Lecture 3 Flashcards
What roles must a cell perform
manufacture cell material- proteins obtain raw materials- amino acids from food Remove Waste Generate required energy- for tasks Control all of the above
what are the Functions of Organelles
Provide special condition/compartments for cell processes
keep incompatible processes apart
allow substances to be concentrated
form concentration gradients
package substances for transport or export
What is the function of the cell membrane
to provide special conditions for life within the cell
what are the characteristics of a plasma membrane
semi-permeable stops some substances but not everything
Controls movement in and out of the cell
interaction with environment limits the maximum size of cells
small cell> surface to volume ratio larger cell
What organelles have membranes
endoplasmic reticulum
lysosomes
mitochondria(2)
nucleus- nuclear envelope
what is a phospholipid bilayer
in the cell membrane
unsaturated tails- prevent packing and make the bilayer fluid
Saturated tails- pack together and allow no fluidity, viscous
hydrophobic head
cholesterol- stabilises membrane fluidity
what is diffusion
passive transport from a high to low concentration
through lipid permeable membrane
what is facilitated diffusion
passive diffusion, however, aids substances with a carrier and channel proteins across the membrane
what is an active transport
transport that requires transport proteins that use ATP energy, goes against concentration gradient to allow different internal concentration
What is Co-Transport
indirect active transport, with one substance going against a gradient and simultaneously goes against powers movement of a second substance against the concentration gradient
What are the roles of membrane proteins
signal transduction- send messages from body to cell.
cell recognition- glycoproteins
intercellular joining- connections between cells
links cytoskeleton and ECM
