Cell Parts and Functions

1. Cell Parts and Functions Biology 11 S.Dosman

2. Classification of Cells

3. Cell Membrane • Outermost boundary of the cell. • Made of proteins and a bilayer(double) of lipid (fat)molecules. • Holds the cell content in place. • Regulates the movement of materials into and out of the cell.

4. Nucleus • Control center of the cell. • Contains threadlike chromosomes made of genes. Chromosomes are made of DNA (deoxyribonucleic acid). • Pores in the nuclear envelope allow some things to pass through.

5. Nucleolus • Located inside the nucleus. • Cell may contain one or more nucleoli. • They produce or manufacture ribosomes.

6. Mitochondria • Oval shaped with 2 membranes – a smooth outer & and inner folded membrane called cristae. • Often referred to as the “power house”of the cell. • Site of cellular respiration – energy is released from sugar & energy is stored in ATP. • Mitochondria contain their own DNA!

7. Golgi Apparatus • Stores, modifies & packages proteins from the RER. • Looks like a stack of flattened pancakes. • Pinches off to form small protein filled vesicles. • Forms lysosomes.

8. Ribosomes • Site of protein synthesis. • Amino acids are joined together to make proteins here. • Made of rRNA and proteins, the smallest organelles (20nm). • There are many ribosomes in one cell attached to the endoplasmic reticulum or floating freely in the cytoplasm.

9. Rough Endoplasmic Reticulum • Organelle with a double membrane and ribosomes attached. • Extends from the nuclear membrane to the cell membrane. • Transports proteins made by the ribosomes to the Golgi apparatus.

10. Smooth Endoplasmic Reticulum • Double membrane bound organelle without ribosomes. • Also extends throughout the cell. • Produces lipids for the cell.

11. Lysosome • Organelles bound by a single membrane and formed by the Golgi apparatus. • Contain enzymes to break down large molecules & cell parts. Nick named Suicide sac • Only found in animal cells

12. Vacuole • Fluid filled sacs that act as storage for sugars, minerals, proteins & water. • Gives plant cells physical support. • Plant cells have large, central vacuoles. • Animal cells have many smaller vacuoles.

13. Cytoskeleton • Microfilaments are threadlike structures in the cytoplasm that help provide shape & movement. • Microtubules are tubelike fibres (made of protein) that transport materials through the cytoplasm – also found in flagella & cilia.

14. Centrioles • Composed of nine bundles of three microtubules. • Found only in animal cells. • Play a key role in cell division.

15. Plastids • Chemical factories or storehouses for food or pigments. • Chloroplasts – contain chlorophyll & are the site of photosynthesis. • Chromoplasts – store pigments (orange, yellow). • Amyloplasts – colorless and store starch (potato).

16. Cell Wall • Protects & supports the cell. • Primary cell wall made of cellulose. • Some plant cells have an additional secondary wall with a middle lamella in between that contains a sticky pectin to hold cells together.

17. Cytoplasm • A jelly-like substance that fills the interior of the cell. • Many metabolic reactions occur within the cytoplasm.

18. Cilia and Flagella • A flagellum is a whip like tail • that aids in movement • Flagella spin like a propeller • Cilia (cilium)are shorter, hair like structures that aid in movement and moving materials.