Cell physiology of Ions 1

Question 1

What is a solvent?

Answer 1

the fluid present

Question 2

What is the solute?

Answer 2

the particles dissolved in the solvent

Question 3

What is Ionic Gradient?

Answer 3

the difference in concentration of ions between two points in space

Question 4

How much of the body is water?

Answer 4

60%

Question 5

How much of the water in our body is in our intracellular fluid?

Answer 5

2/3

Question 6

How much of the water in our body is in our extracellular fluid?

Answer 6

1/3

Question 7

What does the extracellular fluid consist of?

Answer 7

Interstitial fluid 3/4 + Plasma 1/4

Question 8

List the four fluid compartments of the body?

Answer 8

plasma, interstitial, intracellular and transceullar

Question 9

What is the chemical composition of plasma?

Answer 9

Na+

Question 10

What is the composition of interstitial fluid?

Answer 10

plasma + lack of blood proteins

Question 11

What is the composition of intracellular fluid?

Answer 11

potassium based + lots of proteins (anions)

Question 12

Where can transcellular fluid be found?

Answer 12

in the lumen of tubes and organs

Question 13

Give examples of Transcellular fluid.

Answer 13

CSF, Urine, chyme (GI Tract)

Question 14

What is Diffusion?

Answer 14

The process of solute molecules passively moving down their concentration gradient

Question 15

What does diffusion not involve the movement of ?

Answer 15

the solvent

Question 16

What is Osmosis?

Answer 16

the process of water molecules passively moving down their concentration gradient

Question 17

What is an Ion?

Answer 17

an charged atom or molecule

Question 18

What is a cation?

Answer 18

a positively charged ion

Question 19

What is an anion?

Answer 19

a negatively charged Ion

Question 20

What are electrolytes ?

Answer 20

ionised components of living fluid

Question 21

List 5 cations.

Answer 21

Na+, K+, Ca2+, H+, Mg2+

Question 22

List 5 anions.

Answer 22

OH-, Cl-, HCO3-, SO4-, PO4- (phosphate)

Question 23

What 2 things is phosphate important for?

Answer 23

in reactions involving ATP and in the Bone

Question 24

Why is sulphate important?

Answer 24

structurally in glycosaminoglycans (molecule which make connective tissue and bone)

Question 25

Where can we find Ions (6) ?

Answer 25

``` Free in a solution Tightly bound to another molecule Sequestered behind a membrane organelle In teeth/bones Buffered- non specifically bound Chelated - specifically bound ```

Question 26

Explain how ions cross the membrane via Channels

Answer 26

Channels- membrane proteins which open and close to specific ions. Using a pore

Question 27

Explain how ions cross the membrane via Co-Transporters.

Answer 27

Co-Transporters- 2 ions will attach to a protein which moves them both through membrane. Down conc. gradient.

Question 28

Explain how ions cross the membrane via Pumps.

Answer 28

Pumps- SLOWEST only active one membrane proteins which use ATP to pump ions across the membrane (usually against conc gradient) K+ Na+ ATPase

Question 29

Explain how ions cross the membrane via exchangers.

Answer 29

one ion goes out another goes in. CL, HC03-

Question 30

Explain how ions cross the membrane via Leak.

Answer 30

unexplained movement of ions.

Question 31

What 2 main jobs do ions do?

Answer 31

They start cellular processes + Act as second messengers

Question 32

Explain how second messengers work in fertilisation?

Answer 32

Ca2+ | sperm hits the outside of the egg, which leads to Ca2+ increase inside the egg.

Question 33

Explain how second messengers work in muscle contraction?

Answer 33

neural signal --> muscle. a signal is sent across the membrane which triggers an increase in intracellular calcium

Question 34

Explain how second messengers work in exocytosis?

Answer 34

stimulated from outside the cell

Question 35

what 4 things can Ions do?

Answer 35

create energy ATP move water activate enzymes control transmembrane voltage

Question 36

What Ion does water usually follow?

Answer 36

Chloride

Question 37

High levels of calcium stimulates which enzyme used to phosphorylate other proteins?

Answer 37

Protein Kinase C

Question 38

What is oedema?

Answer 38

collection of fluid in the extracellular space

Question 39

What Is voltage?

Answer 39

a potential difference between 2 points in space of an electric field

Question 40

What is the equation for voltage?

Answer 40

V = I x R or I = g xV (g is conductance)

Question 41

Which Ions form the majority of those found inside and outside the cell?

Answer 41

Potassium (cation) inside cell, Sodium (cation) outside of cell

Question 42

What does the movement of Ions across the cell membrane lead to?

Answer 42

electrical currents

Question 43

What is the sign for membrane potential?

Answer 43

Vm. (Reality)

Question 44

What is the sign for resting membrane potential?

Answer 44

RMP or Vrest. (hypothetical)

Question 45

What are the 2 forces on each Ion?

Answer 45

Chemical force | Electrical force

Question 46

What is the chemical force on an Ion?

Answer 46

the difference in concentration across the membrane

Question 47

What is chemical force also known as in Ions?

Answer 47

diffusional force

Question 48

What measurement is electrical force based on in Ions?

Answer 48

Vm membrane potential

Question 49

What is electrical force in Ions?

Answer 49

a few positive charges are unpaired with negative charges on the same side of the membrane