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Biological Systems and ProcessesLesson 1: The Skeletal SystemThe human body is made up of an organisational hierarchy:3648578549900Cells - the basic units of lifeTissues – groups of similar cells working togetherOrgans – groups of tissues working together Organ systems – organs working together to form organ systemsThe skeleton is made of more than 200 bones. Calcium and other minerals make the bone strong but slightly flexible. Bone is a living tissue with a blood supply. It is constantly being dissolved and formed, and it can repair itself if a bone is broken.The skeleton has four main functions; Support for the body, movement, protection of vital organs, synthesis and storage of blood cells. 327803869472600The bones contain bone marrow which is a source of stem cells. These cells can become new blood cells. This is why bone marrow transplants are often used to treat patients with leukaemia.Bones are connected by joints, there are different types of joints and they all allow the body to move. Movement of the bone happens when a muscle contracts or relaxes to pull on a bone, via ligaments and tendons. Cartilage covers the bones to stop them rubbing together. The synovium contains fluid and reduces friction when the bones move within the joint. Add the functions of the structures of the joint to the diagram belowAntagonistic musclesMuscles can only pull and cannot push. This would be a problem if a joint were controlled by just one muscle. As soon as the muscle had contracted and pulled on a bone, that would be it, with no way to move the bone back again. This problem is solved by having muscles in pairs, called antagonistic muscles. One muscle of the pair contracts to move the body part, the other muscle in the pair then contracts to return the body part back to the original position. Muscles that work like this are called antagonistic pairs.For example, your elbow joint has two muscles that move your forearm up or down. These are the biceps on the front of the upper arm and the triceps on the back of the upper arm:0-270800To raise the forearm, the biceps contracts and the triceps relaxesTo lower the forearm again, the triceps contracts and the biceps relaxesPractical 444627038036500Model the elbow joint using cardboard bones and elastic bands to show how one lengthens and one shortens in order to bring about movement in the arm.Put the following in order of size from smallest to largest:Tissue, Cell, Organ, Organism, Organ systemWhat are tissues made from?What are organs made from?Describe what antagonistic muscles areExplain how this practical model represents movement of the forearmExplain how antagonistic muscles work together to move the arm.Give an example of an organisational hierarchy in the human body, name the cells, tissues, organs and organ systemsWhat are the four functions of the skeletal system?Your skeleton provides structural support for your body, it also protects vital organs. Which three vital organs do the skull and ribcage protect?What does a ligament join? What does a tendon join? Why do you think there is cartilage and fluid between the two bones? 45392191479500Use the diagram of a joint to explain how bones moveAnother example of a pair of antagonistic muscles is found in your legs. Here your quadriceps and hamstrings work together. Explain how these contract and relax to move your legs.Look at the pictures on the right, describe two ways the damaged joint is different than the normal joint. Explain why arthritis in the joints causes painLesson 2: MusclesYou have around 650 muscles in your body, and they make up roughly half of your bodyweight.?Muscles are made of muscular tissue which needs energy to contract. This energy is released during respiration, respiration takes place in the mitochondria inside the muscle cells. 42751174958440041207381398369044031562393752330079632623093265714332217200950032669029-63525781000Label the organelles of the animal cell and state the function of each organelle:Muscle typesThere are three types of muscle in the body:Smooth muscle – found in the internal organs and blood vessels - this is involuntaryCardiac muscle – found only in the heart - this is involuntarySkeletal muscle – attached to the skeleton and allow movement - this is voluntaryInvoluntary muscles are not under our conscious control which means we can't make them contract when we think about it.Voluntary muscles are under our conscious control so we can move these muscles when we want to.Smooth muscle390271081564400Smooth muscle is found in the walls of hollow organs like your intestines and stomach. They work automatically without you being aware of them. Smooth muscle tissue contracts slowly and automatically. Smooth muscles are involved in many 'housekeeping' functions of the body. The muscular walls of your intestines contract to push food through your body. Muscles in your bladder wall contract to expel urine from your body. Smooth muscles in a woman's uterus (or womb) help to push babies out of the body during childbirth.Describe how the muscular tissue in the intestines works 78377124929900Cardiac muscle Your heart is an incredibly powerful organ. It works constantly and automatically without ever pausing to rest. It is made of cardiac muscle, which only exists in the heart. Cardiac muscular tissue relaxes to allow the heart to fill with blood, then contracts to pump the blood out to the lungs and body. Your heart is a single organ, but it acts as a double pump. The first pump (right side) carries oxygen-poor blood to your lungs, where it unloads carbon dioxide and picks up oxygen. It then delivers oxygen-rich blood back to your heart. The second pump (left side) delivers oxygen-rich blood to every part of your body. In one day your heart transports all your blood around your body about 1000 times!The muscular walls of the left ventricle are thicker than those of the right ventricle, making it a much more powerful pump. For this reason, it is easiest to feel your heart beating on the left side of your chest.Skeletal muscleSkeletal muscles cover your skeleton, giving your body its shape. They are attached to your skeleton by strong, springy tendons or are directly connected to rough patches of bone. They are under voluntary control. Just about all body movement, from walking to nodding your head, is caused by skeletal muscle contraction. Your skeletal muscles function almost continuously to maintain your posture, making one tiny adjustment after another to keep your body upright. Skeletal muscle is also important for holding your bones in the correct position and prevents your joints from dislocating.Is your cardiac muscle a tissue or an organ? Give a reason for your answerWhy is the heart called a double pump?What is the meaning of involuntary when used to describe muscle?Complete the table using the information above for smooth and skeletal muscle, cardiac muscle has been done for you.QuestionSmooth muscleSkeletal muscleCardiac muscleWhere its located?In the heartUnder voluntary or involuntary controlInvoluntaryFunctionT pump the blood out to the lungs and body33246701117680018 Identify which are the main skeletal muscle(s) used during: WalkingSwimmingRowing Sitting on a chairJumpingPractical: Measuring muscle strength - Muscles exert a force on bones when they contract. This happens for example when you lift or hold an object, or when you move a part of your body. The way in which muscles and bones work together to exert forces is called biomechanics.left52133500Measure the strength of your, arm and grip using Newton scales. Place the scales up against a wall, place feet on them and push, then do the same with your arms, then try gripping them. Take care not to drop the scales as they will break!Identify which muscles of the body you used for all three testsWhy is it not possible to be more specific about which muscle is working when taking these measurements?What is the function of mitochondria?Explain how muscular tissue is adapted for its function.What are the three types of muscle in the body? Give examples of each.Describe the difference between involuntary and voluntary musclesThe heart is a double pump, because… Why is the left ventricle cardiac muscle thicker than the right ventricle? How does the smooth muscular tissue in the stomach work?How does the smooth muscular tissue in the intestines work?What are the functions of skeletal muscles?Complete the sentence belowSome people think muscles are only working when we are moving, this is wrong because…Lesson 3: The respiratory system structure & gas exchangePart 1: The Respiratory system takes air into and out of the body and is where gas exchange occurs. Respiration is the chemical reaction that releases energy in cells in living organisms. 49136308689440359410877977038560088540030026741888540030015786338626300Living things need energy to move, grow and build new molecules. Respiration takes place all the time in all living cells. Remember - respiration is NOT the same as breathingBreathing or ventilation is the mechanical process to get air in and out of the lungs.Label the products and reactants in the equation for respiration (energy, carbon dioxide, glucose, water, oxygen).4963853173361600496388614250400501138765314300264668011842300The lungs are enclosed in the thorax, surrounded and protected by 12 pairs of ribs. The trachea, or windpipe, branches into two bronchi – one bronchus to each lung. Rings of C shaped cartilage in the walls of the trachea help to keep it open as air is drawn in. The trachea is lined with cells that have tiny hair like projections called ‘cillia’. Which trap dirt and pathogens in the mucus and move them up towards the mouth for the body to remove.The bronchi split into smaller branches and then into smaller tubes called bronchioles. Each bronchiole ends in a cluster of microscopic air sacs called alveoli.Add the following labels to the diagram:NucleusCilia 62484018923000Basement membrane7950204969510thorax, ribs, rib muscles, trachea, bronchus, alveoli, lung, bronchioles, abdomen, diaphragm00thorax, ribs, rib muscles, trachea, bronchus, alveoli, lung, bronchioles, abdomen, diaphragmLabel the diagram with the following words:Why do we need to breathe? A whale can hold their breath for about 90 minutes! The record for a human is 22minutes! The average human can hold their breath for only about 30 seconds. Suggest how the whale might be adapted to be able to hold its breath for so long.Part 2: Gas exchangeGas exchange occurs in the alveoli.Diffusion is the movement of particles from an area of high concentration to an area of low concentration. When we breathe, air rich in oxygen arrives in the alveoli. Oxygen diffuses, down a concentration gradient, into the bloodstream.290893516573500Waste carbon dioxide diffuses from the blood into the alveoli to be exhaled.We need to continuously breathe to maintain the concentration gradients in the lungs so that diffusion does not slow.The lungs are well adapted for their job of gas exchange. There are many alveoli, with thin highly folded membranes, reducing the diffusion distance and increasing the surface area. The alveoli are also surrounded by blood vessels for efficient gas exchange into the blood. The alveoli are also moist with mucus. This increases the speed of diffusion.Add arrows to the diagram to show the direction of diffusion of carbon dioxide and oxygenUse the information in the diagram to help you complete the tableGasOxygenCarbon dioxideWhere is the concentration the highest? Alveoli or bloodstreamAlveoli or bloodstreamWhere is the concentration the lowest?Which way will the gas move?By which process?What does the gas have to pass across?Complete the table below to show how the features of the respiratory system help gas exchange:StructureFeatures ReasonTracheaRings of C shaped cartilageAlveoliShort diffusion pathAlveoliGood blood supplyAlveoliHighly folded membraneDemonstration: Lung dissectionWatch the demonstration and make some notes on the following: Look for the C shaped cartilage supporting the trachea, the bronchi and the bronchioles. What is its function?Does a piece of lung float in water? Why?What gas moves from the alveoli into the blood?What gas moves out of the blood into the alveoli?What is the difference between breathing and respiration?Name three factors that affect the rate of gas exchangeDescribe what happens to oxygen and carbon dioxide inside the alveoli. Explain why this happens using the idea of diffusion and concentration gradients.How do the following features of the lungs make them good at their job of gas exchange:Rings of C shaped cartilage in tracheaThin membranes Highly folded membranesA good blood supplyThe blood high in oxygen leaves the lungs and is returned to the heart to be pumped around the body. As it travels around the body, the blood passes cells that are low in oxygen. What do you think happens?What are the reactants required for the process of respiration?What are the products of respiration?What is the function of the cell membrane?Why do cells need a constant supply of oxygen?The trachea is lined with tiny hair like projections called cilia, so…Lesson 4 Breathing and Lung VolumesBreathing involves movements of the ribs,?intercostal muscles?and?diaphragm?to move air into and out of the lungs:179070163830361954721200When we breathe in, we?inhale. Changes in the diaphragm and ribcage reduce the pressure in the chest, and air moves into the lungsWhen we breathe out, we?exhale. Changes in the diaphragm and ribcage increase the pressure in the chest, and air is moved out of the lungsThe table describes the changes involved:InhalingExhalingDiaphragmContracts and moves downwardsRelaxes and moves upwardsIntercostal musclesContract, moving the ribs upwards and outwardsRelax, letting the ribs move downwards and inwardsVolume of ribcageIncreasesDecreasesPressure inside the chestDecreases below atmospheric pressureIncreases above atmospheric pressureMovement of airMoves into the lungsMoves out of the lungsDescribe how we breathe in and outExplain why we need to breathe.Keywords: diaphragm, pressure, intercostal muscles, volumePractical: Lung volumeLung volume is the volume of air that can be held inside your lungs. We can measure this using equipment called a spirometer or a lung volume bag. Measure the volume of air you can fit in your lungs by taking a deep breath in and blowing out either into the spirometer or the lung volume bag.Add your result to the class results table to compare lung volumes between body and girls:Calculate the average for each genderWhat is the range of readings for each gender?Can you draw a conclusion? What is diffusion?Which gas diffuses from the blood into the alveoli?Which structure is a sheet of muscle separating the thorax and the abdomen? Give two ways the alveoli are adapted for their functionWhat happens to the oxygen that crosses into the bloodstream?How can we measure lung volume?Why is it important to sterilise the mouthpiece before use?What factors affect lung volume? People who suffer from asthma have inflamed and narrowed airways. During an asthma attack, the muscles contract, narrowing the airway even more. Use the information in the diagram below to describe what happens to the airways when someone has an asthma attack. How will this affect their breathing and their lung volumeleft825500Lesson 5 The effects of exercise on the respiratory system4055037291522448830412114Used for:Muscle contraction Internal organsMuscles that bring about movementMaintaining body temperature (mammals & birds)Building up larger molecules from small onesIn plants to build up sugars, nitrates and others into amino acids, then into proteins00Used for:Muscle contraction Internal organsMuscles that bring about movementMaintaining body temperature (mammals & birds)Building up larger molecules from small onesIn plants to build up sugars, nitrates and others into amino acids, then into proteinsRespiration is a chemical reaction that occurs inside the mitochondria of all living cells, its releases energy from the food you’ve eaten. Aerobic respiration uses oxygen: When the body cannot supply the cells with the oxygen needed to break down glucose, then it must carry out anaerobic respiration. Energy is released without oxygen:right12164Requires oxygenProduces lactic acidDoesn’t need oxygenRequires glucose Releases a lot of energyReleases a little energyCarbon dioxide and water producedEnergy released00Requires oxygenProduces lactic acidDoesn’t need oxygenRequires glucose Releases a lot of energyReleases a little energyCarbon dioxide and water producedEnergy releasedThis would generally only take place in animal cells when there is an insufficient supply of oxygen – e.g. during sprinting or intense exercise when you can’t breathe fast enough to get enough oxygen in.Lactic acid can build up, causing cramp. Less energy is released, causing muscle fatigue.Put the following words/phrases into the correct area in the Venn diagram3217982154751Anaerobic020000Anaerobic1329690154305Aerobic020000Aerobic182842913988900-20188116420900Effect of exercise Condition Description of changeExplanationHeart rateHow hard the heart beatsBreathing rateBreathing depthBlood flow to musclesLook at the three pieces of evidence below and use these to complete the table. Use the data to back up your statements. Be careful with language. Remember – respiration is already happening in all cells before any exercise starts. The word ‘more’ or ‘increased’ needs to feature in your explanationsThe effect of exercise – Evidence piece 1 The effect of exercise – Evidence Piece 23432810444500The table below shows typical effects of heart and -33655026162000breathing rates during exercise. The sketch graph above shows the effect of exercise on how hard the heart beats.34487619160200The effects of exercise - evidence piece 3What do we need oxygen for?What do we need respiration for?Where does respiration happen?What type of cells have lots of these?How do the cells get all the things they need for respiration?Describe the difference between anaerobic and aerobic respirationWhen does the body respire anaerobically? Who is the fittest? Steve and Derek wanted to find out which of them was the fittest. They both did some exercise which made them breathe faster. They then stopped exercising and timed how long it took for their breathing rates to return to normal again. The graph shows the results.After how many minutes did Steve and Derek stop exercising?Derek said that the faster a person’s breathing rate returned to a steady resting rate, the fitter the person was.From the information in the graph, state who was the fittest person and explain why?Suggest how this investigation may not have been fair.What else could you measure after exercise as an indication of fitness?Outline a plan for you and a partner to compare fitness levels.Lesson 6 – The effect of smoking on the respiratory system and gestationA drug is a substance chemically alters the body:medicines are drugs that help people suffering from pain or diseaserecreational drugs are taken by people because they like the effects they have on their bodiesSome recreational drugs are legal, such as tobacco and alcohol, although there are restrictions on who can buy them. Caffeine, found in coffee, is another recreational drug. Most other recreational drugs are illegal, and these include cannabis, ecstasy and heroin.Recreational drugs can be classified as a depressant or a stimulant. Most recreational drugs can be addictive.Depressants - A depressant slows down messages in the brain and along the nerves. Alcohol is a depressant. Effects depressants have on the body:lowered inhibitionslowed thinkingslowed muscular activitya distorted view of the world, or hallucinationsSome of the long-term effects of depressants on the body include damage to the liver, brain and heart. Write a definition for a depressantSome people think that alcohol makes you feel more alert, this is wrong because…319024071945500Stimulants - Stimulants speed up messages in the brain and along the nerves. This makes you feel more alert. Nicotine from tobacco is a stimulant. Caffeine is another stimulant and is found in cola drinks, coffee and tea. It makes you feel more energetic and alert, but it can also cause insomnia (difficulty in sleeping), headaches and nervousness.Write a definition for a stimulantSmoking Demonstration – cigarette smoke is very harmful to health. It’s estimated that nearly one in every five deaths (of adults aged over 35 in England) is connected to smoking. Tobacco smoke contains many harmful substances: TarTar causes cancer of the lungs, mouth and throat. It coats the inside of the lungs, including the alveoli, causing coughing. It damages the alveoli, making it more difficult for gas exchange to happen.SmokeCells in the lining of the trachea, bronchi and bronchioles produce sticky mucus. This traps dirt and microbes. Cells with tiny hair-like parts, called cilia then move the mucus out of the lungs.However, hot smoke and tar from smoking damages the cilia. As a result of this, smokers cough to move the mucus and are more likely to get bronchitis.NicotineNicotine is addictive. It causes a smoker to want more cigarettes. Nicotine also increases the heart rate and blood pressure, and makes blood vessels narrower than normal. This can lead to heart disease.Carbon monoxideCarbon monoxide is a gas that takes the place of oxygen in red blood cells. This reduces the amount of oxygen that the blood can carry. It means that the circulatory system has to work harder, causing heart disease.751708-48600Why are smokers more likely to get bronchitis?Why can smoking lead to heart disease?What could this mean for the person’s health?What is the name of the tube running from the nose and mouth to the lungs? The cells of this pipe are lined with cells like the one below. What is their function? Why are the alveoli membranes so highly folded? What happens to the oxygen that crosses the alveoli into the blood? Where does respiration take place?What the difference between a stimulant and a depressantLook at the differences between a healthy person and a smoker in the diagrams on the left.What differences can you see between the healthy person and the smoker? The graph below shows how the effect of the number of cigarettes smoked per day affected the number of people dying from lung cancer. Describe the pattern shown in the graph.b. Can you explain this pattern?center18986500Lesson 7 - Alcohol and other drugsAlcohol is a depressant which slows down messages in the brain and along the nerves.Alcohol can diffuse across the stomach lining into the blood – food cannot do this. Once in the bloodstream, alcohol interferes with the transmission of nerve impulses, meaning reactions are slower, vision is impaired, speech slurred and balance affected.How does alcohol affect your heart?Does intoxication cause dehydration? Use information from the diagram to explain how.Sort these impacts of alcohol into the right columns. Add at least one more for each yourself.6038508208Policing of town centres drunken behaviour liver transplants Drink driving deaths bottle/can litter in parks liver disease mouth cancerBabies born with FAS A&E admissions for alcohol poisoning0Policing of town centres drunken behaviour liver transplants Drink driving deaths bottle/can litter in parks liver disease mouth cancerBabies born with FAS A&E admissions for alcohol poisoningHealth Social impactEconomical impactReaction timeA researcher tested reaction time of 5 subjects with different levels of blood alcohol. The results are shown below:Blood alcohol level (%)Average reaction time (s)0.080.320.100.380.120.440.140.500.160.510.180.63Plot a graph of the data collected (Use fully labelled axes, including units, sensible scales, plotting a line that best fits the points)Describe the pattern shown in as much detail as you can. Identify the anomalous result. Suggest what it should have been. Suggest a possible method the researchers used to collect this data.How could the data be improved? Foetal alcohol syndrome Most substances can diffuse across the wall of the placenta, so alcohol and other drugs taken by a pregnant woman will reach a baby in the womb. This can potentially lead to a variety of physical, developmental and behavioural effects on the foetus. The most serious is foetal alcohol syndrome, where the foetus: is smaller in size, has a smaller brain, has long-term learning and behavioural difficulties, has facial abnormalities.What is foetal alcohol syndrome and how is the foetus affected?Alcohol useThe graph below shows the results of a study of 200 boys and 200 girls into the alcohol they consumedleft25717500a. Describe the differences between boys and girls in the types of drink they consume (2)b. A newspaper headline said ‘All boys drink alcohol’ Give one reason why this headline may be incorrect (1)c. Describe how this data could be improved (1)d. A town contains 2500 teenage girls. Calculate the number you would expect to drink alcopops (3)Describe the effects of alcohol on the body and behaviourDescribe the effects of alcohol on health and the developing foetusLesson 8 - DNA, genes and chromosomesGenetic information is passed from one generation to the next. This is called heredity and why we resemble our parents. The genetic information itself is contained in a complex molecule called DNA.DNADNA stands for?deoxyribonucleic acid. It is made up of two long molecules. The molecules are arranged in a spiral, like a twisted ladder. We call this the?double helix?structure.There is DNA in the?nucleus?of every cell. DNA carries genetic information. It has all the instructions that a living organism needs to grow, reproduce and function.GenesGenes are short sections of DNA. Genes carry information for particular characteristics, such as ear shape or eye colour. Different sets of genes carry information for different characteristics. There are many genes in a chromosome.ChromosomesIn a cell nucleus, DNA is organised into coiled strands called?chromosomes.Humans have 46 chromosomes in each body cell. The fruit fly has only 8 chromosomes and is often used to study patterns of inheritance, while red king crabs have a whopping 208!Half the chromosomes are inherited from one parent and half from the other. Human gametes (eggs and sperm) each contain 23 chromosomes. When an egg is fertilised by a sperm, it becomes a cell with 23 pairs of chromosomes.This is why children resemble both their parents – half of their chromosomes and DNA come from their mother, and half from their father. -5435601539740034846161656715X-ray diffraction’ images of DNA0X-ray diffraction’ images of DNA50378261628332Watson & Crick’s ball and stick model00Watson & Crick’s ball and stick model509778036004500 34591921232800Scientists worked out the structure of DNA in the 1950s. Rosalind Franklin first made ‘X-ray diffraction’ images of DNA. James Watson and Francis Crick used information from one of her images to work out a model for the structure of DNA. Watson and Crick were able to work out how DNA was arranged and the tiny distances between its different features. They worked out that in a DNA molecule:there are two strandsthe strands are twisted around each other to form a double helixthe strands are held together by bonds between base pairsBase pairs are formed by nucleotides joining together, C always joins to C and A to TWatson, Crick and Wilkins were awarded the 1962 Nobel Prize in Physiology or Medicine for their discovery.3017520-5778500Label the diagram: Nucleus, Chromosome, Gene, DNAWhy are the marshmallows (nucleotides) in pairs?Which DNA bases pair up?What does the lace represent?What does the cocktail stick represent?Where do we find all our DNA?What is a chromosome?How many chromosomes are in an adult human cell?How many chromosomes are in an egg/sperm cell?What has happened to the chromosome number?Why is it important that this happens?Sheep have 54 chromosomes. How many will be in each sex cell?All organisms have an even number of chromosomes in their body cells. Why is this?Most cells contain two sets of chromosomes which can be sorted into pairs. Some chromosomes are bigger than others and so the pairs can be arranged in size order, apart from the last two. The picture shows human chromosomes from a cheek cell.Three of the chromosomes are missing. Draw in the missing ones on the diagram.Where in a cell would you find the chromosomes? Chromosomes are divided into sections called genes. Each of the chromosomes labelled number ‘22’ contain about 100 genes. Would you expect to find more, less or the same number of genes in a chromosome like number ‘1’? Explain your answer to number 2. What do genes do? Look at the bar chart.How many chromosomes does a body cell in a cat have?Which species has 66 chromosomes in its cells? On the chart, fill in the missing bar for humans. Numbers of chromosomes in the body cells of different species.Why do you think that the total number of chromosomes in the cells of each species is an even number? Do you think there is a relationship (pattern) between the number of chromosomes in the cells and the size of the organism? John said “If you look more like one parent than another it is because you have more of their genes”. Is he correct? Give a reason. A sperm cell image measures 20mm on a microscope slide at x400 magnification. What is it’s actual size? (Actual = Image / magnification)75049923330900Draw the complementary strand of DNA below:Lesson 9 – Inheritance - each genetically controlled characteristic we have two genes – one from each parent.Different versions of the same gene are known as alleles - e.g. the hair colour gene has 4 alleles – black, brown, blonde and red.Some alleles are ‘stronger’ than others and will always show in the individual’s characteristics. These are known as dominant alleles, and we represent them using capital letters – e.g the allele for brown hair is dominant (B), so a person with even only one B will have brown hair. Weaker alleles are known as recessive, and will only be expressed if there is not a dominant allele. We use lower case letters to represent them – e.g. the allele for blonde hair is recessive (b)The pair of alleles for a particular characteristic can be the same or could be different. If the two alleles are the same (e.g. BB), the person is said to be homozygous for that trait. If the two alleles are different (Bb), the person is said to be heterozygous.The pair of alleles is known as the genotype. The characteristics shown because of the allele combination is the phenotype. E.g – (Bb) the genotype is heterozygous, the phenotype is brown hair. 0-66300Punnett squaresThe possible genotypes and phenotypes of the offspring can be determined using a Punnett square, a grid that shows the possible combinations of alleles that can result at fertilisation.The Punnett square below shows the expected genotypes of the offspring of parent pea plants that both have the genotype Rr. Each of their gametes only contains one allele of the gene for seed shape.The Punnet square below shows the possible genotypes of the offspring. Three quarters of the possible combinations of alleles (one RR and two Rr) will give rise to plants that produce seeds with the dominant round phenotype. Only one combination of the male and females alleles (rr) will give rise to plants that produce seeds with the recessive, wrinkled phenotype.This means the expected ratio of offspring plants that produce round seeds to plants that produce wrinkled seeds will be 3:1.What is an allele?Why do we have at least 2 genes for every characteristic? What does homozygous mean? What is the ‘genotype’ of a person?What is the ‘phenotype’? For each genotype, state whether the combination is homozygous or heterozygous and then identify the phenotype (how it looks). The first ones have been done for you.34348801079500Brown eyes (B) are dominant to blue eyes (b)BB – homozygous – brown eyesBb – bb- For each phenotype given below, list the possible genotypes32838891176100Straight hair is dominant to curly. SS straight____ straight ____ curlyA market gardener wanted to grow sweet peas with red flowers.When two red-flowered plants were crossed, however, plants with white flowers were sometimes produced.a)Complete the diagram using these symbols :R = red (dominant)r = white (recessive)15240024257000b)What was the ratio of the red to white flowers?A red-flowered plant was crossed with a white-flowered plant.a) Complete the diagram using the same symbols.12573027051000b)What was the ratio of the red to white flowers from this cross?141. If a heterozygous couple with brown eyes have a baby, what is the probability of their child having brown eyes? Complete the Punnett square to work this out.2651125-254000 B – brown eyes b – blue eyes9753601841500If a homozygous couple with blue eyes have a baby, what is the probability of their child having blue eyes?1630680-63500b- blue eyes158496028574900A male grey (Gg) rabbit has babies with a female white rabbit (gg). What is the probability of their babies having white fur?Gg = greygg = white The drawings show identical twins, Sara and Helen and their parents.Sara and Helen have brown hair like their father and blue eyes like their mother.Why do children have characteristics of both parents?Sara and Helen are identical twins. Why do they have identical characteristics?Sara now spends a lot of her time working outdoors in a hot country. Helen now works in an office in England. Complete the table. characteristicIs it identical forSara and Helen?eye colourskin colourweightNeither Helen nor Sara have blond hair like their mother – they have both brown hair like their father. Explain why, even though they have inherited a gene for hair colour from their Calculate the probability of a third child having brown hair. The father’s genotype is Bb and the mother is bb, use a Punnett square.What are the 4 functions of the skeleton?What is an antagonistic muscle pair?Where in the respiratory system are gases exchanged?What happens to the pressure in the thorax during inhalation?Write a word equation for aerobic respiration. Name the chemical found in cigarettes which binds to red blood cellsIn asthmatics, which part of the respiratory system is affected by spasms?Describe the difference between breathing and respirationWrite a word equation for anaerobic respiration Place the following in order from smallest to largest: cell, chromosome, nucleus, DNA, geneWhich scientists took the credit for the discovery of DNA?What is the term for an allele which is expressed when only two copies of the same allele are present?Define the term alleleDefine the term phenotypeA person’s physical characteristics are affected by genes and……What is respiration? … Poor/incorrect statementCorrect statementMuscles contract and expandWe respire to get oxygen into our bodiesRespiration takes place in the lungsWe need oxygen to liveRespiration produces energyWe need to breathe more during exercise because our heart rates go upBlocked coronary arteries can cause a heart attack because the heart has to work too hard and gives upGirls get more of their characteristics from their mum and boys from their dadsWe need to get more blood to the muscles during exercise because they start to respire ................
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