Biology Year 9+ PDF

Biology Bioenergenetics Respiration Lipids (fat or oils composed of fatty acids), carbohydrates, proteins are all needed in the body Aerobic respiration. Respiration takes place in the mitochondria it is a slow and controlled process. Most organisms can’t respire without oxygen. This energy is u...

Biology Bioenergenetics Respiration Lipids (fat or oils composed of fatty acids), carbohydrates, proteins are all needed in the body Aerobic respiration. Respiration takes place in the mitochondria it is a slow and controlled process. Most organisms can’t respire without oxygen. This energy is used to make new molecules in the cell glucose +oxygen -> Carbon dioxide + Water Anaerobic respiration- This respiration takes place without oxygen for a shorter period, this is called anaerobic respiration (far less efficient), it turns glucose into lactic acid Glucose -> lactic acid + Energy released This reaction takes place in yeast when making alcoholic drinks when yeast cells are made oxygen runs out and uses anaerobic respiration ethanol and carbon dioxide produced, Certain plants respire anaerobicly where air concentration is low Muscles use energy to contract so exercising causes muscles to need more oxygen. During long periods of vigorous activity lactic acid builds up and glycogen reserves (a stored form of glucose) get lower. You also go into oxygen debt which is the amount of extra oxygen required by the body for recovery after vigorous exercise Low amounts of glycogen causes muscle fatigue Lactic acid is taken to the liver by the blood and oxidised to carbon dioxide or into glucose to restore liver and muscle glucose levels Metabolism Metabolism is the sum of the chemical reactions in the body Glucose in plants- glucose causes cellulose which strengthens the plant wall, Starch which stores a form of glucose and Glucose + Nitrate Ions used to synthesise proteins Glucose in humans- makes glycogen which is a storage form of glucose, 1 molecule of glycerol + 3 fatty acid molecules = lipid found in the cell membrane Excess Protein is sent to the urea Which is excreted from the kidneys Photosynthesis Carbon dioxide + water -light and chlorophyl> glucose + oxygen 6 CO2 + 6 H2O -light chlorophyll > C12H12 06 + 6 O2 Factors affecting photosynthesis- the rate of oxygen output The rate of carbon dioxide uptake The rate of carbohydrate production Light intensity Carbon dioxide Temperature The compensation point these graphs have been plotted with the rate of photosynthesis against the factor under investigation if oxygen production is used as a measure of photosynthetic rate the graphs are slightly different the line does not got through origin this is due to oxygen production and carbon dioxide uptake are affected by respiration. Infections and responses All types of pathogens have a simple life cycle. They infect a host, reproduce themselves or replicate if it is a virus, spread from their host and infect other organisms. They also all have structural adaptations that make them successful at completing their life cycles, which enable them to cause further disease. Diseases caused by pathogens are called communicable diseases. This means they can be transferred from one person to another. There are other types of disease which cannot be caught: Inherited genetic disorders like cystic fibrosis. Deficiency diseases which are caused by a lack of essential vitamins or minerals, such as scurvy which occurs when an individual has insufficient vitamin C. Diseases like cancer that develop as a result of exposure to carcinogens or develop naturally as cell division occurs incorrectly. All organisms are affected by pathogens. Even bacteria are infected by certain types of viruses. Some of these infections can be transferred to organisms of a different species. Viral diseases Viruses are not alive because they do not complete all 7 life processes (movement respiration nutrition excretion reproduction and growth) we strain virus and not species they are made of relatively short length of genetic material DNA which is surrounded by a protein coat. When they infect a suitable host they replicate thousands of times over they replicate them selves perfectly with the same DNA The host cell or cell bursts and other nearby cells can be infected with a virus. HIV/Aids HIV stands for human immunodeficiency virus. This infection is transmitted by body fluids, often during unprotected sex, but also through cuts and injecting drugs using shared needles. Immediately after infection, people often suffer mild flu-like symptoms. These pass and for a period of time infected people might not know they are infected. AIDS stands for acquired immune deficiency syndrome. Months or years after the infection of the HIV virus, it becomes active and starts to attack the patient's immune system. HIV at this point has become AIDS. There is no cure for HIV /AIDS although many scientists are trying to find one. Currently, infected people are given antiviral drugs, which can slow the development of AIDS. Measles Measles is a very infectious viral disease that is often caught by young children. It is transmitted through the air in tiny droplets after an infected person sneezes. It causes a fever and skin rash. Many children in developed countries are given vaccines against measles, but sadly this is not the case throughout the world. Infection can cause more serious effects like infertility in adults who did not catch the disease as children. Malaria Spread by Plasmodium Protist in a mosquito found in higher temperature countries like Africa. It causes headaches vomiting diarrhoea. It also caused damage it the blood and liver. Sleep under mosquito nets and dry up puddles Athletes Foot It is a rash caused by a fungus found between people toes it causes dry flaky red skin or white wet cracked skin it is found in communal areas it is spread by infected skin or surfaces. Rose black spot Causes black spots spread by other dead plants Removed by burning plants Cells