Cell Membrane

1. Cell Membrane • Every cell is surrounded by a protective membrane called a cell membrane. • This membrane is flexible & protects the inside of the cell from the environment outside of the cell. • Mostly made up of two different types of macromolecules- proteins and a type of lipid called phospholipids.

2. Cell Wall • Plant cells, fungal cells, bacteria and some types of protists have cell walls. • Cell wall is a stiff structure outside the cell membrane & protects a cell from attack by viruses and other harmful organisms. • In plant & fungal cells, a cell wall helps to provide structural support in order to maintain the cell’s shape.

3. Cell Appendages • Cell appendages are used for movement • Flagella are long, tail-like appendages that whip back & forth and move a cell • Cells can also have cilia which are short hair like structures. Cilia can move a cell or move molecules away from a cell.

4. Cytoplasm & Cytoskeleton • Most of the water in cells is in the cytoplasm. • Cytoplasm is the fluid inside a cell that contains salts & other molecules. • The cytoplasm also contains the cell’s cytoskeleton which is a network of threadlike proteins that are joined together. • The cytoskeleton is made up of proteins. The cytoskeleton helps give the cell its shape & helps it move.

5. Prokaryotic Cells • Is one of the two types of cells • The genetic material in a prokaryotic cell is not surrounded by a membrane (this is most important feature in prokaryotic cells) • Missing many other cell parts • Most prokaryotic cells are unicellular organisms

6. Eukaryotic Cells • Plant, animal, fungi and protists are made of eukaryotic cells. • Most eukaryotic cells have genetic material that is surrounded by a membrane. • Eukaryotic cells have cell structures called organelles, which have special jobs. • Eukaryotic cells are usually larger than prokaryotic cells.

7. The Nucleus • The largest organelle inside most eukaryotic cells • The nucleus directs cell activities & contains genetic information stored in DNA. • Chromosomes is where the DNA is stored inside the nucleus • Also the nucleus contains the nucleolus which looks like a dark spot in a cell. The nucleolus makes ribosomes, which make proteins. • The nucleus is surrounded by two membranes that forms structure called the nuclear envelope. Nuclear envelope has many pores. Certain molecules move in & out of the nucleus through these pores.

8. Manufacturing Molecules • Proteins are important molecules in cells. • Proteins are made on small structures called ribosomes. • Ribosomes do not have cell membranes & are in the cell’s cytoplasm. They also attach to the rough endoplasmic reticulum (ER). • Rough ER is where protein is made. • Smooth ER has no ribosomes and is where lipids like cholesterol is made. Smooth ER is important because it helps remove harmful substances from a cell.

9. Processing Energy • All living things require energy to in order to survive. Cells process some energy in special organelles. • Two organelles that process energy through chemical reactions are: mitochondria and chloroplasts(in plant cells only). • In mitochondria the energy made is stored in molecules called ATP. ATP is the fuel for cell jobs such as: growth, cell division & material transport. • Plant cells & some protists like algae contain organelles called chloroplasts. Chloroplasts use light energy & make food (sugar called glucose) through a process called photosynthesis. The sugar contains stored chemical energy & releases it when the cell needs it.

10. Processing, Transporting & Storing Molecules • The golgi apparatus (looks like a stack of pancakes) is near the ER in a cell. It prepares proteins to do their jobs in the cell and then puts the proteins in little packages called vesicles. • The vesicles then transport substances from one area in the cell to other areas. In animal cells these vesicles are called lysosomes. • Some cells haves have saclike structures called vacuoles. Vacuoles store food, water & waste material. A typical plant cell usually has one large vacuole (central vacuole). Some animal cells have many small vacuoles.