Membrane Transport 1.4 Flashcards
1
Q
Essential Idea (Membrane Transport 1.4)
A
Membranes control the composition of cells by active and passive transport
2
Q
Imported Material in the Membrane
A
Glucose which is necessary for cell metabolism, hormones and ions
3
Q
Exported materials out the Membrane
A
Toxic waste produced, enzymes and hormones
4
Q
Importance of Transport
A
- Used for cell defence and discharge and important of necessary products for normal function
- Cellular homeostasis
- Maintaining the osmotic pressure
5
Q
Methods of Passive Transport
A
- Simple diffusion
- Facilitated diffusion
- Osmosis
6
Q
Membrane Diffusion Affecting Factors
A
- Movement across a partially permeable membrane is affected by temperature, surface area, size of particles and concentration gradients of diffusing particles
- If the temperature is higher the molecules diffuse faster
- Increase of membrane surface area allows more molecules to diffuse
- Smaller sized particles diffuse faster
- If the concentration gradient is bigger the faster the diffusoin
7
Q
Simple Diffusion
A
- Occurs in gas or liquid medium and only required a concentration gradient
- Occurs in living and non living systems
- If a particle is to big it cannot pass the phospholipid bilayer and simple diffusion fails
8
Q
Facilitated Diffusion
A
- Similar to simple diffusion but required a channel or carrier protein which are specific to the molecule being transported
- Shape and size of protein determines which substances can cross, chloride ion channels only allows facilitated transport of chloride ions
9
Q
Transportation of K+ Ions
A
- Helps in moving K+ ions out of the axons to cause repolarisation (decrease in voltage)
- Channel specific to K+ ion are voltage gated, so they open and close with changes in electrical potential to control movement
10
Q
Osmosis
A
- Passive movement of water molecules from a region of higher to lower solute concentration
- Only involves water
- Solutes are particles that are dissolved in water, water is the solvent, and they are important in determining the direction the water molecules move
11
Q
Tissues / Organs in Medical Procedures
A
- Transplant operations, tissues need to be kept in a saline solution
- Important osmolarity is the same as the cytoplasm to prevent osmosis (gain or loss of water)
- can be stored hypertonic (higher concentration), isotonic (equal), or hypotonic (lower concentration)
12
Q
Hypertonic Solution
A
- When put into a hypertonic solution this means it has a higher concentration than the cell
- Causes water to move out of the cell causing it to shrink
13
Q
Hypotonic Solution
A
- When put into a hypotonic solution this means it has a lower concentration than the cell
- Causes water to move into the cell causing it to swell and burst
14
Q
Methods of Active Transport
A
- Endocytosis
- Exocytosis
15
Q
Membrane Active Transport
A
- Required energy in the form of ATP
- Energy is used to move substances against a concentration, low to high
- Evidence that it is active rather than passive is if ATP is required, the substance moves via a pump or if it moves from low to high concentration
