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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Cells Chapter 4 Copyright © McGraw-Hill Companies Permission required.

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Presentation on theme: "Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Cells Chapter 4 Copyright © McGraw-Hill Companies Permission required."— Presentation transcript:

1 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Cells Chapter 4 Copyright © McGraw-Hill Companies Permission required for reproduction or display

2 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Outline Cell Theory Plasma Membrane Prokaryotic Cells Eukaryotic Cells Cytoskeleton Cell Organelles Cell Movement Diffusion and Osmosis Bulk Passage

3 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Cell Theory Robert Hooke (1665) Observed thin slice of nonliving plant tissue. - Observed honeycombed compartments he called cellulae (small rooms). Matthias Schleiden (1838) first statement of cell theory.

4 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Cell Theory All organelles are composed of one or more cells, within which life processes occur. Cells are smallest living things. Life evolved only once, 3.5 billion years ago. Cells arise only by division of a previously existing cell.

5 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Cell Size Cells range in size from 5-20 micrometers to 5 cm long. Most cells are small because larger cells do not function as efficiently. As cell size increases, volume increases more rapidly than surface area. - Larger cells have less surface area per unit volume, thus less opportunity to interact with the environment. - Cytoplasm fills cell interior.

6 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Plasma Membrane Cell membrane made up of diverse collection of proteins floating within lipid framework. Fluid Mosaic Model - Lipid bilayer forms when phospholipids are placed in water. Hydrophobic tails pointing in, hydrophilic heads pointing outward.

7 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Copyright © McGraw-Hill Companies Permission required for reproduction or display Lipid Bilayer

8 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Plasma Membrane Membrane Proteins - Float freely within lipid bilayer. Cell Surface Proteins - Act as markers to identify particular types of cells. Transmembrane Proteins - Span entire membrane. Provide channels for molecule passage.

9 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Copyright © McGraw-Hill Companies Permission required for reproduction or display Lipid Bilyer

10 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Prokaryotic Cells Prokaryotes have a relatively uniform cytoplasm not subdivided by interior membranes (No interior compartments). Bacteria are simplest cellular organisms. - Over 2,500 recognized species. - Almost all are contained by a cell wall. Some bacteria contain another layer (capsule) enclosing the cell.

11 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Prokaryotic Cells

12 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Eukaryotic Cells Contain many membrane-bound interior compartments and a variety of organelles. Specialized structures performing specific processes. - Nucleus

13 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Cytoskeleton Cytoskeleton - dense network of protein fibers supporting cell shape. Microfilaments Microtubules Intermediate Fibers

14 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Cell Organelles Eukaryotic cells thought to have evolved from endosymbiosis between different species of prokaryotes. Engulfed prokaryotes provided hosts with certain metabolic advantages.

15 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Nucleus Nucleus - Command and control center. Bound by nuclear envelope. - Covered with nuclear pores embedded by proteins permitting proteins and RNA to pass in and out of nucleus. Contain chromosomes holding DNA. Nucleolus - Cluster of genes encoding rRNA. Ribosome reads RNA and directs protein building.

16 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Nucleus

17 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Endomembrane System Endoplasmic Reticulum Internal membrane creating channels and membrane-enclosed vesicles. - Carbohydrates and lipids manufactured on the surface. - Proteins for export produced on surface covered with ribosomes (Rough ER).

18 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Endomembrane System Golgi Complex Golgi bodies are scattered throughout the cytoplasm. Function in collection, packaging, and distribution of molecules manufactured in the cell. Lysosomes Arise from Golgi complex and break down macromolecules. (Recycling center) Peroxisomes - Vesicles carrying out specific chemical functions.

19 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Endomembrane System Copyright © McGraw-Hill Companies Permission required for reproduction or display

20 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies DNA Containing Organelles Mitochondria Double membrane organelles that extract energy from organic molecules. - (Oxidative Metabolism) Inner membrane bent into numerous folds (cristae) that partitions mitochondrion into inner matrix and outer compartment.

21 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Mitochondria

22 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies DNA Containing Organelles Chloroplasts Double membrane organelles that serve as site of photosynthesis. Inner membranes fused to form stacks of thylakoids, which are stacked on top of one another to form a column (granum). - Interior bathed with semiliquid (stroma).

23 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Chloroplasts

24 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Cell Movement Microvilli project outward form surface of animal cells. Arrangement of actin filaments within cell cytoplasm allow cells to crawl. Flagella are fine, threadlike organelles protruding from cell surface. Arise from basal body and consist of nine microtubule pairs surrounding two central pairs. Cilia - Short, numerous flagella.

25 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Flagella and Cilia

26 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Plant Cells Are Unique Central Vacuole - Large storage center for certain cell substances, and increases surface to volume ratio. Cell Walls - Composed of cellulose fibers. Primary Walls Middle Lamella Secondary Walls

27 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Diffusion and Osmosis Diffusion Random motion of molecules produces uniform mixture due to net movement of molecules down a concentration gradient (high concentration to low concentration). Copyright © McGraw-Hill Companies Permission required for reproduction or display

28 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Diffusion and Osmosis Osmosis Diffusion of water across a membrane toward the side with polar molecules that cannot traverse the membrane. Copyright © McGraw-Hill Companies Permission required for reproduction or display

29 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Diffusion and Osmosis Solute - Substance dissolved in a solution. Hyperosmotic - Solution with higher concentration of solutes. Hypoosmotic - Solution with lower concentration of solutes. Isomotic - Osmotic concentration of both solution are equal. Osmotic Pressure - Pressure caused by movement of water into a cell.

30 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Bulk Passage Endocytosis - Cell membrane engulfs particle and forms a vesicle, bringing the particle into the interior of the cell. Excoytosis - Reverse of endocytosis. Copyright © McGraw-Hill Companies Permission required for reproduction or display

31 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Selective Permeability Protein channels in membrane only allow passage of certain kinds of molecules. Selective Diffusion allows molecules to move through channels and equalize concentrations. Facilitated Diffusion - net movement down a concentration gradient facilitated by carrier proteins.

32 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Facilitated Diffusion Copyright © McGraw-Hill Companies Permission required for reproduction or display

33 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Active Transport Active Transport - Using energy to move molecules through membrane protein channels against a concentration gradient. Sodium-Potassium Pump Proton Pump

34 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Active Transport Copyright © McGraw-Hill Companies Permission required for reproduction or display

35 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies How Cells Get Information Chemical information sensed by surface receptor proteins. Hormone signals Voltage sensed by specialized ion channels. Copyright © McGraw-Hill Companies Permission required for reproduction or display

36 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Review Cell Theory Plasma Membrane Prokaryotic Cells Eukaryotic Cells Cytoskeleton Cell Organelles Cell Movement Diffusion and Osmosis Bulk Passage

37 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Copyright © McGraw-Hill Companies Permission required for reproduction or display


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