LEC 1: The Cell

cell theory

• all organisms are made of cells

• the cell is the basic unit of life in all living organisms 

• all cells come from existing cells 

prokaryotic cells

• have no nuclear membrane 

• organelles are not covered by membranes 

• have circular DNA 

• examples are bacteria 

eukaryotic cells

• have a nuclear membrane

• have membranes covered organelles

• have linear DNA

• most other cells

organelles

are structures that enable the cell to live, grow, and reproduce

cell membrane

• outer layer of the cell

• allows nutrients into the cell and wastes out of the cell

• “gate into the city”

cytoplasm

• is a jelly like fluid contained the cell that holds the organelles

nucleus

• the control center of the cell

• contains the cell’s DNA

mitochondria 

• power center of cell 

• provides the energy the cell needs to move, divide, etc. 

• “electric company of the cell”

ribosomes

• site where protein synthesis takes place

• cell parts are made of proteins

endoplasmic reticulum

• transport system of the cell

rough ER

ribosomes attached

smooth ER

no ribosomes

golgi complex 

• packaging house of cell 

• packages, processes, and ships out of the substances the cell makes 

lysosomes

• digests food particles and cell parts

• “garbage men”

• protects cell by digesting foreign invaders

• “police men”

vacuole

• stores water, food and wastes

• is a largest organelle in plant cell

cell wall

• found only in plant cells

• protects and support the cell

chloroplasts

• found only in plant cells

• contains chloropyll which gives the green coloring of plants

• where photosynthesis takes place