Unit 1 - Test 2 Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

what do multicellular organisms use to signal between each other?

A

extra-cellular molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

examples of extra-cellular signalling molecules

A

hormones (steroid + peptide), neurotransmitters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are receptor molecules on target cells?

A

proteins with a binding site for a specific signal molecule.
binding changes the conformation of the receptor, which initiates a response within the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

variation in responses?

A

different cell types may show a specific and different tissue response to the same signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

steriod hormones

A
  • are lipophilic so can freely diffude across the membrane
  • they bind to nucleus or cytoplasm of target cell
  • examples include oestrogen and testosterone
  • hormone-receptor complex moves to the nucleus where it bonds to specific sites on DNA and affects gene expression
  • specific DNA sites are called hormone response elements (HREs), binding here influences the rate of transcription
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

peptide hormones

A
  • they are lipophobic (fat-hating) so cannot freely diffuse across membrane
  • bind to specific receptors on the surface of target cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

neurotransmitters

A
  • chemical messengers
  • transmit messages over much shorter distances than hormones
  • carry messages across the synapse
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

hydrophobic signalling molecules

A
  • able to directly diffuse through the phospholipid bilayer
  • once inside cell they bind to intracellular receptors
  • these intracellular receptors are 𝐭𝐫𝐚𝐧𝐬𝐜𝐫𝐢𝐩𝐭𝐢𝐨𝐧 𝐟𝐚𝐜𝐭𝐨𝐫𝐬
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

hydrophilic signalling molecules

A
  • bind to transmembrane receptors
  • conformational change of receptor after ligand binds
    *signal molecule is tranduced across the plasma membrane; transmembrane receptors act as signal transducers by converting the extracellular ligand-binding event into specific intracellular signals, altering the behaviour of the cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

transduction

A
  • involves a series of reactions that occur inside the cell through a signal transduction pathway
  • transduced hydrophilic signals often involve G-proteins or cascades of phosphorylation by kinase enzymes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

G- proteins

A
  • relay signals from activated receptors to target proteins (e.g. enzymes and ion channels)
  • they are a family of proteins that act as molecular switches inside cells, involved in transmitting stimul from outside to the interior of the cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

transduction by phosphorylation cascades

A
  • involves a series of events with one kinase activating the next in the sequence, and so on
  • can result in the phosphorylation of many proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

GLUT4 proteins

A
  • glucose transporters
  • binding of insulin to GLUT4 receptor triggers phosphorylation of this receptor, starting a 𝗰𝗮𝘀𝗰𝗮𝗱𝗲 within the cell
  • eventually leads to GLUT4-containing vesicles being transported to the membrane to increase GLUT4 activity in the membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is a transcription factor?

A

a protein, when bound to DNA, will either activate or inhibit transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is resting membrane potential?

A

a state where there are no net flow of ions across the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what does the transmission of a nerve impulse require?

A

a change in the membrane potential of a neurons plasma membrane

17
Q

what is an action potential?

A

an action potential is a wave of electrical excitation along a neurons plasma membrane

18
Q

what does binding of a neurotransmitter to its receptor trigger?

A

the opening of ligand-gated ion channels at 𝘀𝘆𝗻𝗮𝗽𝘀𝗲.

19
Q
A