Membrane + Organelles Flashcards
Primary Function of Cell membrane
Controls substance movement into/out of cell
Saturated vs unsaturated phospholipids
Saturated are viscous (packed together), unsaturated are fluid ( bent tails prevent packing)
Role of Cholesterol within cell membrane
Stabilises membrane fluidity
Name the 5 key organelles in animal cells:
- Endoplasmic reticulum
- Nucleus
- Golgi apparatus
- Lysosome
- Mitochondrion
Name the 6 key organelles in Plant Cells:
- Nucleus
- Endoplasmic reticulum
- Central Vacuole
- Chloroplast
- Mitochondrion
- Golgi apparatus
What is a plasma membrane?
A semi-permeable barrier composed of a phospholipid bilayer
What is the function of a plasma membrane?
- controls movement of substances into and out of the cell
What factor limits the maximum size of a cell or organelle
Surface area to volume ratio
What are the two types of passive transport?
- Diffusion
- facilitated diffusion
How does diffusion across a plasma membrane work?
- membrane are permeable to lipid soluble ( hydrophobic) molecules such as steroid molecules and gasses
- The move across the membrane down the concentration gradient so don’t require energy
What are the two types of membrane proteins that aid in facilitated diffusion?
channels and carriers
What are the key points to consider about facilitated diffusion?
- It is the movement of hydrophilic molecules across the membrane using channels and carriers
- Substances are moving down the concentration gradient and thus do not require energy
- Channels can open/ close in response to signals
- carriers undergo shape change to help guide the molecule
What is the name of the channels that are required for osmosis?
- aquaporins
What does osmoregulation prevent?
Swelling of cell in hypotonic conditions and shrinking of cell under hypertonic conditions
What are the key points of Active transport?
- Requires transport proteins that use ATP energy
- Move specific substances against concentration gradient
- Active transport allows a cell to have different internal/ external concentration of substances
What is co-transport?
indirect active transport where active transport of one substance creates a gradient used to passively move another substance into/ out of a cell
What diseases can be caused by defects in transport proteins? (3)
- Albinism ( tyrosine transporter)
- Wilsons disease ( Cu2+ and Ag+ transporter)
- Cystic Fibrosis ( chloride channel)
What are the roles of membrane proteins? (5)
- signal transduction
- Cell recognition
- intercellular joining
- linking cytoskeleton and ECM
- transport
What does a membrane protein do that is involved in signal transduction?
Relay messages from the body into the cell ( grow, divide, move, make something …)
What does a membrane protein that is responsible for intercellular joining do?
Forms long-lasting connections between cells
What does a membrane protein do that in responsible for linking cytoskeleton and ECM?
Allows the cell to physically connect with protein structures outside the cell
