IGCSE Biology Paper 1 Specification Exam Questions and Answers, Exams of Biology

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STRUCTURE OF CARBOHYDRATES, PROTEINS & LIPIDS - CORRECT ANSWERS LARGE ,molecules made up from smaller basic units STARCH & GLYCOGEN - CORRECT ANSWERS From simple sugar PROTEIN - CORRECT ANSWERS From amino acids LIPIDS - CORRECT ANSWERS From fatty acids and glycerol ROLE OF ENZYMES IN METABOLIC REACTIONS - CORRECT ANSWERS Enzymes lower the activation energy of a reaction- making it faster (BIOLOGICAL CATALYST) HOW FUNCTIONING ENZYMES ARE AFFECTED - CORRECT ANSWERS By changes in TEMPERATURE and changes in PH DIFFUSION - CORRECT ANSWERS The net overall MOVEMENT of particles of a GAS or SOLUTE from an area of HIGH CONCENTRATION to an area of lower concentration DOWN the concentration gradient OSMOSIS - CORRECT ANSWERS When WATER moves across a PARTIALLY PERMEABLE MEMBRANE, from an area of HIGH CONCENTRATION to an area of lower concentration DOWN the concentration gradient ACTIVE TRANSPORT - CORRECT ANSWERS The movement of substances AGAINST a concentration gradient/across a cell membrane, using ENERGY MOVEMENT OF SUBSTANCES INTO AND OUT OF CELLS - CORRECT ANSWERS Can be by diffusion, osmosis and active transport PHOTOSYNTHESIS EQUATION - CORRECT ANSWERS Carbon dioxide + water > glucose + oxygen

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6CO2 + 6H2O = C6H12O6 + 6O

MINERAL IONS FOR GROWTH - CORRECT ANSWERS MAGNESIUM ions are needed for CHLRORPHYLL; NITRATE ions are needed for AMINO ACIDS RESPIRATION PURPOSE - CORRECT ANSWERS Respiration is a reaction that occurs in living things to create energy. It breaks down glucose to release energy AEROBIC RESPIRATION - CORRECT ANSWERS The process by which FOOD molecules are BROKEN DOWN using OXYGEN to release ENERGY for the cells ANAEROBIC RESPIRATION - CORRECT ANSWERS Cellular respiration in the ABSENCE of OXYGEN AEROBIC RESPIRATION EQUATION - CORRECT ANSWERS Glucose + Oxygen > Carbon dioxide + Water

• Energy C6H12O6 + 6O2 → 6CO2 + 6H2O (+ energy) ANAEROBIC RESPIRATION EQUATION - CORRECT ANSWERS PLANTS: Glucose > Lactic acid + Energy ANIMALS: Glucose > ethanol + carbon dioxide + energy ROLE OF DIFFUSION IN GAS EXCHANHANGE - CORRECT ANSWERS In the circulatory system oxygen enters the blood and carbon dioxide leaves the blood via gaseous exchange. Gasses move across the walls of alveoli to an area of lower density than they are in: Oxygen moves into the blood as there is a low density of oxygen in the blood; Carbon dioxide moves into the lungs as it is an area of lower density. GAS EXCHANGE IN RELATION TO RESPIRATION AND PHOTOSYNTHESIS - CORRECT ANSWERS In photosynthesis: 6CO2 + 12H2O > C6H12O6 + 6O2 + 6H2O

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So the plant takes up carbon dioxide and gives out oxygen In respiration: C6H12O6 + 6H2O > 6CO2 + 6H2O So the plant gives out carbon dioxide ROLE OF STOMATA IN GAS EXCHANGE - CORRECT ANSWERS Guard cells regulate the opening and closing of the stomata; allowing carbon dioxide and oxygen to be exchanged between the leaf and the atmosphere. The stomata is open during the day. At night, the stomata is closed ADAPTATION OF LEAF STRUCTURE - CORRECT ANSWERS Leaves are thin which allows gasses to diffuse quickly through them. In addition the stomata at the bottom of the leaf allow the diffusion of gasses in to the leaf- when a guard cell is shrunk gasses can enter the leaf ROLE OF INTERCOSTAL MUSCLES AND DIAPHRAGM IN VENTILATION - CORRECT ANSWERS The intercostal muscles and diaphragm control ventilation in the lungs. When they contract the create more space in the lungs: drawing air in. When the relax the constrict the rings: pushing air out of the lungs ADAPTATION OF ALVEOLI FOR GAS EXCHANGE - CORRECT ANSWERS The alveoli have are thin, this allows gasses to diffuse through them easily. They are small and there are many of them meaning there is a large surface area through which much gas can diffuse at once. It also means there is a lot of surface in contact with the blood stream for gasses to diffuse into. Alveoli have a moist lining for gasses to dissolve into

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BIOLOGICAL CONSEQUENCES OF SMOKING - CORRECT ANSWERS 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. UNICELLULAR- NO NEED FOR TRANSPORT SYSTEM - CORRECT ANSWERS Unicellular organisms- including fungi and bacteria- have a large surface area to volume ratio and they are small and so the diffusion distance is short, meaning diffusion happens very quickly MULTICELLULAR SYSTEM- NEED FOR TRANSPORT SYSTEM - CORRECT ANSWERS Multicellular organisms have a small surface area to volume ratio and the distance for diffusion would be very large and so very slow. This wouldn't support the organism; so they have developed transport systems, like the ventilation system and the circulatory system which speed up diffusion enough to support themselves ROLE OF XYLEM - CORRECT ANSWERS Transport nitrates, phosphates, water and other mineral salts from the roots to other parts of the plants, like the leafs, flowers and buds. Xylem consists of columns of hollow, dead cells. Substances are carried up the tube dissolved in water HOW WATER IS ABSORBED BY ROOT HAIR CELLS - CORRECT ANSWERS Roots branch to increase the surface area and to increase the chances of finding a water source. Root hairs are epidermal cells on the surface of the root: they also increase the surface area for absorption. They absorb minerals by active transport and water by osmosis. These substances then move to the xylem TRANSPIRATION - CORRECT ANSWERS The EVAPORATION if water from the surface of a plant COMPOSITION OF BLOOD - CORRECT ANSWERS Red blood cells / White blood cells / Platelets / Plasma

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URINE - CORRECT ANSWERS Contains WATER, UREA and SALTS RE-ABSORPTION OF WATER - CORRECT ANSWERS Water is reabsorbed into the blood from the COLLECTING DUCT SELECTIVE RE-ABSORPTION OF GLUCOSE - CORRECT ANSWERS Occurs at the PROXIMAL convoulted tubule ULTRAFILTRATION IN THE BOWMANS CAPSULE - CORRECT ANSWERS 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 glomerulas filtrate (water, slats ect.) STRUCTURE OF NEPHRON - CORRECT ANSWERS Bowman's capsule, Glomerelus, Tubules, Loop od henley, Collecting duct STRUCTURE OF URINARY SYSTEM - CORRECT ANSWERS Kidneys, ureters, bladder, urethra ORGANISM RESPONSE - CORRECT ANSWERS 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 HOMEOSTASIS - CORRECT ANSWERS The maintenance of a constant internal environment and that body water content and body temperature are both examples of homeostasis COORDINATED RESPONSE - CORRECT ANSWERS Requires a STIMULUS, a RECEPTOR and an EFFECTOR PLANTS - CORRECT ANSWERS Respond to STIMULI DESCRIPTION OF GEOTROPIC RESPONSE - CORRECT ANSWERS Geo-tropism is when a plant grows in response to gravity.

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Roots always carry out posotive geo-tropism, towards gravity/ down.Shoots always carry out negative geo-tropism, away from gravity/ up. DESCRIPTION OF POSITIVE PHOTOTROPISM - CORRECT ANSWERS Stems experience positive photo- tropism, this means they always grow towards light. In a place where light shines there will be fewer auxins (growth hormones) this encourages the stem to bend towards the source of light. CENTRAL NERVOUS SYSTEM - CORRECT ANSWERS consists of the BRAIN and SPINAL CHORD and is LINKED to SENSE ORGANS by NERVES HUMAN RESPONSE - CORRECT ANSWERS The SIMULATION of RECEPTORS in SENSE ORGANS sends ELECTRICAL IMPULSES along NERVES into and out of the CNS, resulting in RAPID RESPONSES ADH - CORRECT ANSWERS source: PITUITARY GLAND roles: Controls WATER CONTENT of BLOOD effects: The KIDNEYS ADRENALINE - CORRECT ANSWERS source: ADRENAL GLANDS roles: PREPARES body for STRESSFUL or PHYSICALLY ACTIVE situations effects: 'FIGHT OR FLIGHT' INSULIN - CORRECT ANSWERS source: PANCREAS roles: lower and raise BLOOD GLUCOSE LEVELS

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TESTOSTERONE - CORRECT ANSWERS source: TESTES roles: controls development of male secondary SEXUAL CHARACTERISTICS effects: SPERM PRODUCTION PROGESTERONE - CORRECT ANSWERS source: OVARIES roles: REGULATES MENSTRUAL CYCLE OESTROGEN - CORRECT ANSWERS source: OVARIES roles: controls development of female secondary SEXUAL CHARACTERISTICS SEXUAL REPRODUCTION - CORRECT ANSWERS Reproduction which involves the JOINING of TWO special HAPLOID SEX CELLS/ GAMETES to produce DIPLOID OFFSPRING which are genetically different from their parents ASEXUAL REPRODUCTION - CORRECT ANSWERS Reproduction which involves only ONE PARENT and produces IDENTICAL OFFSPRING to the parents FERTILISATION - CORRECT ANSWERS Involves the FUSION of a male and female GAMETE to produce a ZYGOTE that undergoes CELL DIVISION and develops into an EMBRYO SEED AND FRUIT FORMATION - CORRECT ANSWERS is lead to by the growth of the POLLEN TUBE followed by FERTILISATION ASEXUAL REPRODUCTION IN PLANTS - CORRECT ANSWERS Can be by NATURAL METHODS and by ARTIFICIAL METHODS

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ROLE OF OESTROGEN IN SECONDARY SEXUAL CHARACTERISTIC DEVELOPMENT - CORRECT ANSWERS

Develops BREASTS, BODY HAIR and the MENSTRUAL CYCLE begins ROLE OF TESTOSTERONE IN SECONDARY SEXUAL CHARACTERISTIC DEVELOPMENT - CORRECT ANSWERS The GROWTH of the PENIS, TESTES, FACIAL & BODY HAIR, MUSCLE DEVELOPMENT AND VOICE BREAKING NUCLEUS - CORRECT ANSWERS Contains CHROMOSOMES on which GENES are located GENE - CORRECT ANSWERS Is a section of a molecule of DNA and a gene CODES FOR A SPECIFIC PROTEIN DNA BASES - CORRECT ANSWERS ADENINE & THYMINE, CYTOSINE & GUANINE ALLELES - CORRECT ANSWERS Are GENES existing in ALTERNATIVE FORMS, which gives rise to DIFFERENCES IN INHERITED CHARACTERISTICS SEX DETERMINATION - CORRECT ANSWERS The sex of a person is controlled by ONE PAIR of CHROMOSOMES FEMALE CHROMOSOMES - CORRECT ANSWERS XX MALE CHROMOSOMES - CORRECT ANSWERS XY DIPLOID CELL DIVISION BY MITOSIS - CORRECT ANSWERS Produces TWO CELLS which contain IDENTICAL sets of CHROMOSOMES MITOSIS - CORRECT ANSWERS Occurs during GROWTH, REPAIR, CLONING and ASEXUAL REPRODUCTION

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CELL DIVISION BY MEIOSIS - CORRECT ANSWERS Produces FOUR CELLS, EACH WITH HALF the number of CHROMOSOMES. This results in the formation of GENETICALLY DIFFERENT HAPLOID GAMETES RANDOM FERTILISATION - CORRECT ANSWERS Produces GENETIC VARIATION of offspring HUMAN CELLS (CHROMOSOME NUMBER) - CORRECT ANSWERS HAPLOID= 23 DIPLOID= VARIATION IN A SPECIES - CORRECT ANSWERS Can be GENETIC, ENVIRONMENTAL, or a COMBINATION of both MUTATION - CORRECT ANSWERS Is a RARE, RANDOM change in GENETIC MATERIAL that can be INHERITED PROCESS OF EVOLUTION BY MEANS OF NATURAL SELECTION - CORRECT ANSWERS Organisms produce more offspring than the environment can support. Only those BEST ADAPTED to their environment will SURVIVE to breed and PASS ON THEIR CHARACTERISTICS MUTATION EFFECTS - CORRECT ANSWERS MANY are HARMFUL, but SOME are NEUTRAL and FEW are BENEFICIAL RESISTANCE TO ANTIBIOTICS - CORRECT ANSWERS Can INCREASE in BACTERIAL POPULATIONS and an increase can lead to INFECTIONS being DIFFICULT TO CONTROL POPULATION - CORRECT ANSWERS A group of individuals of the SAME SPECIES living in the SAME HABITAT and BREEDING TOGETHER COMMUNITY - CORRECT ANSWERS ALL OF THE POPULATIONS of LIVING ORGANISMS living in an ecosystem at a PARTICULAR TIME

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HABITAT - CORRECT ANSWERS The place where an animal or plant lives, including both the LIVING AND NON-LIVING aspects of the area ECOSYSTEM - CORRECT ANSWERS ALL of the ANIMALS and PLANTS in an area, along with things that affect them, such as the SOIL and WEATHER. Includes all INTERACTIONS between all DIFFERENT LIVING ORGANISMS and the NON-LIVING COMPONENTS of their home QUADRATS TO ESTIMATE POPULATION SIZE - CORRECT ANSWERS A sample square is taken at random. The number of a population in that square is taken. This is repeated in different areas and compared to show where populations are dense and not. QUADRATS TO ESTIMATE POPULATION SIZE IN 2 DIFFERENT AREAS - CORRECT ANSWERS A square of around a meter takes a sample from a area and the populations are counted. This can be repeated many times before being multiplied out as if it were the complete area of the land. Two different samples can be put in two separate areas and the sampling done for both will estimate population for both areas. TROPHIC LEVELS - CORRECT ANSWERS PRODUCER, PRIMARY CONSUMER, SECONDARY CONSUMER, TERTIARY CONSUMER, DECOMPOSER STAGES IN CARBON CYCLE - CORRECT ANSWERS Respiration is carried out by animals and plants to release energy from glucose, the equation is: C6H12O6 + 6O2 → 6CO2 + 6H2O. This means carbon is produced. Photosynthesis is what plants do to create glucose the equation is: 6 CO2 + 12 H2O → C6H12O6 + 6 O2 + 6 H2O. This means carbon is used.

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Decomposition is happens when an animal dies, it is then eaten by a decomposer which releases the carbon in it back into the atmosphere. Combustion is burning, if something with carbon is burnt it will release it into the atmosphere, e.g. a tree, fossil fuel. GREENHOUSE GASES - CORRECT ANSWERS WATER VAPOUR, CARBON DIOXIDE, NITROUS OXIDE, METHANE, CFCs INCREASE IN GREENHOUSE GASES - CORRECT ANSWERS Result in an ENHANCED GREENHOUSE EFFECT and this may lead to GLOBAL WARMING and it's consequences EUTROPHICATION - CORRECT ANSWERS Can result from leached MINERALS FROM FERTILISER SELECTIVE BREEDING - CORRECT ANSWERS Can be used to develop ANIMALS and plants with DESIRED CHARACTERISTICS HUMAN INSULIN - CORRECT ANSWERS Can be manufactured from genetically modified bacteria that are grown in a fermenter PLASMIDS AND VIRUSES ACTING AS VECTORS - CORRECT ANSWERS When a virus or plasmid is inside a host cell it may pick up DNA, it may then carry this into another host cell. The foreign DNA is known as recombinant DNA MICROPROPAGATION - CORRECT ANSWERS Plant clippings are taken and placed in a sterile growth medium. Roots will develop from the clipping (and shoots) making a whole new plant. The plant will then be transferred into compost and grown as a normal plant. The plant is a clone of the one is was taken from because it has the same DNA. This means that there will be no variation, so you can have the same plant every time.

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HOW MICROPROPAGATION IS USED TO PRODUCE COMMERCIAL QUANTITIES OF CLONE PLANTS -

CORRECT ANSWERS In micropropagation, plant clippings are taken and put in a growth medium. They will develop into a new plant with the same DNA. This means that every plant made from the clippings of one plant will be clones with exactly the same characteristics. If many clippings are taken then you will have many clones STAGES IN PRODUCING CLONED MAMMALS - CORRECT ANSWERS A egg cell with the nucleus removed has the DNA of another cell put in (this will be have a complete set of chromosomes (diploid number of)). The embryo that forms will then have DNA from only one parent: the one the DNA was taken from. This means it will be a clone! for example dolly the sheep. NUCLEUS STRUCTURE - CORRECT ANSWERS Contains all GENETIC INFORMATION and CONTROLS actions of the cell CYTOPLASM - CORRECT ANSWERS Where the reaction in cells takes place CELL MEMBRANE - CORRECT ANSWERS CONTROLS movement of CHEMICALS in and out of the cell CELL WALL - CORRECT ANSWERS STRENGTHENS the cell (Made from CELLULOSE) CHLOROPLAST - CORRECT ANSWERS Used in PHOTOSYNTHESIS (Contain CHLOROPHYLL) VACUOLE - CORRECT ANSWERS Keeps the cell TURGID ANIMAL CELL STRUCTURE - CORRECT ANSWERS A nucleus is in the centre of the cell; it is surrounded by cytoplasm; around the outside edge is the cell membrane PLANT CELL STRUCTURE - CORRECT ANSWERS A vacuole in the centre is surrounded by cytoplasm; with in this is the nucleus and chloroplasts; surrounding this is the cell membrane; and around that is the cell wall CARBOHYDRATE AND LIPID COMPOSITION - CORRECT ANSWERS CARBON, HYDROGEN, OXYGEN

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PROTEIN COMPOSITION - CORRECT ANSWERS CARBON, HYDROGEN, OXYGEN, SULFUR,

PHOSPHORUS, NITROGEN

TEST FOR GLUCOSE - CORRECT ANSWERS Heat object with Benedict's Reagent. if it turns from blue to orange then glucose is present. TEST FOR STARCH - CORRECT ANSWERS Apply iodine to the object you are testing, if it turns from red to blue/black then there is starch. ENZYME ACTIVITY EFFECTED BY TEMPERATURE (TEST) - CORRECT ANSWERS 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 HOW SURFACE AREA AFFECTS THE RATE OF MOVEMENT OF SUBSTANCES INTO AND OUT OF CELLS - CORRECT ANSWERS with a larger surface area- molecules have more surfaces through which to diffuse, this increases the rate of moment

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HOW TEMPERATURE AFFECTS THE RATE OF MOVEMENT OF SUBSTANCES INTO AND OUT OF CELLS -

CORRECT ANSWERS Increased temperature means increased kinetic energy- this will mean molecules collide with the cell wall more often making movement through it more likely HOW CONCENTRATION GRADIENT AFFECTS THE RATE OF MOVEMENT OF SUBSTANCES INTO AND OUT OF CELLS - CORRECT ANSWERS This is the difference between the concentration inside and outside of the cell. The bigger the difference is the more opportunity molecules have of diffusing. EXPERIMENT TO INVESTIGATE DIFFUSION - CORRECT ANSWERS 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 EXPERIMENT TO INVESTIGATE OSMOSIS - CORRECT ANSWERS 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 less highly concentrated salt water. Where as in the pure water the potato will have gained mass as it was less dens with water. PHOTOSYNTHESIS & IMPORTANCE OF ENERGY CONSERVATION - CORRECT ANSWERS Photosynthesis is the process in which energy- from the sunlight- is used to create glucose.

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Light energy is absorbed by chlorophyll in plants leaves. It is then used to convert carbon dioxide (from the air) and water (from the ground) into glucose; which is used for respiration. Oxygen is a by- product of this process. This is using light energy, from the sun, to create chemical energy (glucose); which conserves the energy from the sun. This energy is then passed through the food chain, which is why plants are called the producer (producing the chemical energy in the chain from the sun light.) HOW CARBON DIOXIDE CONCENTRATION AFFECTS RATE OF PHOTOSYNTHESIS - CORRECT ANSWERS If there is insufficient carbon dioxide a plant will not be able to photosynthesis to its full potential. Because there is less carbon dioxide- less reactant- there has to be less product being made. HOW LIGHT INTENSITY AFFECTS RATE OF PHOTOSYNTHESIS - CORRECT ANSWERS If the light is at a low intensity the rate of photosynthesis is lowered because the energy that the light provides is less, so the reaction is slowed down. A higher light intensity will enable photosynthesis to happen faster. HOW TEMPERATURE AFFECTS RATE OF PHOTOSYNTHESIS - CORRECT ANSWERS In colder temperatures the rate of photosynthesis will decrease. If the temperature is too high however, the plant will not be able to photosynthesise LEAF ADAPTATIONS FOR PHOTOSYNTHESIS - CORRECT ANSWERS In terms of the basic features leaves have a large surface area; this allows them to absorb more sunlight. They are also thin, meaning that carbon dioxide has a shorter way to travel. In addition the stomata allow the entrance of carbon dioxide. EXPERIMENT TO INVESTIGATE PHOTSYNTHESIS - CORRECT ANSWERS he most common experiment for this is using pond weed, which is placed under water then factors are varied: A lamp is moved further from the plant; Baking powder is added to the water (increasing CO2);

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A white leaved plant is tested against a green leaved plant (green has more chlorophyll). The gas it gives off- being the products of photosynthesis- is counted as bubbles or measured by downwards displacement. This shows the speed of photosynthesis under different conditions. Iodine can be used to test the production of starch. CARBOHYDRATE FUNCTION - CORRECT ANSWERS IMMEDIATE ENERGY bananas, brown rice, wholemeal foods and potatoes. PROTEIN FUNCTION - CORRECT ANSWERS GROWTH & REPAIR sea food, eggs, pork and soy LIPID FUNCTION - CORRECT ANSWERS LONG TERM ENERGY STORE, INSULATION & PROTECTION fish, eggs, milk and beef. VITAMIN A FUNCTION - CORRECT ANSWERS MAINTAINING NORMAL REPRODUCTION, GOOD VISION, FORMATION AND MAINTENANCE OF HEALTHY SKIN, TEETH AND SOFT TISSUES & IMMUNE FUNCTION Milk, cheese, eggs, fatty fish, yellow-orange vegetables and fruits such as carrots, pumpkin, mango, apricots, and other vegetables such as spinach, broccoli.

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VITAMIN C FUNCTION - CORRECT ANSWERS AIDING ABSORPTION OF IRON AND COPPER, HEALTHY

BONES & HELPS TO FIGHT INFECTION

Blackcurrants, orange, grapefruit, guava, kiwi fruit, raspberries, sweet peppers (Capsicum), broccoli, sprouts VITAMIN D FUNCTION - CORRECT ANSWERS IMMUNE FUNCTION, HEALTHY SKIN & MUSCLE STRENGTH Sunlight on skin allows the body to produce Vitamin D. Few foods contain significant amounts however main dietary sources are fortified margarine, salmon, herring, mackerel, and eggs. CALCIUM FUNCTION - CORRECT ANSWERS DEVELOPMENT AND MAINTENANCE OF BONES AND TEETH, GOOD FUNCTIONING MUSCLES AND NERVES & HEART FUNCTION Milk, cheese, yoghurt, bony fish, legumes, fortified soy beverages and fortified breakfast cereals. IRON FUNCTION - CORRECT ANSWERS HAEMOGLOBIN IN RED BLOOD CELLS, COMPONENT OF MYGLOBIN Red meats - beef, lamb, veal, pork, fish, chicken and wholegrain cereals WATER FUNCTION - CORRECT ANSWERS CHEMICAL REACTIONS IN CELLS NEED WATER & FOR RESPIRATION DIETARY FIBRE FUNCTION - CORRECT ANSWERS KEEPS BOWELS FUNCTIONING WELL Cereals, bread, rice, beans and nuts. THE MOUTH (HUMAN ALIMENTARY CANAL) - CORRECT ANSWERS Mechanical digestion happens here- your jaw action.

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A bolus is created; this is a ball of food covered in saliva. This is help full as the food is lubricated to enable swallowing and enzymes in the saliva can begin to break down the food. (amylase) THE OESOPHAGUS (HUMAN ALIMENTARY CANAL) - CORRECT ANSWERS this tube connects you mouth and stomach. It is next to the trachea which is covered by the epiglottis when you swallow so the food only enters the oesophagus. Peristalsis- or muscular contractions- moves the food downward. THE STOMACH (HUMAN ALIMENTARY CANAL) - CORRECT ANSWERS Churning mechanically digests whilst enzymes do so chemically. Chyme is the name for liquid food existing in the stomach. THE SMALL INTESTINE (HUMAN ALIMENTARY CANAL) - CORRECT ANSWERS This absorbs digested molecules into the blood stream. Villi cover the inside giving it a large surface area which many molecules can diffuse through into the blood. THE LARGE INTESTINE (HUMAN ALIMENTARY CANAL) - CORRECT ANSWERS This absorbs water from undigested food, producing faeces. THE PANCREAS (HUMAN ALIMENTARY CANAL) - CORRECT ANSWERS This produces the enzymes lipase, amylase and protease. HUMAN ALIMENTARY CANAL STRUCTURE - CORRECT ANSWERS MOUTH> OESOPHAGUS>STOMACH>SMALL INTESTINE>LARGE INTESTINE>PANCREAS DIGESTION - CORRECT ANSWERS The process in which large insoluble molecules of food are broken down into smaller ones.

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ABSORPTION - CORRECT ANSWERS the process by which soluble molecules produced by digestion are taken from the gut (occurs mostly in the small intestine.) The soluble products of digestion are then transported to the various tissues by the circulatory system. ASSIMILATION - CORRECT ANSWERS the cells of the tissues absorb the molecules for use. EGESTION - CORRECT ANSWERS removal of waste- undigested- products as faeces. EXCRETION - CORRECT ANSWERS removal of waste products that have been in the body. HOW AND WHY FOOD IS MOVED THROUGH THE GUT - CORRECT ANSWERS Food is moved through the gut by peristalsis. Muscles move food because mechanical action is needed to get food through the system. ROLE OF ENZYMES - CORRECT ANSWERS Enzymes break down food into useful things that our boddies need. Different enzymes break down different components of our food. CONVERSION OF STARCH TO GLUCOSE - CORRECT ANSWERS AMYLASE & MALTASE CONVERSION OF PROTEINS TO AMINO ACIDS - CORRECT ANSWERS PROTEASE CONVERSION OF LIPIDS TO FATTY ACIDS AND GLYCEROL - CORRECT ANSWERS LIPASE BILE - CORRECT ANSWERS PRODUCED IN THE LIVER & STORED IN THE GALL BLADDER NEUTRALISING STOMACH ACIDS - CORRECT ANSWERS 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.

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EMULSIFYING LIPIDS - CORRECT ANSWERS Bile also emulsifies fat; this gives it a larger surface area, which means that it is easier for lipase to work. VILLI - CORRECT ANSWERS in the small intestine. The are like lumps on this inside of the small intestine. They are the surface through which food diffuses into the blood stream. They have very thin walls, only one cell thick, this enables molecules to pass through easily. They also increase the surface area of the small intestine wall On the outside of villi there are capillaries which pick up the diffused food into the blood stream. WHEN ANAEROBIC RESPIRATION IS USED - CORRECT ANSWERS 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. EXPERIMENT TO INVESTIGATE THE EFFECT OF EXERCISE ON BREATHING IN HUMANS - CORRECT ANSWERS During exercise cells respire more quickly (to provide more energy for movement) this means oxygen has to be delivered more quickly and carbon dioxide taken away more quickly. As a result of this the lung muscles contract and relax more rapidly and the heart beats faster. Measure a persons breaths per 10 seconds when stationary. Then after one minute after running at 5mph then at two minutes and so on. You will find a linear relationship as described above between the two. ROLE OF DIFFUSION IN GAS EXCHANGE - CORRECT ANSWERS In the circulatory system oxygen enters the blood and carbon dioxide leaves the blood via gaseous exchange. Gasses move across the walls of alveoli to an area of lower density than they are in: Oxygen moves into the blood as there is a low density of oxygen in the blood; Carbon dioxide moves into the lungs as it is an area of lower density

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GAS EXCHANGE IN RELATION TO RESPIRATION & PHOTOSYNTHESIS - CORRECT ANSWERS In photosynthesis: 6CO2 + 12H2O > C6H12O6 + 6O2 + 6H2O So the plant takes up carbon dioxide and gives out oxygen In respiration: C6H12O6 + 6H2O > 6CO2 + 6H2O So the plant gives out carbon dioxide BREATHING IN - CORRECT ANSWERS 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 o the right- which then split into even smaller tubes, called bronchiles; these end in alveoli where gas exchange takes place. The pleural membranes prevent friction BREATHING OUT - CORRECT ANSWERS 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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EFFECT OF HUMIDITY ON RATE OF TRANSPIRATION - CORRECT ANSWERS Increased humidity decreases transpiration. This is because high water content outside the leaf will mean there is little difference in concentration, so the water will not be able to move- as it naturally does- from an area of low concentration to an area of high concentration. EFFECT OF WIND SPEED ON RATE OF TRANSPIRATION - CORRECT ANSWERS Increased wind speed will increase transpiration. Because if the wind blows away the water vapour being produced their will be a greater difference in water concentration, meaning water will be able to continue leaving the leaf. EFFECT OF TEMPERATURE ON RATE OF TRANSPIRATION - CORRECT ANSWERS Increased temperature increases transpiration, as increased heat makes evaporating easier. EFFECT OF LIGHT INTENSITY ON RATE OF TRANSPIRATION - CORRECT ANSWERS Increased light intensity increases transpiration, as more heat is absorbed by the leaf meaning more water will be evaporated, also there is more photosynthesis meaning more water is being transported through the leaf (so more will need to leave the leaf.) EXPERIMENT TO INVESTIGATE THE ROLE OF ENVIRONMENTAL FACTORS IN DETERMINING THE RATE OF TRANSPIRATION - CORRECT ANSWERS Support a plant in a tray filled with a given amount of water. Place in different conditions and record the time taken for all the water in the way to be taken up by the plant. ROLE OF PLASMA IN TRANSPORT OF WATER - CORRECT ANSWERS Is a solvent and a liquid; so plasma carries these different things around the body disolved in water: Carbon- Hydrogen carbonate Digested food- soluble sugars and amino acids Urea Hormones.

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Water also carries heat, which is important in the regulation of body temperature. ADAPTATIONS OF RED BLOOD CELLS - CORRECT ANSWERS They have haemoglobin- which is made from iron- that can bond to oxygen. They have no nucleus to make more room for haemoglobin.There are no mitochondria as the cells respire anaerobically. The biconcave shape enables them to pass through narrow capillaries and increase the surface area and decrease the distance for diffusion meaning that diffusion of oxygen happens quickly. PHAGOCYTES (SPECIALISED WHITE BLOOD CELL) - CORRECT ANSWERS They can detect the presence of pathogens because of chemicals they give off. The cell then engulfs the pathogen. If then destroys the cell with digestive enzymes. LYMPHOCYTES (SPECIALISED WHITE BLOOD CELL) - CORRECT ANSWERS They release anti-bodies that are specific to the pathogen. When a lymphocyte meets its specific pathogen it divides: one cells it creates being a memory cell; the other being the cell which will create anti-bodies. One type of anti-body will attach to the pathogen to attract phagocytes. The other type will disable the cell. A third type will group the pathogens together so that phagocytes can engulf them all. If the memory cells every meet the pathogen again they will create the anti-bodies very quickly. HOW HEART RANGE CHANGES DURING EXERCISE - CORRECT ANSWERS During exercise muscles require more energy which is created by respiration, that requires more oxygen to be brought to cells and more carbon dioxide to be taken away, this means the heart needs to increase its speed so that more blood is sent to muscles. HEART RANGE CHANGES UNDER THE INFLUENCE OF ADRENALINE - CORRECT ANSWERS Adrenaline is produced in the adrenal glands in top of the kidneys- stimulates adrenegic receptors in the heart which increase the rate that your heart cells work at.

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FUNCTION OF THE HEART - CORRECT ANSWERS he right atrium fills with blood (from the vena cava) and the valve is closed; This area is squeezed forcing the blood through an atrio-ventricular valve into the right ventricle; This area contracts forcing the blood through the pulmonary artery where it is oxygenated at the lungs; the pulmonary vein fills the left atrium with blood; This contracts forcing the blood into the left ventricle; when the left ventricle contracts the blood is forced out through the aorta. ARTERIES - CORRECT ANSWERS Take blood away from the heart Blood in them is under high pressure They are delivering blood to an organ Thick, muscle wall; small lumen (to give high blood pressure) VEINS - CORRECT ANSWERS Take blood to the heart Blood is under low pressure Their blood is returning from an organ Relatively thin wall; large lumen (to give ow blood pressure) Valves stop blood flowing back in the wrong direction CAPPILARIES - CORRECT ANSWERS Exchange is taken place Very thin cell walls (one cell thick) so that substances can diffuse easily VEIN - CORRECT ANSWERS TO the heart

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ARTERY - CORRECT ANSWERS AWAY from the heart LUNG - CORRECT ANSWERS PULMONARY LIVER - CORRECT ANSWERS HEPATIC KIDNEY - CORRECT ANSWERS RENAL STOMACH - CORRECT ANSWERS GASTRIC HEPATIC PORTAL VEIN - CORRECT ANSWERS BETWEEN GUT AND LIVER ORIGIN OF CARBON DIOXIDE & OXYGEN AS A WASTE PRODUCT OF OXYGEN AND LOSS THROUGH THE STOMATA OF A LEAF - CORRECT ANSWERS RESPIRATION-carbon dioxide is a waste product and is excreted from the leaf through the stomata. PHOTOSYNTHESIS-the glucose is used for energy and oxygen is a waste product, it leaves the leaf through the stomata. ORGANS OF EXCRETION - CORRECT ANSWERS LUNGS, KIDNEYS and SKIN HOW KIDNEYS CARY OUT EXCRETION - CORRECT ANSWERS amino acids contain nitrogen- which is toxic to the body- the liver converts it into urea. The kidneys filter urea from the blood stream and combine it with water to create urine which then moves into the bladder. HOW KIDNEYS CARRY OUT OSMOREGULATION - CORRECT ANSWERS The kidneys react to ADH hormone released by the pituitary gland. If there is too little water ADH will be released and the kidneys won't absorb any water, but if there is too much water then less ADH is released and the kidneys absorb water from the blood stream.