Question

1. which types of cells have a cell membrane? 2. true or false: the phospholipid bilayer is also referred to as the fluid mosaic model. 3. what is the purpose of the cell membrane? 4. what are the 3 components of a phospholipid? 5. describe how phospholipids are arranged in the cell membrane. 6. what does it mean that the cell membrane is selectively permeable? 7. what molecules can be found in the cell membrane (list 4)? 8. where can a cholesterol be found within the cell membrane? 9. what is the purpose of the proteins that are found in the cells membrane? 10. what are carbohydrates used for within the cell membrane?

Explanation:

1. All cells (prokaryotic and eukaryotic) have a cell - membrane. It is a fundamental feature of cells.
2. False. The fluid - mosaic model describes the structure of the cell membrane which includes the phospholipid bilayer along with proteins, cholesterol, and carbohydrates. The phospholipid bilayer is just one part of the model.
3. The cell membrane serves as a barrier, controls the movement of substances in and out of the cell (selective permeability), and also plays a role in cell - cell recognition and communication.
4. A phospholipid has a glycerol backbone, two fatty acid tails, and a phosphate - containing head group.
5. Phospholipids are arranged in a bilayer in the cell membrane with the hydrophilic heads facing the aqueous environments (inside and outside the cell) and the hydrophobic tails facing each other in the interior of the bilayer.
6. Selective permeability means that the cell membrane allows certain substances (such as small non - polar molecules, some ions) to pass through while restricting the passage of others (large polar molecules, most macromolecules).
7. Four molecules found in the cell membrane are phospholipids, proteins, cholesterol, and carbohydrates.
8. Cholesterol is found embedded within the phospholipid bilayer, interspersed among the fatty acid tails.
9. Proteins in the cell membrane have functions such as transport (channel and carrier proteins), cell - cell recognition, enzymatic activity, and signal transduction.
10. Carbohydrates in the cell membrane are mainly used for cell - cell recognition and also play a role in cell adhesion.

Answer:

1. All prokaryotic and eukaryotic cells have a cell membrane.
2. False
3. It acts as a barrier, controls substance movement, and is involved in cell - cell recognition and communication.
4. Glycerol backbone, fatty acid tails, phosphate - containing head group.
5. Arranged in a bilayer with hydrophilic heads facing aqueous environments and hydrophobic tails in the interior.
6. Allows certain substances to pass while restricting others.
7. Phospholipids, proteins, cholesterol, carbohydrates.
8. Embedded within the phospholipid bilayer among the fatty acid tails.
9. Transport, cell - cell recognition, enzymatic activity, signal transduction.
10. Cell - cell recognition and cell adhesion.