there is a high concentration of water particles to a concentrated solution where there is a lower concentration of water particles across a selectively permeable membrane
How does size affect the rate of diffusion?
The higher the surface area ratio, the increase in the time it takes for the rate of penetration
What are the examples of diffusion through gas exchange?
Oxygen and carbon dioxide are transported through diffusion through respiration
What factors affect the rate of diffusion?
- Particle size
- Distance
- Different in concentration between the two gradients
- Temperature
What is active transport?
Active transport is the movement of molecules through a cell membrane from an area of low concentration to an area of high concentration
Why do cells that carry out active transport require many mitochondria?
The mitochondria are needed for respiration and the synthesis of energy needed to move molecules up a concentration gradient
What happens during the process of active transport?
A transport protein picks up a useful molecule. It then rotates and release the molecule inside the cell while using energy. It then rotates around to the outside of the cell (often using energy)
What is mean by Isotonic?
Applied to a solution that has the same water potential as a cell and changes volume
or
The concentration of solutes is equal inside and outside the cell so water moves across the membrane in both directions maintaining cell size
What is meant by Hypertonic?
Applied to a solution and causes the immersed cell to expand through osmosis
What is meant by Hypotonic?
Applied to a solution and causes the immersed cell to shrink through osmosis
What is meant by Lysis?
Where the cell swells (swells) and bursts
What is meant by Crenated?
Where the cell shrinks and shrivels
What are the common factors which increase the effectiveness of an exchange surface?
Having a thin exchange surface and a higher surface area
What increases the effectiveness of the diffusion of gases?
Having good ventilation by removing diffused molecules and maintaining the concentration gradient
