Cell Biology Lecture Notes PDF

Cell Biology Introduction and Cell Theory 1st Year Pharmacy Students Department of Pharmaceutical Microbiology and Immunology Cell Biology What is life History (origin of life) Cell biology Characteristics of living organisms Classification Cell Biology What is life History (o...

Cell Biology Introduction and Cell Theory 1st Year Pharmacy Students Department of Pharmaceutical Microbiology and Immunology Cell Biology What is life History (origin of life) Cell biology Characteristics of living organisms Classification Cell Biology What is life History (origin of life) Cell biology Characteristics of living organisms Classification What is Life? Life is the quality that distinguishes a vital and functional being from a dead body or purely chemical matter functional activities: –Metabolism ‫األيض‬ –Growth ‫النمو‬ –Reproduction ‫التكاثر‬ Cell Biology What is life History (origin of life) Cell biology Characteristics of living organisms Classification What is the origin of life? This issue is very controversial ‫ مثري للجدل‬all over the world and through out the history So lets get a quick look on some debates 1. Special Creation Theory ‫اخللق اخلاص‬ The hypothesis that life forms were put on earth by supernatural or divine forces ‫ القوي ا إللهية‬. It forms the core of most major religions. It is oldest and most widely accepted hypothesis. It is considered an "unscientific" explanation (because it cannot be tested) What scientists think? 2. Spontaneous Generation ‫التكوين العشوايئ‬ Aristotle: The theory of spontaneous generation holds that living matter can and does arise from non-living matter Examples: 1. Just throw garbage in the street. In a few days, rats will appear. 2. Rotting meat will generate maggots ‫ديدان‬ 2. Spontaneous Generation ‫التكوين العشوايئ‬ John Needham (1745) supported this theory as when he boiled meat broth to kill all living organisms in it then left it in air for some time, it developed these animalcules. Disproof of Spontaneous Creation In 1668, Francesco Redi believed that maggots hatched ‫ فقست‬from eggs laid by flies. Was he able to prove it? Redi’s Experiment Disproof of Spontaneous Creation Spallanzini (1776): sealed the container containing meat broth after boiling, the meat did not develop microorganisms (seal might deprive broth from vital elements).  Disproof of Spontaneous Generation In 1859, Louis Pasteur disproved Spontaneous Generation and proved that some M.Os are airborne. Father of Microbiology Disproof of Spontaneous Generation Cell Biology What is life History (origin of life) Cell biology Characteristics of living organisms Classification What the cells looks like? Robert Hooke (1665) The origin of the idea that living organisms are made of cells is often traced back to observations of thin slices of cork made by Robert Hooke in 1665 Anthony van Leewenhoek Microorganisms are first seen in (1674) Anthony van Leewenhoek (Netherlands) He made his own microscopes and was first to observe bacteria, yeasts, and protozoa. Ernest Abbe (1880s) Developed microscope lenses in early 1880s that were corrected for chromatic and spherical aberrations, and developed the oil immersion lens. 3. The Cell Theory All living organisms are made of one or more cells. Cells are basic units of the structure and function of all organisms. All cells arise from existing cells …… the only exception was the first created cell. The Cell The cell is the building block of life. The cell is the structural and functional unit of all known living organisms. The cell is the simplest unit of an organism that is classified as living. 4. Theory of Chemical Evolution Early earth atmosphere has a very high temperature + reducing atmosphere (CO2 + N2 + Hydrogen + water). - In 1953, Stanley and Harold made experiment: CH4 + H2 + NH3 with moist → electric charges for days → amino acids, hydroxy acids and organic compounds. Characteristics of living organisms All living organisms on earth exhibit these fundamental properties: Cellular organization Sensitivity Energy use Growth and Development Reproduction Regulation Homeostasis Heredity Cellular organization All organisms consist of one or more cells Complex, organized group of molecules enclosed within membranes Sensitivity All organisms respond to stimuli Not all organisms respond to stimuli in the same way Energy Use All living things assimilate energy and use it to grow via a process called metabolism All life on earth is based upon the transfer of the energy in covalent bonds This energy is used to carry out everything they do. Plants use energy from the sun for photosynthesis, to make their own ‘food’ (glucose). Animals and humans must ingest food for this purpose. Growth and Development All organisms grow and change. Organisms growing, changing, and becoming more complex is called development. Differentiation happens, as well, when cells mutate into other types of cells, making a more complex organism. Single-celled organisms do grow as well, but they will only become slightly larger – this is nearly immeasurable Reproduction All organisms reproduce in order to continue the species' life. This is combining genetic information (in sexual reproduction) or splitting into two organisms (in asexual reproduction) in order to create another of the same species. In sexual reproduction, the new organism will have some characteristics from the mother, and some from father. It may look like either of them, or it may not. In asexual reproduction, the new organism is an exact copy of the first. Homeostasis All organisms have stable internal conditions which must be maintained in order to remain alive. These include temperature, water content, heartbeat, and other things. In a way, this has to do with energy use, because a certain level of energy must be kept within the body at all times. For this, obviously, humans must then ingest food on a regular basis. Heredity All organisms on earth possess a genetic system that is based on the replication of a long, complex molecule called DNA This mechanism allows for adaptation and evolution over time and for the distinguishing characteristics of living things Regulation All organisms have regulatory mechanisms that coordinate internal processes Cell Biology What is life History (origin of life) Cell biology Characteristics of living organisms Classification Two Kingdom Classification Prokaryote: in that class the cell lacks a true nucleus structure (primitive nucleus). Eukaryote: in that class the cell possess a membrane-enclosed nucleus (true nucleus) and usually other organelles.  What meant by “Pro” “Karyon” “Eu” ? Eu, "well" or "true" karyon, "nut" or "kernel” Pro, "before" Eukarotes vs Prokaryotes Eukaryotic Prokaryotic Nucleus True No nucleus Nuclear Present No membrane DNA Linear Circular Histones Present Absent Chromosomes DNA packed in Single chromosomes chromosome Ribosomes 80 S 70 S Organelles Present Absent Animal vs. Plant cells Animal vs. Plant cells They are both Eukaryotic cells They have similar organelles such as: Nucleus, Mitochondria, Endoplasmic reticulum, Golgi apparatus, and Lysosomes. They contain similar membranes and cytosol Animal vs. Plant cells Plant cells can be larger than animal cells Plant cells get their energy from Chloroplasts while animal cells get their energy from Mitochondrion. Plant cells have a very rigid cell wall which helps provide stability to the plant. Animal cells have no cell wall. Plant cells contain Vacuoles that act as a space filler for the cell.