Cell structure & organisation
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The document discusses cell structure and organization. It describes the main organelles found in plant and animal cells like the nucleus, chloroplasts, mitochondria, vacuoles, and cell wall. It explains their various functions, for example that mitochondria extract energy from glucose to produce ATP for cell activities. The plasma membrane controls what enters and exits the cell. Plant cells have a cell wall, central vacuole and chloroplasts that animal cells lack. Specialized cells like xylem vessels, root hair cells and red blood cells are adapted for their functions of transport, absorption and oxygen carriage.
Cell structure & organisation
- 1. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 • Identify the main organelles and membranes in the cell. • Explain the various functions of the different organelles. • Compare the structure of plant and animal cells. • Describe the relationship between structure and function as seen in root hair cells, xylem vessels and red blood cells. • Differentiate between the levels of organisation in an organism. Learning Outcomes
- 2. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 • A light microscope uses light rays to produce images; an electron microscope uses electron beams. • Magnification: degree to which the image is enlarged. 1.1 Structure of Cells
- 3. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 • Resolution: the smallest distance needed for two points to be distinguished. 1.1 Structure of Cells • Depth of field: different tissues lie on different planes.
- 4. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 • Preparing slides for use with the light microscope: 1.1 Structure of Cells
- 5. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 • Preparing slides for use with the light microscope: 1.1 Structure of Cells
- 6. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 • Caring for the microscope: – When shifting the microscope, hold on to the microscope handle with one hand and support the base with the other. Do not swing it around. – Do not touch the lenses with your fingers and use only lens paper to clean the glass. – Before keeping the microscope, first rotate the nosepiece to the low power objective, then lower it until it nearly touches the stage. – Be careful when working with the slides and cover slips. 1.1 Structure of Cells
- 7. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 • Prokaryotes do not have a nucleus and are more primitive. • Eukaryotes like the animal cell (left) and plant cell (right) have a nucleus where the genetic material resides. 1.1 Structure of Cells
- 8. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 1.1 Structure of Cells
- 9. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Nucleus • Chromosomes are uncoiled chromatin, visible during nuclear division. • A man has 46 chromosomes (i.e. 23 pairs of chromosomes) in all his cells except the sex cells. 1.1 Structure of Cells
- 10. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Nucleus • Nucleolus is the most visible part, responsible for formation of ribosomes. 1.1 Structure of Cells
- 11. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Endoplasmic Recticulum (ER) • Extension of the outer layer of nuclear membrane. 1.1 Structure of Cells
- 12. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Endoplasmic Recticulum (ER) • Smooth ER: – Without ribosomes – Responsible for producing lipids and cholesterol. – Where harmful substances are detoxified. • Rough ER: – With ribosomes. – Where proteins are synthesised. 1.1 Structure of Cells
- 13. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Golgi Body • Stack of membrane-enclosed sacs. • Modify small vesicles from ER: – Small vesicles fuse with one side of this complex. – Finished products bud off from the opposite face. 1.1 Structure of Cells
- 14. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Mitochondria • Double-membraned organelle. • Cristae is the inner membrane, thrown into deep folds. 1.1 Structure of Cells
- 15. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Mitochondria • Energy extracted from sugar molecules is stored in bonds of adenosine tri-phosphate (ATP) molecules. • Bonds can be easily released with the help of enzymes during respiration. 1.1 Structure of Cells
- 16. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Vacuole • Fluid-filled sacs. 1.1 Structure of Cells
- 17. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 • Vacuoles in animal cells are called vesicles; they are temporary and have different functions such as: – Storing sugars. – Transporting products. – Containing digestive enzymes to digest invading bacteria. – Helping the cell expel excess water. 1.1 Structure of Cells Vacuole
- 18. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 • Plant cells have a large and relatively permanent central vacuole. 1.1 Structure of Cells Vacuole
- 19. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Cytoplasm and Plasma Membrane 1.1 Structure of Cells • The fluid in which all organelles are suspended is known as the cytosol (in blue). • The plasma membrane (in orange) controls substances entering or leaving the cell.
- 20. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Cytoplasm • Entire region of the cell between the nucleus and the plasma membrane. • Includes the organelles, various membrane and cytosol. 1.1 Structure of Cells
- 21. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Plasma Membrane • Transfers chemical messages from the outside of the cell to the inside. • Keeps the cell contents in place. • Made of lipids and proteins. • Constantly reforms to allow movement of materials into and out of the cell. 1.1 Structure of Cells
- 22. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 1.1 Structure of Cells
- 23. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 1.1 Structure of Cells Cell Wall • Only in plant cells. • Presence of strong cellulose fibrils for reinforcement. • Functions: – Protects the cell from harmful external influences – Helps the cell keep its shape – Prevents the cell from absorbing too much water that it bursts.
- 24. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 1.1 Structure of Cells Cell Wall • Plasmodesmata are channels that allow small molecules and water molecules to move between plant cells.
- 25. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Central Vacuole • Makes up 90% of the cell’s volume in a fully grown plant. 1.1 Structure of Cells
- 26. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Central Vacuole • Tonoplast is the membrane enclosing the cell sap which is mainly water. • Maintains turgidity of the cell. • Stores nutrients, wastes, pigments and poisonous substances. 1.1 Structure of Cells
- 27. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Chloroplasts • Oval or spherical. • Found only in plant cells. 1.1 Structure of Cells
- 28. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Chloroplasts • Give plant cells their green colour. • Give petals and fruits their colour. • Others do not contain colour but act as centres of starch grain storage or storage of oils and proteins. 1.1 Structure of Cells
- 29. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 • The cell is the basic unit of all living organisms. • All activities of the cell are controlled by information stored in the nucleus. • Mitochondria in the cell extract energy from glucose and store it as ATP molecules. • The energy stored in ATP is used by various organelles in the cell such as the ribosomes, which use the ATP to produce proteins for cell repair or for export to other parts of the organisms.
- 30. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 • The plasma membrane controls the movement of substances into or out of the cell. • Plant cells are rigid because of the cell wall surrounding the cell. The cell wall helps to provide support for the plant. • Unlike the temporary small vacuoles of animal cells, plant cells usually have a permanent, large, central vacuole. This helps to maintain the shape of the cell as well as store various substances. • The most characteristic feature of the plant cell is the chloroplast which allows the plant to make food in the presence of sunlight.
- 31. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Xylem Vessels • Pipe-like columns. • Provide support. • Transport water and mineral salts from roots to other parts. 1.2 Specialised Cells, Tissues and Organs
- 32. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Root Hair Cell • Long narrow extension of the cell. • Increases cell surface area. • Increases the rate of diffusion of water and mineral salts. 1.2 Specialised Cells, Tissues and Organs
- 33. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Red Blood Cell • Contains red pigment called haemoglobin. • Supplies oxygen to other body cells. 1.2 Specialised Cells, Tissues and Organs
- 34. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 Relationship Between Structure and Function of Red Blood Cell 1.2 Specialised Cells, Tissues and Organs • Haemoglobin combines easily with oxygen. • Absence of nucleus – can pack more haemoglobin. • Biconcave shape – increases surface area. • Thin and elastic plasma membrane – able to squeeze through narrow capillaries.
- 35. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 1.2 Specialised Cells, Tissues and Organs Cell, Tissue, Organ and Organ System • Similar cells work together as a tissue to carry out a particular function. • Organs contain a number of different kinds of tissues. • Several organs may work together in an organ system. • Each organ system serves a specific function.
- 36. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 • The structure of a cell is related to its function. • Similar cells work together as a tissue to carry out a particular function. • Organs contain a number of different kinds of tissue. (a) (b) (c) (d)
- 37. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1 • Several organs may work together in an organ system. • Each organ system serves a specific function. Most activities involve more than one organ system functioning at the same time.
- 38. Cell Structure and Organisation T H E M E O N E : P R I N C I P L E S O F B I O L O G Y C h a p t e r 1