cell membrane Flashcards
The role of the membrane
-separate cell contents from external environment
-regulate transport of materials in and out cell
-contains enzymes which involved in specific metabolic pathways
-has antigens so immune system can recognise as being “self” and not attack it
-release chemical signals to other cell
-contain receptors for chem signals for cell communication
-hormones and drugs bind to membrane bound receptors
role of membrane in chloroplasts
-thylakoid membranes contain chlorophyll
-so first stage of photosynthesis happens here
role of membrane in mitochondria
-cristae increases surface area
-localise (resrtict to a part of the body) the enzymes for aerobic respiration
integral protein function
cell signalling and transport of substances across membrane
function of a pore
type of integral protein through will certain molecules can move in/out
function of cytoskeleton
-helps maintain shape
-aids cell to cell attachment
-carry out essential functions by providing mechanical support (e.g. muscle contraction and division)
function of glycolipids
-act as receptors
-involved in cell recognition of other cells and harmful cells
-involved in membrane stability
glycoprotein
-cell recognition
-membrane stabilization
-receptor molecules
function of glycocalyx
-the carbohydrate molecules outside of cell
-very hydrophillic and attract water with dissolved solutes
-help cell interact with watery environments
-obtain dissolved substances
parts of membrane
-cholesterol
-channel and carrier protein
-cytoskeleton filaments
-protein receptor site
-peripheral protein
-glycolipid/glycoprotein
cell membrane composition of neurons
-in neurons protein channels and carriers in plasma membrane covering long axon allow entry and exit of ions to bring about conduction of electrical impulses along their length
cell membrane composition of white blood cells
-special protein receptors that enable them to recognise the antigens on foreign cells
cell membrane composition of root hair cells
-many carrier proteins to actively transport nitrate ions from the soil into the cells
integral protein/intrinsic/
transmembrane
span whole width
peripheral or extrinsic membrane
-confined to outer surface of membrane
carrier molecules and channels (function)
-help transport substances (e.g. ions, sugars, amino acids) that cannot diffuse across membrane but vital to cell functioning
-other are receptors for hormones and neurotransmitters, or enzymes for catalysing reactions
where peripheral proteins are found
may be free on membrane surface or bound to integral protein
role of peripheral protein
-on extracellular side act as receptors for hormones or neurotransmitters, or cell recognition
-on cytosolic side involved in cell signalling or chemical reactions, can dissociate from membrane and move into cytoplasm
how do some proteins work as carriers/ peripheral
-some change their shape and have ability to carry specific molecules across membrane
-others attached to carrier proteins function as enzymes, antigens or receptor sites for complementary shaped signalling chemicals (hormones)
function of channel
allow ions which have charge surrounded by water to pass through main non polar region
why transport across membrane is vital for living cell
-receiving raw materials or reactants for reactions such as respiration to make ATP
-need O2 and glucose
-Need to remove toxic metabolic waste products
-export molecules they make e.g. enzymes and hormones
features of membranes that affect diffusion across them
-pores which act as channels
-proteins on surface of membrane which change shape and carry molecules across
Describe how cell signalling happens
-release of signal by exocytosis
-glycoprotein/lipid act as specific receptor
-to the complementary shaped signal
-attachment of molecule causes a change
-cell surface membrane allows entry of some signal molecules
Outline how the vesicles are moved from one organelle to another
-microtubules provide pathways to guide vesicles
-vesicles move along microtubules which are extended/ broken down
-uses ATP
