Cell Types Review and Plasma (cell) membrane

1. Cell Types Review and Plasma (cell) membrane

2. Section 2 Objectives – page 175 Section Objectives • Identify the differences between eukaryotic and prokaryotic cells. • Review the structure and function of the plasma membrane

3. Section 7.1 Summary – pages 171-174 Two Basic Cell Types Cells that do not contain internal membrane-bound structures are called prokaryotic cells. • The cells of most unicellular organisms such as bacteria do not have membrane bound structures and are therefore called prokaryotes.

4. 7.1 Section 7.1 Summary – pages 171-174 Two Basic Cell Types Cells containing membrane-bound structures are called eukaryotic cells. • Most of the multi-cellular plants and animals we know are made up of cells containing membrane-bound structures and are therefore called eukaryotes.

5. Section 7.1 Summary – pages 171-174 Two Basic Cell Types The membrane-bound structures within eukaryotic cells are called organelles. • Each organelle has a specific function that contributes to cell survival.

6. Section 7.1 Summary – pages 171-174 Two Basic Cell Types • Separation of organelles into distinct compartments benefits the eukaryotic cells. The nucleus is the central membrane-bound organelle that manages cellular functions.

7. Section 1 Check Check-up: What makes this cell eukaryotic? A. Because it has membrane-bound organelles. Nucleus Nucleolus Chromosomes B. Because it does not have DNA. Organelles Plasma membrane

8. Summary Section 2 – pages 175-178 All living cells must maintain a balance regardless of internal and external conditions. Survival depends on the cell’s ability to maintain the proper conditions within itself.

9. Summary Section 2 – pages 175-178 Why cells must control materials The plasma membrane is the boundary between the cell and its environment.

10. Summary Section 2 – pages 175-178 It is the plasma membrane’s job to: • allow a steady supply of glucose, amino acids, and lipids to come into the cell no matter what the external conditions are. • remove excess amounts of these nutrients when levels get so high that they are harmful. • allow waste and other products to leave the cell.

11. Summary Section 2 – pages 175-178 This process of maintaining the cell’s environment is called homeostasis. Selective permeabilityis a process used to maintain homeostasis in which the plasma membrane allows some molecules into the cell while keeping others out.

12. Summary Section 2 – pages 175-178 Plasma Membrane Water

13. Summary Section 2 – pages 175-178 Structure of the Plasma Membrane The plasma membrane is composed of two layers of phospholipids back-to-back. Phospholipids are lipids with a phosphate attached to them.

14. Summary Section 2 – pages 175-178 Makeup of the phospholipid bilayer The phosphate group is critical for the formation and function of the plasma membrane. Phosphate Group is polar like water. The tails are non- Polar and do not Interact with water

15. Summary Section 2 – pages 175-178 Makeup of the phospholipid bilayer The fluid mosaic modeldescribes the plasma membrane as a flexible boundary of a cell. The phospholipids move within the membrane.

16. Summary Section 2 – pages 175-178 Other components of the plasma membrane: Cholesterol plays the important role of preventing the fatty acid chains of the phospholipids from sticking together – it gives it strength. Cholesterol Molecule

17. Summary Section 2 – pages 175-178 Other components of the plasma membrane: Transport proteins allow needed substances or waste materials to move through the plasma membrane. Click image to view movie.