1.4: Communcication and Signalling.

Question 1

Type of signalling molecule sent between cells in a multicellular organism.

Answer 1

Extracellular

Question 2

Examples of extracellular signals.

Answer 2

Steroid hormones OR Peptide hormones OR Neurotransmitters.

Question 3

Target cell protein with a binding site for a specific signal molecule.

Answer 3

Receptor.

Question 4

Consequence of the change of conformation of receptor resulting from binding with a signalling molecule.

Answer 4

Response initiated.

Question 5

Term for different cell types responding differently to the same signal.

Answer 5

Tissue-specific

Question 6

Type of signalling molecule that can diffuse through the phospholipid bilayer of a membrane.

Answer 6

Hydrophobic signalling molecules.

Question 7

Examples of hydrophobic extracellular signalling molecules.

Answer 7

Steroid hormones OR Oestrogen Or Testosterone.

Question 8

Role of receptors for hydrophobic signalling.

Answer 8

Transcription factors.

Question 9

Site of receptors for steroid hormones.

Answer 9

Cytosol or Nucleus

Question 10

DNA sequence to which a steroid hormone-receptor binds to affect the expression of many different genes.

Answer 10

Hormone response element OR HREs

Question 11

Affect of transcription factor protein bound to the DNA HREs on the rate of transcription.

Answer 11

Stimulate OR Inhibit

Question 12

Type of molecules that cannot pass through a membrane phospholipid bilayer.

Answer 12

Hydrophilic

Question 13

Examples of hydrophilic extracellular signalling molecules

Answer 13

Peptide hormones Or Neurotransmitter

Question 14

Protein which responds to the binding of a hydrophilic extracellular signalling molecule by undergoing a conformational change.

Answer 14

Surface Receptor OR Transmembrane Receptor

Question 15

Consequence of the surface receptor undergoing a conformation change in response to the binding of a peptide hormone.

Answer 15

Transduction (across the plasma membrane).

Question 16

Act as signal transducers by converting extracellular ligand-binding into an intracellular signal.

Answer 16

Transmembrane receptor.

Question 17

Protein attached to an activated receptor that relays the signal to a target protein kinase enzyme to begin a protein kinase cascade.

Answer 17

G-protein.

Question 18

Term of one protein kinase phosphorylating many others. Then phosphorylate many more.

Answer 18

Cascade

Question 19

Peptide hormone involved in the regulation of blood glucose.

Answer 19

Insulin

Question 20

Type of glucose transporter protein recruited to the cell membrane as a result of insulin binding to it’s receptor.

Answer 20

GLUT4

Question 21

Type of enzyme cascade that leads to GLUT4 vesicles being transported to the cell membrane.

Answer 21

Phosphorylation OR Protein kinase

Question 22

Types of cell in which GLUT4 is most active in glucose regulation.

Answer 22

Fat AND Muscle.

Question 23

Type of diabetes mellitus caused by failure to produce insulin.

Answer 23

Type 1

Question 24

Type of diabetes mellitus caused by loss of insulin receptor function

Answer 24

Type 2

Question 25

Which type of diabetes is associated with obesity.

Answer 25

Type 2

Question 26

Reason exercise improves the health of people with type 2 diabetes.

Answer 26

More GLUT4 receptors recruited OR Weight loss.

Question 27

Inside of a neuron is negative compared to the outside and no net flow of ions across the membrane.

Answer 27

Resting potential.

Question 28

Wave of depolarisation of the membrane that travel along the entire length of a neuron.

Answer 28

Action potential.

Question 29

Initiate a response by binding to ligand-gated ion channel receptors at a synapse.

Answer 29

Neurotransmitters

Question 30

Ions that move into a neuron when ligand-gated ion channel open.

Answer 30

Na+

Question 31

Channels that open to allow Na+ to flow down the electrochemical gradient once depolarisation passes the threshold value.

Answer 31

Voltage-gated sodium

Question 32

Ion that moves out of the neuron once the sodium channels are inactivated.

Answer 32

K+

Question 33

Released into the synapse once the action potential reaches the end of the neuron.

Answer 33

Neurotransmitters.

Question 34

Pump that re-establishes the ion concentration gradients of a resting potential.

Answer 34

Na+/K=-ATPase.

Question 35

Retinal photoreceptor cells that need bright light and are responsible for colour vision.

Answer 35

Cones.

Question 36

Retinal photoreceptor cells that can function in dim light but do not allow colour perception.

Answer 36

Rods.

Question 37

The light sensitive molecule that combines with the membrane protein opsin to form photoreceptors.

Answer 37

Retinal

Question 38

Name for the retinal-opsin complex in rod cells.

Answer 38

Rhodopsin

Question 39

Change in rhodopsin conformation when retinal light absorbs a photon of light.

Answer 39

Photoexcited

Question 40

Name for the hundreds of G-protein molecules activated by a single photoexcited rhodopsin.

Answer 40

Transducin

Question 41

Enzyme activated by each transducin G-protein and name for the thousands of molecules hydrolysed by it.

Answer 41

PDE and Cyclic GMP/ cGMP.

Question 42

Affect of low rod cell cGMP levels.

Answer 42

Ion channels closed AND Triggers nerve impulse.

Question 43

Term for one photpexcited molecule starting a series of reactions involving a greater number of molecules at each step.

Answer 43

Cascade.

Question 44

Term for cascade if proteins allowing rod cells being able to respond to low intensities of light.

Answer 44

Amplification.

Question 45

Combine to produce different photoreeptor proteins in cone cells.

Answer 45

Retinal AND Different Opsin proteins.

Question 46

Wavelengths of light detected by cone cells.

Answer 46

Red AND Blue AND Green AND UV.