Signal transduction

Question 1

Define: signal transduction

Answer 1

process by which a signal is received and converted into a specific response.

Question 2

3 stages?

Answer 2

signal reception, signal transduction, cellular response

Question 3

Define: signal recepion

Answer 3

a signal from the extracellular environment of a cell is transmitted and detected.

Question 4

signalling molecules can only bind to their

Answer 4

complementary receptor

Question 5

what happens when the signalling moelcule binds to the receptor?

Answer 5

receptor’s shape changes, activating it.

Question 6

example of hydrophobic signal?

Answer 6

steroids

Question 7

how are hydrophobic signals transported?

Answer 7

in blood, with aid of carrier proteins

Question 8

describe how signal reception occurs for hydrophobic signals

Answer 8

CAN cross cell membrane and bind to intracellular receptors (located in cytosol/fluid of nucleus)

Question 9

example of hydrophilic signal?

Answer 9

proteins/hormones

Question 10

how are proteins/hormones transported?

Answer 10

in solution in blood plasma

Question 11

describe how signal reception occurs for hydrophilic signals

Answer 11

Bind to cell surface receptors (transmembrane, located on cell surface)

Question 12

define: signal transduction

Answer 12

converts signal from extracellular environment of cell into an intracellular response.

Question 13

describe hydrophobic signal transduction

Answer 13

binds to intracellular receptor, exposing region of it that was previously inside it.
hormone receptor complex moves into nucleus and exposed region attaches to DNA region which activates genes

Question 14

in hydrophobic transduction, genes are

Answer 14

directly activated, making a longer lasting response

Question 15

describe hydrophilic signal transduction

Answer 15

hormone (first messenger) binds to cell surface recptor, casuing shape chagne
shape change activates enzyme in plasma membrane, catalysing multiple copies of a secondary messenger, and each of which activate multiple copies of the next enzymes.
signal relayed to nucleus where specific genes are activated.

Question 16

describe how the first messenger (original stimulus like a hormone) is amplified.

Answer 16

because when it binds to reeceptor causing shape change, catalyses enzyme in plasma membrane to catlyse multile secondary messengers which catalyse multiple copies of enzymes and so one. one first messenger causes all ofthis!

Question 17

in hydrophilic transduction, genes are

Answer 17

indirectly activated, causinga a shorter lasting response

Question 18

describe cellular response

Answer 18

• Activation of genes produces effector proteins, which produce various cellular responses

Question 19

examples of cellular responses

Answer 19

apoptosis, cell division, changes in cell metabolism