Transcript Cell Theory
Cells Robert Hooke -1655 • In his book entitled Micrographia was the first to use the term cell • From the Latin “cella” meaning “small chamber” Anton van Leeuwenhoek • A Dutch cloth merchant who became interested in studying cells. • Was the first to see and describe bacteria, sperm cells and protista • Theodor Schwann (1838) – all animals are composed of cells. • Matthias Schleiden (1838) – all plants are composed of cells. • Rudolf Virchow (1856) “Omnis cellula e cellula” • “where a cell arises, there a cell must previously have existed” Modern Cell Theory • All organisms are composed of cells. • Cell come from other cells. • Cells are the smallest unit of structure and function in living organisms. Prokaryotic Cells • Lack a true nucleus • Size: 1-10 microns • Include bacteria Basic Bacterial Cell Eukaryotic Cells • Have a true nucleus • Size: 10-100+ microns • Include plants, animals, fungi and protista Basic Cell Design • • • • Cell Membrane – surrounds the cell Cytosol – “cell liquid” Organelles – “little organs” Nucleus Cell Membrane • Regulates the passage into and out of the cell • Provides protection • Helps in cellular recognition of molecules Cytosol/Cytoplasm • Cytosol: the liquid portion inside the cell membrane • Cytoplasm: the cytosol and organelles, but not the nucleus Nucleus Nucleus • Contains DNA or chromosomes. Also called chromatin. • The cell’s “brain” or CPU. • DNA codes for protein production. Cytoplasm • Contains the cytosol and organelles Organelles • • • • • • Ribosomes Endoplasmic reticulum Golgi bodies or complex Lysosomes Mitochondria Chloroplasts Ribosomes Ribosomes • Are the cell’s protein factories • Read mRNA code as seen on the right • Maybe free in the cytoplasm • Or bound to the ER Endoplasmic Reticulum • A membrane network within the cytoplasm • Two types: Rough – with ribosomes attached (RER) • Or Smooth – with no ribosomes (SER) Rough ER • Helps the ribosomes in the formation of proteins. • Used to transport proteins to other parts of the cell Smooth ER • Stores Calcium in muscles • Forms fats • Detox center in liver cells Golgi Body Golgi Body • Processes unfinished proteins • Packages finished proteins • Distributes finished proteins Lysosomes Lysosomes • Digestive sacs • While digest microbes in white blood cells called macrophages • Helps to form fingers and toes • Aids in the loss of the tadpole’s tail • Helps to recycle cellular structures • Sometimes called “suicide sacs” • Involved in rheumatoid arthritis Mitochondria • The cell’s powerhouse • Involved in cellular respiration • Helps to convert “food” into cellular energy ATP Chloroplasts • Site of photosynthesis • Helps to convert light energy, water, and carbon dioxide into sugars. Vacuole • Storage area • Helps to give support in plant cells