Lecture 4: Plasma membrane and organelles Flashcards
What does a cell do:
manufacture new material
obtain raw materials
Remove waste
generate required energy
seperate compartments with specific conditions are called…
organelles
Plasma membrane provides ……
and acts …..
- special conditions with in a cell
- as a semi permeable membrane
Organelles provide…
special conditions for specific processes
Organelles keep…
incompatible processes apart
Organelles allow…
specific substances to be concentrated
Organelles form…
concentration gradients
Organelles package…
substances for transport or export
Cellular membranes are composed of a…
phospholipid bilayer
Organelles common to animal and plant cells:
Nucleus
Endoplasmic reticulum
Golgi apparatus
Mitochondrion
Organelles unique to animal cells:
Lysosome
Organelles unique to plant cells:
central vacuole
chloroplast
Plasma membranes…
control movement of substances
Phospholipid bilayers are made of:
Hydrophilic (phosphate) heads
hydrophobic tails
cholesterol…
stabilises membrane fluidity
Three types of transport:
Passive transport
Active transport
Co-transport
Fluid membranes
phospholipid tails are unsaturated (bent)
Viscous membranes
phospholipid tails are saturated (straight)
Examples of passive transport:
diffusion
facilitated diffusion
osmosis
Hydrophobic molecules include:
steroid hormones/gasses
Facilitated transport requires…
membrane proteins called channels/carriers
Channel proteins for water to move are called
aquaporins
Passive transport needs
no energy
Active transport needs
energy (ATP)
Active transport allows
movement against concentration gradient
Co-transport uses
concentration gradient of a substance to power the movement of a second against its gradient
Co-transport needs
energy (ATP)
Roles of membrane proteins:
signal transduction,
cell recognition,
intercellular joining,
linking cytoskeleton and extracellular matrix
signal transduction relays
messages from body/environment into cell
cell recognition involves…
glycoproteins (proteins with added sugars)
