Biology 8.1&8.2

Components of cell theory

• all living things are made up of cells

• Cells are the most basic unit of structure and function in all organisms]

• New cells can only arise from existing cells

Nucleus

directs all activity in the cell (contains all of the cell’s DNA)

Ribosomes

make proteins! (Made of rRNA and protein.) They are found floating in the cytoplasm, and attached to the rough ER.

Endoplasmic Reticulum

Proteins and lipids are synthesized in the endoplasmic reticula.

Golgi Apparatus

Packages proteins in vesicles, tagging them with chemical markers for proper delivery.

Vacuoles & Vesicles

Vacuoles are used for storage, (and are larger) while vesicles are used for transport (both are membrane-bound “containers.” The central vacuole in plant cells plays an important role in cell structure.

Lysosomes

Enzyme-rich organelles that break down proteins, carbohydrates, lipids, and even worn-out organelles into smaller pieces that can be salvaged/recycled by the cell. Cells will reuse/recycle whenever it is possible.

Cytoskeleton

Provides the cell with structural framework, and aids in cellular motility (cellular movement).

Chloroplasts

(found in plants and some other organisms such as algae) covert solar energy into chemical energy stored in food (carbohydrates).

Mitochondria

Convert chemical energy (in food) into a form of energy that is more readily available for the cell to use.

Cell wall

Protects and supports the cell (but is only found in certain kinds of cells)

Cell membrane

Regulates what enters and exits the cell in all cells (selective permeability). Comprised of: phospholipids and membrane proteins.