Regulating Flow, Biological Signalling + Calcium Flashcards Preview

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Flashcards in Regulating Flow, Biological Signalling + Calcium Deck (18)
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1
Q

What 2 factors does Passive Diffusion depend on?

Rank the Permeability levels of

  • Hydrophobic
  • Small uncharged
  • Large uncharged
  • Ions
A

Ionic gradient + Permeability

Most permeable - Hydrophobic
Highly Permeable - Small Uncharged
Low Permeability- Large Uncharged
Impermeable- Ions

2
Q

3 roles of transport processes

A
  • Maintain pH and ion concentrations
  • Regulate Cell volume
  • Excretion of waste and toxic products
3
Q

What are the Intra AND Extracellular concentrations for

  1. Ca
  2. K
  3. Cl
  4. Na
A

Ca: 1.5 mM outside, 0.1 microMolar inside
K: 4mM outside, 155mM Inside
Cl: 123mM outside, 4.2 mM Inside
Na: 145mM outside, 12nM Inside

4
Q

How does PMCA work?

A

Hydrolyses ATP to transport Ca2+ out of the cell

5
Q

How does the Na-K Pump work?

A

ATP Hydrolysed
3Na+ are transported out
2K+ are taken into cell

6
Q

How does the Na-Ca-Exchanger (NCX) work?

What effect does depolarisation have on this process?

A
  • Uses Na gradient from Na-K Pump
  • 3Na into cell, 1Ca out of cell

Activity reversed, as NCX depends on membrane potential

7
Q

How does Ischaemia affect the NCX exchanger?

A
  • ATP is depleted, so Na-K Pump stops and Na gathers in cell

- Activity is reversed, so Na is moved out of cell and Ca is moved into cell, which is toxic

8
Q

How does the Na-H-Exchanger (NHE) work?

A
  • Uses Na gradient from Na-K Pump

- One Na moves into cell, One H moved out of cell

9
Q

How is Na used to move Glucose into the cell?

A

Na gradient
Causes Na to move into cell, along with Glucose
Through a Symport

10
Q

Which 3 co-transporters are involved in regulating intracellular pH
How do they work?

A
  • NHE ( Na in, H out)
  • NBC ( Na, HCO3- in. H, Cl- out) Alkanises the cell
  • Anion Excanger (HCO3- out, Cl- in) acidifies the cell
11
Q

At the Set Point pH, which two transporters have equal activity?
Which transporter has a higher activity, what is the effect on pH of cell?

A

NHE and AE

NBC works more, Alkanises the cell

12
Q

What are 4 process involved in increasing [Ca] inside the cell?

A
  • Ligand Gated Calcium Channels
  • Voltage Operated Calcium Channels
  • IP3R open when binded to IP3, allowing Ca to leave SR/ER to enter cytoplasm
  • CICR/ Ryanodine receptors detect high cytoplasmic Ca, allowing more Ca to enter cytoplasm, from SR/ER
13
Q

How does SERCA work?

A

Uses ATP to release Ca into cytoplasm

14
Q

What is the [Ca] inside the SR/ ER?

A

0.2 mMolar

15
Q

Which 3 factors oppose an increase in Cytoplasmic Calcium?

A
  • Impermeability of Membrane to Ca2+
  • Ca transporters, proteins move Ca out of cytoplasm
  • Ca buffer proteins (Decrease Free Ca Level)
16
Q

How do Nuclear/ Intracellular Receptors work?

A

Hydrophobic ligand binds to receptor
Ligand-receptor complex binds to gene transcription factor
Activates/ inactivates a gene/ set of genes

17
Q

Explain how a Kinase-linked receptor works

A
  1. Agonist binds to a receptor, activating Tyrose Kinase
  2. Autophosphorylation: TK Phosphorylates the adjacent chain of same molecule
  3. Enzymes bind to phosphorylated TK and gets phosphorylated itself
18
Q

Compare Paracrine, Autocrine, Endocrine Signalling

A

Para: Signalling molecule affects adjacent cells
Auto: Signalling molecule affects cell that it was released from
Endo: Signalling molecule released directly into blood to distant target cells