The Cell.pptx
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This document provides an overview of cell structure and function. It discusses the key principles of cell theory, including that all living things are made of cells, cells come from pre-existing cells, and cells have common characteristics. It describes the main parts of prokaryotic and eukaryotic cells, including the cell membrane, cytoplasm, organelles, and cell walls. Specific organelles like the nucleus, mitochondria, chloroplasts, and lysosomes are explained in terms of their functions in cellular processes like respiration and photosynthesis.
The Cell.pptx
- 1. General Biology 1 Type in the chat box ‘present sir’ for your attendance.
- 4. Cells • Smallest living unit • Most are microscopic
- 5. Discovery of Cells • Robert Hooke (1660’s) – Observed a slice of cork – Saw “row of empty boxes” – Coined the term ‘cell’
- 6. Cell theory • Matthias Schleiden: “All plants are composed of cells.” (1838) • Theodor Schwann: “All animals are composed of cells.” (1839) “all living things are made of cells” • Rudolf Virchow: “All cells came from cells.” (1855)
- 7. Principles of Cell Theory 1. All living things are made up of cells. 2. The smallest living unit of structure and function of all organisms is the cell. 3. All cells arise from preexisting cells. (this principle discarded the idea of spontaneous generation)
- 8. additional 4. Energy flow occurs within cells. 5. Heredity information (DNA) is passed from cell to cell. 6. All cells have the same basic chemical composition.
- 9. Cell Size
- 12. Cells Have Large Surface Area-to-Volume Ratio
- 13. Characteristics of All Cells • It has surrounding membrane. • Cytoplasm – cell contents in thick fluid • Organelles – structures for cell function • Control center with DNA
- 14. Cell Types • Prokaryotic • Eukaryotic
- 15. Prokaryotic Cells • First cell type on earth • Cell type of Bacteria and Archaea
- 16. Prokaryotic Cells • No membrane bound nucleus • Nucleoid = region of DNA concentration • Organelles not bound by membranes
- 17. Eukaryotic Cells • Nucleus bound by membrane • Include fungi, protists, plant, and animal cells • Possess many organelles Protozoan
- 22. Endosymbiotic Theory -proposes that the mitochondrion and the chloroplast were once prokaryotic cells, living inside larger host cells. The prokaryotes may initially have been parasites or even an intended meal for the larger cell, somehow escaping digestion.
- 24. The Organelles of the Cell
- 25. Bacteria-Like Organelles • Derived from symbiotic bacteria • Endosymbiotic theory –Evolution of modern cells from cells & symbiotic bacteria
- 26. Plasma Membrane • Contains cell organelles • Double layer of phospholipids & proteins
- 27. Phospholipids • Polar – Hydrophilic head – Hydrophobic tail • Interacts with water
- 29. Movement Across the Plasma Membrane • A few molecules move freely –Water, Carbon dioxide, Ammonia, Oxygen • Carrier proteins transport some molecules –Proteins embedded in lipid bilayer –Fluid mosaic model – describes fluid nature of a lipid bilayer with proteins
- 31. Review 1. This theory explains how eukaryotic cells came about. 2. He said that all animals are made of cells. 3. The cell membrane allows all molecules to pass through. (True/False) 4. Eukaryotic cells were the first organisms on earth. (True/False) 5. The tail of a phospholipid is hydrophobic. (True/False)
- 33. Organelles • Cellular machinery • Two general kinds –Derived from membranes –Bacteria-like organelles
- 34. Membrane Proteins 1. Channels or transport proteins –Move molecules in one direction 2. Receptor proteins –Recognize certain chemicals to trigger a response inside the cell. 3. Adhesion Proteins –Enables the cell to stick to another.
- 35. Membrane Proteins 4. Glycoproteins/ Recognition proteins – Identify cell type; serves as 'name tags' 5. Enzymes – Facilitates chemical reactions.
- 37. Cell Walls • Found in plants, fungi, bacteria & many protists • Surrounds plasma membrane
- 38. Cell Wall Differences • Plants (and other protists) – mostly cellulose • Fungi – contain chitin • Bacteria – made of peptidoglycan
- 39. Cytoplasm • Viscous fluid containing organelles • components of cytoplasm – Interconnected filaments & fibers – Fluid = cytosol – Organelles (not nucleus) – storage substances
- 40. Cytoskeleton • Filaments & fibers • Made of 3 fiber types – Microfilaments – Microtubules – Intermediate filaments • 3 functions: – mechanical support – anchor organelles – help move substances
- 41. A = actin, IF = intermediate filament, MT = microtubule
- 42. General Biology 1 Type in the chat box ‘present sir’ for your attendance.
- 43. Cilia & Flagella • Provide motility • Cilia – Short – Used to move substances outside human cells • Flagella – Whip-like extensions – Found on sperm cells • Basal bodies like centrioles
- 44. Cilia & Flagella Structure • Bundles of microtubules • With plasma membrane
- 46. Ciliary Action
- 47. Centrioles • Pairs of microtubular structures • Play a role in cell division
- 48. Membranous Organelles • Functional components within cytoplasm • Bound by membranes
- 49. Nucleus • Control center of cell • Double membrane • Contains – Chromosomes – Nucleolus
- 50. Nuclear Envelope • Separates nucleus from rest of cell • Double membrane • Has pores
- 51. DNA • Hereditary material • Chromosomes – DNA – Proteins – Form for cell division
- 52. Nucleolus • Most cells have 2 or more • Directs synthesis of RNA • Forms ribosomes
- 53. Endoplasmic Reticulum • Helps move substances within cells • Network of interconnected membranes • Two types – Rough endoplasmic reticulum – Smooth endoplasmic reticulum
- 54. Rough Endoplasmic Reticulum • Ribosomes attached to surface – Manufacture proteins – Not all ribosomes attached to rough ER • May modify proteins from ribosomes
- 55. Smooth Endoplasmic Reticulum • No attached ribosomes • Has enzymes that help build molecules – Carbohydrates – Lipids
- 56. Golgi Apparatus • Involved in synthesis of plant cell wall • Packaging & shipping station of cell
- 57. Golgi Apparatus Function 1. Molecules come in vesicles 2. Vesicles fuse with Golgi membrane 3. Molecules may be modified by Golgi
- 58. Golgi Apparatus Function (Continued) 4. Molecules pinched-off in separate vesicle 5. Vesicle leaves Golgi apparatus 6. Vesicles may combine with plasma membrane to secrete contents
- 60. Lysosomes • Contain digestive enzymes • Functions – Aid in cell renewal – Break down old cell parts – Digests invaders
- 61. Vacuoles • Membrane bound storage sacs • More common in plants than animals • Contents – Water – Food – wastes
- 62. Bacteria-Like Organelles • Release & store energy • Types – Mitochondria (release energy) – Chloroplasts (store energy)
- 63. Mitochondrion • pl. mitochondria • Have their own DNA • Bound by double membrane
- 64. Mitochondrion • Break down fuel molecules (cellular respiration) – Glucose – Fatty acids • Release energy – ATP
- 65. Chloroplasts • Derived form photosynthetic bacteria • Solar energy capturing organelle
- 66. Photosynthesis • Takes place in the chloroplast • Makes cellular food – glucose