LIGAND GATED CHANNELS Flashcards
WHAT IS THE FUNCTION OF SIGNALLING SYSTEMS
RECOGNISE A STIMULUS TRANSFER A STIMULUS INTO A CELL AMPLIFY CYTOPLASMIC SIGNAL MODULATE EFFECTOR SYSTEMS ADAPT THROUGH FEEDBACK
IN MULTI CELLULAR ORGANISMS …………………….. EXPRESSION OF CERTAIN RECEPTORS AND THEIR MOLECULES INVOLVED IN SIGNAL …………………….. ALLOWS CELLS TO RESPOND…………………………. TO PARTICULAR STIMULI
SELECTIVE
TRANSDUCTION
SPECIFIC
WHAT IS THE ROLE OF RECEPTORS
TO DETECT CHEMICAL AND PHYSICAL STIMULI
PHYSICAL INTERACTION BETWEEN STIMULUS AND …………….. PROVIDES………………. TO CHANGE THE STRUCTURE OF THE RECEPTOR IN SUCH A WAY THAT MAY INITIATE ……………………..
RECEPTOR
ENERGY
SIGNALLING
WHAT KIND OF RECEPTOR ARE INVOLVED
MOST ARE EMBEDDED IN THE PLASMA MEMBRANE
SOME CAN BE IC RECEPTORS
SOME ARE TRANSMEMBRANE RECEPTORS
HOW MANY RECEPTOR FAMILIES ARE IN THE MAMMALIAN GENOME
25
HOW MANY GENES CODE FOR ION CHANNELS
400
WHAT TYPES OF GATED ION CHANNELS ARE THERE
LIGAND
VOLTAGE
ION SELECTIVITY OF A PORE IS DEFINED BY WHAT FACTORS
THE SIZE OF THE ‘FILTER’
THE AMINO ACID LINING THE PORE
EVOLUTIONARILY SIMPLE ORGANISMS HAD SIMPLE CHANNELS. OVER ………………….. OF A GENE CODING FOR 2TM DOMAIN CHANNELS GAVE RISE TO A FAMILY OF 2 - …………… TM DOMAINS.
POSITIVE CHARGES IN THE AMINO ACIDS IN TM……. GAVE RISE TO …………………… SENSITIVITY.
DUPLICATION
24
4
VOLTAGE
DESCRIBE THE STRUCTURE OF A Kir CHANNEL
- 2 TM DOMAINS
- NH2 AND COOH TERMNII CYTOPLASM FACING
- EXTRACELLULAR LOOP THAT FOLDS BACK TO FOR THE PORE LINING ION SELECTIVITY FILTER
- 4 OF THESE UNITS COME TOGETHER TO FORM A TETRAMER
- THIS IS THE BASIC STRUCTURE OF MOST ION CHANNELS
IF THE BASIC STRUCTURE OF KIR CHANNEL FUNCTIONS AS NEEDS, WHY ARE THERE OTHER CHANNELS WITH MORE TM DOMAINS
MOST CHANNELS ARE BUILD AROUND THE BASIC STRUCTURE, THE EXTRA DOMAINS IN MORE COMPLEX CHANNELS ARE THE REGULATORY ELEMENTS THAT CONTROL THE OPENING OF CHANNELS AS WELL AS OTHER MORE COMPLEX FEATURES OF VOLTAGE SENSORS ETC
DO ALL CHANNELS EVOLVE FROM THE PRIMORDIAL BACTERIAL K CHANNEL
NO, SOME ARE THOUGHT TO HAVE EVOLVED SEPARATELY
WHAT IS AN EXAMPLE OF A CHANNEL THAT HAS EVOLVED SEPARATELY FROM THE PRIMORDIAL BACTERIAL K CHANNEL
NICOTINIC ACH CHANNELS
GABA CHANNELS
WHAT ARE THE STRUCTURE OF NICOTINIC ACH CHANNELS AND GABA CHANNELS THAT MAKE THEM DIFFERENT FROM THE EVOLUTIONARY PRIMORDIAL BACTERIAL K CHANNEL
THEY ARE PENTAMERIC
THEY HAVE NO P LOOP