Cell Membrane: 17 flashcards
All 17 flashcards from this kit, free and with no sign-up.
1. What is the primary structural framework of the cell membrane?
Show the answer
A phospholipid bilayer, with hydrophilic heads facing outward and hydrophobic tails facing inward.
2. Name the model that describes the cell membrane as a fluid mosaic.
Show the answer
The Fluid Mosaic Model, proposed by Singer and Nicolson in 1972.
3. What does 'fluid' refer to in the Fluid Mosaic Model?
Show the answer
The ability of lipids and proteins to move laterally within the membrane, giving it flexibility and dynamic behavior.
4. What does 'mosaic' refer to in the Fluid Mosaic Model?
Show the answer
The patchwork of different components (phospholipids, proteins, cholesterol, carbohydrates) embedded in the membrane.
5. List the four main components of the cell membrane.
Show the answer
Phospholipids, proteins (integral and peripheral), cholesterol, and carbohydrates (glycolipids and glycoproteins).
6. What is the role of cholesterol in the cell membrane?
Show the answer
It stabilizes membrane fluidity, reducing fluidity at high temperatures and preventing solidification at low temperatures.
7. What are integral (transmembrane) proteins?
Show the answer
Proteins that span the entire lipid bilayer, often serving as channels, transporters, or receptors.
8. What are peripheral proteins?
Show the answer
Proteins that are loosely attached to the surface of the membrane (either inner or outer), often involved in signaling or structural support.
9. What is the primary function of membrane carbohydrates?
Show the answer
They are involved in cell-cell recognition, adhesion, and as receptors (forming glycoproteins and glycolipids).
10. What is selective permeability?
Show the answer
The property of the cell membrane that allows some substances to pass through while blocking others, maintaining internal balance.
11. Which types of molecules can easily pass through the lipid bilayer by simple diffusion?
Show the answer
Small, nonpolar (hydrophobic) molecules like oxygen, carbon dioxide, and nitrogen, as well as small uncharged polar molecules like water (to a limited extent).
12. What is facilitated diffusion?
Show the answer
The passive movement of molecules (like glucose or ions) across the membrane through specific transport proteins (channels or carriers), without energy input.
13. What is active transport?
Show the answer
The movement of molecules against their concentration gradient, requiring energy (ATP) and specific transport proteins (pumps).
14. Give an example of active transport in cells.
Show the answer
The sodium-potassium pump, which moves Na+ out and K+ into the cell against their gradients.
15. What is endocytosis?
Show the answer
The process by which the cell membrane engulfs large particles or fluids to bring them into the cell, forming a vesicle.
16. What is exocytosis?
Show the answer
The process by which vesicles fuse with the cell membrane to release their contents outside the cell.
17. Why is the cell membrane described as 'asymmetric'?
Show the answer
Because the outer and inner faces have different lipid and protein compositions, which is crucial for their distinct functions (e.g., extracellular carbohydrates vs. intracellular cytoskeletal attachments).
Your notes can be a kit like these
Every kit here was made from real study material. Point Veda at a chapter, a PDF, a photo or a link and get notes, flashcards, practice MCQs, games and a scored test — free, in 42 languages.
- Chapter notes
- Flashcards
- Practice MCQs
- Scored tests
- Exam prep
Get Veda free See what students get
Free to start · No ads · Works in 42 languages