Looking Inside Cells Plant / Animal / Bacterial

Cell Size  Most cells range in size between 1 to 100 micrometers  In 1 meter there are 100,000 micrometers (µm), in 1 mm there are 100 micrometers (µm)  Most cells are visible only with the aid of a microscope

Types of Cells

Cell Wall  Surrounds plant, bacterial, fungi and some protist cells  Function = Used for support / shape and protection  Made of cellulose in plants/ proteins / polysaccharides (big sugar)  Allows water and oxygen to pass through

Cell Membrane  Surrounds all cells  Has protein pores  Function = Controls what substances go in and out of the cell  Made of lipids (fats)

Nucleus  Not found in bacterial cells (prokaryotes)  Found in plant and animal cells (eukaryotes)  Located near the center of the cell  Function = Control center, directs cell’s activities, holds genetic material (DNA)  Has 3 main parts

3 Main Parts of the Nucleus  Nuclear Membrane (has pores/controls what moves in and out/protects)  Chromatin (genetic material or DNA and proteins, contains instructions to life)  Nucleolus (makes ribosomes)

Cytoplasm  Thick, jellylike fluid  Function = Cushions and protects the internal organelles, filling the empty space, and keeping everything in place.  Cytoplasmic Streaming (always moving to move things in the cell)  Contains Cytoskeleton (support)

Mitochondria  Many found throughout the cell  Jelly bean shaped  Function = “Powerhouse”- produce most of the cell’s energy  Where RESPIRATION takes place  Have own double membrane and DNA/RNA

Endoplasmic Reticulum  Found coming out of the nucleus  Looks like a maze of passageways  Function = Carries proteins and other materials around cell  Rough ER- Ribosomes attached  Smooth ER- No Ribosomes attached

Ribosomes  Found attached to ER or floating in cytoplasm  Very small organelles that contain tRNA  Function = Help produce proteins by reading mRNA

Golgi Bodies or Apparatus  Found out in the cytoplasm  Look like flattened sacs and tubes  Function = Receive and package proteins etc. to be shipped around and out of the cell  “Blebs” are the bubble like packages they create

Vacuoles  Found in the cytoplasm  Look like a fluid filled bubble  Function = Used as a storage area for extra food / water / wastes / etc.  Plant cells have a central vacuole that is important in maintaining plant turgidity  Some animal cells have no vacuoles

Lysosomes  Found floating in the cytoplasm  Look small and round  Contain harsh chemicals and enzymes (type of protein)  Function = Used to breakdown food and old cell parts

Chloroplasts  Not found in animal cells or most bacterial cells  Found in all plant cells and some protists  Large, green jellybean structures  Function = Contain Chlorophyll (green pigment) that captures energy from the sun  Where part of photosynthesis takes place

Comparing Cells Bacterial Cell Plant CellAnimal Cell Cell WallYes No VacuoleNoYes (central vacuole) Sometimes No central ChloroplastsNoYesNo Eukaryote (nucleus) NoYes Prokaryote (no nucleus) YesNo

Connecting it All Cells TissuesOrgans Organ SystemsOrganisms Cells – basic unit of structure and function Tissues - groups of cells that perform a common function Organs - group of tissues that perform a specific function Organ System – collection of organs that work together Organism – a living thing

Specialized Cells