These B.Pharm notes on transport across cell membrane (Chapter 4 of Human Anatomy, Physiology and Pathophysiology I) summarise the key points for first semester pharmacy students and link to the complete PDF.
Table of Contents
Read the following document for full information
Chapter overview
This chapter describes the structure and functions of the cell and how substances move across the cell membrane. The membrane follows the fluid mosaic model, a phospholipid bilayer with embedded proteins. Passive transport includes diffusion, osmosis, facilitated diffusion and filtration, while active transport and vesicular transport such as endocytosis and exocytosis need energy. The chapter also covers the cell cycle, mitosis and meiosis, and the cell junctions, tight junctions, desmosomes and gap junctions, that connect neighbouring cells.
Key points on transport across cell membrane
- Cell membrane structure (fluid mosaic model) and organelle functions
- Passive transport: diffusion, osmosis, facilitated diffusion, filtration
- Active transport, endocytosis and exocytosis
- Cell cycle, mitosis and meiosis
- Cell junctions: tight junctions, desmosomes, gap junctions
Relevance to pharmacy practice
Transport across the cell membrane is the key to drug absorption and distribution. Small lipid-soluble drugs cross by passive diffusion, some drugs use carrier proteins, and others are moved out of cells by efflux pumps. Tight junctions in the intestinal and capillary walls decide how freely drugs pass between cells. Cell division is also the target of anticancer drugs, which is why this topic links directly to pharmacology and pharmaceutics.
Frequently asked questions
What is the fluid mosaic model?
It describes the cell membrane as a flexible phospholipid bilayer in which proteins float, allowing selective movement of substances.
How do active and passive transport differ?
Passive transport moves substances down a concentration gradient without energy. Active transport moves them against the gradient and uses ATP.
What are the three main types of cell junctions?
Tight junctions seal the space between cells, desmosomes anchor cells together, and gap junctions allow direct communication between adjacent cells.
Quick revision checklist
Before moving on, check that you can do each of the following without looking at your notes. Use this list on transport across cell membrane as a self-test: tick a statement only when you can answer it aloud. Revisit any statement you cannot answer, then re-read the matching section of the PDF. Repeating this cycle two or three times before an exam builds the recall and confidence you need for both theory papers and viva.
- I can explain: cell membrane structure (fluid mosaic model) and organelle functions
- I can explain: passive transport: diffusion, osmosis, facilitated diffusion, filtration
- I can explain: active transport, endocytosis and exocytosis
- I can explain: cell cycle, mitosis and meiosis
- I can explain: cell junctions: tight junctions, desmosomes, gap junctions
Study and exam tips
Read the key points on transport across cell membrane first, then study the PDF notes and redraw the main diagrams from memory. Link each concept to a drug or clinical example, and revisit the chapter before your internal and university examinations. Short daily revision works better than one long session. For additional reading, see the NCBI Bookshelf.
In B.Pharm examinations, short answer questions usually ask for definitions, classifications and labelled diagrams, while long answers on transport across cell membrane ask for detailed descriptions with examples. Learn the headings in the order given in your syllabus, and add one clinical or drug-related example to each long answer to earn extra marks.
This post is part of the free B.Pharm Guru notes for the first semester. Every chapter of Human Anatomy, Physiology and Pathophysiology I has a short summary, key points and a downloadable PDF written for the B.Pharm course, so you can revise quickly or study in depth.
Previous chapter (Chapter 3): levels of structural organization and body systems, basic life processes, homeostasis, basic anatomical terminologies. Next chapter (Chapter 5): general principles of cell communication, forms of intracellular signalling. View all HAP-I chapters.
