Biophysics

Question 1

what is equlibrium potential?

Answer 1

Equilibrium Potential (E): Voltage at which net ion flow across a membrane is zero.

Question 2

what is the nerst equation?

Answer 2

Nernst Equation:
𝐸
=
𝑅
𝑇
𝑧
𝐹
ln
⁡
[
𝐼
𝑜
𝑛
]
outside
[
𝐼
𝑜
𝑛
]
inside
E=
zF
RT
​
ln
[Ion]
inside
​

[Ion]
outside
​

​
, calculates equilibrium potential for a specific ion.

Question 3

what is resting membrane potential in neurons?

Answer 3

Maintained by ion gradients (Na⁺, K⁺) and selective permeability of K⁺ channels. Typical value: ~ -70 mV.

Question 4

what is the ionic basis of action potential ?

Answer 4

Depolarisation: Voltage-gated Na⁺ channels open; Na⁺ influx.
Repolarisation: Voltage-gated K⁺ channels open; K⁺ efflux.
Hyperpolarisation: Delayed closing of K⁺ channels.

Question 5

what are the roles of the voltage gated channel?

Answer 5

Na⁺ Channels: Initiate depolarisation.
K⁺ Channels: Restore resting potential.
Ca²⁺ Channels: Facilitate neurotransmitter release.

Question 6

What is action potential progation?

Answer 6

Occurs via local depolarisation of adjacent membrane segments.
Myelination increases conduction speed via saltatory conduction (nodes of Ranvier)