Cell signalling

Question 1

define signal transduction

Answer 1

the reception of a stimulus by a cell, leads to changes that adapt the cell to the stimulus

Question 2

types of signals

Answer 2

antigens
hormones
neurotransmitters
light
touch
pheromones

Question 3

where can signals originate from

Answer 3

hormones (act at a distance)
growth factors (action is long-lasting)
neurotransmitters (secretion close to target cells)
pheromones (act upon cells in a different organism)

Question 4

what changes can the signal cause in cell composition

Answer 4

differentiation and antibody production
growth in size or strength
sexual versus asexual cell division

Question 5

6 types of cell-cell communication

Answer 5

1. synthesis of signal
2. release of the signalling molecule by the signalling cell: exocytosis, diffusion, cell-cell contact
3. transport of the signal to the target cell
4. detection of the signal by a specific receptor
5. change in cellular metabolism, function or development triggered by the receptor-signal complex
6. removal of the signal

Question 6

3 models of cell-cell communication

Answer 6

direct contact
hormone signalling
synaptic signalling

Question 7

direct contact

Answer 7

signal molecule and receptor are attached to different cells and require cell-cell contact
gap junctions: specialised intercellular connection between a multitude of animal cell types. directly connect the cytoplasm of two cells, allows molecules, ions and impulses to pass through a regulated gate between the cells

Question 8

hormone definition

Answer 8

any member of a class signalling molecule produced by glands in multicellular organisms that are transport by the circulatory system to target distant organs to regulate physiology and behaviour

Question 9

what are the three mechanisms that hormones use

Answer 9

paracrine
autocrine
endocrine

Question 10

paracrine

Answer 10

involves being directed at neighbouring cells
is produced and liberated by specialised local cells where signals elicit quick responses and last only a short amount of time

Question 11

autocrine

Answer 11

produced by signalling cells that can also bind to the ligand that is released, means the signalling cell and the target cell can be the same or occur by transferring signalling molecules across gap junctions

Question 12

endocrine

Answer 12

transportation of information to an organ via the bloodstream
long distance

Question 13

synaptic signalling

Answer 13

similar to paracrine signalling but synapse between cell originating and cell receiving the signal

Question 14

synaptic signalling

Answer 14

similar to paracrine signalling but synapse between cell originating and cell receiving the signal

Question 15

phosphorylation

Answer 15

protein kinases regulate proteins by phosphorylation of amino acids with ATP and phosphate
induces a conformational change that alters the activity of the target protein
some are intracellular and others embedded
protein phosphates reverse the process

Question 16

what are the receptor classes

Answer 16

G-protein coupled receptor
receptor tyrosine kinase
ligand-gated ion channel