May 30, 2024

Transport process across the cell membranes: Medicinal Biochemistry

Transport process across the cell membranes: Medicinal Biochemistry

Transport processes across cell membranes are essential for maintaining cellular homeostasis and for allowing the cell to communicate with its environment. There are two primary modes of transport across the cell membrane: passive transport and active transport.

Passive transport is a mode of transport that does not require energy expenditure by the cell. It occurs down a concentration gradient, which is the difference in concentration of a substance between two regions. Passive transport can occur through two mechanisms: diffusion and facilitated diffusion.

Diffusion is the movement of molecules or ions from a region of higher concentration to a region of lower concentration, down their concentration gradient. This can occur through the lipid bilayer of the cell membrane for small, non-polar molecules such as oxygen and carbon dioxide. For larger, polar molecules such as glucose or ions such as sodium or potassium, facilitated diffusion through membrane proteins such as channels or carriers is required.

Facilitated diffusion involves the movement of molecules or ions through membrane proteins such as channels or carriers. Channels are transmembrane proteins that form aqueous pores that allow the passage of specific ions or molecules. Carriers are transmembrane proteins that undergo conformational changes to move molecules or ions across the membrane.

Active transport is a mode of transport that requires energy expenditure by the cell. Active transport can occur against a concentration gradient, allowing the cell to accumulate substances that are present at a lower concentration outside the cell. Active transport can occur through two mechanisms: primary active transport and secondary active transport.

Primary active transport involves the use of ATP to directly transport molecules or ions across the membrane through specialized proteins known as pumps. Examples of pumps include the sodium-potassium pump, which maintains the concentration gradients of sodium and potassium in animal cells, and the proton pump, which is involved in the production of ATP in mitochondria.

Secondary active transport involves the use of an electrochemical gradient established by primary active transport to drive the movement of molecules or ions across the membrane. For example, the sodium gradient established by the sodium-potassium pump can be used to drive the movement of glucose or amino acids into the cell through transporters that use the energy stored in the sodium gradient.

Overall, transport processes across cell membranes are essential for the survival and function of the cell, and are tightly regulated to maintain cellular homeostasis.

First Year Pharm D Subjects Syllabus, Notes, PDF Books, MCQ

1.1Human Anatomy and Physiology
1.2Pharmaceutics
1.3Medicinal  Biochemistry
1.4Pharmaceutical Organic Chemistry
1.5Pharmaceutical Inorganic Chemistry
1.6Remedial Mathematics/ Biology

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