Cell Theory & Prokaryotic/Eukaryotic Cells PDF

Cell Theory The cell was first discovered by Robert Hooke in 1665, which can be found to be described in his book Micrographia. : Theodor Schwann and Matthias Jakob Schleiden – CELL THEORY All living organisms are composed of one or more cells The cell is the most basic unit of life...

Cell Theory The cell was first discovered by Robert Hooke in 1665, which can be found to be described in his book Micrographia. : Theodor Schwann and Matthias Jakob Schleiden – CELL THEORY All living organisms are composed of one or more cells The cell is the most basic unit of life All cells arise only from pre-existing cells Modern interpretation - cell theory All known living things are made up of one or more cells. All living cells arise from pre-existing cells by division. The cell is the fundamental unit of structure and function in all living organisms. The activity of an organism depends on the total activity of independent cells. Energy flow (metabolism and biochemistry) occurs within cells. Cells contain DNA which is found specifically in the chromosome and RNA found in the cell nucleus and cytoplasm. All cells are basically the same in chemical composition in organisms of similar species.  Modern version Energy flow occurs within cells. Heredity information (DNA) is passed on from cell to cell. All cells have the same basic chemical composition.  TYPES OF CELLS Prokaryotic cell: Pro- primitive/incipient/ unorganized/indefinite/false/psuedo; karyon- nucleus. Eg. Bacteria, Blue green algae, mycoplasma, ricketts, actinomycetes. Eukaryotic Cell: Eu – advanced/organized/ definite/true. Eg. Protozoan, animal and plant cell, fungal cells  PROKARYOTE Vs. EUKARYOTE Groups – bacteria Algae, fungi, protozoa, plants, animals Size – 1-2 by 1-4 micron or less > 5 micron in width or diameter Genetic system – nucleoid; Well organized Nucleus chromatin body, 1 Plasmids (ECDna)- present These are present Nucleolus and nuclear Plasmids like DNA with membrane are absent chloroplast, mitochondria ,etc Functionally related genes clustered Not clustered One circular chromosome No histones More than 1 chromosome Zygote – merozygotic (partial Histones present diploid) Zygote - diploid  PROKARYOTE Vs. EUKARYOTE (contd...) Gas vacuoles and mesozomes – These are absent present Cytoplasmic streaming and pinocytosis absent Cytoplasmic streaming and pinocytosis present Ribosomes – 70S – distributed in cytoplasm with 50s and 30s sub 80S – arranged well – 60s and units 40s sub units - polysomes Cell wall – peptidoglycan (DAP, NAG, NAM) Absence of peptidoglycan Locomotor organelles – simple 9 + 2 arrangement fibril Plasma membrane contains Do not carry out respiration / respiratory / photosynthetic photosynthesis but performed machinery -enzymes respective organelle. G+ C % - 28 to 73 About 40.  PROKARYOTE Vs. EUKARYOTE (contd...) Mitochondria – absent Present Chloroplast – absent Present Golgi bodies – absent Present Endoplasmic reticulum – absent Present