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Cell Theory BZ 62 Levels of Organisation Structural organization in multicellular organisms is hierarchical, with new properties arising at each higher level of complexity. BZ 29 The Cell Theory The cell is the basic unit of life. 1. All living things are composed of cells and cell products. 2. New cells come from the division of pre-existing cells 3. Cells contain genetic information that is transmitted to inform, growth, function and development. 4. All life sustaining chemical reactions take place inside the cell. BZ 29 Ans Generalized cell diagrams BZ 30 Types of living things Living things include: 1. Prokaryotes - bacteria. 2. • Lack membrane bound organelles (no nucleus) • Circular chromosome • Size 0.5 – 10 um Eukaryotes – protists, fungi, plants and animals. • Membrane bound organelles – (nucleus, mitochondria etc) • Linear chromosomes • Size 30 – 150 um Non-living things 1. Viruses • Non-cellular, no cytoplasm, no chromosome • Size 20-20 nm BZ 30 Types of living things Archaea - These microbes are Prokaryotes, meaning that they have no cell nucleus or any other membranebound organelles in their cells, but are different to Bacteria Bacteria – are also Prokaryotes were among the first life forms to appear on Earth, and are present in most of its habitats. Eukaryotes - is any organism whose cells contain a nucleus and other organelles enclosed within membranes. BZ 30 Types of living things Living organisms are divided into five kingdoms: Protista, Fungi, Plantae, Animalia Prokaryotae, Characteristics of living things - Living things are made of cells, obtain and use energy, grow and develop, reproduce, respond to their environment, adapt to their environment. Prokaryotae (Monera) - Unicellular and Microscopic. Nonmembrane bound (no nuclear membrane, no ER, no mitochondria). Cell wall made of murein. Examples: Bacteria, Cyanobacteria. BZ 30 Types of living things Protista - Unicellular (mainly) Many live in aquatic environments. Includes organisms that aren't animals, plants or fungi that don’t form tissues. Examples: Algae, slime molds and the malaria causing Plasmodium. Fungi - Multicellular, Cell wall made of chitin. Don't possess photosynthetic pigments and are therefore heterotrophic. Examples: Mushroom, Mold, Puffball BZ 30 Types of living things Plantae - Eukaryotic, Multicellular, Cell wall made of cellulose. Contain photosynthetic pigment and gain their energy through it and are therefore autotrophic. Animalia - Eukaryotic, Multicellular, Heterotrophic. Can split into two groups, vertebrates and invertebrates. Viruses (not living) - Acellular structures composed of nucleic acid enclosed by a protein coat. Not classified as living. BZ 30 Ans BZ 31 Types of cells Cells come in a wide range of shapes and sizes – each cell is adapted for a specific role. Generalized cell diagrams BZ 31 Ans Cellulose cell wall, chloroplasts and permanent large vacuoles BZ 33 Cell sizes Cells vary in sizes from (2-100 um) with Prokaryotic cells being approximately 10x smaller than Eukaryotes. BZ 33 Ans BZ 35 Optical Microscopes Optical microscopes use light focused through a series of lens to magnify objects up to several hundred times. BZ 35 Ans BZ 35 Ans BZ 36 Microscopy Techniques Correct sample preparation and use of the appropriate stain help to view the material under the microscope. Biozone Activity – 35 Magnification is calculated by multiplying the magnification of the objective lens with the magnification of the ocular lens. The magnification of microscope lenses is engraved on the lens casing. Example, if you used a 20X eyepiece with a 20X objective lens = 400 Magnification What would be the magnification if you used a 10X eyepiece with a 40X objective lens? Calculating Magnification of Microscopes - BBC Bitesize View the next slide on comparison of animal and plant diagram BZ 37 Calculating linear magnification Magnification is how much larger an object appears compared to its actual size. It can be calculated from the ratio of image height to object height. BZ 37 Ans BZ 40 Animal cells Animal cells are eukaryotic. 1. Plasma membrane – flexible barrier 2. Cytoplasm – cellular fluid 3. Nucleus – genetic material 4. Mitochondria – energy production 5. Golgi apparatus – protein packaging and transport 6. Smooth ER – hormone synthesis 7. Rough ER – protein synthesis 8. Lysosomes - enzymes BZ 42 Plant cells Plant cells are eukaryotic but have extra features not found in animal cells. 1. Cell wall – made of cellulose 2. Chloroplasts – photosynthesis 3. Starch granules – stored in plastids (unique to plants) 4. Large Vacuoles – storage, waste disposal and growth