Cells-and-Organisation-Y10-IGCSE-CIE.pptx

IGCSE Cells and Organisation

1. IGCSE BIOLOGY 2 cells and organisation

2. Learning Objectives Identify and describe the structure of plant cells and animal cells, and describe the functions of their parts. Describe the difference between animal cells and plant cells. Explain the structure and function of specialised cells: red blood cell, muscle cells, ciliated cells, xylem vessels and root hair cells. Define the terms tissue, organ and organ systems, with examples.

3. Cutting sections The slice of tissue must be only 0.01-0.1 mm thick if cells are to be seen clearly. Thin slices of plant tissue can be made by hand using a sharp razor blade The slices are called sections. Special apparatus and techniques are needed to make very thin sections.

4. Cutting sections Transverse section Longitudinal section

5. 2.1 Animal Cells

6. CELL STRUCTURE (ANIMAL ) 2.2 describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole You need to know the differences between plant and animal cells, the functions of the organelles and be able to recognize them in a microscope picture or drawing. Mircro scope

7. A section through a liver cell cell membrane cytoplasm nucleus DNA 0.00001mm thick, encloses cytoplasm & controls what enters and leaves the cell contains many structures & all metabolic (chemical) reactions occur here contains the DNA, regulates all chemical changes in cytoplasm & sends chemical signals to cytoplasm to signal start or stop reactions contains the coded instructions to make proteins & controls cell division

8. Complexity of Animal Cells smooth ER rough ER vacuole centriole cytoplasm mitochondria Golgi apparatus nucleus DNA ribosome cell membrane

9. Cell Membrane Present in all cells Also called as plasma membrane or cell surface membrane Made up of thin layer of protein and fats Partially permeable Inside cell membrane lies cytoplasm and other cell organelles.

10. TM of Animal Cell with Rough Endoplasmic Reticulum

11. Mitochondria Are powerhouses of cells Are found in all cells except those of a prokaryote In aerobic respiration, oxygen is used to release oxygen from the contents of the mitochondrion (starch in plants and glycogen in animals) Cells containing mitochondria are- Muscle cell- to work Sperm cell- to swim in the semen Neurons- to carry electrical nerve impulses

12. Cytoplasm Jelly like substance Contains 70% water Metabolic reactions of the cell take place over here Harmful and useful substances diffuse in and out of cells through the cytoplasm

13. Liver Cells Nucleus (large) Cytoplasm Cell membrane Liver cells are particularly active in protein synthesis and lipid synthesis.

14. Cells from the Cheek Lining © Biophoto Associates cytoplasm nucleus cell membrane 0.01mm 8

15. 2.2 Plant Cells

16. CELL STRUCTURE (PLANT) 2.2 describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole

17. Onion cell

18. Cell Wall The cell wall is made of cellulose. Many animals digest cellulose using bacterial enzymes, but humans cannot digest it. The cell wall protects, supports and gives shape to the plant cell. Present in plant and prokaryote cells In plants, made up of cellulose Cellulose forms fibres in criss-cross patterns over one other Cell wall forms very strong covering to cell Prevents cell from bursting

19. Vacuole nucleus mitochondria chloroplast vacuole cell wall cell membrane cytoplasm Vacuoles are spaces in cells containing a solution called cell sap Large vacuoles are present in plant cells to store the useful products formed in photosynthesis In animal cells, small vacuoles or no vacuoles at all can be present as animal cells are heterotrophic Small vacuoles in animal cells often store food and water

20. Chloroplasts Green plants contain the pigment chloroplast. This is where sun light is absorbed and photosynthesis takes place. Starch is also stored in the chloroplast. vacuole chloroplast cell wall © Biophoto Associates 0.2mm 10

21. Section through a palisade cell of a leaf cell membrane nucleus cytoplasm chloroplast large sap vacuole cellulose cell wall partially permeable & contains cytoplasm controls all activities of cell metabolic reactions take place here green pigment where starch is produced and stored fluid filled cell sap which exerts pressure to keep shape support, protect, keep shape

22. Complexity of plant cell

23. CELL STRUCTURE (PLANT & ANIMAL) 2.3 describe the functions of the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole Functions of the Organelles (These are the basic definitions you must know) Cytoplasm - site of chemical reactions in the cell Cell Membrane - controls what enters / leaves the cell (selectively permeable) Nucleus - contains nucleic acids, which code for the synthesis of specific proteins. These proteins control all activity in the cell Mitochondrion - site of respiration Chloroplast - site of photosynthesis (contains chlorophyll) Cell Wall - made from cellulose. Strengthens the cell and allows it to be turgid Sap Vacuole - contains the cell sap. Acts as a store of water, or of sugars or, in some cases, of waste products the cell needs to excrete. Helps keep plant cell turgid.

24. Structure of a leaf cell cell wall cell membrane cytoplasm Longitudinal section Transverse section vacuole nucleus The diagram shows how a 3-dimensional leaf cell would appear in transverse and longitudinal section 12

25. You should be able to: Identify and describe the structure of plant cells and animal cells, and describe the functions of their parts. Describe the difference between animal cells and plant cells. Explain the structure and function of specialised cells: red blood cell, muscle cells, ciliated cells, xylem vessels and root hair cells. Define the terms tissue, organ and organ systems, with examples.

26. Comparing animal and plant cells Found in both animal and plant cells Found only in plant cells cell membrane cellulose cell wall nucleus large sap vacuole cytoplasm chloroplast

27. 2.3 Specialized Cells

28. You should be able to: Identify and describe the structure of plant cells and animal cells, and describe the functions of their parts. Describe the difference between animal cells and plant cells. Explain the structure and function of specialised cells: ciliated cells , root hair cells, xylem vessels, palisade mesophyll , nerve cells, red blood cell and nerve cell. Define the terms tissue, organ and organ systems, with examples.

29. CELL STRUCTURE (PLANT & ANIMAL) 2.2 describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole SOME SAMPLE CELL DIAGRAMS: White blood cell SPERM CELL Root hair cell

30. Ciliated cells move bacteria and dust away from the lungs cilia magnification X3000 nucleus Cilia are small extensions of the cell. They beat rhythmically to sweep mucus, which has trapped bacteria and dust, away from the lungs

31. Root hair cells absorb minerals and water from the soil contains no chloroplasts as no photosynthesis is needed Cross-section of a root hair cell cytoplasm root hair increases surface area for absorption of water and mineral ions cell membrane semi-permeable, so will allow water and mineral ions into the cell

32. Xylem vessels transport water and minerals up the plant xylem vessel lignin no cytoplasm longitudinal section cross-section water-proof and strong; helps support the plant hollow: allows for continuous flow of water and dissolved mineral ions xylem vessels are continuous tubes

33. Palisade mesophyll cells where most photosynthesis takes place nucleus chloroplast cytoplasm vacuole cell wall cell membrane green pigment where photosynthesis takes place made of cellulose fully permeable sap filled to keep the shape of cell partially permeable

34. Nerve cells carry electrical impulses gap between two neurons where neurotransmitters/ neurochemicals are passed part of the cell that carries nerve impulses Axon

35. Gametes are involved in Reproduction haploid: 23 chromosomes haploid: 23 chromosomes

36. Red blood cells transport oxygen cell surface membrane cytoplasm contains no nucleus cytoplasm contains haemoglobin bi-concave disc shape allows more room for haemoglobin increases surface area over which absorption of oxygen can occur haemoglobin is a protein which carries the oxygen molecules

37. Muscle cells contract and enable movement of the body (not included in syllabus) The strands of protein slide over each other making the muscle cell (fibre) shorter and causing the muscle to contract Muscle cells have many nuclei nucleus cell surface membrane protein strands muscle

38. 2.4 level of organisation

39. You should be able to: Identify and describe the structure of plant cells and animal cells, and describe the functions of their parts. Describe the difference between animal cells and plant cells. Explain the structure and function of specialised cells: red blood cell, muscle cells, ciliated cells, xylem vessels and root hair cells. Define the terms tissue, organ and organ systems, with examples .

40. A tissue is a group of cells of similar structure that perform a shared function Animal tissues: muscle tissue nervous tissue upper epidermal tissue palisade mesophyll tissue spongy mesophyll tissue lower epidermal tissue Tissues found in the leaf Cross-section of a leaf

41. An organ is a structure made of a group of tissues working together to perform specific functions Plant organs include the stem and the leaves heart stomach lungs liver brain kidneys

42. An organ system is a group of organs that coordinate to perform related functions In plants the shoot is an organ system consisting of leaves and the stem lymphatic system respiratory system digestive system excretory system reproductive system muscular system skeletal system nervous system endocrine system circulatory system

43. Levels of organisation nerve cell nervous tissue brain nervous system Homo sapiens smallest largest cell tissue organ organ systems organism

44. LEVELS OF ORGANIZATION 2.1 describe the levels of organisation within organisms: organelles, cells, tissues, organs and systems. Organisms are made from organizations of smaller structures. You need to know the following hierarchy of structures. Organelles - intracellular structures that carry out specific functions within a cell Cells - the basic structural and functional unit from which all biological organisms are made Tissues - a group of specialized cells, which are adapted to carry out a specific function Organs - a collection of two or more tissues, which carries out a specific function or functions Organ Systems - a group of two or more organs Nucleus Chloroplast Mitochondria Ribosome Vacuole Neurone Skin cell Muscle cell Phagocyte Red Blood Cell Muscle Nerves Blood Bone Adipose (Fat) Heart Skin Brain Artery Kidney Pulmonary Cardiac Nervous Endocrine Skeletal

45. LEVELS OF ORGANIZATION 2.1 describe the levels of organisation within organisms: organelles, cells, tissues, organs and systems.

46. 2.5 microscopy and magnification

47. The difference between magnification and resolution. Magnification is the degree to which the size of an image is larger than the image itself. Resolution is the degree to which it is possible to distinguish between two objects that are very close together.

48. 1000 1000 1000 1000 mm Micrometre nm

49. Nanometre Micrometre Millimetre 5 0.005 0.000005 1       1       1   3   7         0.5       0.001 0.000001 1000 0.001 1 000 000 1000 3000 0.003 0.007 0.000007 500 000 500

50. How do we find the overall magnification of a light microscope? Eyepiece Magnification Objective Magnification Overall Magnification X10 X4   X10 X10 X10 X40   X10 X100   Eyepiece Objective lens 40 100 400 1000

51. 2.1 Cell structure and function Observing cells You must be able to calculate the magnification or actual size from a micrograph (picture from a microscope). To do this use the IAM triangle.

52. The diagram below is a drawing of an organelle from a ciliated cell as seen with an electron microscope. Calculate the actual length of the organelle as shown by the line AB in the diagram. Express your answer to the nearest micrometer (mm). Show your working.   Answer = ........................................... m m A = I M = 102mm 20000 = 102000 m m 20000 5.1

53. The diagram below is a drawing of an alveolus together with an associated blood capillary. The line AB in the diagram represents an actual distance of 1.5 µm. Calculate the magnification of the drawing. Show your working. Answer = × ................................................. M = I A = 21mm 1.5 m m = 21000 m m 1.5 m m 14000

54. The diagram below shows the general structure of an animal cell as seen under an electron microscope. _________ 5  m 1) Calculate the magnification factor of the diagram M = I A = 24mm 5 m m = 24000 m m 5 m m = 4800

55. The diagram below shows the general structure of an animal cell as seen under an electron microscope. _________ 5  m 2) Calculate the actual length of structure G A = I M = 12mm 4800 = 12000 m m 4800 = 2.5 m m

56. The diagram below shows the general structure of an animal cell as seen under an electron microscope. _________ 5  m 3) Calculate the diameter of the nucleolus (structure B) A = I M = 8mm 4800 = 8000 m m 4800 = 1.666 m m = 1.7 m m

57. The diagram below shows the general structure of an animal cell as seen under an electron microscope. _________ 5  m 4) Calculate the diameter of the nucleus A = I M = 36mm 4800 = 36000 m m 4800 = 7.5 m m

58. The diagram below shows the general structure of an animal cell as seen under an electron microscope. _________ 5  m 5) Calculate the diameter of the cell at its widest point A = I M = 116mm 4800 = 116000 m m 4800 = 24.16666 m m = 24.2 m m

59. The diagram below shows the general structure of a plant cell when viewed under and electron microscope. ___________ 40  m 1) Calculate the magnification factor of the diagram M = I A = 23mm 40 m m = 23000 m m 40 m m = 575

60. The diagram below shows the general structure of a plant cell when viewed under and electron microscope. ___________ 40  m 2) Calculate the thickness of the cellulose cell wall. A = I M = 3mm 575 = 3000 m m 575 = 5.2 m m

61. The diagram below shows the general structure of a plant cell when viewed under and electron microscope. ___________ 40  m 3) Calculate the length of the cell. A = I M = 98mm 575 = 98000 m m 575 = 107.4 m m

62. The diagram below shows the general structure of a plant cell when viewed under and electron microscope. ___________ 40  m 4) Calculate the length of structure C. A = I M = 24mm 575 = 24000 m m 575 = 41.7 m m

63. The diagram below shows the general structure of a plant cell when viewed under and electron microscope. ___________ 40  m 5) Calculate the length of the vacuole. A = I M = 71mm 575 = 71000 m m 575 = 123.5 m m

64. M = I A = 82mm 20 m m = 82000 m m 20 m m = 4100 Calculate the actual length of structure C. Show your working and give your answer in micrometres ( μm ).

65. M = I A = 82mm 20 m m = 82000 m m 20 m m = 4100 Calculate the actual length of structure C. Show your working and give your answer in micrometres ( μm ). A = I M = 15mm 4100 = 15000 m m 4100 = 3.6 m m