M1 L4 Plasma membrane and organells Flashcards
Identify some of the key organelles in eukaryotic cells. • Outline the importance of organelles and subcellular compartments in cells. • Describe the structure of the plasma membrane and outline its importance to cell function. • Outline mechanisms by which substances cross the plasma membrane (passive transport, active transport and co-transport). • Outline the role of membrane proteins
1
Q
organells
A
- Provides special conditions for perticuler process
- keep incompatible process apart
- allow creation of conc gradient
- allow specitic substances to be concetrated for a specifc proces.
- packages substances for transport and export
2
Q
The plasma membrane
A
- Amphipathic
Hydrophobi and hydrophilic - has 2 layers
hyphophilic head and hydrophobic tail
3
Q
cholestrol in membrane
A
- helps reduce membrane fluidity and reduce phospolipid movement
- almost always acts as a stiffen membane
warm temp
- more fluid tail eg coconu oil when hot
cold temp
- viscous eg gel coconut
4
Q
premeability
A
- memebrane component
- soluble to lipids eg hormone and gas
- restricted movement of charge and water soluble molecules (poler)
5
Q
Membrane protein
A
- channels, carrier , pumps
- can be regulated
- voltage gated - electric stimuli
- ligand gated - response to chemical messager
- defect in channel can cause disease eg epilepsy
6
Q
Roles of membrane protein
A
- Give cell character —-> cell recognition
- signal transduction
- Enzymatic aticity
- intercellular joining/ linking with Extra cellular matrix
7
Q
Modes of transport through cell membrane
A
- simple diffusion
- faccilated diffusion
- active transport
8
Q
simple disfusion
A
- Lipid soluble eg steroid hormones and gases - conc gradient - passive (no energy ) - Retriction of water soluble and charged molecules. (needs facilitated diffusion)
9
Q
Faccilated diffusion in membrane
A
- Requires membrane protein such as channels and carriers
- No energy input
- conc gradient
- channels are gated
10
Q
Active transport in membrane
A
- requires energy
- moving against conc gradient
- allows a cell to have a conc of a substance that is different from the surrounding.
- indirect or directly need energy
11
Q
co transport across membrane
A
- indirectly needs energy
- 2 substance go across without energy then one is pumped out using energy, therefore indirectly needs energy.
12
Q
cell recognition using proteins
A
- some glycoproteing acts as an identification tag, recognized by other membrane proteins of other cell
- important for sorting cells into tissue and organs
- rejection of foreign cells by immune system.
13
Q
Linking cytoskeleton and extra cellular matrix using protein
A
- the intergrins connects to the extracllular matrix with the actin cytoskeleton inside the cell.
