1. This Test has 8 Questions 
2. There is 1 Mark for each correct Answer

MCQ – 1

Transport of two substances across the cell membrane in the same direction is known as?





Explanation :
  • When a carrier protein transports two or more substances in the same direction, it constitutes a symport e.g. Na- glucose symport.
  • When a carrier protein transports two substances in opposite direction, it is known as antiport. 
  • Eg. Na+ – H+ antiport in proximal convoluted tubules in the kidney or Na+-K+ ATPase pump.
  • Exocytosis is a type of vesicular transport. Vesicles with contents are transported to the cell membrane. 
    • Then they fuse with the cell membrane with the discharge of their contents outside the cell.
  • Pinocytosis is basically endocytosis and the ingested material is liquid.
  • In endocytosis, the sequence of events proceeds in almost the opposite direction of exocytosis.

MCQ – 2

Which among the following is TRUE regarding transport of substances through the cell membrane, EXCEPT:

Glucose is transported via facilitated diffusion

Active transport is an energy driven process

Facilitated diffusion requires energy

Facilitated diffusion requires carrier protein

Explanation :

Facilitated diffusion is a form of transporter-mediated membrane transport that does not require energy input. Just as in passive diffusion, the transport of ionized and non-ionized compounds across the plasma membrane occurs down their electrochemical potential gradient. Therefore, steady state will be achieved when the electrochemical potentials of the compound on both sides of the membrane become equal.

Active transport is the form of membrane transport that requires the input of energy. It is the transport of solutes against their electrochemical gradients, leading to the concentration of solutes on one side of the plasma membrane and the creation of potential energy in the electrochemical gradient formed.
Ref: Giacomini K.M., Sugiyama Y. (2011). Chapter 5. Membrane Transporters and Drug Response. In L.L. Brunton, B.A. Chabner, B.C. Knollmann (Eds), Goodman & Gilman’s The Pharmacological Basis of Therapeutics, 12e.

MCQ – 3

Glucose in renal tubules reabsorbed and is transported through the following mechanism:

Na anteport

Na cotransport

K anteport

K symport

Explanation :
Glucose reabsorption in the kidneys is similar to glucose reabsorption in the intestine. Glucose and Na+ bind to the sodium-dependent glucose transporter (SGLT) 2 in the apical membrane, and glucose is carried into the cell as Na+ moves down its electrical and chemical gradient. The Na+ is then pumped out of the cell into the interstitium, and the glucose exits by facilitated diffusion via glucose transporter (GLUT) 2 into the interstitial fluid. 
Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 37. Renal Function & Micturition. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong’s Review of Medical Physiology, 24e.

MCQ – 4

Glucose symport occurs with:





Explanation :

A i.e. Na+

MCQ – 5

Which of the following occurs along with glucose transport into a cell:

Sodium symport

Sodium anteport

Potassium transport

Amino acid transport

Explanation :

A i.e. Sodium symport

Glucose and Na+ share the same Co-transporter (or symport) – the sodium dependent glucose transporter: (SGLT – sodium glucose co- transporter)Q.

Sodium dependent glucose transporter (symport)

– Since the intracellular Nat concentration is low in intestinal & renal cells, Nat moves into the cells along its concentration gradient.

Glucose moves with the Na+ & released into the cell.

–  The Na+ is then transported to lateral intercellular spaces & the glucose is transported by GLUT-2 into the interstitium & then into capillaries.

– This is an example of secondary active transport i.e. the energy for glucose transport is provided by the active transport of Na+ out of cells.

Also know: Glucose mechanism also transport glactoseQ. Fructose utilizes different mechanism, it is transported by facilitated diffusionQ.

Glucose is incorporated in ORS to facilitate Na* absorptionQ.

MCQ – 6

True regarding transport across a cell membrane is :

Cl- with glucose symport

Na+ with glucose antiport 

Na+ with glucose symport

K+ with glucose symport

Explanation :

C i.e. Na+ with glucose symport

  • In this along with Na+, another substance is carried by the carrier protein called symport. 
  • The energy is obtained from the diffusion process of Na+ due to the concentration gradient across the cell membrane.
  • Na+ depended on glucose co-transporters (SGLT, members of a large family transporter. Gene name SLC5A).
  • Facilitative Na+ independent sugar transporter (GLUT family, gene name SLC2A).
  • The transport of most hexoses is dependent on Na+ in the intestinal lumen.
  • The glucose and galactose both uses the same transport SGLT-1. 
  • SGLT-1 transports either glucose or galactose along with Na+ from intestinal lumen to cell (Secondary active transport).
  • Fructose is absorbed by facilitated diffusion from the intestinal lumen into the enterocytes by GLUT-5. 
  • This process is Na+ independent.

MCQ – 7

Active transport across the cell membrane is mediated by :


Na+-K+ ATPase

Carrier protein

Channel protein

Explanation :

C i.e. Carrier protein

  • To move substances against a concentration or electrochemical gradient, the cell must utilize energy in the form of ATP during active transport.
  • Primary active transport, which is directly dependent on ATP, moves ions across a membrane and creates a difference in charge across that membrane.
  • Secondary active transport, created by primary active transport, is the transport of a solute in the direction of its electrochemical gradient and does not directly require ATP.
  • Carrier proteins such as uniporters, symporters, and antiporters perform primary active transport and facilitate the movement of solutes across the cell’s membrane.

MCQ – 8

Which of the following statements about facilitated diffusion is true ?

It is a form of active transport.

It requires a carrier protein.

The rate of transport is proportionate to the concentration gradient.

Requires creatine phosphate.

Explanation :

Ans.B i.e. It requires a carrier protein

  • Facilitated diffusion is a form of passive (no energy) transport that occurs along an electrochemical gradient and requires no energy. The rate of transport is not always proportionate to the concentration gradient because it is mediated through carrier proteins.
  • At lower concentrations before the carrier protein becomes saturated (or before Vmax is reached), the rate of facilitated diffusion is proportionate to concentration gradient whereas, at higher concentrations when carrier protein becomes saturated (Vmax has reached) the rate of facilitated diffusion becomes constant.


Simple Diffusion

Facilitated Diffusion

 Active Transport





ATP (energy) expenditure

Not required

Not required



Electrochemical (EC)


Along EC gradient

Along EC gradient

Against EC gradient



(Can be) Bidirectional


Carrier proteins

Not required




Not saturable



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