E N D
1. GCSE Biology Revision 2006-2007
2. Life Processes Movement
Respiration
Sensitivity
Growth
Reproduction
Excretion
Nutrition
3. Plant and Animal Cells
4. Cell specialisation
5. Cell organisation
6. Transport In and Out of Cells Diffusion – from a high to a low concentration until they are evenly spread
Osmosis – from a region of high water concentration to a region of low (weak to a strong solution) through a semi permeable membrane
Active transport – from a low to a high concentration across a cell membrane
7. Digestion
8. Balanced Diets Carbohydrates
Protein
Lipids / Fats
Vitamins
Minerals
Fibre
Water
9. The Duodenum
10. The Ileum
11. Absorption and Assimilation
12. Assimilation All digested glucose and amino acids pass into the liver in the Hepatic Portal Vein.
Fats enter the lymphatic system which enters the blood and returns them to the liver.
The food is used for growth, repair, respiration.
Excess food is mostly stored as fat.
13. Food Testing Starch – add iodine – turns black
Glucose or reducing sugar – add Benedict's solution and boil – turns brick red
Protein – Biuret test – add NaOH or KOH and then 1% copper sulphate – a violet colouration
14. Aerobic Respiration With oxygen
C6H12O6 + 6O2 6H2O + 6CO2 + energy
15. Anaerobic Respiration Animals
Glucose Lactic acid
Plants
Glucose Ethanol and carbon dioxide
Oxygen debt – the amount of oxygen needed to breakdown the lactic accumulated
16. Structure of Thorax
17. The Thorax
18. Breathing in Is controlled by the intercostal muscles and the diaphragm.
When we breathe in the intercostal muscles contract and the ribs move up and out. The diaphragm contracts and moves down.
This increases the space inside the chest and air rushes into the lungs.
19. Breathing out The intercostal muscles and the diaphragm relax.
The ribcage drops down and the diaphragm moves upwards.
This reduces the space inside the chest and pushes air out of the lungs.
20. Breathing Rate and Depth Rate - how many breaths per minute
Depth – how much air is being taken in, normally ˝ litre per breath
Measured with a spirometer
21. % of different gases in inhaled and exhaled air
22. Gaseous exchange
23. What makes the lung good at gaseous exchange? Large surface area – greater volume of gases exchanged
Good blood supply – O2 and CO2 exchanged more quickly
Thin membranes – allows diffusion
Moist lining – for the gases to dissolve
24. Keeping the Lungs Clean Dust, bacteria and other particles stick to the mucus secreted by cells lining the airways
Cilia attached to these cells waft the mucus and dirt out of the lungs and it is swallowed.
Acid in the stomach kills the bacteria
25. Effects of Smoking
27. Photosynthesis lightcarbon dioxide+water glucose+oxygen chlorophyll
6H2O + 6CO2 C6H12O6 + 6O2
28. Leaf Structure
29. The leaf has a waxy cuticle to stop it losing water.
The epidermis is a protective layer of cells and contains no chloroplasts.
The palisade layer contains the most chloroplasts as it is near the top of the leaf. The chloroplasts contain the pigment chlorophyll. It is here that photosynthesis takes place.
The palisade cells are arranged upright. This means the light has to pass through the cell lengthways and so increases the amount of light absorbed.
30. Stomata
33. Limiting Factors Photosynthesis is a chemical reaction, its rate depends upon temperature, how much CO2 is available, light intensity, amount of chlorophyll or water.
Without enough light a plant cannot photosynthesise very fast, even if there is plenty of water and carbon dioxide. Increasing the light intensity will make photosynthesis faster.
34.
Sometimes photosynthesis is limited by the level of carbon dioxide. Even if there is plenty of light a plant cannot photosynthesise if it has run out of carbon dioxide.
Temperature can be a limiting factor too. If it gets too cold the rate of photosynthesis will slow right down; equally, plants cease to be able to photosynthesise if it gets too hot.
35. If you plot the rate of photosynthesis against the levels of these three limiting factors you get graphs like the ones below.
36. Maximising growth
Understanding the factors that limit photosynthesis enables greenhouse farmers to maximise the conditions for plant growth. They often use paraffin lamps inside the greenhouse because burning paraffin produces carbon dioxide as well as heat, and so makes photosynthesis proceed faster. They may also use artificial light to enable photosynthesis to continue beyond daylight hours.
37. Uses of Glucose Turned into starch for storage
Converted into lipid/fat for storage – energy rich
Nitrogen can be added and turned into protein
Stored in fruit
Used in respiration
38. Mineral Requirements
39. The Heart
40. The Heart Pumps blood around the body
Pumps blood to the lungs
To pick up oxygen
Remove carbon dioxide
41. Double Circulation
42. Arteries Veins and Capillaries
43. Blood
44. Platelets Used in the clotting of blood
Damage cause them to clump and they begin the conversion of soluble fibrinogen (blood protein) into insoluble fibrin which meshes over the wound and traps red cells. They dry and form a scab
45. Blood Cells
46. Tissue exchange
47. The lymphatic system Transports excess fluid from the tissues
Transports digested fat
Contains white blood cells that fight infection
48. William Harvey 1578-1657
Observed blood flow around the body
Noticed existence of valves in veins
Concluded blood pumped via veins round body
Major medical breakthrough!
49. Galen Lived 1,000 years before Harvey
Did not use the scientific method
Observation and experimentation
Thought blood went from side to side
Did not realise transport existed round body through capillaries
50. Transport in Plants
51. The Plant Transport System
52. Xylem consists of dead cells with no end walls, which contain lignin to form stiff tubes. They are impermeable.
55. Transpiration
56. Ecology – Competition and Adaptation
57. Plant adaptations
58. Predators, Prey and Co-operation
59. Food Chains
60. Woodland Food Web
61. Pyramid of Numbers
62. Pyramid of biomass
63. Decomposition
64. The Carbon Cycle
65. Nitrogen Cycle
66. Food Production and farming methods Monoculture
Hedgerow removal
Biological pest control
Pesticides and herbicides and insecticides
67. Energy and Waste Burning fossil fuels such as coal, oil or gas
Greenhouse effect
Sulphur dioxide and nitrous oxides are formed which dissolve in water to form acid rain
Reduce the demand for energy so it reaches a sustainable level- will not use up the resources or pollute the planet
68. Global Warming and Acid Rain
69. Conservation
70. The Nervous System
71. Motor neuron
72. The Eye
73. Accommodation
74. Nerves Synapses and Drugs
75. The CNS and Reflex Actions
76. Hormones Proteins that are chemical messengers in the body
Carried in the blood to target cells
Response is slower
May last for hours
Can stimulate more than one target
77. Controlling glucose, After eating a lot of carbohydrate blood sugar level rises.
Islets of Langerhans in the pancreas release insulin, the glucose is stored as glycogen in the liver.
The blood sugar level drops .
When blood sugar levels are low the insulin production stops.
Glucagon is produced by the pancreas allowing glucose release from the liver and muscles.
78. Uses of Hormones Controlling fertility – the contraceptive pill, may contain oestrogen and progesterone and controls the release of pituitary hormones and ovulation
Mini pill, progesterone allows ovulation but makes the vagina and uterus unsuitable for sperm
Anabolic steroids build muscle – reduce the production of testosterone
79. Uses of plant hormones Auxins allow plants to respond to the environment – tropic responses
Auxin (IAA) causes -
They stimulate shoots to grow rapidly
Stops side shoots growing
Stimulates growth of roots from the base of stems or leaves
Auxin from seeds cause fruit to swell
80. Plant responses and Auxins
81. Homeostasis Temperature Control
Water Control
Salt Balance
Sugar control
Carbon Dioxide Control
Urea
82. Temperature Control Thermoregulation keeps the body at constant temperature (37oC).
Enzymes work best.
Temperature is regulated by the hypothalamus.
83. Temperature Control Heat is made in most cells but in particular muscle and liver.
Heat is lost by convection, conduction and radiation.
Evaporation of water from a surface removes heat.
84. Keeping Cool Vasodilation, more blood flows nearer the skin and heat is lost.
Sweating, evaporation causes heat loss.
Hairs lie flat allowing more heat out.
85. Keeping Warm Vasoconstriction - less blood flows to the skin’s surface, keeping heat in. You may look pale!!
Decrease in sweat.
Shivering generates heat (respiration).
Hairs stand up and trap insulating air.
86. Carbon dioxide Excess carbon dioxide results in a drop in the body’s pH (acidic).
Breathing out removes this excess.
The rate and depth of breathing will alter to suit the amount of CO2.
87. The Kidney
88. Urea Urea is produced when proteins and amino acids are broken down in the liver.
It is poisonous.
The kidneys remove it but so does sweating !!
89. The kidney
90. The kidneys have four functions:
Regulation of blood water levels
Reabsorption of useful substances into the blood
Adjustment of the levels of salts and ions in the blood
Excretion of urea and other metabolic wastes
91. Kidneys: how they work
92. Kidney transplant This is when the diseased kidney is surgically removed and replaced by a fully functioning kidney from a deceased or a live donor.
It is only possible after a satisfactory tissue-match. Even after a successful tissue-match the recipient's immune system has to be drugged or suppressed to stop it from rejecting the new kidney.
93. Kidney failure In the event of kidney failure due to infection or disease, the kidney can no longer remove metabolic waste products from the body. Excretion of metabolic waste is a vital function and their accumulation will result in eventual death.
There are two solutions to the problem of kidney malfunction or failure:
Kidney transplant
Kidney dialysis
95. Kidney dialysis In the absence of a suitable donor kidney, the alternative solution is for the patient to be hooked-up to a dialysis machine every 2 - 3 days.
A dialysis machine mimics the functioning of the kidney. Blood from an artery in the patient's arm is pumped into the kidney machine which removes urea and excess salts from it.
The blood is checked for air bubbles before being returned to a vein in the arm.
96. Osmoregulation Is keeping the water and salt levels constant in the blood.
They are regulated by the hypothalamus.
Water moves into the cells by osmosis and could cause them to burst.
97. Blood concentration too high The hypothalamus senses too little water in the blood.
A message is sent to the pituitary gland to release anti-diuretic hormone.
This stops the kidneys removing water and going to the loo!!
98. Blood concentration too low. Too much water in the blood stops the hypothalamus signalling the pituitary.
Water is removed by the kidneys.
Large amounts of dilute urine produced.
99. Cell Division - Mitosis
101. DNA
102. Genetic and Environmental causes of Variation Variation is inherited
Genetic – skin colour
Environmental – hair length
Both – height, weight, intelligence
103. Asexual reproduction Produces identical copies called clones – onions, strawberries, potatoes, greenfly
This type of cell division is mitosis
Cuttings and grafting in plants
Micropropogation used by growers
104. Mutations Change in the DNA of an organism caused by an error when it is copied
Radiation and certain chemicals such as cigarette smoke can cause mutations
Most are harmful and leads to illness or death
Useful ones are rare but have a dramatic impact on a species and its evolution
105. Harmful mutations Down’s syndrome – an extra chromosome number 21
Cystic fibrosis is caused by a mutation in the DNA. It is a recessive allele which affects 1 in 2000 children.
It causes sticky mucus which blocks the lungs and pancreas
106. Genetic Engineering Is the ability to alter DNA
A gene from one organism can be transferred into the DNA of a completely different organism
In some cases the all the DNA is removed from a cell and replaced with the DNA from another organism
Dolly the sheep was the first example of genetic cloning
107. Selective Breeding In animals – dogs, cows, sheep, cats and so on. To produce certain traits
In plants for taste, texture, shelf life
Is done by choosing parents with the required traits. These are then bred to produce offspring.
Sexual reproduction will ensure variation
108. Mendel
109. Genetic Crosses
111. Evolution Most organisms overproduce
Population numbers remain constant
Sexual reproduction ensures that all offspring exhibit variation
These variations are inherited from the parents
From these Darwin produced his theory of evolution
112. Darwin
113. New Species – Survival of the Fittest The peppered moth
Pale ones no longer camouflaged during the Industrial Revolution – were no longer camouflaged
Darker ones survived to reproduce and some of their offspring were even darker
This is survival of the fittest