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Slide 2 History of the Cell Robert Hooke (1665) Used compound scope to examine thin cork slices. Coined the term cell referring to the many little boxes. Actually saw dead plant cells Anton van Leeuwenhoek (1673) with his simple scope, observed first living cells Matthias Schleiden (1838) and Theodor Schwann stated that all plants and animals (respectively) are made up of cells. Rudolph Virchow (1855) cells come only from other cells Slide 3 The Cell Theory All living things are made up of cells Cells are the basic unit of structure and function in all living things Cells come from pre-existing cells Slide 4 Cells vary by: 1. Size Range from 2m (giraffe nerve cell from leg to spine) to.2um (bacteria - Mycoplasm)Size Limited by the ratio between outer surface area and their volume. As the surface area to volume ratio decreases, it makes it difficult for information to get around cell and also nutrients to get and then be circulated around the cell Slide 5 Slide 6 Side Length Surface Area L x W x 6 Volume L x W x H Surface area to Volume ratio 1mm6mm 2 1mm 3 6 to 1 2mm24mm 2 8mm 3 3 to 1 3mm54mm 2 27mm 3 2 to 1 Slide 7 2.Shape 2.Shape Form reflects function. Red Blood Cells are like tubes at Sesame Place so they flow easier Nerve cells are like electrical wires Cheek cells (Epithelial cells) are flat to act like a shield White Blood cells are amoeboid shaped to move and squeeze into all areas Slide 8 Internal Organization 3. Internal Organization Organelles Organelles internal structures in a cell. Each has a specific function All cells contain: a. Cell membrane thin membrane. Porous to certain compounds b. Cytoplasm cells liquid Organelles are suspended in it c. Ribosomes Protein factories in cells d. DNA Slide 9 Types of cells 1.Prokaryotic cells cells that lack a nucleus and membrane bound organelles - Bacteria & Archaebacteria - Have a cell wall, cell membrane, cytoplasm, DNA & ribosomes - Pigments and enzymes are suspended in cytoplasm suspended in cytoplasm Slide 10 Eukaryotic Cells 2. Eukaryotic Cells contain a membrane bound nucleus and membrane bound organelles. - Much more complex cell - All cells other than bacteria. - Protists, Fungus, Animals and Plants Nucleus Slide 11 Comparing the Two Cell Membrane Cytoplasm DNA Slide 12 Parts of the Eukaryotic cell Three main components: Nucleus Cell membrane Cell organelles Cell membrane Slide 13 Central Problem #1: A living system MUST be separated from its environment if it is to maintain complex order in a chaotic physical world. Cell Membrane Separates the cells internal environment from the external environment. - Allows for the passage of some substances based on size and concentration Selectively Permeable Some things can pass through while others cant Slide 14 Made up of a bilipid layer (lipid bilayer) 2 layers of phospholipids with proteins floating through it. Tails of phospholipids are hydrophobic while the heads are hydrophilic Slide 15 Peripheral membrane proteins do not penetrate the hydrophobic core of the membrane. They can be easily removed without destroying the membrane structure. Integral proteins : these are fully incorporated into the membrane and are in contact with both the inside and the outside of the cell. Some can act as channel ways for the transport of substances. Others have carbohydrate attached to them recognition sites Peripheral protein Integral proteins Slide 16 In the "fluid mosaic model" of membrane structure, the membrane is a fluid phospholipid bilayer in which protein molecules are either partially or wholly embedded. These layers easily move around. Rap Slide 17 Cell Organelles ytoplasm Cytoplasm area between nuclear envelope and plasma membrane cytosol cells liquid Made of gelatinous cytosol where nutrients and minerals carried in solution within it. Typical Animal Cell Typical Plant Cell Slide 18 Mitochondria - Powerhouse of the cells. - Where cellular respiration occurs and glucose is broken down to release energy (in the form of ATP) to the cell. FFound in greater numbers in cells such as muscle cells & liver cells (2500/cell) DDouble membraned with Cristae (folds) to > surface area for reactions to take place HHave their own DNA (mDNA) and ribosomes. Replicate by binary fission as needed Cristae Double Membrane Slide 19 Ribosomes MMost numerous organelle in the cell. Site of protein synthesis. NNot membrane bound therefore, theyare in prokaryotic cells. MMade up of RNA and protein. MMay be free floating in cytoplasm or attached on Endoplasmic Reticulum Slide 20 Endoplasmic Reticulum Channels or passageways in the cell. There are two types of ER: 1 Rough with ribosomes attached for the production and distribution of proteins. 2 Smooth Synthesis of steroids (lipids) in gland cells, Ca+ regulation in muscle cells and breakdown of toxins Slide 21 1 Nuclear Envelope 2 Nucleopore 3 Rough endoplasmic reticulum (RER) 4 Smooth endoplasmic reticulum SER) 5 Ribosome on the RER 6 Proteins that are transported in 7 Transport vesicle 8 - 10 Golgi apparatus Slide 22 Golgi Apparatus (Bodies) oStack of smooth flat sacs. oProcessing, packaging and secreting organelle of the cell. oMuch like a processing & exporting plant. Work in close association with ER Slide 23 Lysosomes Single membrane - are the cells' garbage disposal system. They breakdown worn out organelles such as mitochondria & produce hydrolytic enzymes to that degrade DNA, proteins, lipids &carbohydrates Responsible for the un-webbing of hands of fetus while developing in utero These are rare in plant cells Slide 24 Cytoskeleton Network of protein strands that provide support and mobility of organelles in cytoplasm. 2 components of cytoskeleton - Microfilaments made of actin (protein threads). Involved with cellular movement and muscle contractions Microtubules larger structures. Involved in cell division, make up flagella and cilia. Also make up spindle fibers that assist in chromosome migration during cell division. 9 2 arrangement Slide 25 Cilia and Flagella Extensions from cell membrane. Assist in movement. Have 9-2 arrangement like microtubules Cilia - when short and multiple numbers. Covering of Paramecium, lining of respiratory tract and nasal passages. Flagella- long and usually only 1 to a few. Sperm cells, Euglena. Used for propulsion Slide 26 Nucleus Only in Eukaryotic cells. Stores hereditary information in DNA. Surrounded by a double nuclear envelope. Nuclear pores perforate membrane. Chromatin - strands of a combination of DNA & protein within nucleus. These will later become chromosomes. NucleolusNucleolus (1 or >) produces ribosomes Slide 27 Plant Cells Are eukaryotic and have most of the same organelles as animal cells except: Cell Walls 1.Cell Walls Made up of cellulose & pectin (glue between walls) Gives cells rigidity, protection & support. Is also porous. Slide 28 Cell Wall Primary cell wall Forms just on the outer surface. Expands by adding on more cellulose. Grows as cell grows Secondary cell wall Develops between primary and cell membrane. Tough and woody. No more growth Slide 29 Vacuoles 2. Vacuoles - Store enzymes, food, water and wastes. (Central Vacuole) - Huge water vacuole (Central Vacuole) in plant cells. turgor - Gives plant cell turgor (full of water and fully supported) 90% of cells may be water. - Some contain metabolic wastes which may be toxic to other organisms (poison ivy). Slide 30 3.Plastids Double membrane, DNA containing to store starch, fats or Pigments such as chlorophyll. Thylakoids Chloroplast where photosynthesis occurs. Made up of stacks called Thylakoids. Here is where the energy conversion occurs. Leucoplast/Amyloplasts store starch Slide 31 Slide 32 Slide 33 1. _______________ 2. _______________ 3. _______________ (Dots) 4. _______________ 5. _______________ 6. _______________ 7. _______________ 8. _______________ 9. _______________ 10._______________ 11._______________ 12._______________ 13._______________ Typical Animal Cell Slide 34 Typical Plant Cell Slide 35 Epithelial (Cheek) Cells Cell Membrane Cytoplasm Nucleus Slide 36 Elodea Cyclosis Slide 37 Onion Cells Slide 38 Potato Cells Slide 39 Red Blood Cells 2 White Blood Cells Red Blood Cells (& 2 White Blood Cells) Slide 40 OrganelleFunction Plant Cells Animal Cells Mitochondria Site of cellular respiration - transfer of energy - Folds called Cristae Yes RibosomesSite of Protein synthesisYes Endoplasmic Reticulum Rough - Protein packaging & transport site Smooth - Sythesis of lipids Yes Golgi ApparatusProcessing & packaging center for cell secretionsFewMany LysosomesProduce hydrolytic enzymesFewMany Cytoskeleton Network of protein filaments - keep cell's shape and for movement Yes Microfilaments & microtubules Support, movement and cell divisionYes Cilia & Flagella Cell movement & circulation Cilia - many & short, Flagella - 1or 2 & long Yes NucleolusProduction of ribosomesYes NucleusContains DNA, synthesizes RNA & RibosomesYes ChromatinDNA & protein - genetic informationYes Cell Wall Outmost layer of plant cell - support & protection Made of cellulose & pectin glue between walls YesNo Vacuole Stores enzymes, wastes, water & food Large water in plants - support Yes, large water vacuole Many Plastid Stores food and pigments - Chloroplasts (photosynthesis) & leucoplasts (stores starch) YesNo CentriolesMicrotubules that function during cell divisionNoYes Cell MembraneSelectively permeable - made of a bilipid layer & proteinsYes