The Cell: The Smallest Unit of Life

Prokaryotic and Eukaryotic Cells  Prokaryotic 1.No nuclear membrane 2.No membrane bound organelles 3.Found only in kingdoms Eubacteria & Archaebacteria 4.Size 0.1 um -10 um  Eukaryotic 1.Definite membrane bound nucleus 2.Contains membrane bound organelles 3.Found in Kingdoms: Animal, Plant, Fungi, & Protista 4.10 um – 100 um

Cellular Organelles

Cell Membrane (Plasma Membrane)  Double layer of lipids & proteins  Gatekeeper of cell  Semi permeable (lets certain things in and keeps other things out)

NUCLEUS  Surrounded by a double-layered membrane.  Control center of the cell  The DNA with proteins form chromosomes  The nucleolus is also found in the nucleus. It produces ribosomes

Ribosomes  Function in protein synthesis. They do not contain a membrane.  Found: Bound to ER Floating free in the cytoplasm

Endoplasmic Reticulum (ER)  Consists of a network of membranous tubules and sacs  The ER is continuous with the nuclear membrane  There are 2 types:

Smooth ER  Produces lipids & detoxifies drugs & poisons. It also helps in muscle contraction

Rough ER  Antibody production  Involved with membrane production

Golgi Apparatus  Series of flattened membranous sacs, stacked like pita bread  Synthesis, storing, and shipping material

Lysosomes  Bag of hydrolytic enzymes  Intracellular digestion, autophagy, and programmed destruction

Vacuoles  Sacs that function in digestion, pumping excess material, storage, cell stabilizer, and are found in many protists and plants

Mitochondria  Converts energy to forms the cell can use  It is a double membrane structure  The outer membrane is smooth while the inner membrane (cristae) is folded  POWERHOUSE of the cell

Chloroplast  Convert light into energy: Site of Photosynthesis  Found only in plant cells  Green in color: contains CHLOROPHYLL  ONLY IN PLANT CELLS

Cytoskeleton  Contains microtubules and microfilaments  Microtubules: straight hollow rods that support and help organelles around the cell. They form centrioles  Microfilaments: function in muscle contraction, cytoplasmic streaming, amoeboid movement, and changes in cell shape

Cell Wall  Is made of a material called cellulose  Only found in plants

Cytoplasm  Liquid portion of the cell  All organelles are contained within the cytoplasm.

Centrioles  Made up of microtubules  Help direct mitosis.

PLANT CELLS vs ANIMAL CELLS  Have a cell wall  Contain chloroplasts  Can do photosynthesis  Large central vacuole  mitochondria No cell wall No Chloroplasts No photosynthesis Mitochondria centrioles