They are solid, thinner filament structures (6-8 nm, in diameter) composed of a double-helical polymer of the protein actin. And microfilaments play a key role of in virtually all types of contractility and location of cells as well as motility within cells
The plasma membrane has a dual responsibility as a selective ely permeable barrier and transductor. The plasma membrane regulares the traffic of molecules into and out of the cell. Gases and small hydrophobic molecules by passive diffusion transport; Ions, sugars, amino acids, and sometimes water must be transported by a group of integral membrane proteins including
Chapter 11 Cell proliferation and its regulation Significance: 1. For the growth and development of a multicellular organism, and for the generation of offspring; 2. Produce new organisms in unicellular species; 3. Renew the aging, apoptotic cells, and damaged tissue;
Chapter 7 Energy Generation in Mitochondria and Chloroplasts (1)Mitochondria: in all eukaryotic cells The relationship between the structure and function of mit. ()Chloroplasts: in plant cells The relationship between the structure and function of chI. Mit: Oxidative phosphorylation→atp hl: Photosynthesis→atp+ NADPH→ Sugar
