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NEET MDS Exam Preparation – Physiology
Subject: PHYSIOLOGY
Topic: ACTIVE TRANSPORT
Movement of substances against the chemical, electrical or electrochemical gradient.
Also called uphill transport and active pump mechanism.
Requires energy which is obtained mainly by breakdown of ATP. Also needs a carrier protein.
Mechanism of active transport:
Substances to be transported combines with carrier protein forming a substance-protein complex. Carrier proteins can be uniport, that carries only one substance in a single direction called uniport pump. symport which carries 2 different substance in the same direction and antiport in opposite direction.
Substances transported:
Ionic substances - Na+, K+, Ca2+, Cl- and I-. Non-ionic substances - glucose, amino acid and urea.
Types:
Primary active transport, where energy is liberated directly from the breakdown of ATP or some other high energy phosphate compound.
Eg: sodium-potassium pump and potassium hydrogen pump.
Secondary active transport includes cotransport where transport of substance is in the same direction along with sodium.
Counter transport, substance transported in the opposite direction of that of sodium.
Also called uphill transport and active pump mechanism.
Requires energy which is obtained mainly by breakdown of ATP. Also needs a carrier protein.
Mechanism of active transport:
Substances to be transported combines with carrier protein forming a substance-protein complex. Carrier proteins can be uniport, that carries only one substance in a single direction called uniport pump. symport which carries 2 different substance in the same direction and antiport in opposite direction.
Substances transported:
Ionic substances - Na+, K+, Ca2+, Cl- and I-. Non-ionic substances - glucose, amino acid and urea.
Types:
Primary active transport, where energy is liberated directly from the breakdown of ATP or some other high energy phosphate compound.
Eg: sodium-potassium pump and potassium hydrogen pump.
Secondary active transport includes cotransport where transport of substance is in the same direction along with sodium.
Counter transport, substance transported in the opposite direction of that of sodium.
Questions
1. Uphill transport is:
(A) Facilitated diffusion
(B) Osmosis
(C) Active transport
(D) Simple diffusion
2.The transport takes place at the expense of cell's metabolic energy -ATP is called
(A) Diffusion
(B) Facilitated diffusion
(C) Osmosis
(D) active transport
3. Which among the following is not transported by active transport:
(A) Na+
(B) Mg2+
(C) Glucose
(D) Cl-
(A) Facilitated diffusion
(B) Osmosis
(C) Active transport
(D) Simple diffusion
2.The transport takes place at the expense of cell's metabolic energy -ATP is called
(A) Diffusion
(B) Facilitated diffusion
(C) Osmosis
(D) active transport
3. Which among the following is not transported by active transport:
(A) Na+
(B) Mg2+
(C) Glucose
(D) Cl-
Answer
1 - (C)2 - (D)
3 - (B) Mg2+ transported by passive transport
