Fluids, Electrolytes and Action Potential

Question 1

What is the Molecular make up and its common elements of the human body

Answer 1

• Oxygen (O) 65% of body mass
• Carbon (C) 18.5%
• Hydrogen (H) 9.5%
• Nitrogen (N) 3.2%
• Sodium (S) 0.2%
• Chlorine (CL) 0.2%

Question 2

Define Cellular Respiration

Answer 2

• The cell seems to “respire” in a way that it takes in molecular oxygen (as an electron acceptor) and releases carbon dioxide (as an end product), hence, the process is described to be aerobic. There are organisms that use other organic molecules as electron acceptors instead of oxygen. This type of respiration in which oxygen is not used as a final electron acceptor is referred to as anaerobic.

In anaerobic respiration (respiration in absence of oxygen), pyruvate is not metabolized by cellular respiration but undergoes a process of fermentation. The pyruvate is not transported into the mitochondrion, but remains in the cytoplasm, where it is converted to waste products that may be removed from the cell.

Cellular respiration is essential to both eukaryotic and prokaryotic cells since biochemical energy is produced to fuel many metabolic processes, such as biosynthesis, locomotion, transportation of molecules across membranes.

The entire process occurs in the cytoplasm of prokaryotes. In eukaryotes, glycolysis occurs in the cytoplasm whereas the Krebs Cycle and oxidative phosphorylation in the mitochondrion. Prokaryotic cells can yield a maximum of 38 ATP molecules while eukaryotic cells can yield a maximum of 36.

Question 3

How does anything move through a membrane wall

Answer 3

• Passive - Simple diffusion
  - Osmosis
  - Facilitated Diffusion
• Active - Active Transport
  - Cellular Endo/Exoctosuis = encapsulating and expelling

Question 4

Define Action Potential

Answer 4

• The rapid change in electric potential that parts of a nerve cell undergo when a nerve impulse is generated. Unlike ordinary electric current, which consists of the flow of electrons, the action potential involves the movement of sodium and potassium ions across the cell membrane.

Question 5

Name the types of Ionic Channels

Answer 5

• Leakage Channel
• Ligard Gate Channel
• Mechanically Gated Channel
• Voltage Gate Channel

Question 6

Define what a Leakage Channel does

Answer 6

• These gates randomly open and close allowing K+ and Na+ to pass

Question 7

Define what a Ligard Gate Channel does

Answer 7

• Open and close to chemical command e.g., neurotransmitters

Question 8

Define what a Mechanically Gated Channel does

Answer 8

• Opens and closes to mechanical stimulation like stretch, touch, or sound e.g., baroreceptors

Question 9

Define what a Voltage Gate Channel does

Answer 9

• Responds to change in membrane potential (voltage)

Question 10

What is a action potential or impulse

Answer 10

Its a rapid sequence of events that produces a large membrane potential

• First phase Depolarisation
• Second Phase Repolarisation

Question 11

Define Resting Membrane Potential

Answer 11

Its the electrical potential difference that exists across a plasma membrane in a cell at a resting state

Question 12

Define Threshold

Answer 12

AP will not be generated if the required voltage is not achieved

Question 13

Define Refractory Period

Answer 13

Time after AP in which the cell cannot generate another action potential