Cell Structure & Function 2 Major Classes of Cells & the Organelles

2 Major Classes of Cells I. Prokaryotes ◦ Very small and simple ◦ Lack a nucleus ◦ Lack membrane-bound organelles ◦ Have a tough outer wall, sometimes a sticky capsule II. Eukaryotes o usually larger (about 10x larger) o Internally complex, most organelles surrounded by membranes o Animal cells lack cell walls o Plant cell walls made of cellulose o Fungal cell walls made of chitin

Prokaryote vs Eukaryote

Structure vs Function Cells size & shape related to cell function: a. Nerve cells can be very long for communication. b. Egg cells are very large cells, composed mostly of food reserves for the embryo. c. Blood cells are very small (and round) so that they can flow through capillaries for gas exchange.

Main Cell Parts 1. Cell Membrane: physically separates cell’s internal environment from the outside environment. Made up of phospholipids and protein. 2. Cell Wall: a non-living part of the cell that surrounds the cell membrane. Found in plant, fungal, and bacterial cells. 3. Cytoplasm: includes the fluid inside the cell and its organelles, except the nucleus. 4. Nucleus: contains genes (DNA) found on chromosomes; control center of cell.

Cell Membrane

Cell Walls

Nucleus

Organelles 1. Endoplasmic Reticulum: flattened sac or tubes Membranes provide surface for synthesis, storage, & transport of molecules. 2 Types: a)Rough ER: covered with ribosomes; makes protein b)Smooth ER: processes & transports; makes lipids

Rough & Smooth ER

Organelles 2. Golgi: finishes, sorts, and ships materials.

Organelles 3. Lysosome: digests cell’s food & waste. *(animal cells only)

Organelles 4. Vacuole: stores water & nutrients.

Organelles 5. Cytoskeleton: provides support and movement in animal cells.

Organelles 6. Mitochondria: converts glucose into ATP.

Organelles 7. Chloroplast: converts solar energy into chemical energy (photosynthesis). Plants only!

Organelles 8. Ribosomes: site of protein synthesis.

Animal Cell

Plant Cell