Cell signalling 1.1

Question 1

Where are cell surface receptors found?

Answer 1

Spanning the plasma membrane

Question 2

Cell signalling basic description?

Answer 2

Cell receives a signal from outside which causes an effect within the cell

Question 3

Where are intracellular receptors found?

Answer 3

Within the cell

Question 4

What must signalling molecules that enter the cell be?

Answer 4

Small and hydrophobic

Question 5

Why must signalling molecules that enter the cell be hydrophobic?

Answer 5

So they can pass the plasma membrane

Question 6

Where in the cell can intracellular receptors be found?

Answer 6

In the nucleus or sometimes in the cytosol

Question 7

What are some outputs of cell signalling?

Answer 7

Survival, growth and division , differentiation

Question 8

What is the default cell setting?

Answer 8

Apoptosis

Question 9

What is the result of a cell receiving no signalls?

Answer 9

Apoptosis

Question 10

What can a signalling molecule do to a cell surface receptor?

Answer 10

Activate it or repress it

Question 11

What happens after a cell surface receptor is activated by a signalling molecule?

Answer 11

Intracellular signalling molecules are activated/repressed

Question 12

What do the intracellular signalling molecules do?

Answer 12

They control the effector proteins

Question 13

What do effector proteins do?

Answer 13

Cause the output

Question 14

Examples of effector proteins?

Answer 14

Metabolic enzymes, cytoskeletal proteins, transcriptional regulators

Question 15

How can a signal be amplified within a cell?

Answer 15

One relay protein (connected to the cell surface receptor) can activate many small intracellular messenger molecules.

Question 16

What is the role of scaffold proteins?

Answer 16

To act as a docking stage for proteins to all come together

Question 17

What speeds can a response to cell signalling be?

Answer 17

fast or slow

Question 18

What kind of signalling pathway typically elicits a fast response?

Answer 18

Altering a proteins shape (thus function) as the protein already exists

Question 19

What kind of signalling pathway typically elicits a slow response?

Answer 19

Altering a transcriptional pathway as proteins take time to be synthesised

Question 20

Reversal of fast responses?

Answer 20

Fast

Question 21

Reversal of slow responses?

Answer 21

Slow

Question 22

What is endocrine signalling?

Answer 22

Involves hormones travelling through the blood to the target cell

Question 23

What do endocrine cells do?

Answer 23

Make and secrete the hormones involved in endocrine signalling

Question 24

How is it ensured that the hormones in endocrine signalling only affect specific cells?

Answer 24

Only specific cells have the receptors that are complementary to the hormone, so those that don’t won’t be affected

Question 25

What is paracrine signalling?

Answer 25

Involves signalling molecules affecting target cells that are close by

Question 26

What do paracrine cells do?

Answer 26

Synthesise and secrete “local mediators” that binds to receptors on nearby target cells

Question 27

What is a local mediator?

Answer 27

A paracrine signalling molecule

Question 28

What is neuronal signalling?

Answer 28

A presynaptic cell secretes neurotransmitter across a synapse to continue an action potential across it

Question 29

What is a neurotransmitter?

Answer 29

A type of signalling molecule specifically involved in neuronal signalling

Question 30

What is contact dependant signalling?

Answer 30

The signalling cell holds the molecule on its plasma membrane, meaning the target cell can only be activated if it is in direct contact w/ the signalling cell

Question 31

When is contact-dependant signalling usually used?

Answer 31

Common when organisms are developing