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Cells
- 1.
- 2. What is thesmallest Cell in the World? • http://www.cellsalive.com/howbig.htm
- 3. Learning Outcomes At theend of the lesson, you should be able to: • Identify chloroplasts, cell membrane, cell wall, cytoplasm, cell vacuoles, nucleus, mitochondria, ribosomes • Identify endoplasmic reticulum and Golgi apparatus (Pure) • State the functions of the organelles identified above • Compare the structure of typical animal and plant cells
- 4. • state, insimple terms, the relationship between cell function and cell structure for the following: • absorption – root hair cells • conduction and support – xylem vessels • transport of oxygen – red blood cells • Differentiate cell, tissue, organ and organ system Learning Outcomes….con’t
- 5. What is acell?? • Basic structural and functional unit of living things • Building block of life • All living things are made up of one or more cells • How big is a cell? http://www.cellsalive.com/howbig.htm
- 6. What can wefind in the cell?
- 7. What can wefind inside a cell? • Each living cell consists of living material called protoplasm • Protoplasm is made up of cell membrane, nucleus and cytoplasm. • Protoplasm is jelly-like, containing mainly water and many other substances • Protoplasm in one part of the body may be different from another part of the body
- 8. What does acell consist of?
- 9. Scientific Drawing Lets trydrawing an animal cell • Use only pencil • Write the Title of the drawing and underline • Draw in 2D • Clear solid lines; no sketching • Label & annotate structures • Label figure (e.g. Figure 1) • Include scale *if applicable
- 10. Parts of acell • Cell surface membrane (plasma membrane) • Cytoplasm • Organelles • Nucleus • Mitochondria • Vacuole • Ribosomes • Endoplasmic Reticulum ( Rough & Smooth) • Golgi Apparatus • Chloroplast (in plant cell)
- 11. Cell surface membrane (Plasma membrane) StructureFunction Partially permeable layer around the cell Control movement of substances in and out of the cell. Only allow some substances to pass through, small molecules such as glucose, oxygen and water can enter, but not others such as waste substances.
- 12. Cytoplasm Structure Function Jelly-like substance madeup mainly of water (70% water) Acts as a medium for most chemical activities of the cell to occur; Contains enzymes and organelles. Cytoplasm
- 13. • are subcellularstructures (structures smaller than cells) that perform specific jobs inside the cell. • Eg: mitochondria, ribosomes, chloroplasts, vacuoles Organelles
- 14. Nucleus Structure Function Contains chromatin / chromosome (genetic materials) Controlscell activities, such as cell repair and growth; Controls cell division.
- 15. Vacuole Structure Function A fluid-filled spaceenclosed by a membrane; Exists temporarily in animal cells. Store substances such as water and food temporarily. vacuoles
- 16. Mitochondria Structure Function Small, rod- shaped organelles; Highlyfolded inner membrane Site where aerobic respiration takes place and energy is released. (singular: mitochondrion; plural: mitochondria) “The power house of the cell”
- 17. Ribosomes Structure Function Small, roundstructures; Can be attached to ER or found freely in the cytoplasm. Site where protein synthesis takes place.
- 18. Lets Recap! Parts ofa cell
- 19. Cell surface membrane (Plasma membrane) StructureFunction Partially permeable layer around the cell Control movement of substances in and out of the cell. Only allow some substances to pass through, small molecules such as glucose, oxygen and water can enter, but not others such as waste substances.
- 20. Cytoplasm Structure Function Jelly-like substance madeup mainly of water (70% water) Acts as a medium for most chemical activities of the cell to occur; Contains enzymes and organelles. Cytoplasm
- 21. Nucleus Structure Function Contains chromatin / chromosome (genetic materials) Controlscell activities, such as cell repair and growth; Controls cell division.
- 22. Vacuole Structure Function A fluid-filled spaceenclosed by a membrane; Exists temporarily in animal cells. Store substances such as water and food temporarily. vacuoles
- 23. Mitochondria Structure Function Small, rod- shaped organelles; Highlyfolded inner membrane Site where aerobic respiration takes place and energy is released. (singular: mitochondrion; plural: mitochondria) “The power house of the cell”
- 24. Ribosomes Structure Function Small, roundstructures; Can be attached to ER or found freely in the cytoplasm. Site where protein synthesis takes place.
- 25. Endoplasmic Reticulum (ER) Two types: Rough ER Smooth ER
- 26. Rough ER Structure Function Ribosomesare attached to its outer surface, hence its surface appears rough when seen under the microscope Rough ER helps to transport proteins made by the ribosomes to the Golgi apparatus for secretion out of the cell.
- 27. Smooth ER Structure Function SmoothER does not have ribosomes attached to its membrane; Smooth ER is more tubular than rough ER. It is connected to the rough ER. Synthesises substances such as fats and steroids; Converts harmful substances into harmless substances – Detoxification
- 29. Golgi Apparatus Structure Function TheGolgi apparatus consists of flattened spaces surrounded by membranes. Vesicles (small spherical spaces) fuse with one side of the Golgi apparatus and pinch off from the opposite side. Stores and modifies substances made by the ER; and packages these substances in vesicles for secretion out of the cell
- 30. Transport of substancesin the cell • Vesicles are tiny spherical spaces enclosed by a membrane. • Vesicles containing substances made by the ER are pinched off from the ER • These vesicles then fuse with the Golgi apparatus and release their contents into the Golgi apparatus for modification
- 31. • Secretory vesiclescontaining these modified substances are pinched off from the Golgi apparatus and moves towards the cell membrane • They fuse with the cell membrane and release their contents outside the cell Transport of substances in the cell
- 33. Brain Squeeze • Whatdoes a cell remind you of ?? • Think of the different compartments within the cell • And the different functions of the compartments (organelle)
- 35. Analogy of aCell Cell Structures: Chemical Factory: 1. Nucleus (Chromosomes that contain genes) Main office 2. Mitochondria Power Plant 3. Ribosomes Factory workers 4. Golgi Apparatus Packaging & Delivery 5. Lysosomes Recycling Centre 6. Vesicles Delivery Truck
- 37. Plant Cell What arethe Structural and Functional difference of a plant cell from an animal cell?
- 38. chloroplast central vacuole rough endoplasmic reticulum ribosomes cellwall mitochondrion Golgi complex plasma membrane smooth endoplasmic reticulum free ribosome vesicle nuclear pore chromatin nucleolus nuclear envelope nucleus
- 39. **Remember the pointsto take note! Lets try drawing a plant cell
- 40. • Its structuresare similar to an animal cell except for the presence of: • Cellulose cell wall • Chloroplasts • One large central vacuole Plant Cell
- 41. Cell Wall Structure Function Madeof cellulose and surrounds the entire plant cell, surrounding the cell membrane. Cellulose is a type of carbohydrates The tough cellulose protects the cell from injury and gives the cell a regular shape. The cell wall is fully permeable, unlike the cell membrane. Fun Fact: Can humans digest cellulose?
- 42. Chloroplast Structure Function Has stacksof disc-like structures which contain the green substance called chlorophyll. Chlorophyll enables light energy to be trapped and be converted into chemical energy stored in food (glucose) during the process photosynthesis.
- 43. Vacuole Structure Function A plantcell has one large central vacuole containing cell sap. The large vacuole is enclosed by a membrane called the tonoplast. Cell sap contains water and dissolved substances such as sugars, mineral salts and amino acids.
- 44. Micro-Question 1 Structure Animalcell Plant cell Cellulose cell wall Absent Present Chloroplasts Absent Present Vacuoles Small, temporary and many Large, normally one present
- 45. Micro-Question 2 The diagramshows four types of cells. Which cell does not contain a nucleus?
- 46. Micro-Question 3 The diagrambelow shows a plant cell. Which of the following is not a function of part T? A to store food substances B to secrete substances C to store wastes D to store water
- 47. Micro-Question 4 Which ofthe following statements describing the cell membrane is incorrect? A It is supported by lignin to give it a regular shape. B It is a thin and elastic layer. C It is a partially permeable membrane. D It is mainly composed of fats and proteins.
- 48. Micro-Question 5 Which ofthe following is a correct description of the permeability of the cell membrane and cell wall in a plant? Cell wall Cell membrane A fully fully B fully partially C partially fully D partially partially
- 49. 1.4 Cell Organisation SpecializedCells, Tissues, Organs and Systems
- 50. • Cell isthe smallest working unit in a multicellular organism.
- 51. • A tissueis a group of similar cells which work together to perform a specific function Muscle tissue Nerve tissue
- 52. Specialised Tissues Tissues MainFunction Animal Blood Tissue Transports food and oxygen Muscle Tissue Produces Movement Nerve Tissue Transmits impulses Epithelial Tissue Protects Cell Plant Epidermal Tissue Forms and protects surface of cell Xylem Tissue Transports water and mineral salts Phloem Tissue Transports food
- 53. What is anorgan made up of? • different tissues working together to perform a particular function
- 54.
- 55. What are organsystems? • An organ system is made up of different organs working together to perform a main body function Respiratory System Digestive System
- 57. • Can youname some examples of organs? • Eg) In Animals: Respiratory system – Circulatory system – Excretory system – Digestive system – Reproductive System – Lung Heart Kidney, Lung, Skin Stomach, Small intestines Ovary, Testes Micro-Question 6
- 58. Organ systems inPlants? • Reproductive system • Transport system • Root system Flowers Vascular bundle Roots & vascular bundle
- 59. Differentiation •Differentiation is theprocess by which a cell becomes specialised for a specific function •3 examples: • Red blood cell • Xylem vessel • Root hair cell
- 60. Red Blood Cells Function: •Haemoglobin (red pigment) in cytoplasm transports oxygen from the lungs to all parts of the body. • When haemoglobin combines with oxygen, oxyhaemoglobin is formed.
- 61. Adaptations: i.Absence of nucleusso as to contain more haemoglobin and hence more oxygen ii.Circular biconcave shape – increases surface area to volume ratio for faster diffusion of gases in and out of cell iii.Elastic and can turn bell-shaped in order to allow the cell to squeeze through small blood vessels iv.Contain a red pigment, haemoglobin, to allow oxygen to bind to the RBC to form oxyhaemoglobin. Red Blood Cells
- 62. Xylem Vessels Function i.Transport waterand mineral salts from roots up the stem and to the leaves ii.Provide mechanical support for the plant when bundled together
- 63. Adaptations i.Absence of cross-wallsand protoplasm enable water to move easily through the lumen (central space). ii.Lignin deposited in the walls of xylem vessels strengthens it and prevents the vessel from collapsing. iii.Narrow and hollow lumen allows water to be moved easily up the stem. Xylem Vessels
- 64. Root hair cell •Absorb water via osmosis and mineral salts from soil via diffusion.
- 65. • Adaptations 1. longand narrow protrusion/extension of an epidermal cell to increase surface area to volume ratio for more efficient absorption of water and mineral salts from soil. Root hair cell
- 66. • Adaptations 1. Ithas a very large vacuole that contains concentrated cell sap solution, resulting in a lower water potential thus allowing absorption of water from the soil. Root hair cell
- 67.
- 68. The table showsthe presence, absence of a nucleus in three types of cells. Which of the following is correct? Red blood cell Root hair cell Xylem Vessel A Present Absent Absent B Present Absent Present C Absent Present Absent D Absent Present Present Micro-Question 7