1. IGCSE BIOLOGY SECTION 2 LESSON 5

2. Content Section 2 Structures and functions in living organisms a) Levels of organisation b) Cell structure c) Biological molecules d) Movement of substances into and out of cells e) Nutrition f) Respiration g) Gas exchange h) Transport i) Excretion j) Coordination and response

3. Content Lesson 5 h) Transport 2.49 understand why simple, unicellular organisms can rely on diffusion for movement of substances in and out of the cell 2.50 understand the need for a transport system in multicellular organisms Flowering plants 2.51 describe the role of phloem in transporting sucrose and amino acids between the leaves and other parts of the plant 2.52 describe the role of xylem in transporting water and mineral salts from the roots to other parts of the plant 2.53 explain how water is absorbed by root hair cells 2.54 understand that transpiration is the evaporation of water from the surface of a plant 2.55 explain how the rate of transpiration is affected by changes in humidity,wind speed, temperature and light intensity 2.56 describe experiments to investigate the role of environmental factors in determining the rate of transpiration from a leafy shoot

4. Content Lesson 5 h) Transport Humans 2.57 describe the composition of the blood: red blood cells, white blood cells, platelets and plasma 2.58 understand the role of plasma in the transport of carbon dioxide, digested food, urea, hormones and heat energy 2.59 explain how adaptations of red blood cells, including shape, structure and the presence of haemoglobin, make them suitable for the transport of oxygen 2.60 describe how the immune system responds to disease using white blood cells, illustrated by phagocytes ingesting pathogens and lymphocytes releasing antibodies specific to the pathogen 2.61 understand that vaccination results in the manufacture of memory cells, which enable future antibody production to the pathogen to occur sooner, faster and in greater quantity 2.62 understand that platelets are involved in blood clotting, which prevents blood loss and the entry of micro-organisms 2.63 describe the structure of the heart and how it functions 2.64 explain how the heart rate changes during exercise and under the influence of adrenaline 2.65 describe the structure of arteries, veins and capillaries and understand their roles 2.66 understand the general structure of the circulation system to include the blood vessels to and from the heart, the lungs, the liver and the kidneys.

5. Diffusion in living organisms

6. In: Food oxygen

7. Diffusion in living organisms In: Food oxygen Out: Carbon dioxide Waste products

8. Diffusion in living organisms Eg. movement of oxygen in Amoeba

9. Diffusion in living organisms Eg. movement of oxygen in Amoeba Low oxygen concentration High oxygen concentration

10. Diffusion in living organisms Eg. movement of oxygen in Amoeba Low oxygen concentration High oxygen concentration Oxygen will move from a high concentration outside the cell to a lower concentration inside the cell. It is moving from high to low – i.e. down a concentration gradient.

11. Diffusion in living organisms Fine for single-celled organisms

12. Diffusion in living organisms Fine for single-celled organisms But for bigger organisms ……….

13. Diffusion in living organisms Fine for single-celled organisms But for bigger organisms ………. Multi-cellular organisms (both plants and animals) need transport systems.

14. Transport in flowering plants Water and mineral salts. Roots

15. Transport in flowering plants Water and mineral salts. Roots Sucrose and amino acids. Leaves Products of photosynthesis

16. Transport in flowering plants Water and mineral salts. Roots Sucrose and amino acids. Leaves Products of photosynthesis XYLEMPHLOEM

17. Transport in flowering plants Water and mineral salts. Roots XYLEM

18. Water (and mineral) movement into the root

19. More concentrated solution inside Less concentrated solution outside (more DILUTE)

20. Water (and mineral) movement into the root More concentrated solution inside Less concentrated solution outside (more DILUTE) WATER

21. Water (and mineral) movement into the root More concentrated solution inside Less concentrated solution outside (more DILUTE) WATER In root hair cells water moves from the surrounding soil into the cell by osmosis, along a concentration gradient

22. Water (and mineral) movement into the root Root hair cell with a high concentration of nitrate ions. Soil with a lower concentration of nitrate ions.

23. Water (and mineral) movement into the root When substances are moved into a cell where there is already a higher concentration, then ENERGY from respiration will be required. Root hair cell with a high concentration of nitrate ions. Soil with a lower concentration of nitrate ions.

24. Water (and mineral) movement into the root When substances are moved into a cell where there is already a higher concentration, then ENERGY from respiration will be required. Root hair cell with a high concentration of nitrate ions. Soil with a lower concentration of nitrate ions. Energy will be used to ‘pull’ nitrate ions from the surrounding soil into the cell

25. Water (and mineral) movement into the root When substances are moved into a cell where there is already a higher concentration, then ENERGY from respiration will be required. Root hair cell with a high concentration of nitrate ions. Soil with a lower concentration of nitrate ions. Energy will be used to ‘pull’ nitrate ions from the surrounding soil into the cell This is Active Transport

26. Water (and mineral) movement into the root When substances are moved into a cell where there is already a higher concentration, then ENERGY from respiration will be required. Root hair cell with a high concentration of nitrate ions. Soil with a lower concentration of nitrate ions. Energy will be used to ‘pull’ nitrate ions from the surrounding soil into the cell This is Active Transport Root hairs provide roots with a much greater surface area.

27. Water movement through the plant Water (and dissolved mineral salts) are moved from the roots up through the plant in xylem vessels.

28. Water movement through the plant Water (and dissolved mineral salts) are moved from the roots up through the plant in xylem vessels.

29. Water movement through the plant Water (and dissolved mineral salts) are moved from the roots up through the plant in xylem vessels.

30. Water movement through the plant Water (and dissolved mineral salts) are moved from the roots up through the plant in xylem vessels. Xylem vessels contain a strengthening material called lignin and are dead. Water movement is ‘passive’.

31. Leaf structure Cross section through a leaf

32. Leaf structure Cross section through a leaf Vascular bundle containing xylem vessels and phloem tubes

33. Leaf structure Cross section through a leaf Vascular bundle containing xylem vessels and phloem tubes Xylem Phloem

34. Water movement through the plant

35. 1. Water evaporates from the internal leaf cells through the stomata (TRANSPIRATION)

36. Water movement through the plant 1. Water evaporates from the internal leaf cells through the stomata (TRANSPIRATION) 2. Water passes from xylem vessels in the stem to leaf cells by osmosis.

37. Water movement through the plant 1. Water evaporates from the internal leaf cells through the stomata (TRANSPIRATION) 2. Water passes from xylem vessels in the stem to leaf cells by osmosis. 3. This ‘pulls’ the water up through the xylem to replace that being lost.

38. Water movement through the plant 1. Water evaporates from the internal leaf cells through the stomata (TRANSPIRATION) 2. Water passes from xylem vessels in the stem to leaf cells by osmosis. 3. This ‘pulls’ the water up through the xylem to replace that being lost. 4. Water enters the xylem vessels in the stem from root tissue to replace the water that has moved upwards.

39. Water movement through the plant 1. Water evaporates from the internal leaf cells through the stomata (TRANSPIRATION) 2. Water passes from xylem vessels in the stem to leaf cells by osmosis. 3. This ‘pulls’ the water up through the xylem to replace that being lost. 4. Water enters the xylem vessels in the stem from root tissue to replace the water that has moved upwards. 5. Water enters the root hair cells by osmosis to replace water which has entered the xylem.

40. Water movement through the plant 1. Water evaporates from the internal leaf cells through the stomata (TRANSPIRATION) 2. Water passes from xylem vessels in the stem to leaf cells by osmosis. 3. This ‘pulls’ the water up through the xylem to replace that being lost. 4. Water enters the xylem vessels in the stem from root tissue to replace the water that has moved upwards. 5. Water enters the root hair cells by osmosis to replace water which has entered the xylem. Evaporation of water from the leaf results in water being drawn through the plants from the roots = the TRANSPIRATION STREAM

41. Water loss from the leaf Stoma

42. Water loss from the leaf H2OH2O H2OH2O H2OH2O Water evaporates from the stomata ( = TRANSPIRATION)

43. Water loss from the leaf H2OH2O H2OH2O H2OH2O The Stomata can open and close in order to control the amount of water lost.

44. Water loss from the leaf H2OH2O H2OH2O H2OH2O If the plant loses too much water then it will wilt

45. Water loss from the leaf H2OH2O H2OH2O H2OH2O If the air around the leaf is very humid then less water will be lost.

46. Water loss from the leaf H2OH2O H2OH2O H2OH2O On a windy day more water will be lost from the leaf surface.

47. Water loss from the leaf H2OH2O H2OH2O H2OH2O On a hot day more water will be lost from the leaf surface.

48. Water loss from the leaf H2OH2O H2OH2O H2OH2O As light intensity increases, the stomata open more, so more water is lost.

49. Sucrose and amino acid movement through the plant Sucrose and amino acids are made in the leaves. They are transported to all parts of the plant in phloem tubes.

50. Sucrose and amino acid movement through the plant Sucrose and amino acids are made in the leaves. They are transported to all parts of the plant in phloem tubes.

51. Sucrose and amino acid movement through the plant Sucrose and amino acids are made in the leaves. They are transported to all parts of the plant in phloem tubes.

52. Sucrose and amino acid movement through the plant Sucrose and amino acids are made in the leaves. They are transported to all parts of the plant in phloem tubes. The cross walls do not completely break down, but instead from sieve plates.

53. Sucrose and amino acid movement through the plant Sucrose and amino acids are made in the leaves. They are transported to all parts of the plant in phloem tubes. Phloem tubes are living, and the movement of sucrose and amino acids is thought to be an active process.

54. Content Lesson 5 h) Transport 2.49 understand why simple, unicellular organisms can rely on diffusion for movement of substances in and out of the cell 2.50 understand the need for a transport system in multicellular organisms Flowering plants 2.51 describe the role of phloem in transporting sucrose and amino acids between the leaves and other parts of the plant 2.52 describe the role of xylem in transporting water and mineral salts from the roots to other parts of the plant 2.53 explain how water is absorbed by root hair cells 2.54 understand that transpiration is the evaporation of water from the surface of a plant 2.55 explain how the rate of transpiration is affected by changes in humidity,wind speed, temperature and light intensity 2.56 describe experiments to investigate the role of environmental factors in determining the rate of transpiration from a leafy shoot

55. Content Lesson 5 h) Transport Humans 2.57 describe the composition of the blood: red blood cells, white blood cells, platelets and plasma 2.58 understand the role of plasma in the transport of carbon dioxide, digested food, urea, hormones and heat energy 2.59 explain how adaptations of red blood cells, including shape, structure and the presence of haemoglobin, make them suitable for the transport of oxygen 2.60 describe how the immune system responds to disease using white blood cells, illustrated by phagocytes ingesting pathogens and lymphocytes releasing antibodies specific to the pathogen 2.61 understand that vaccination results in the manufacture of memory cells, which enable future antibody production to the pathogen to occur sooner, faster and in greater quantity 2.62 understand that platelets are involved in blood clotting, which prevents blood loss and the entry of micro-organisms 2.63 describe the structure of the heart and how it functions 2.64 explain how the heart rate changes during exercise and under the influence of adrenaline 2.65 describe the structure of arteries, veins and capillaries and understand their roles 2.66 understand the general structure of the circulation system to include the blood vessels to and from the heart, the lungs, the liver and the kidneys.

56. Transport in Humans

58. PLASMA – Straw coloured liquid. transports CO 2 from the tissues to the lungs. transports soluble products of digestion from small intestine to the organs and tissues transports other wastes, such as urea, from the liver to the kidneys. transports hormones around the body carries heat away from organs and tissues

59. Transport in Humans PLASMA – Straw coloured liquid. transports CO 2 from the tissues to the lungs. transports soluble products of digestion from small intestine to the organs and tissues transports other wastes, such as urea, from the liver to the kidneys. transports hormones around the body carries heat away from organs and tissues RED BLOOD CELLS (RBCs) – transport oxygen from the lungs to organs and tissues contains haemoglobin, a red pigment haemoglobin combines with oxygen to form oxyhaemoglobin biconcave in shape no nucleus Large surface area

60. Transport in Humans PLASMA – Straw coloured liquid. transports CO 2 from the tissues to the lungs. transports soluble products of digestion from small intestine to the organs and tissues transports other wastes, such as urea, from the liver to the kidneys. transports hormones around the body carries heat away from organs and tissues WHITE BLOOD CELLS – two main forms, granulocytes and agranulocytes. granulocytes have a lobed nucleus and engulf microbes agranulocytes have a rounded nucleus and produce antibodies to attack microbes

61. Transport in Humans PLASMA – Straw coloured liquid. transports CO 2 from the tissues to the lungs. transports soluble products of digestion from small intestine to the organs and tissues transports other wastes, such as urea, from the liver to the kidneys. transports hormones around the body carries heat away from organs and tissues PLATELETS – Fragments of cells, used in the blood clotting process to close wounds.

62. White cells and immunity

63. White blood cell Micro-organisms

64. White cells and immunity The white blood cell begins to surround the micro-organisms

65. White cells and immunity The micro-organisms are ingested by the white blood cell and are destroyed.

66. White cells and immunity The agranulocytes produce antitoxins which neutralise harmful toxins (poisons) produced by micro- organisms.

67. White cells and immunity Micro-organisms that invade our bodies are called pathogens. Once inside the body these pathogens (eg. viruses) reproduce inside cells and damage them, and produce toxins. Cell damage and toxins cause the symptoms of infectious diseases.

68. White cells and immunity Micro-organisms that invade our bodies are called pathogens. Once inside the body these pathogens (eg. viruses) reproduce inside cells and damage them, and produce toxins. Cell damage and toxins cause the symptoms of infectious diseases. Pathogens contain specific chemicals called antigens that are detected by white blood cells. The white blood cells produce antibodies which latch onto the antigens and destroy the pathogens.

69. White cells and immunity ANTIGEN WHITE BLOOD CELL

70. White cells and immunity Antibodies produced by the white blood cell

71. White cells and immunity Antibodies attach to the antigens, causing them to clump together, and they are then destroyed.

72. White cells and immunity It can take a little time for the antibodies to be produced, so we may feel ill for a time.

73. White cells and immunity The production of antibodies is much faster if we have already had the infectious disease. The white blood cells ‘recognise’ the antigen, respond rapidly and give us natural immunity.

74. Artificial immunity We can acquire immunity to a particular disease by being vaccinated.

75. Artificial immunity We can acquire immunity to a particular disease by being vaccinated. Step 1 A weakened or dead antigen is injected into a person.

76. Artificial immunity We can acquire immunity to a particular disease by being vaccinated. Step 1 A weakened or dead antigen is injected into a person. Step 2 The body produces antibodies to fight the antigen.

77. Artificial immunity We can acquire immunity to a particular disease by being vaccinated. Step 1 A weakened or dead antigen is injected into a person. Step 2 The body produces antibodies to fight the antigen. Step 3 The body has now acquired immunity to this antigen as the white blood cells will now recognise the antigen and respond rapidly with the production of antibodies

78. Our circulatory system

79. HEART LUNGS BODY

80. Our circulatory system HEART LUNGS BODY

81. Our circulatory system HEART LUNGS BODY Deoxygenated blood Oxygenated blood

82. Our circulatory system HEART LUNGS BODY Vena cavaAorta Pulmonary artery Pulmonary vein

83. The Heart

84. RightLeft

85. The Heart

86. Blood from the body (Vena cava) Semi-lunar valve Tricuspid valve Right atrium Right ventricle Blood to the lungs (pulmonary artery)

87. The Heart Blood from the body (Vena cava) Semi-lunar valve Tricuspid valve Right atrium Right ventricle Blood to the lungs (pulmonary artery) Blood from the lungs (pulmonary vein) Blood to the body (Aorta) Left atrium Semi-lunar valve Bicuspid valve Left ventricle

88. The Heart Ventricular diastole (relaxation) From body From lungs

89. The Heart Ventricular diastole (relaxation) From body From lungs When the ventricular muscle relaxes, blood flows into the left and right atria, through veins, from the lungs (left) and from the body (right)

90. The Heart Ventricular diastole (relaxation) From body From lungs When the ventricular muscle relaxes, blood flows into the left and right atria, through veins, from the lungs (left) and from the body (right) The right and left atria then contract, forcing open the bicuspid and tricuspid valves, and squeezing blood into the ventricles.

91. The Heart Ventricular systole (contraction) To the body To the lungs

92. The Heart Ventricular systole (contraction) To the body To the lungs When the ventricular muscle contracts blood is forced through the semi – lunar valves into the arteries, taking blood to the lungs and body

93. The Heart Ventricular systole (contraction) To the body To the lungs When the ventricular muscle contracts blood is forced through the semi – lunar valves into the arteries, taking blood to the lungs and body The valves prevent the blood from flowing in the wrong direction. The cardiac cycle is a repeating sequence of contraction and relaxation.

94. Heart rate and exercise As we exercise, our heart rate increases. The more intense the level of exercise, the faster our heart beats.

95. Heart rate and exercise As we exercise, our heart rate increases. The more intense the level of exercise, the faster our heart beats. The faster our heart beats, the more oxygen can be transported to our muscles, and waste products can also be removed more quickly.

96. Heart rate and adrenaline Adrenaline is a hormone secreted by our adrenal glands. The hormone is secreted when the body anticipates strenuous exercise, or when we are in a stressful situation. Adrenaline is carried in the blood and stimulates the heart to beat faster. More oxygen is therefore pumped to the muscles.

97. Heart rate and adrenaline Adrenaline is a hormone secreted by our adrenal glands. The hormone is secreted when the body anticipates strenuous exercise, or when we are in a stressful situation. Adrenaline is carried in the blood and stimulates the heart to beat faster. More oxygen is therefore pumped to the muscles. Adrenaline is known as the ‘fight or flight’ hormone and prepares the body by increasing the oxygen supply, energy levels, and raising blood pressure.

98. The Blood Vessels

99. ARTERIES Very thick elastic and muscular layers which enable the artery to cope with the high blood pressure Small LUMEN (space through which the blood passes) Other features: no valves needed (high blood pressure). Carry blood away from the heart (all oxygenated, except the Pulmonary Artery). Substances cannot pass from the blood through the artery walls.

100. The Blood Vessels VEINS Much thinner elastic and muscular layers (blood is carried at much lower pressure) Large LUMEN (compared to the thickness of the walls) Other features: valves needed (low blood pressure). Carry blood towards the heart (all de-oxygenated, except the Pulmonary Vein). Substances cannot pass from the blood through the veins’ walls. Valve

101. The Blood Vessels CAPILLARIES Narrow, very thin-walled vessels, just one cell thick Microscopic, just enough room for blood cells to pass through. Connect arteries to veins Exchange of substances (oxygen, glucose, waste) between the blood and the surrounding tissues takes place here.

102. The Blood Vessels cell Artery rich in oxygen and food Vein rich in carbon dioxide and waste Capillary network in a muscle Arteries branch into tiny one cell thick capillaries which pass close to each cell before re-uniting to form a vein.

103. Blood capillary Glucose Muscle cell Glucose + Oxygen  Carbon dioxide + Water Glucose and oxygen diffuse from the blood into the muscle cell Carbon dioxide and water diffuse from the muscle cell into the blood Deoxygenated red blood cells Energy Energy is used for muscle contraction

104. Content Lesson 5 h) Transport Humans 2.57 describe the composition of the blood: red blood cells, white blood cells, platelets and plasma 2.58 understand the role of plasma in the transport of carbon dioxide, digested food, urea, hormones and heat energy 2.59 explain how adaptations of red blood cells, including shape, structure and the presence of haemoglobin, make them suitable for the transport of oxygen 2.60 describe how the immune system responds to disease using white blood cells, illustrated by phagocytes ingesting pathogens and lymphocytes releasing antibodies specific to the pathogen 2.61 understand that vaccination results in the manufacture of memory cells, which enable future antibody production to the pathogen to occur sooner, faster and in greater quantity 2.62 understand that platelets are involved in blood clotting, which prevents blood loss and the entry of micro-organisms 2.63 describe the structure of the heart and how it functions 2.64 explain how the heart rate changes during exercise and under the influence of adrenaline 2.65 describe the structure of arteries, veins and capillaries and understand their roles 2.66 understand the general structure of the circulation system to include the blood vessels to and from the heart, the lungs, the liver and the kidneys.

105. End of Section 2 Lesson 5 In this lesson we have covered: Transport in flowering plants Transport in humans