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Cell Structure and Function
The document provides an overview of cell structure and function. It defines the cell and outlines the cell theory. The major components of plant cells are described, including organelles like the nucleus, chloroplasts, mitochondria, and cell membrane. It also discusses the cytoskeleton and movement of substances across the cell membrane through passive diffusion, facilitated transport, osmosis, and active transport processes like endocytosis and exocytosis. The overall purpose is to introduce learners to key aspects of cell biology.
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Cell Structure and Function
- 1. CELL STRUCTURE ANDFUNCTION Presented by: Fasama Hilton Kollie Lecturer, Department of Biology Mother Patern College of Health Sciences CHP’T-2 September 17, 2018
- 2. LESSON OUTLINE 1. Overviewof cell • Definition and Discovery of the cell • Cell Theory and Principle of the Cell Theory • Characteristic of Cell • Types of Cell 2. Major Plant Cell Organelles • Overview of Organelles (Bacteria-like & Membranous Organelles) • Nucleus, Ribosomes, Endoplasmic Reticulum, Golgi Apparatus, Chloroplast, Mitochondria, Cytoplasm, Microbodies, Vacuole…
- 3. 3. Cytoskeleton • Overviewof cytoskeleton • Microtubules, Microfilaments, Motor proteins • Intermediate Filament 4. Membrane and Cell Wall • Cell membrane • Cell wall LESSON OUTLINE CONT.
- 4. 5. Movement AcrossCell Membrane • Passive Transport • Simple diffusion • Facilitated diffusion • Osmosis • Hypotonic, Isotonic and Hypertonic solutions • Active Transport • Endocytosis • Pinocytosis and Phagocytosis • Exocytosis LESSON OUTLINE CONT.
- 5. LESSON OBJECTIVE • Bythe end of this session, the learners will be able to; 1. Define cell, cell theory, and organelle 2. Demonstrate plant and animal cell 3. Identify and describe the major plant cell organelles 4. Discuss cytoskeleton 5. Describe plant cell wall and membrane 6. Describe the movement of substance across the cell membrane
- 6.
- 7. CELLS • From latin- cella, meaning "Small room“ • The basic structural, functional, and biological unit of all known living organisms • Often called the "building blocks of life"Plant cells
- 8. DISCOVERY OF CELLS •Robert Hooke (Mid-1600s) ̶ Observed sliver of cork ̶ Saw “row of empty boxes” ̶ Coined the term “Cell”
- 9. CELL THEORY • MatthiasSchleiden (1838) All plants are made up of cell Schleiden Schwann Virchow • Theodor Schwann (1839) All animals are made up of cell • Rudolf Virchow (1855) All cells comes from preexisting cells
- 10. PRINCIPLES OF CELLTHEORY 1. All living things are made of one or more cells 2. The Cell is the smallest living unit of structure and function of all organisms 3. All cells arise from preexisting cells through cell division Schleiden SchwannVirchow
- 11.
- 12. Cells Have LargeSurface Area-to-Volume Ratio
- 13. Cell Shape • Acell’s shape reflects its function Bacteria cell Plant cell Red blood cell
- 14.
- 15. PROKARYOTIC CELLS • Firstform of life on earth • Single-celled organisms • Cell type of bacteria and archaea • A prokaryotic cell contain three architectural regions: ̶ Cell envelop ̶ Cytoplasmic region ̶ Flagella and pili
- 16. PROKARYOTIC CELLS • Lackmembrane-bound organelles • Nucleoid :region of DNA concentration • Most are the smallest of all organisms ranging from 0.5 – 2.0 µm in diameter
- 17. EUKARYOTIC CELLS • Nucleusbound by membrane • Include fungi, protist, plant, and animal cells • Possess many organelles Animal cell
- 18.
- 19.
- 20. CHARACTERISTICS OF ALL CELLS •Contain a surrounding membrane (plasma membrane) • Protoplasm – cell contents in thick fluid • Control center with DNAs
- 21.
- 22. MAJOR PLANT CELLORGANELLES • “Little organs” • Specialized subunit within a cell that has specific function • Cellular machinery • Two general kinds: ̶ Bacteria-like organelles ̶ Derived from membranes
- 23. Bacteria-Like Organelles • Derivedfrom symbiotic bacteria • Ancient association • Endosymbiotic theory ̶ Evolution of modern cells from cells & symbiotic bacteria
- 24. • Release &store energy • Types: ̶ Mitochondria (release energy) ̶ Chloroplasts (store energy) Bacteria-Like Organelles Mitochondria Chloroplast
- 25. Cytoplasm • Viscous fluidcontaining organelles • Components of cytoplasm: ̶ Interconnected filaments & fibers ̶ Fluid = cytosol ̶ Organelles (not nucleus) ̶ Storage substances (Examples) Cytoplasm
- 26. Membranous Organelles • Functionalcomponents within cytoplasm • Bound by membranes ̶ Nucleus ̶ Ribosomes ̶ Endoplasmic reticulum ̶ Golgi Apparatus ̶ Lysosomes ̶ Vacuole ̶ Microbodies
- 27. Nucleus • Control centerof cell • Double membrane • Contains: ̶ Chromosomes (DNA) ̶ Nucleolus ̶ Nuclear envelop ̶ Nuclear pole
- 28. Nucleus and It’sComponents Nucleus 1. Nuclear envelop • Outer membrane • Inner membrane 2. N 3. Chromatin 4. Nucleolus 5. Nuclear pore Nuclear envelop Nucleoplasm Chromatin Nucleolus Nuclear pole
- 30. • Site ofprotein synthesis • Usually exit in large numbers in living cells Ribosomes • Organelles that direct the synthesis of proteins using genetic instruction in the form of messenger RNA Ribosomes
- 31. • Free ribosomes •Suspended in the cytosol • Synthesize proteins that function in cytosol Types of Ribosomes Free Ribosomes Bound Ribosomes • Bound ribosomes • Attached to endoplasmic reticulum • Synthesize proteins for export or for membranes • Proteins work within endomembrane system or outside cell
- 32. • Network ofinterconnected membranes • Helps move substances within cells • Serves as assembly site for making proteins, lipids … • Two types; – Rough Endoplasmic Reticulum – Smooth Endoplasmic Reticulum Endoplasmic Reticulum ER
- 33. • Ribosomes attachedto surface ̶ Manufacture protein ̶ Contain cisternae • May modify proteins from ribosomes Rough Endoplasmic Reticulum Rough ER
- 34. Smooth Endoplasmic Reticulum •No attached ribosomes • Has enzymes that help build molecules ̶ Carbohydrates ̶ Lipids Smooth ER
- 35. Golgi Apparatus • Acomplex of vesicles and folded membranes involved in secretion and intracellular transport • Transport vesicles • Consist of stacks of cisternae, known as Golgi stacks • Consist of two main networks: ̶ Cis Golgi Network (CGN) ̶ Trans Golgi Network (TGN)
- 36. 1. It modify,sort and package the macromolecules that are synthesized by the cell 2. They are also involved in the transport of lipid molecules around the cell 3. It is also a major site of carbohydrate synthesis Golgi Apparatus Function
- 37.
- 39. Lysosomes • Spherical vesiclesthat contain hydrolytic enzymes that can break down many kinds of biomolecules • Contain digestive enzymes • Functions: ̶ Aid in cell renewal ̶ Break down old cell parts ̶ Digests invaders
- 40. • Membrane boundstorage sacs • Single membrane structure • Contents: ̶ water, food, wastes, enzymes • Function: ̶ Isolating harmful materials ̶ Storing waste products ̶ Storing valuable water in a plant cell ̶ Balancing the ph of a cell ̶ Storing proteins for seed germination Vacuole
- 41. • Single membrane–enclosedorganelles • Found in cells of plants, protozoa, and animals • Usually a vesicle with spherical shape • Constitute: peroxisomes, glyoxysomes… • Function: ̶ Contain enzymes that participate in biochemical reactions in cells ̶ Detoxification of peroxides ̶ Photorespiration in plants Microbodies
- 42. Chloroplasts • Organelle withinthe cells of plants and green algae that is the site of photosynthesis • Contains green chlorophyll pigment • Double membrane structure • Chloroplast is a type of plastid ̶ Include leucoplasts and chromoplasts
- 43. Chloroplast Cont. • Endosymbiotictheory explains the origin of chloroplast ̶ Which has a two membranes and; ̶ A small circular chromosome
- 44.
- 45. Mitochondria • Organelles thatare the cell’s “power plant” • It breaks down sugar to store its chemical energy in ATP • Consist of; ̶ Double membrane, Matrix, Thylakoids, ̶ Stoma, Mitochondria DNA • Production of energy for cell is its most prominent function
- 46. CYTOSKELETON • Filaments &fibers • Made of 3 fiber types ̶ Microtubules ̶ Microfilaments ̶ Intermediate filaments • 3 functions: ̶ Mechanical support ̶ Anchor organelles ̶ Help move substances
- 47. • Long hollowtubes in the cytoskeleton • Made up of a protein called Tubulin • Function; • Helps maintain cell shape • Movement of multicellular organisms through water – Cilia and Flagella • All movement controlled by microtubules involves “walking molecules” Microtubules:
- 48. Cilia & Flagella Cilia: •Short hair-like projections • Used to move substances outside human cells Flagella: • Whip-like extensions • Found on sperm cells
- 49. • Made upof globular protein called actin • Function: → Helps living cell change shape → Help in the movement of cell content around the vacuole in a circular motion known as cytoplasmic streaming Microfilaments:
- 50. • A typeof cytoskeletal elements made of multiple strands of fibrous proteins wound together • Average diameter of 8-10nm • Function: → Help in holding the nucleus in its permanent position → Control the shape of the nucleus Intermediate Filaments:
- 51. • “Walking molecule” •Motor proteins require energy for movement • Involve in many movement in cells • These include; ̶ Chloroplast moving from the bottom to the side of a cell ̶ Cyclosis Motor Proteins
- 52. • “ Plasmamembrane” • Membranes are barriers that control what enters and leaves the cell • Fluid mosaic model provides a broader description of the cell membrane MEMBRANES AND CELL WALLS Cell Membrane:
- 53.
- 54. • Protective layerthat surrounds the plasma membrane • Plant cell wall consist primary of cellulose • Plant cell wall consist of two components: ̶ Primary cell wall ̶ Secondary cell wall Cell Wall
- 55. MOVEMENT ACROSS CELLMEMBRANES 1. Passive Transport 2. Active Transport 3. Endocytosis Phagocytosis & Pinocytosis 4. Exocytosis
- 56. Passive Transport • Noenergy required • Move due to gradient • Movement is down the concentration gradient ̶ High moves toward low • Consist of 3 types: ̶ Simple Diffusion ̶ Facilitated diffusion ̶ Osmosis
- 57. Simple Diffusion: • Moleculesmove to equalize concentration
- 58. • Movement ofspecific molecules down a concentration gradient • Pass through membranes via specific carrier protein • Selection is by size, shape, charge Facilitated Diffusion:
- 59. • Channels (arespecific) help molecule or ions enter or leave the cell Facilitated Diffusion Cont. • Channels usually are transport proteins • (Aquaporin facilitate the movement of water)
- 60. Process of FacilitatedTransport
- 61. Osmosis: • Special formof diffusion • Fluid flows from lower solute concentration to higher • Requires selective permeable membrane
- 62. Solvent + Solute= Solution • Hypotonic ̶ Solutes in cell more than outside ̶ Outside solvent will flow into cell • Isotonic ̶ Solutes equal inside & out of cell • Hypertonic ̶ Solutes greater outside cell ̶ Fluid will flow out of cell Solution Difference & Cell
- 63. Effect of OsmosisOn Cells
- 64. Active Transport • Molecularmovement • Requires energy (against concentration gradient) • Eg: Sodium-potassium pump
- 65. Endocytosis • Movement oflarge material – Particles, organisms ,large molecules • Movement is into cell Cytoplasm Vesicle Outside cell
- 66. Forms of Endocytosis •Phagocytosis – “cell eating” • Pinocytosis – “cell drinking”
- 67. Exocytosis • Reverse ofendocytosis • Cell discharges material
- 68. REFERENCE • Nabor, MurrayW., INTRODUCTION TO BOTANY, Copyright 2004 Pearson Education, Inc., publishing as Benjamin Cummings, 1301 Sansome St., San Francisco, CA 94111 • Kingsley R. Stern, James E. Bidlack & Shelley H. Jansky., INTRODUCTORY PLANT BIOLOGY, Copyright © 2008 by The McGraw- Hill Companies, Inc. Published by McGraw-Hill, 1221 Avenue of the Americas, New Yours, NY 10020. www.mhhe.com • Movement across membranes http://www.biologymad.com/resources/diffusionrevision.pdf Google Advance Image search