L1

Question 1

intercellular communication =

Answer 1

cell signalling which is a multistep process

Question 2

step 1 of cell signalling

Answer 2

synthesis of signal molecule

Question 3

step 2 of cell signalling

Answer 3

release of signal molecule

Question 4

step 3 of cell signalling

Answer 4

transport of signal molecule to target - signal will be degraded on the way

Question 5

step 4 of cell signalling

Answer 5

detection of signal (reception) by target cell by a receptor

Question 6

step 5 of cell signalling

Answer 6

response by target cell - the action the signal said it’d do

Question 7

step 6 of cell signalling

Answer 7

some form of feedback - signal has been received

Question 8

Possible chemical nature of signal

Answer 8

• steroid (e.g. testosterone)
• amino acid
• amine
• gas
• peptide
• protein

Question 9

water soluble or lipid soluble?
can be stored in lipid vesicles within the signalling cell

Answer 9

water soluble

Question 10

water soluble or lipid soluble?
rapid release via exocytosis

Answer 10

water soluble

Question 11

water soluble or lipid soluble? why?
travels in blood without a carrier

Answer 11

water soluble
because blood is watery so don’t need to bind to a carrier molecule to travel in blood

Question 12

water soluble or lipid soluble? why?
cannot enter target cell

Answer 12

water soluble
can’t cross cell membrane because of the phospholipid bilayer

Question 13

water soluble or lipid soluble? why?
message transduced via cell surface receptor

Answer 13

water soluble
because ligand cannot enter cell itself

Question 14

water soluble or lipid soluble?
cannot be stored in lipid vesicles within the signalling cell

Answer 14

lipid soluble

Question 15

water soluble or lipid soluble? why?
slow response

Answer 15

lipid soluble
because it must be made on demand

Question 16

water soluble or lipid soluble? why?
travels in blood with a carrier protein

Answer 16

lipid soluble
because blood is watery - may be longer lasting

Question 17

water soluble or lipid soluble? why?
can enter cells by crossing membrane

Answer 17

lipid soluble
can cross phospholipid bilayer

Question 18

water soluble or lipid soluble? why?
acts on intracellular receptors

Answer 18

lipid soluble
directly regulates gene expression as it can enter the cell

Question 19

juxtacrine 1.0
specificity achieved by

Answer 19

direct contact i.e. doesn’t have to leave a cell, travel and enter another cell

Question 20

juxtacrine 2.0
specificity achieved by

Answer 20

receptor expression and direct contact

Question 21

autocrine
specificity achieved by

Answer 21

selective receptor expression and rapid degradation of signal molecule

Question 22

paracrine
specificity achieved by

Answer 22

selective receptor expression and rapid degradation of signal molecule, only cells that have the right receptor will receive the signal

Question 23

endocrine
specificity achieved by

Answer 23

selective receptor expression, only cells with the right receptor will receive the signal

Question 24

neuronal
specificity achieved by

Answer 24

precise contacts and rapid removal of neurotransmitter to prevent diffusion, ignores other neurons beelines for the right ones

Question 25

neuroendocrine
specificity achieved by

Answer 25

important in regulation of the endocrine system

Question 26

why is this ligand sent?
grow

Answer 26

if cell divided and cells are half the size of the original need to grow

Question 27

why is this ligand sent?
divide

Answer 27

to make more of a cell

Question 28

why is this ligand sent?
die

Answer 28

if cells are cancerous or diseased, cells will send messages to die

Question 29

why is this ligand sent?
change

Answer 29

change form or differentiate

Question 30

why is this ligand sent?
become active

Answer 30

contract, move, fire an AP, release a signal of its own, make more of something e.g. a hormone, break down more of something

Question 31

How do the signals’ effects occur

Answer 31

• receptor activation by a signal may change the amount or the activity of specific proteins which then mediate an effect
• proteins provide the structure of the cell (structure reflects function)
• enzymes do the activity

Question 32

if you want a cell to do something you want to target what the proteins do as cells can’t do the right thing without the right structure/can do what you want if you give it the right structure
what alters can be made to change the activity of a gene? (2)

Answer 32

• alter gene expression of specific proteins (turning specific genes on or off)
• alter the activity of specific proteins
  cell signalling often does both