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7.1 The discovery of cells?
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Do Now: Copy the following in chronological order _1838-Matthias Schleiden- observed plant cells _1650s Anton van Leewenhoek started observing water with primitive Microscopes _1858- Rudolf Virchow studied cell reproduction _1660 Robert Hooke observed cork cells _1839 Theodor Schwann- observed animal cells
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Dust Mite Under the Microscope
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Types of Microscopes Light Microscope (LM)- an optical instrument w/ lenses that refracts light to magnify images. Dissecting Microscope- low magnification but has a work space Micrograph- a photograph taken through a microscope. Magnification- an increase in the apparent size of an object. (Zoom) Resolving Power- a measure of the clarity of an image; the ability to show two objects as separate. (High Def. TV)
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Electron Microscopes Electron Microscope (EM)- an instrument that focuses an electron beam through or onto the surface of a specimen. *1000X greater resolving power than a LM. *One problem they cannot be used to study living specimens, because they would have to be placed in a vacuum chamber. SEM or Scanning electron microscope: Surface of cells TEM or transmission electron microscope: structures within STM or Scanning Tunnel Microscope: atoms on a molecule
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Cell Theory All organisms are made of cells The cell is the smallest unit of life All cells come from pre-existing cells
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Eukaryotic vs. Prokaryotic
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Prokaryotic cells Bacterial cells Much smaller and simpler than eukaryotic cells Organelles include only – a plasma membrane – cell wall – capsule: extra protective layer outside the cell wall – ribosomes – single loop of DNA free in the cytoplasm in nucleiod region – sometimes has pili: small hairs on the outside of the cell used for movement – sometimes has flagella
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Eukaryotic cells – Plants, animals, fungi, protistans (single Celled) – Membrane-bound nucleus & organelles
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7.2 Plasma Membrane
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Objectives: -Understand the structure of the cell membrane -Understand how the properties of the cell membrane make it ideal for it’s function -Does the membrane have any flaws?
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Do Now: List three substances that enter the cells in your body List three substances that leave the cells of your body
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The Plasma Membrane controls what enters and leaves the cell maintains homeostasis (balance in the cell) – Allows water, oxygen, and glucose to enter when there’s not enough – Allows water, carbon dioxide, and waste to leave when there’s too much selective permeability: the membrane allows some molecules, but not all, to pass through Made up of a molecule called a phospholipid – lipid with a phosphate group
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Plasma membrane is a phospholipid bilayer – 2 layers of phospholipids back-to-back – Polar heads face the water inside and outside the cell – Nonpolar tails hide from water inside the membrane In between the phospholipids in the plasma membrane, there are – proteins transport proteins: move needed materials or waste across the cell membrane – cholesterol – carbohydrates
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Fluid mosaic model of the plasma membrane – the membrane is fluid because the phospholipids are constantly moving over the cell – the proteins in the membrane are carried around by the phospholipids, forming different mosaics (patterns) – Types of proteins
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Let’s Go to the Video Tape: http://player.discoveryeducation.com/index.cf m?guidAssetId=EE86FD99-F075-49FD-BBDC- 61DE73CA949F&blnFromSearch=1 http://player.discoveryeducation.com/index.cf m?guidAssetId=EE86FD99-F075-49FD-BBDC- 61DE73CA949F&blnFromSearch=1 http://www.youtube.com/watch?v=Qqsf_UJcf Bc&feature=related http://www.youtube.com/watch?v=Qqsf_UJcf Bc&feature=related http://www.youtube.com/watch?v=C7XliJVJho k
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Organelle Cards
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Cell Wall Plants Only Outside plasma membrane Support and protects
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Nucleus Control Center Contains chromatin (DNA) Controls protein production Contains nucleolus
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Nucleolus Produces ribosomes
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Ribosomes Produces proteins Found on RER and in cytoplasm
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Cytoplasm Clear jelly inside cell
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Rough Endoplasmic Reticulum Chemical Reactions Modifies Proteins
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Smooth ER Chemical reactions Production of lipids
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Golgi Postal Service Sorts and transports proteins
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Vacuoles Storage for enzymes, food and other materials Large in plants Small in animals
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Lysosome Digestive enzymes breakdown food, bacteria, and old organelles Recycling Center Animals only
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Chloroplast Contains chlorophyll Photosynthesis : Sunlight is used to make sugar Plants only
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Mitochondria Converts sugar into usable form of energy ATP
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Cytoskeleton Support structure Microtubules: small hollow tubes Microfilaments: thin solid fibers
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Centrioles Help cell division Animals only
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Cilia Short hairs used for movement Animals only
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Flagella Long tail used for movement Animals only
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