communication and signalling

Question 1

action potential

Answer 1

a wave of electrical excitation along a neurons plasma membrane

Question 2

cones

Answer 2

photoreceptor cells responsable for colour vision only functioning in bright light

Question 3

cyclic GMP

Answer 3

a second messenger for visual transduction, its present in high concentrations of photoreceptor cells

Question 4

depolarisation

Answer 4

an electrical state in an excitable cell whereby the inside of the cell is made less negative relative to the outside than it is at the resting membrane potential

Question 5

diabetes mellitus

Answer 5

an inability to regulate blood glucose levels
type 1- failure to produce insulin
type 2- loss of function of insulin receptors on cell surface

Question 6

extracellular signalling molecule

Answer 6

cues designed to transmit specific information to target cells

Question 7

GLUT4 glucose transporter protiens

Answer 7

insuilin-regulated glucose transporter
insulin triggers the movement to GLUT4 transporters to the membrane surface increasing uptake of glucose to be converted to glycogen

Question 8

G-proteins

Answer 8

act as molecular switches inside cells which are involved in transmitting signals from a variety of stimuli outside a cell to its inside

Question 9

hormone response elements

Answer 9

a short sequence of DNA within the promoter of a gene that is able to bind to a specific hormone-receptor complex and therefore regulate transcription

Question 10

hormnoe receptor complex

Answer 10

formed when steroid hormones bind to specific receptors in the cytosol of the nucleus they bind to specific sites on DNA and affect gene transfer

Question 11

hydrophillic

Answer 11

water loving

Question 12

hydrophillic signalling molecule

Answer 12

signalling molecules that aren’t able to pass through the membrane the signal is transduced across the membrane by receptor molecules on the cell surface

Question 13

hydrophobic

Answer 13

water fearing

Question 14

hydrophobic signalling molecules

Answer 14

signalling molecules that can pass though the membrane so the receptor molecules can be inside the molecule

Question 15

ion concentration gradient

Answer 15

gradients created by ion pump enzymes that transport ionic solutes across the membrane , energy needed

Question 16

opsin

Answer 16

a light sensative protein molecule

Question 17

phosphodiesterase

Answer 17

enzyme that catalyses the hydrolysis of cyclic GMP

Question 18

phosphorylation

Answer 18

addition of a phosphate group to a protein or other organic molecule

Question 19

phosphorylation castcade

Answer 19

a series of events in which one kinase activates the next one in a sequence

Question 20

photon

Answer 20

a basic unit of light

Question 21

photorecptors cells

Answer 21

cells found in the retina that are capable of visual phototransduction

Question 22

repolarisation

Answer 22

the restroration of membrane potential following depolarisation

Question 23

resting membrane potential

Answer 23

thedifference in ion concentration between the inside and outside of a cell

Question 24

retinal

Answer 24

a light sensative molecule that binds with opsin

Question 25

rhodopsin

Answer 25

the retinal-opsine complex in rods

Question 26

rods

Answer 26

photoreceptors cells in the retinal no colour only dim light

Question 27

signal transduction

Answer 27

conversion of extracellular signals into a response

Question 28

threshold value

Answer 28

when depolarisation reaches -55mV then a neuron will fire an action potential

Question 29

transcription factor

Answer 29

a proctien binds to specific DNA sequences thereby controlling the rate of transcription of gentic information form DNAS to mRNA

Question 30

transducin

Answer 30

a protein naturally in rods and cells