Cell Structure Lecture 04 1 Objectives At the end of this series - PDF document

09 ‐ Feb ‐ 20 Cell Structure Lecture 04 1 Objectives  At the end of this series of lectures you should be able to:  Define terms.  Explain cell theory.  Describe the relative sizes of objects in biology.  Explain why most cells are small.  Distinguish between prokaryotic and eukaryotic cells.  Describe the structure and function of the parts of typical plant and animal cells.  Discuss the theory of endosymbiosis. 2 1

09 ‐ Feb ‐ 20 Relative Sizes  1 meter (m)  1 centimeter = 0.01 m  1 millimeter = 0.001 m or 10 ‐ 3 m  1 micrometer = 0.000001 m or 10 ‐ 6 m  1 nanometer = 0.000000001 m 10 ‐ 9 m 3 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 4 2

09 ‐ Feb ‐ 20 http://htwins.net/scale2/ 5 Cell Theory  All organisms are made up of cells.  Cells are the smallest units of life  Cells come only from preexisting cells. Cells do things. 6 3

09 ‐ Feb ‐ 20 Most Cells are Small  Have to be large enough to contain all of the materials that they need to do their job.  Need to be relatively small to have a large surface to volume ratio.  Efficient transfer of materials into and out of the cell. 7 Figure 4.7 Jeffrey Mahr, CC BY 3.0, http://cnx.org/contents/263caa9c ‐ 31e1 ‐ 4c8a ‐ 80ea ‐ afdc47b43228@2 8 4

09 ‐ Feb ‐ 20 Prokaryotic vs. Eukaryotic Cells  Prokaryotic cells  Eukaryotic cells  Nucleoid – no membrane  Membrane bound nucleus  Small  Large  No internal  Internal compartments compartments  DNA linear  DNA circular  Membranous organelles  Protozoa, Fungi, Plants and  Bacteria and Archea Animals. 9 Eukaryotic  The structures and organelles perform four basic functions.  Genetic control of the cell  Nucleus and ribosomes  Manufacture, distribution, and breakdown of molecules  Endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and peroxisomes  Energy processing  Mitochondria and chloroplasts  Structural support, movement, and communication  Cytoskeleton, plasma membrane, and cell wall 10 5

09 ‐ Feb ‐ 20 Plant vs. Animal Cells  Plant Cells  Animal Cells  Cell wall  Lysosomes  Chloroplasts  Centrioles  Vacuole 11 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 12 6

09 ‐ Feb ‐ 20 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 13 Plasma Membrane  Function  Keeps the cell intact.  Regulates what enters and exits the cell.  Is semipermeable – some things can enter the cell others are blocked.  Made of a phospholipid bilayer with embedded proteins (Fluid mosaic model) 14 7

09 ‐ Feb ‐ 20 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 15 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 16 8

09 ‐ Feb ‐ 20 Cytoplasm  The portion of the cell between the nucleus and the plasma membrane  A semifluid medium made mostly of water and dissolved or suspended molecules. 17 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 18 9

09 ‐ Feb ‐ 20 Nucleus  Contains the DNA  Controls the cell activities by directing protein synthesis.  A dark structure in the nucleus – nucleolus  Synthesizes ribosomal RNA (rRNA)  Enclosed in a double membrane – nuclear envelope.  Perforated – nuclear pores 19 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 20 10

09 ‐ Feb ‐ 20 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 21 Ribosome  Site of protein synthesis  Made of rRNA and protein  Free in the cytoplasm or attached (bound) to the endoplasmic reticulum (rough ER). 22 11

09 ‐ Feb ‐ 20 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 23 Jeffrey Mahr, CC BY 3.0, http://cnx.org/contents/b848f154 ‐ 6e98 ‐ 4237 ‐ 9c03 ‐ 7cb75a0d1905@1 24 12

09 ‐ Feb ‐ 20 Endoplasmic Reticulum  Membranous tubules and sacs  Two types  Smooth ER – No attached/bound ribosomes  Synthesis of many types of lipids  Rough ER – Attached/bound ribosomes  The ribosomes produce proteins that are embedded in the membrane, transported to other organelles, or secreted by the cell. 25 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 26 13

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09 ‐ Feb ‐ 20 Golgi Apparatus  Slightly curved stack of large flattened vesicles. (Stack of pancakes)  The Golgi apparatus serves as storage and finishing facility for products from the ER.  Products travel in vesicles from the ER to the Golgi.  Contains enzymes that modify proteins and lipids. 29 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 30 15

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09 ‐ Feb ‐ 20 Lyososomes  Lysosomes help digest food particles engulfed by a cell.  A food vacuole binds with a lysosome.  The enzymes in the lysosome digest the food.  The nutrients are then released into the cell.  Lysosomes also help remove or recycle damaged parts of a cell. 33 Vacuoles  Large vesicles that have a variety of functions.  Protists/Protozoa  Contractile vacuoles that eliminate excess water.  Plants  Digestive functions  Contain pigments  Contain toxins for protection or storage 34 17

09 ‐ Feb ‐ 20 Peroxisomes  Break down fatty acids to use as fuels  Detoxifiy materials 35 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 36 18

09 ‐ Feb ‐ 20 Mitochondria  Site of most ATP synthesis ‐‐ Converts energy from glucose to ATP (adenosine triphosphate).  Aerobic cellular respiration  Small peanut ‐ shaped organelles  Double membrane  Outer membrane is smooth  Inner membrane is heavily folded – folds are called cristae.  The inner most portion is the matrix.  Endosymbiosis  DNA, ribosomes (type), double membrane, antibiotics 37 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 38 19

09 ‐ Feb ‐ 20 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 39 Chloroplast  Occurs in plants and some protists.  Where photosynthesis occurs ‐‐ convert solar energy to chemical energy .  Double membrane  Thylakoid – flattened sacs with chlorophyll  Granum – a stack of thylakoids  Stroma ‐‐ thickened fluid that surrounds the granum 40 20

09 ‐ Feb ‐ 20 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 41 Cytoskeleton  A network of filaments and microtubules  Similar to an animal’s skeleton  Provides structure and movement.  Can change shape and configuration. 42 21

09 ‐ Feb ‐ 20 Movement  Flagellum  Cilia (Cilium)  Psuedopodium 43 22