Mixed+WS+JO

(1) p. 31 Describe the structure of a phospholipid (insert an image). Indicate the parts that hydrophillic and the parts that are hydrophobic. The structure is that of a polar head and two nonpolar tails. The tails are hydrophobic while the heads face towards the liquid and are hydrophilic.

(2) p. 31 How do phospholipids arrange themselves in water? The heads face towards the water while the tails create an interior. ( the tails on both sides face each other)

(3) p. 46 Describe the fluid-mosaic model of a membrane. (insert an image) Which components are the fluid, and why? Which components are the mosaic, and why? The fluid mosaic model is a working description of membrane structure and states that the protein molecules form a shifting pattern within the fluid phospholipids’ bilayer. The outer surface consists of the phospholipids’ heads and proteins. The inner surface consists of the tails.

(4) p. 46 What is the function of the membrane? How does the structure of the membrane suit that structure? The membrane keeps everything intact. It only allows certain things to enter and/ or leave the cell.

(5) p. 46 Why is the membrane considered selectively permeable? It is selective because it chooses what goes, what stays and what comes.

(6) p. 46 What is diffusion? Give an example. Diffusion is the random movement of molecules from the area of high concentration to lower concentration until equal. An example would be that of the smell of a cookie within a house, the example is located in the book. But in short the smell starts in one room and as a door is opened the smell defuses and spreads to fill the other room. This process continues until all rooms are filled.

(7) p. 46 What is osmosis? Osmosis is the diffusion of water across a permeable membrane.