General comparisons between prokaryotic cells and eukaryotic cells: Prokaryotes (“pre-nucleus”) Cells typically 0.2-2.0µm diameter No nuclear membrane around genetic material DNA = one circular chromosome DNA not associated with histones Lack membrane-enclosed organelles Chemically complex cell walls e.g. peptidoglycan Simple flagella: two protein building blocks, no cilia Capsule or slime layer glycocalyx (if present) No carbohydrates or sterols in plasma membrane Cytoplasm lacks cytoskeleton and cytoplasmic streaming Small 70s ribosomes Cell division by binary fission Genetic recombination involves DNA fragment exchange Bacteria and Archaea Eukaryotes (“true nucleus”) Cells typically 5-100µm diameter Nucleus with double nuclear membrane houses genetic material separate from cytoplasm DNA = multiple linear chromosomes DNA wound around histone proteins Have membrane-enclosed organelles: Mitochondria, Endoplasmic Reticulum, Golgi Complex, Lysosomes, Chloroplasts, etc. Chemically simple cell walls (if present) e.g. chitin, cellulose Complex flagella or cilia composed of microtubules with membrane Glycocalyx in cells that lack a wall Plasma membrane contains sterols and carbohydrates Cytoskeleton and cytoplasmic streaming present in cytoplasm Large 80s ribosomes Cell division by mitosis Genetic recombination involves meiosis Algae, Protozoa, Fungi, Plants, Animals Amy Warenda Czura, Ph.D.1SCCC BIO244 Chapter 4 HandoutAmy Warenda Czura, Ph.D.2SCCC BIO244 Chapter 4 HandoutBasic Bacterial Shapes and ArrangementsCocciBacilliSpiralAmy Warenda Czura, Ph.D.3SCCC BIO244 Chapter 4 HandoutRepresentative Prokaryotic CellAmy Warenda Czura, Ph.D.4SCCC BIO244 Chapter 4 HandoutBacterial Cell WallsAmy Warenda Czura, Ph.D.5SCCC BIO244 Chapter 4 HandoutChromosome is replicated and isolated to one side of the cellby an in-growth of membrane called the spore septumProtein spore coat formsaround the outer membraneThe forespore dehydrates and matures intoan endospore containing only DNA,ribosomes, and enzymes.Parent cell lyses to release the endosporeAmy Warenda Czura, Ph.D.6SCCC BIO244 Chapter 4 HandoutStylized Eukaryotic CellAmy Warenda Czura, Ph.D.7SCCC BIO244 Chapter 4 HandoutMitosisProphase: chromatin condenses into chromosomes that pair with their duplicate: sisterchromatids attached by a centromerenuclear envelope breaks downcentrioles migrate to opposite polesspindle fibers form and attach to centromeresMetaphase: chromosomes align on the metaphase plateAnaphase: centromeres split and sister chromatids are pulled to opposite poles by the spindle apparatus (once separate they are called chromosomes)Telophase: nuclear membranes formchromosomes decondense into chromatinspindle disassemblesCytokinesis occurs: cytoplasm constricts at the metaphase plate forming a cleavagefurrow that pinches the cells apartAmy Warenda Czura, Ph.D.8SCCC BIO244 Chapter 4 HandoutMeiosisAmy Warenda Czura, Ph.D.9SCCC BIO244 Chapter 4 HandoutMitosis produces two daughter cells that areclones of the original parent cell.Meiosis produces four sex cells/spores that each only have halfthe number of chromosomes as the parent (parent is diploid,resulting cells are haploid). None of the four cell are identicalto the parent, and they are usually not identical to each other.Amy Warenda Czura, Ph.D.10SCCC BIO244 Chapter 4