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194 Cards in this Set
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Biology |
Unit 1: The Variety of Living Organisms Unit 2: Life Processes Unit 3: Animal Physiology Unit 4: Plant Physiology Unit 5: Variation and Selection Unit 6: Ecology and Environment Unit 7: Micro Organisms and Genetic Engineering |
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Unit 1: The Variety of Living Organisms |
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1.1: understand that living organisms share the following characteristics: - they require nutrition - they respire - they excrete their waste - they respond to their surroundings - they move - they control their internal conditions - they reproduce - they grow and develop |
Movement Reproduction Sensitivity Nutrition Excretion Respiration Growth |
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1.2: describe the common features shared by organisms within the following main groups: plants, animals, fungi, bacteria, protoctists and viruses, and for each group describe examples and their features |
Plants - Multicellular organisms - Their cells contain chloroplasts- able to carry out photosynthesis - Their cells have cellulose cell walls - They store carbohydrates as starch or sucrose - Examples include flowering plants |
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Animals - Multicellular organisms - They have no cell walls - They usually have nervous coordination and are able to move from one place to another - They often store carbohydrate as glycogen - Examples include mammals and insects |
Fungi - Some are single-celled - Their cells have walls made of chitin - They feed by extracellular secretion of digestive enzymes onto food material and absorption of the organic products - They may store carbohydrate as glycogen - Examples include Mucor (hyphal example) and yeast (single cell example) |
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Bacteria - Microscopic single-celled organisms - They have a cell wall, cell membrane, cytoplasm and plasmids - No nucleus but contain a circular chromosome of DNA - Some bacteria can carry out photosynthesis but most feed off other living or dead organisms - Example: Pneumococcus (pathogen causing pneumonia) |
Protoctists - These are microscopic single-celled organisms - Some, like Amoeba, that live in pond water, have features like an animal cell - Some like Chlorella, have chloroplasts and are more like plants - A pathogenic example is Plasmodium, responsible for causing malaria |
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Viruses - These are small particles, smaller than bacteria - They are parasitic - Can reproduce only inside living cells - They can infect every type of living organism - They have a wide variety of shapes and sizes - They have no cellular structure but have a protein coat and contain one type of nucleic acid, either DNA or RNA - Examples include the influenza virus (causes ‘flu’) and the HIV virus (causes AIDS) |
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1.3: recall the term ‘pathogen’ and know that pathogens may be fungi, bacteria, protoctists or viruses. |
Pathogens are microorganisms that cause disease. Fungi - Aspergillus Bacterium - Salmonella Protoctists - Plasmodium Falciparum Viruses - Influenza Virus |
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2.1: describe the levels of organisation within organisms: organelles, cells, tissues, organs and systems. |
Organelles: specific function within a cell, eg Mitochondria, the powerhouse of the cell - Cells: made of Organelles, basis of living things - Tissues: collection of similar cells all doing the same thing - Organs: different kinds of tissues together forming a unit - Systems: several organs forming a system, eg cardiovascular system is made up of the heart, blood and blood vessels. |
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2.2: describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole |
Animal cell Nucleus is in the centre of the cell, surrounded by cytoplasm, around the edge is the cell membrane. Plant cell Vacuole in the centre, surrounded by cytoplasm, this contains the nucleus and chloroplasts, surrounded by the cell membrane and the cell wall |
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2.3: describe the functions of the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole |
Nucleus: brain of the cell, contains the chromosomes, controls cell activity - Cytoplasm: surrounds the nucleus, where the reactions take place - Cell membrane: controls the movement of chemicals in and out of the cell - Cell wall: made up of cellulose, strengthens the cell - Chloroplast: contain chlorophyll, and are used in photosynthesis - Vacuole - keeps the cell turgid |
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2.4: compare the structures of plant and animal cells |
Differences - Plant cells have a vacuole - Plant cells have chloroplasts - Plant cells have a cell wall Similarities - They have a nucleus - They have cytoplasm - They have a cell membrane |
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Unit 2: Life Processes |
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2.5: identify the chemical elements present in carbohydrates, proteins and lipids (fats and oils). |
Carbohydrates and Lipids - Carbon - Hydrogen - Oxygen Proteins -Carbon - Hydrogen - Oxygen - Sulphur - Phosphorous - Nitrogen |
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2.6: describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from simple sugar; protein from amino acids; lipid from fatty acids and glycerol |
Carbohydrates Monosaccharides - such as glucose are the basic carbohydrates. They join together to make more complex disaccharides and polysaccharides |
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Proteins Made up of amino acids, type of acid depends on what the 'R' (rest) is |
Lipids Made from combining glycerol and three fatty acids |
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2.7: describe thetests for glucose and starch |
Glucose Heat object with Benedict’s Reagent. If it turns from blue to orange then glucose is present. Starch Apply iodine to the object you are testing, if it turns from red to blue/black then there is starch. |
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2.8: understand the role of enzymes as biological catalysts in metabolic reactions |
Enzymes lower the activation energy of a reaction- making it faster- and they are unchanged from beginning to end of a reaction. These two things mean it's a catalyst. |
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2.9: understand how the functionality of enzymes can be affected by changes in temperature, including changes due to change in active site |
Increasing the Temperature - Causes the kinetic energy to increase, therefore the more collisions per second - If above optimum temperature (~37 degrees) the enzymes can denature, the bonds that hold the shape break - The substrate will no longer fit into the active site and cannot be broken down Decreasing the Temperature Decreasing the temperature causes the kinetic energy to decrease meaning the enzyme and substrate collide less frequently per second so the reaction slows down |
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2.10: understand how the functioning of enzymes can be affected by changes in active site caused by changes in pH |
Change in pH can denature enzymes by breaking the bonds that hold the structure in place. So the active site no longer fits with the the substrate it is meant to be breaking down. The pH at which this happens is different for different enzymes, but generally an extreme pH will denature any enzyme. |
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2.11: describe experiments to investigate how enzyme activity can be affected by changes in temperature. |
- Put starch into a test tube; either heat or cool it. - Add amylase - With this mixture on white tiles, add iodine - Time how long it takes for the iodine to stop being blue/black - Repeat at different temperatures and compare When the iodine stops being blue/black there is no starch present, so it must have been digested by the enzymes. |
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2.12: understand definitions of diffusion, osmosis and active transport |
Diffusion When molecules passively move down a concentration gradient across a partially permeable membrane. Osmosis Movement of water, it follows the rule that water will move from a dilute solution to a concentrated solution. Active transport Molecules being moved from an area of low concentration to an area of high concentration energy is needed to make this happen hence 'active' |
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2.13: understand that movement of substances into and out of cells can be by diffusion, osmosis and active transport |
These three processes (defined in 2.12) are the ways in which substances move in and out of cells. http://www.youtube.com/watch?feature=player_embedded&v=BN1m5OThsJE |
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2.14: understand the importance in plants of turgid cells as a means of support |
A turgid cell is one whose full of water; this increases the volume of the cytoplasm, which exerts pressure outwards. These cells are stronger so they support the plant-meaning that a plant grows upwards. This is why a dehydrated plant will wilt. |
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2.15: understand the factors that affect the rate of movement of substances into and out of cells, to include the effects of surface area to volume ratio, temperature and concentration gradient |
Surface area: Molecules have more surfaces through which to diffuse, this increases the rate of movement - Temperature: Increased kinetic energy, more collision with the membrane per second makes movement more likely - Concentration gradient: The higher the concentration gradient, the easier it is for diffusion to occur |
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2.16: describe experiments to investigate diffusion and osmosis using living and non-living systems. |
Diffusion - Put a coloured substance (like food colouring) into a clear one (like water) - Time how long it takes for all the liquid to be the same colour. - Change the temperature of the liquid and make observations. - The higher the heat, the more kinetic energy meaning the colour moves through the liquid faster. |
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Osmosis - Cut two roughly equal pieces of potato and weigh them - Put one in distilled water and one in salt water - After a given amount of time weigh them - The one in salt water will have lost mass as the water in the potato moves to the more highly concentrated salt water - Whereas in the pure water the potato will have gained mass as it was less dense with water. |
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2.33: understand that the process of respiration releases energy in living organisms |
Respiration is a reaction that occurs in living things to create energy. It breaks down glucose to release energy. |
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2.34: describe the differences between aerobic and anaerobic respiration |
Aerobic respiration Glucose + Oxygen → Carbon Dioxide + Water + Energy. In this form of respiration all of the energy is released from the glucose as it is fully broken down. It is used for day to day life processes, like movement and reproduction, and keeping warm. |
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Anaerobic respiration Glucose → Lactic acid + Energy. Anaerobic respiration takes place when the heart and lungs cannot work fast enough to provide to oxygen needed for aerobic respiration: for example when exercising, the energy released is less in anaerobic respiration because the glucose cannot be fully broken down. |
The lactic acid produced accumulates in muscles; often making them feel sore. After this process 'excess post-exercise oxygen consumption' takes place. This process involves heavy breathing and fast heart rate to transport oxygen around the body so it can help break down lactic acid into carbon dioxide and water. Note that the time taken for the lactic acid to be removed and for the breathing and heart rate to return to normal is called the recovery period. |
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2.35: write the word equation and the balanced chemical symbol equation for aerobic respiration in living organisms |
Glucose + Oxygen → Carbon dioxide + Water + Energy C6H12O6 + 6O2 → 6CO2 + 6H2O (+ energy) |
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2.36: write the word equation for anaerobic respiration in plants and in animals |
Animals Glucose → Lactic acid + Energy C6H12O6 → 2C3H6O3 + energy Plants Glucose → ethanol + carbon dioxide + energy C6H12O6 → 2C2H5OH + 2CO2 |
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2.37: describe experiments to investigate the evolution of carbon dioxide and heat from respiring seeds or other suitable living organisms. |
Collect the gas coming off the seed and bubble through lime water to see if it turns cloudy. Place in a cool environment and measure the surrounding air heating up. |
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Unit 3: Animal Pyhsiology |
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2.23: understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre |
Balanced diet: Carbohydrates - potato Protein - fish Fats - avocado Vitamins - lemon Minerals - milk Fibre - fruit Water |
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2.24: identify sources and describe functions of carbohydrate, protein, lipid (fats and oils), vitamins A, C and D, the mineral ions calcium and iron, water and dietary fibre as components of the diet |
Carbohydrates - Bread - Noodles - Grains - Energy source for cells in respiration - Includes glucose and starch - General formula is (CH2O)x - x is any number between 3 and 8 |
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Lipids - Contained in fats and oils - Same elements as carbs, but much less oxygen - Energy stores, insulating layer - Ingesting too much fat has been linked to heart disease |
Protien - Makes in 18% of our body mass - Found in most foods, but has a larger concentration in meat, fish, cheese and eggs - Typically more abundant in animal products - Deficiency can cause Kwashiorkor - It is a long line of smaller molecules called amino acids. |
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Minerals and Vitamins |
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2.25: understand that energy requirements vary with activity levels, age and pregnancy |
Different foods contain different amounts of energy. Energy is measured in joules (calories). It is important to take in the right amount of energy for your body’s needs. If you take in too much energy, you will get fat. With too little energy from your food, you will become very thin. The amount of energy you need varies with your age, with how active you are, and whether you are pregnant. |
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2.26: describe the structures of the human alimentary canal and describe in outline the functions of the mouth, oesophagus, stomach, small intestine, large intestine and pancreas |
Mouth - Mechanical digestion - jaw action. - A bolus is created; a ball of food covered in saliva. - This is helpful as the food is lubricated to enable swallowing and enzymes in the saliva can begin to break down the food. (amylase) |
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Oesophagus - This tube connects you mouth and stomach. - Peristalsis, or muscular contractions, moves the food downward. |
Stomach - Churning mechanically digests whilst enzymes do so chemically. |
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Small Intestine - This absorbs digested molecules into the bloodstream. - Villi cover the inside giving it a large surface area which many molecules can diffuse through into the blood. |
Large Intestine - This absorbs water from undigested food, producing faeces. Pancreas - This produces the enzymes lipase, amylase and protease. |
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2.27: understand the processes of ingestion, digestion, absorption, assimilation and egestion |
Digestion: process in which large insoluble molecules of food are broken down into smaller ones. Absorption: the process by which soluble molecules produced by digestion are taken from the gut (occurs mostly in the small intestine.) Assimilation: the cells of the tissues absorb the molecules for use. Egestion: removal of waste- undigested- products as faeces. Excretion: removal of waste products that have been in the body. |
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2.28: explain how and why food is moved through the gut by peristalsis |
The muscle is organised around the oesophagus, and when the muscle contracts the muscle gets shorter - this means the diameter of the oesophagus will decrease. Enters the gut and stretches the wall, this causes a reflex of the muscle behind the bolus, this contraction pushes the bolus downwards through out guts. |
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2.29: understand the role of digestive enzymes to include the digestion of starch to glucose by amylase and maltase, the digestion of proteins to amino acids by proteases and the digestion of lipids to fatty acids and glycerol by lipase |
Enzymes break down food into useful things that our boddies need. Different enzymes break down different components of our food. Amylase and Maltase convert starch to glucose Proteases convert proteins to amino acids Lipases convert lipids to fatty acids and glycerol. |
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2.30: recall that bile is produced by the liver and stored in the gall bladder, and understand the role of bile in neutralising stomach acid and emulsifying lipids |
Bile is produced by the liver and stored in the gall bladder. Enzymes in the small intestine work best in alkaline conditions but the food is acidic after being in the stomach. Bile is alkaline and so when it is released into the small intestine it enables the enzymes to work. Bile also emulsifies fat; this gives it a larger surface area, which means that it is easier for lipases to work. |
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2.31: describe the structure of a villus and explain how this helps absorption of the products of digestion in the small intestine |
Villi - Located in the small intestine - Lump-like shapes: larger surface area, maximise absorption of nutrients from food - Walls are one cell thick- nutrients can pass through and be absorbed easier - Lots of capillaries allow more nutrients to be absorbed into blood |
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2.32: describe an experiment to investigate the energy content in a food sample |
Independent Variable: Type of sample Dependent Variable: Temperature change of water due to energy content of food Control Variables: Volume of water, temp. of room and distance between burning food and boiling tube with water Control experiment: Done with just boiling tube of water at an angle |
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Apparatus - 1 measuring cylinder - 1 retort stand/clamp - 1 balance - 1 mounted needle - 1 Bunsen burner - 1 heating mat - 1 thermometer - Calculator, notebook.pen - 1 boiling tube - Food samples: corn curls, crispbread, dry pasta (4 each for 4 trials) |
Method - Set up retort stand/clamp such that the boiling tube can be supported when placed at an angle - Measure 20㎤ of water using a measuring cylinder - Pour the water into the boiling tube - Secure the boiling tube on the retort stand/clamp - Place the thermometer into the boiling tube and record initial temperature of water |
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- Using a balance, find the mass of a piece of crispbread - Record this for calculation later - Spear the crispbread on the end of the mounted needle - Place the Bunsen burner on a heating mat and turn it on - Hold the crispbread on top of the flame until it catches fire |
- Hold the burning food under the boiling tube, flame heats up water - Repeat steps 9-10 until the food no longer burns (relight each time the flame goes out) - Stir the water gently using the thermometer so heat is evenly distributed - Measure/record final temperature of water - Repeat steps 2-13 with other food samples (including remaining crispbread) for repeated trials |
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J/g = (Final temp.- initial temp) × 20g (water) × 4.2 (J/℃) / mass of food (g) |
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2.38 understand the role of diffusion in gas exchange |
Diffusion (in the alveoli) allows oxygen into the blood and carbon dioxide into the alveoli. |
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Blood arriving at the alveoli has a higher concentration of CO2 than the air inside the alveoli. This difference in concentration creates a concentration gradient allowing carbon dioxide to diffuse into the alveoli air from the blood. |
The blood arriving in the alveoli has a lower concentration of oxygen than the air in the alveoli (as the oxygen has already been used for respiration inside cells). This allows the oxygen to move into the blood by diffusion. |
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2.44: describe the structure of the thorax, including the ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membranes |
Once air is breathed in through the mouth or nose it travels down the trachea. The trachea splits into two- one going into the left lung and one going into the right lung- these pipes are called bronchi. |
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Each bronchus will then divide further into many bronchioles: each ending in a sac called an alveoli. The trachea and bronchi have walls of muscle that are supported by cartilage. The cartilage is in partial rings so that the tubes can be moved in any direction. Cilia on the walls move mucus out of the breathing system and into the stomach. |
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2.45: understand the role of the intercostal muscles and the diaphragm in ventilation |
Breathing in - The intercostal muscles contract - The ribs move up and out - The diaphragm contracts and moves down - The trachea carries air towards the lungs; it splits into two bronchi- one leading to the left lung, and one to the right- which then split into even smaller tubes, called bronchioles; these end in alveoli where gas exchange takes place. - The pleural membranes prevent friction. |
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Breathing out - The intercostal muscles relax - The ribs drop down - The diaphragm also relaxes and moves upward - These things reduce the space inside the lungs, pushing the air out. |
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2.46: explain how alveoli are adapted for gas exchange by diffusion between air in the lungs and blood in capillaries |
- They are many air sacs, which present a large surface area for diffusion - The lining of the air sacs is only one cell thick for easy diffusion, as the gas only has to travel a short distance. - The air sacs are supplied by a close and dense network of capillaries- this means it always has a fresh supply of blood. - The lining of the air sacs is moist so that gases can dissolve before then diffuse across the thin membrane. |
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2.47: understand the biological consequences of smoking in relation to the lungs and the circulatory system, including coronary heart disease |
- Tar can cause cancerous mutations in the lungs. - Smoke removes the cilia- tiny hairs- which keep the lungs clean. - Smoking also hardens the arteries, constricting the blood flow and putting strain on the heart, resulting in coronary heart disease. |
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2.48: describe experiments to investigate the effect of exercise on breathing in humans. |
- Record resting breathing rate - Next, get them to do 10 sets of an exercise of your choice. - Then record their breathing rate after the 10 sets. - Once they reach their resting breathing rate again, have them increase the number of sets of the exercise you chose (for example, now do 20 sets). - Record the person’s breathing rate after they’ve carried out the amount of sets you chose. - Lastly, repeat step 4, increasing the amount of sets each round until a given amount of times. |
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2.57: recall the composition of the blood: red blood cells, white blood cells, platelets and plasma |
- Red blood cells - White blood cells (lymphocytes, phagocytes) - Platelets - Plasma |
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2.58: understand the role of plasma in the transport of carbon dioxide, digested food, urea, hormones and heat energy |
- Carbon Dioxide as hydrogen carbonate ions - Digested foods: Amino acids, glucose, minerals and vitamins - Urea (Product of excessive amino acids) - Hormones: Antidiuretic hormone (ADH), insulin, adrenaline, heat energy |
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Digested food products are usually absorbed by the ileum in the small intestine by the villi. These are absorbed into the plasma and are transported to different parts of the body. Glucose is transported to the muscles or the liver to be stored as glycogen. Amino acids are used in tissue growth and repair throughout the body. Minerals and vitamins are used in their respective areas: Calcium for teeth and bones, Vitamin C in the gums. |
Plasma acts as a public transport system for the body as hormones “get on and off” from where they are produced to where they are needed. ADH travels from its release point, the pituitary gland, (although produced in hypothalamus) and travels to the kidneys. Insulin is secreted by endocrine glands and travels in the plasma to the liver where it stimulates a conversion of glucose to glycogen. |
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Urea is transported in the plasma from the liver to the kidneys to be removedfrom the body by a process called excretion. |
Heat energy is affected by the plasma as the plasma is mostly made up of water.This affects heat energy as water content in the body can be lost as sweat as a way of controlling body heat. Heat is lost as the water (sweat) evaporates from the skin. The water in the plasma provides this “sweat”. |
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2.59: explain howadaptations of red blood cells, including shape, structure and the presence of haemoglobin, make then suitable for the transport of oxygen |
They carry oxygen around the body. Adaptations: - Oxygen attaches to haemoglobin protein, which the RBCs are filled with - Biconcave shape (increases surface area and allows folding) - Made in huge quantities (to carry lots of oxygen) - No nucleus (so more room for haemoglobin) |
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2.60: describehow the immune system responds to disease using white blood cells, illustrated by phagocytes ingesting pathogens and lymphocytes releasing antibodies specific to the pathogen |
Phagocytes - Phagocytes can detect the pathogens because of the chemicals they giveoff - The phagocyte then engulfs the pathogen - A lysosome containing digestive enzyme fuses with the vacuole containing the pathogen - It then destroys the pathogen with digestive enzymes - This process is called phagocytosis. |
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Lymphocytes - A lymphocyte recognises a specific pathogen due to antigens on the surface of the pathogen - It releases antibodies that are specific to the pathogen - The antibodies bind to and neutralise the pathogen - When a lymphocyte meets its specific pathogen it divides to make extra copies. Some of these cells become memory cells which can stay in the blood for years - The second immune response will be much faster and create a higher number of antibodies the second time |
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2.61: understandthat vaccination results in the manufacture of memory cells, which enable future antibody production to the pathogen to occur sooner, faster and in greater quantity |
Vaccination involves putting a small amount of an inactive form of a pathogen,or dead pathogen, into the body e.g. - live pathogens treated to make them harmless - harmless fragments of the pathogen - toxins produced by pathogens - dead pathogens They stimulate your body to manufacture memory cells. These memory cells will help future antibody production to the pathogens to occur sooner faster and in greater quantities to prevent infection and viruses that occur. |
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2.62: recall thatplatelets are involved in blood clotting, which prevents blood loss and the entry of microorganisms |
Platelets are small fragments of cells that can help the blood to clot. They help to prevent loss of blood and prevent microorganisms from entering the bloodstream. |
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2.63: describe thestructure of the heart and how it functions |
The heart is a four pump system that forces blood all around the body and back to the heart again. The heart is made up of 4 sections: left atrium, left ventricle, right atrium and right ventricle |
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- Veins lead to the heart; arteries lead away - The left side is bigger than the right as it has to pump blood through the whole body - The left side is actually the right side as if you were looking at someone else’s heart |
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2.64: explain how the heart rate changes during exercise and under the influence of adrenaline |
- The rate of the heartbeat changes as the demands of the body change - During exercise more food and oxygen are needed by the cells and more carbon dioxide is produced, so the heart beats more rapidly and more strongly - Adrenaline in your bloodstream achieves its effects on your heart rate by stimulating the adrenaline receptors on cells throughout your heart tissue - The overall result of this process is an increase in your heart rate, as well as an increase in the force of each individual heart contraction |
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2.65: describe the structure of arteries, veins and capillaries and understand their roles |
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2.66: understandthe general structure of the circulation system to include the blood vessels to and from the heart, the lungs, the liver and the kidneys. |
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2.68: recall that the lungs, kidneys and skin are organs of excretion |
- Lungs (excrete carbon dioxide) - Kidneys (excrete urea) - Skin (excrete water and salts) |
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2.69: understand how the kidney carries out its roles of excretion and osmoregulation |
Excretion The kidneys remove urea (a toxic waste product of product of protein)from the blood. Osmoregulation The regulation of water content in organisms.
These are both done through ultrafiltration and selective reabsorption. |
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2.70: describe the structure of the urinary system, including the kidneys, ureters, bladder and urethra |
Waste or excess products are filtered from the blood stream by the kidneys, ureters carries urine to the bladder, the urine then leaves the body through the urethra. |
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2.71: describe the structure of a nephron, to include Bowman’s capsule and glomerulus, convolutedtubules, loop of Henlé and collecting duct |
Nephrons are tubular structures within the kidneys which carry out filtration.The blood enters into the glomerulus in the Bowman’s capsule, this is where the blood is filtered to create a filtrate of water, glucose, salts and urea (among other things). This then travels through convoluted tubules, here some components are reabsorbed into the blood stream. The loop of Henlé s where water is where water and sodium chloride and reabsorbed into the blood stream. The filtrate then travels down the collecting duct which transports it to the 'renal pelvis' after which it goes down the ureters to the bladder.
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2.72: describe ultrafiltration in the Bowman’s capsule and the composition of the glomerular filtrate |
Blood arrives in Bowman's casual under the high pressure of an artery, it travels it to the glomerulus where the pressure is further increased (as the tubes are smaller). Components of the blood are forced out of the blood vessel into the glomerulus due to the high pressure, creating glomerular filtrate (water, slats ect.)
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2.73: understand that water is reabsorbed into the blood from the collecting duct
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As components travel through the nephron some are reabsorbed into the blood- as they are needed by the body. Much water of reabsorbed to avoid dehydration. This happens in the collecting duct.
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2.74: understand that selective reabsorption of glucose occurs at the proximal convoluted tubule
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Glucose is a component of golmerula filtrate. Some of the glucose in this filtrate is reabsorbed into the blood stream as it is needed by the body. The first section of convoluted tubules (before the henle loop) is the proximal convoluted tubule, in this area glucose is removed from the nephron and taken back into the blood.
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2.75: describe the role of ADH in regulating the water content of the blood
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Excess or lack of water is detected by the hypothalamus in the brain, it causes the pituitary gland to produce Anti-diuretic hormone, or ADH. This hormone then travels through the blood stream to the kidneys, when it reaches them the kidneys lower the amount of water that is excreted by the body, and increase the amount of water that is reabsorbed into the blood stream. The urine is then more concentrated with a lower volume.If there is too much water the levels of ADH are lowered and the opposite effects happen, resulting with a more dilute urine and less water in the blood.
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2.76: understand that urine contains water, urea and salts
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Urine is made up of waste products in the body that can be harmful if not excreted Among other things this includes water, urea and salts.
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2.77: understand that organisms are able to respond to changes in their environment
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Sensitivity is one of the life processes (mrs gren); it is responding to the environment around. Living things must have receptors to be able to detect the change and effectors to be able to carry out a response. |
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2.78: understand that homeostasis is the maintenance of a constant internal environment and that body water content and body temperature are both examples of homeostasis
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Homeostasis is the regulation of conditions inside the body. For example osmoregulation is the control of water levels in the body. Temperature regulation also needs to take place (as body process work best at 37 degrees) it is called thermoregulation. An example is when you are hot you sweat- so the heat is absorbed from your skin- and when you are cold you body hairs stick out- to trap air as a layer of insulation.
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2.79: understand that a coordinated response requires a stimulus, a receptor and an effector
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To be able to carry out a response several things are needed:A stimulus- a change in the internal or external environment- is needed to prevoke a response.A receptor is needed to detect a stimulus, so that it can send messages to a coordinator to coordinate a response,An effector is needed to carry out the response to the stimulus.
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2.83: describe how responses can be controlled by nervous or by hormonal communication and understand the differences between the two systems
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The nervous system and hormones both coordinate responses with in the body. The nervous does this by electrical impulses so it is very fast. Hormones do this with chemicals which travel, a little slower, at the speed of the blood stream they are travelling in.
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2.84: understand that the central nervous system consists of the brain and spinal cord and is linked to sense organs by nerves
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The CNS is the centre of the nervous system which decides a response for a stimulus. Receptors in sense organs (eg eyes or skin) send messages through nerves to the CNS- either to you brain or spinal chord- it creates a response which it will send in electrical impulses down nerves to effectors to carry out the response.
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2.85: understand that stimulation of receptors in the sense organs sends electrical impulses along nerves into and out of the central nervous system, resulting in rapid responses
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Receptors send a electrical impulse through nerves when stimulate by a stimulus. This message goes to the CNS, here a response is decided and then sent strait back out in electrical impulses through nerves to the effector. The impulses are very fast, as is the reaction time.
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2.86: describe the structure and functioning of a simple reflex arc illustrated by the withdrawal of a finger from a hot object
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A reflex is an automatic reaction, for example removing your hand from extreme heat. A reflex arch is the path of the reaction.It starts at a sense organ e.g a finger;receptors pick up stimuli e.g heat;Sensory neurones carry an electrical impulse to the CNS;A relay neuron carries the impulse through the CNS where a response is decided;The new impulse is sent through a motor neurone;This makes an effector carry out a response e.g muscle contracts to bring finger away from heat.
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2.87: describe the structure and function of the eye as a receptor
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The eye is a receptor of light, it has light receptor cells in its retina. These cells turn stimuli into electrical impulses.
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2.88: understand the function of the eye in focusing near and distant objects, and in responding to changes in light intensity
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In response to increased light you pupil will shrink, in dim light your pupil will dilate (grow bigger). This happens because you iris will contract to make the pupil smaller or relax to make it bigger. Radial muscles also make the pupil bigger by contracting.To focus at different distances the lens in your eye adapts its shape:If an object is near, ciliary muscles will contract which relaxes the suspensory ligaments so that the lens is fat;If an object is far, ciliary muscles will relax making the suspensory ligaments tight so they pull the lens thin.
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2.89: describe the role of the skin in temperature regulation, with reference to sweating, vasoconstriction and vasodilation
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Sweating- when too hot, glands under the skin secrete sweat, this increases heat loss by evaporation.
Vasoconstriction- blood vessels by the skin shrink, this reduces the blood which runs by the surface meaning less heat can be lost to the air. Vasodilation- blood vessels by the skin grow, this means that more blood, and so more heat, is travelling near the surface of your body, in this way heat will be lost as it is conducted by the air.
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2.90: understand the sources, roles and effects of the following hormones: ADH, adrenaline, insulin, testosterone, progesterone and oestrogen.
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ADH
Lack of water is detected by the hypothalamus in the brain, it causes the pituitary gland to produce Anti-diuretic hormone, or ADH. This makes the kidneys to reabsorb more water- so less is lost from the body. Adrenaline Produced in the adrenal glands in stressful situations. Heart rate quickens to increase the flow of blood to muscles- this means that they can respire more (as there is more oxygen available) to provide energy if you need to 'fight or flee'. Insulin Produced in the pancreas when there is too much glucose in the blood. It stimulates cells to convert the glucose into glycogen which is a from that can be stored. This means that you always have the right amount of glucose in your blood. Testosterone Produced in ovaries in girls and testicles in boys. Plays a key role in puberty, developing sex organs and inspiring hair growth. Progesterone Produced in the ovaries it maintains the lining ready for pregnancy, and continues to do so if the egg is fertilised. Oestrogen Produced in the ovaries, it is controls other hormones to regulate the menstrual cycle. It stops the production of FSH and starts the production of LH.
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3.1: understand the differences between sexual and asexual reproduction
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In sexual reproduction two parents create non-identical offspring, inheriting characteristics from both parents.In asexual reproduction a single parent creates genetically identical offspring.
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3.2: understand that fertilisation involves the fusion of a male and female gamete to produce a zygote that undergoes cell division and develops into an embryo
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Gametes are sex cells: the male one being sperm; the female one being an egg.When they join together it is know as fertilisation. At this point the fused gametes become a zygote.A the zygote then divides repeatedly, at this stage it becomes an embryo.
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3.8: describe the structure and explain the function of the male and female reproductive systems |
Male reproductive system Testis- produce sperm cells, they are stored in the epididymus Vas deference- carries sperm to the penis The prostate- adds fluid to the sperm, creating semen (as does the seminal vesicles) The urethra- carries sperm to the end of, and out of the penis. Female reproductive system Ovaries- produce eggs Oviducts- carry the eggs to the uterus, is the site of fertilisation Uterus- develops the fertilised egg on the placenta Cervix- entrance to uterus |
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3.9: understand the roles of oestrogen and progesterone in the menstrual cycle
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Oestrogen and progesterone are both hormones which effect the menstrual cycle.Oestrogen: produced in the ovaries; thickens the womb lining; prompts the release of LH.Progesterone: produced in the corpus lutiem; maintains the lining of the womb
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3.10: describe the role of the placenta in the nutrition of the developing embryo
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The embryo can't breath, digest or excrete.Blood vessels inside the placenta can absorb the digested food molecules and oxygen that the embryo needs to survive. Waste products will be taken out of the embryo and put back into the mothers blood stream for her to excrete.
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3.11: understand how the developing embryo is protected by amniotic fluid
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The fluid (mainly water) cannot be compressed- it absorbs pressure- so any force on the uterus wall will not harm the embryo.
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3.12: understand the roles of oestrogen and testosterone in the development of secondary sexual characteristics.
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Oestrogen- females
- The beginning of the menstrual cycle - Body mass increases and redistributed to hips and breasts - Body hair (pubic) - Voice deepens slowly - Development of sexual organs Testosterone- males - Production of sperm - Growth of sexual organs - Body hair (pubic, arms and face) - Body mass will increase, including muscle mass - Voice breaks (becomes deeper) - Development of a sexual drive
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Unit 4: Plant Physiology |
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2.16: describe experiments to investigate diffusion and osmosis using living and non-living systems
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2.17: describe the process of photosynthesis and understand its importance in the conversion of light energy to chemical energy
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2.18: write the word equation and the balanced chemical symbol equation for photosynthesis
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2.19: understand how carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis
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2.20: describe the structure of the leaf and explain how it is adapted for photosynthesis
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2.21: understand that plants require mineral ions for growth and that magnesium ions are needed for chlorophyll and nitrate ions are needed for amino acids
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2.22: describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll
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2.38: understand the role of diffusion in gas exchange
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2.39: understand gas exchange (of carbon dioxide and oxygen) in relation to respiration and photosynthesis
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2.40: understand that respiration continues during the day and night, but that the net exchange of carbon dioxide and oxygen depends on the intensity of light
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2.41: explain how the structure of the leaf is adapted for gas exchange
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2.42: describe the role of stomata in gas exchange
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2.43: describe experiments to describe the effect of light on net gas exchange from a leaf, using hydrogen-carbonate indicator
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2.67: understand the origin of carbon dioxide and oxygen as waste products of metabolism and their loss from the stomata of a leaf
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2.51: describe the role of phloem in transporting sucrose and amino acids between the leaves and other parts of the plant
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2.52: describe the role of the xylem in transporting water and mineral salts from the roots to other parts of the plant
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2.53: explain how water is absorbed by root hair cells
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2.54: understand that transpiration is the evaporation of water from the surface of a plant
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2.55: explain how the rate of transpiration is affected by changes in humidity, wind speed, temperature and light intensity
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2.56: describe experiments to investigate the role of environmental factors in determining the rate of transpiration from a leafy shoot
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2.80: understand that plants respond to stimuli
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2.81: describe the geotropic responses of roots and stems
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2.82: describe positive phototropism of stems
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3.1: understand the differences between sexual and asexual reproduction
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3.2: understand that fertilisation involves the fusion of a male and female gamete to produce a zygote that undergoes cell division and develops into an embryo
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3.3: describe the structures of and insect-pollinated and a wind-pollinated flower and explain how each is adapted for pollination
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3.4: understand that the growth of the pollen tube followed by fertilisation leads to seed and fruit formation
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3.5: understand the conditions needed for seed germination
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3.6: understand how germinating seeds utilise food reserves until the seedling can carry out photosynthesis
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3.7: understand that plants can reproduce asexually by natural methods (illustrated by runners) and by artificial methods (illustrated by cuttings)
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Unit 5: Variation and Selection
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3.13: understand that the nucleus of a cell contains chromosomes on which genes are located
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3.14: understand that a gene is a section of a molecule of DNA and that a gene codes for a specific protein
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3.15: describe a DNA molecule as two strands coiled to form a double helix, the strands being linked by a series of paired bases: adenine (A) with thymine (T), and cytosine (C) with guanine (G)
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3.16: understand that genes exist in alternative forms called alleles which give rise to differences in inherited characteristics
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3.17: understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, genotype and codominance
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3.18: describe patterns of monohybrid inheritance using a genetic diagram.
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3.19: understand how to interpret family pedigrees
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3.20: predict probabilities of outcomes from monohybrid crosses
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3.21: understand that the sex of a person is controlled by one pair of chromosomes, XX in a female and XY in a male
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3.22: describe the determination of the sex of offspring at fertilisation, using a genetic diagram
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3.23: understand that division of a diploid cell by mitosis produces two cells which contain identical sets of chromosomes
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3.24: understand that mitosis occurs during growth, repair, cloning and asexual reproduction
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3.25: understand that division of a cell by meiosis produces four cells, each with half the number of chromosomes, and that this results in the formation of genetically different haploid gametes
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3.26: understand that random fertilisation produces genetic variation of offspring
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3.27: know that in human cells the diploid number of chromosomes is 46 and the haploid number is 23
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3.28: understand that variation within a species can be genetic, environmental, or a combination of both
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3.29: understand that mutation is a rare, random change in genetic material that can be inherited
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3.30: describe the process of evolution by means of natural selection
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3.31: understand that many mutations are harmful but some are neutral and a few are beneficial
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3.32: understand that resistance to antibiotics can increase in bacterial populations, and appreciate how such an increase can lead to infections being difficult to control
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3.33: understand that the incidence of mutations can be increased by exposure to ionising radiation (for example gamma rays, X-rays and ultraviolet rays) and some chemical mutagens (for example chemicals in tobacco)
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5.10: understand that plants with desired characteristics can be developed by selective breeding
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5.11: understand that animals with desired characteristics can be developed by selective breeding
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5.17: describe the process of micropropagation (tissue culture) in which small pieces of plants (explants) are grown in vitro using nutrient media
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5.18: understand how micropropagation can be used to produce commercial quantities of identical plants (clones) with desirable characteristics
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5.19: describe the stages in the production of cloned mammals involving the introduction of a diploid nucleus from a mature cell into an enucleated egg cell, illustrated by Dolly the sheep
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5.20: evaluate the potential for using cloned transgenic animals, for example to produce commercial quantities of human antibodies or organs for transplantation.
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Unit 6: Ecology and the Environment
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4.1: understand the terms population, community, habitat and ecosystem
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4.2: understand how quadrats can be used to estimate the population size of an organism in two different areas
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4.3: explain how quadrats can be used to sample the distribution of organisms in their habitats.
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4.4: explain the names given to different trophic levels to include producers, primary, secondary and tertiary consumers and decomposers
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4.5: understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer
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4.6: understand the transfer of substances and of energy along a food chain
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4.7: explain why only about 10% of energy is transferred from one trophic level to the next.
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4.8: describe the stages in the water cycle, including evaporation, transpiration, condensation and precipitation
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4.9: describe the stages in the carbon cycle, including respiration, photosynthesis, decomposition and combustion
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4.10: describe the stages in the nitrogen cycle, including the roles of nitrogen fixing bacteria, decomposers, nitrifying bacteria and denitrifying bacteria (specific names of bacteria are not required).
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4.11: understand the biological consequences of pollution of air by sulfur dioxide and by carbon monoxide
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4.12: understand that water vapour, carbon dioxide, nitrous oxide, methane and CFCs are greenhouse gases
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4.13: understand how human activities contribute to greenhouse gases
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4.14: understand how an increase in greenhouse gases results in an enhanced greenhouse effect and that this may lead to global warming and its consequences
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4.15: understand the biological consequences of pollution of water by sewage, including increases in the number of microorganisms causing depletion of oxygen
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4.16: understand that eutrophication can result from leached minerals from fertiliser
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4.17: understand the effects of deforestation, including leaching, soil erosion, disturbance of the water cycle and of the balance in atmospheric oxygen and carbon dioxide.
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Unit 7: Microorganisms and Genetic Engineering
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5.1: describe how glasshouses and polythene tunnels can be used to increase the yield of certain crops
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5.2: understand the effects on crop yield of increased carbon dioxide and increased temperature in glasshouses
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5.3: understand the use of fertiliser to increase crop yield
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5.4: understand the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with crop plants
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5.5: understand the role of yeast in the production of beer
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5.6: describe a simple experiment to investigate carbon dioxide production by yeast, in different conditions
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5.7: understand the role of bacteria (Lactobacillus) in the production of yoghurt
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5.8: interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter, including aseptic precautions, nutrients, optimum temperature and pH, oxygenation and agitation, for the growth of micro-organisms
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5.9: explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality, control of intraspecific and interspecific predation, control of disease, removal of waste, quality and frequency of feeding and the use of selective breeding
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5.12: describe the use of restriction enzymes to cut DNA at specific sites and ligase enzymes to join pieces of DNA together
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5.13: describe how plasmids and viruses can act as vectors, which take up pieces of DNA, then insert this recombinant DNA into other cells
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5.14: understand that large amounts of human insulin can be manufactured from genetically modified bacteria that are grown in a fermenter
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5.15: evaluate the potential for using genetically modified plants to improve food production (illustrated by plants with improved resistance to pests)
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5.16: understand that the term ‘transgenic’ means the transfer of genetic material from one species to a different species.
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