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CELL THEORY AND STRUCTURE 1

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1. All living things are made of cells 2. Cells are the basic unit of structure and function in an organism (basic unit of life) 3. Cells come from the reproduction of existing cells (cell division) 2

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In 1665,Hooke is responsible for naming cells In 1673, Leeuwenhoek was first to view living organisms in pond water In 1838, Schleiden concluded that all plants were made of cells In 1839, Schwann concluded that all animals were made of cells In 1855, Virchow observed, under the microscope, cells dividing and reasoned that all cells come from other pre- existing cells by cell division 3

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In 1970,Lynn Margulis, provided evidence that some organelles within cells were at one time free living cells themselves this is called Endosymbiotic Theory Chloroplasts and mitochondria were the organelles she pointed to as evidence of this theory Chloroplast and Mitochondria have their own DNA which is different from the DNA of the cell 4

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5 Unicellular composed of one cell Ex: bacteria, yeast Multicellular - composed of many cells that may organize Ex: butterfly, flower

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6 Have a nucleoid region contains the DNA (no nucleus) Have a cell membrane & cell wall Contain ribosomes to make proteins in their cytoplasm

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Contain 3 basic cell structures: Nucleus (containing DNA) Cell Membrane Cytoplasm with organelles Organelles have specific functions 7

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8 Plant Cell Animal Cell

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Contain digestive enzymes Use Active Transport to trap and break down food an worn out cell parts 9

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Inside nucleus Produces the ribosomes that make proteins 10

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11 Smooth ER - lacks ribosomes & detoxifies poisons and synthesizes lipids Rough ER - has ribosomes on its surface & makes proteins to EXPORT

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12 Site of Cellular respiration the capturing of energy from food Breaks down glucose to produce energy ATP

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13 Process called photosynthesis occurs here Chloroplast

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Made of cellulose Found in plant cells 14 Cell wall

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15 Have a large central vacuole Vacuole

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16 glycogen granule Glycogen is stored in the cytoplasm of animal cells for food energy

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Near the nucleus in an animal cell Help cell divide 17

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18 Animal cellsPlant cells Relatively small in size Irregular shape No cell wall Relatively large in size Regular shape Cell wall present

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19 Animal cellsPlant cells Vacuole small or absent Glycogen as food storage Nucleus at the center Large central vacuole Starch as food storage Nucleus near cell wall

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Composed of double layer of phospholipids and proteins Controls what enters or leaves the cell Surrounds outside of ALL cells Outside of cell Inside of cell (cytoplasm) Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains 21

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The cell membranes of all cells are selectively permeable This means that some materials can pass easily through the membrane Examples: H 2 0, CO 2 and O 2 This also means that some materials cannot pass easily through the membrane Examples: glucose and salts 22

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Proteins help move large molecules or aid in cell recognition Peripheral proteins are attached on the surface (inner or outer) Integral proteins are embedded completely through the membrane 23

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Provide a binding site for enzymes Interlocking surfaces bind cells together (junctions) Contains the cytoplasm (fluid in cell) 24

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Phospholipid bilayer makes up the cell membrane Contains a polar head (attracts H 2 O) and 2 non-polar fatty acid tails (repels H 2 O) How is a phospholipid different from a triglyceride? 25

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26 Fluid: individual phospholipids and proteins can move side-to-side within the layer, like a liquid. Mosaic: the pattern produced by the scattered proteins on the surface of the cell when the membrane is viewed from above.

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Materials that are soluble in lipids can pass through the cell membrane easily Ex: Oxygen, carbon dioxide, and water 27

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Passive Transport Does not require cellular energy Types: 1. Simple Diffusion 2. Osmosis 3. Facilitated Diffusion Active Transport Does require cellular energy Types: 1. Membrane Pumps 2. Endocytosis 3. Exocytosis 28

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Movement of materials from a region of high concentration to a region of low concentration Materials are moving down/with their concentration gradient Example: Oxygen diffusing into a cell and carbon dioxide diffusing out using kinetic energy 30

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Osmosis is the passive transport (diffusion) of water across a membrane Moves from a region of HIGH water potential (low solute) to a region of LOW water potential (high solute) 32

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The purpose of osmosis is to balance out the concentration of materials between the environment inside of the cell and the environment outside the cell Water moves because the other materials cannot This allows the cell to be in equilibrium - balance 33

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Solution - a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent). Examples salt water or glucose solutions; solutes are salt or glucose, solvent is water Types of solutions: 1. Isotonic 2. Hypotonic 3. Hypertonic 34

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10% NaCL 90% H 2 O ENVIRONMENT CELL 10% NaCL 90% H 2 O Q: What is the direction of water movement in an isotonic solution? 35 A: No net movement (water molecules moving equally back and forth)

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ENVIRONMENT 10% NaCL 90% H 2 O 20% NaCL 80% H 2 O CELL Q: What is the direction of water movement in a hypotonic solution? 36 A: Water moves into the cell

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ENVIRONMENT CELL 15% NaCL 85% H 2 O 5% NaCL 95% H 2 O Q: What is the direction of water movement in a hypertonic solution? 37 A: Water moves out of the cell.

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Hypotonic solution will result in cytolysis cell bursts from build up of water inside cell Hypertonic solution will result in plasmolysis cell membrane pulls away from the cell wall in plant, fungal or bacterial cells Plant cells prefer a hypotonic environment Animal cells prefer an isotonic environment 38

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Uses transport proteins to move materials from high to low concentration Examples: Glucose or amino acids moving from blood stream into a cell. 40

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Types of Membrane Proteins: 1. Structural 2. Cell recognition 3. Communication 4. Transport: a. Channel proteins are embedded in the cell membrane & have a pore for materials to cross b. Carrier proteins can change shape to move material from one side of the membrane to the other 42

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43 Channel proteins act as bridges to allow materials to pass across the membrane

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Some Carrier proteins do not extend through the membrane. They bond and drag molecules through the lipid bilayer 44

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Cells need a steady supply of sodium (Na + ), potassium (K + ), calcium (Ca 2+ ) and hydrogen (H + ) in order to function correctly Protein pumps that span the cell membrane are powered by ATP and supply these materials to the cell on demand This requires a steady supply of ATP Materials are moving from and area of low concentration to an area of high concentration They are moving up/against their concentration gradient 45

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3 Na+ pumped out for every 2 K+ pumped in 46

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Q: What is a vesicle? A: A small bubble within a cell surrounded in its own lipid bilayer. Q: What is the function of a vesicle? A: Vesicles are involved in: Metabolism Transport of materials Enzyme storage Types of active transport using vesicles: Exocytosis Endocytosis 47

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48 Exocytosis -using a vesicle to move big stuff out of the cell

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How it works: 1. Vesicle is formed around some sort of material made by the cell (like proteins or hormones) 2. Vesicle is released and travels toward cell membrane 3. Vesicle fuses with cell membrane 4. Vesicle expels materials to the outside of the cell membrane 49

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Large amount of materials move into the cell by one of two forms of endocytosis: Pinocytosis - Materials dissolve in water to be brought into cell Called Cell Drinking Phagocytosis - Used to engulf large particles such as food, bacteria, etc. into vesicles. Called Cell Eating White blood cells eat foreign substances in your body this way 50

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51 Pinocytosis