10202021 B 1 Understanding Ourselves 10202021 Revision Lessons

10/20/2021 B 1 Understanding Ourselves

10/20/2021 Revision Lessons Does not contain all of the content for B 1 – use checklists. . B 1 Understanding OrganismsB 1 Summary and ChecklistB 1 Checklist FOUNDATION. doc. . B 1 Understanding OrganismsB 1 Summary and ChecklistB 1 Checklist HIGHER. doc

The Circulatory system 10/20/2021 Heart muscle contracts to make the heart beat. This squeezes blood through blood vessels called __(1)____We need blood under pressure around the body because blood contains ___(2)___ and ___(3)___. These are needed so that all the __(4)__ in our bodies can produce ___(5)__ through ___(6)___. Blood is pumped at high pressure. Blood pressure is measured in mm. Hg (millimetres of __(7)__). Diastolic and systolic measurements are used. Normal pressure is about 120/80 mm. Hg. Words – energy, mercury, arteries, glucose, respiration, oxygen, cells

High Blood Pressure 10/20/2021 High blood pressure is a condition where the __(1)__ and blood vessels experience extra strain. It can be caused by: • Excess weight • High stress levels • __(2)__ • Excess ___(3)___ • Diets that are high in saturated __(4)__, sugar or salt Long term high blood pressure can cause blood vessels to weaken or even ___(5)___. Words – alcohol, burst, smoking, heart, fat

Now try these! 10/20/2021 1) Nikki’s blood pressure is 150/90 mm. Hg. Which number is the systolic measurement? 2) What does mm. Hg mean? 3) Her blood pressure is high. What are the dangers of high blood pressure? 4) What lifestyle changes can she make to reduce her blood pressure? Answers • 150 • Millimetres of mercury • Blood vessel burst - Stroke, kidney, brain damage • better/low fat diet, regular exercise, not smoking, low or no alcohol intake, not overweight, reduce stress levels. Extreme cases = drugs

Heart Disease 10/20/2021 • 1. Smoking – increases BP - carbon monoxide-combines with haemoglobin reduces oxygen, heart rate increases - nicotine – stimulant – increases heart rate 2. Saturated fat – cholesterol builds up-forms a plaque-narrows artery 3. High salt levels – body retains too much water – higher volume of blood pumped Qu. Fatty deposits can build up on coronary arteries. Explain how this can lead to a heart attack Blood flow is restricted, heart muscle receives less oxygen. A thrombosis may occur blocking blood flow to areas of the heart restricting oxygen so it will die – heart attack.

Deep Vein Thrombosis (Higher) When we don’t move for a long time (e. g. on a plane journey), our leg muscles can’t squeeze the veins in our legs, so blood in the veins begins to move very slowly. A blood clot (thrombosis) may eventually form, blocking the vein and leading to Deep Vein Thrombosis (DVT). Flight socks can help prevent DVT by applying pressure to the legs, which helps squeeze blood through the veins. Leg exercises can also help to prevent DVT.

Measuring fitness - higher Flexibility: amount of joint movement Strength: amount of weight lifted Agility: ability to change direction Speed: ability to sprint Stamina: time of sustained exercise

Balanced diet 10/20/2021 A balanced diet should contain fats, proteins and carbohydrates in roughly these amounts: It should also contain water, vitamins, minerals and fibre.

Balanced diets 10/20/2021 Nutrient Function Carbohydrate Make haemoglobin Protein To prevent Scurvy (bleeding gums) Vitamin C Energy store and insulation Water Growth and repair Iron Provides energy Fats Prevent dehydration

Protein 10/20/2021 Proteins are long chains of amino acids. There are two main types of these: • Essential amino acids (must be eaten) • Non-essential amino acids (can be made in the body) Meat and fish are “first class” proteins People who do not eat enough protein will not grow properly. Protein deficiency can result in a disease called kwasiorkor, where the muscles waste away and the belly swells. How much protein should we eat? EAR of protein (in g) = 0. 6 x body mass (in kg)

Food storage - higher 10/20/2021 • How are fats, carbohydrates and proteins stored in the body? • Carbohydrates stored in liver as glycogen or converted to fats • Fats stored under skin and around organs – adipose tissue • Proteins can’t be stored. First class proteins (meat, fish) contain all essential amino acids that can’t be made by the body. Second class proteins (plant proteins) don’t contain all essential amino acids

Body-Mass Index 10/20/2021 A commonly-used way to indicate is someone is overweight or underweight is the Body Mass Index (BMI): BMI = Mass (kg) Height 2 (m 2) BMI Meaning <18. 5 Underweight 18. 5 -25 Ideal 25 -30 Overweight 30 -40 Obese

Try these 10/20/2021 1) Elaine is 1. 78 m tall and has a mass of 66 kg. Calculate her BMI. 2) Anthony is not overweight. Why could his BMI be so high? 3) What is EAR of protein and why is it important? 4) What does EAR depend on? (higher) 5) What can a balanced diet depend on? - 66/(1. 78)2 - Estimated Average daily requirement - Age and pregnancy Age, gender, physical activity, religious, personal, medical reasons - Doesn’t account for muscle mass of protein, eating too little protein – kwashiorkor

Eating disorders 10/20/2021 Anorexia nervosa – this is a condition where sufferers restrict what they eat and sometimes starve themselves, leading to possible weight loss, abdominal pains, discoloured skin, irregular periods etc. Bulimia nervosa – this is when people vomit or take laxatives straight after eating to get the food out as quickly as possible. It can lead to weight fluctuations, poor skin, hair loss, irregular periods, tiredness etc.

10/20/2021 Now try this! 1) Link each food type to the correct product. Food Enzyme Product Carbohydrate Amino acids Protein Fatty acids Fat Glucose

Fitness and Health • Joe catches a cold. He is surprised because he is very fit. • His coach explains that being fit does not stop bacteria and viruses entering his body and causing infections. Q. What is the difference between fitness and health? • Fitness is the ability to do physical activity. • Healthy is being free from disease.

Malaria 10/20/2021

Now try this! 1) 2) 3) 4) o o o 1) 2) 3) 10/20/2021 What is a pathogen? Give 4 examples of pathogens What is the best way to control malaria? A mosquito is which of the following? Parasite Prey Vector A micro-organism that causes disease. Fungi, bacteria, viruses, protozoa Spray/drain stagnant water, Insecticides, mosquito nets 4) Vector

Microbes: our defence against them 10/20/2021 Our bodies have defence mechanisms against invading microbes: Tears contain lysozyme, an enzyme that kills bacteria The skin acts as a waterproof barrier If our skin is cut platelets seal the wound by clotting The breathing organs have hairs and produce mucus to cover the lining of these organs and trap the microbes Our blood contains white blood cells

Cleaning our air 10/20/2021 Our respiratory system has two types of specialised cell that help to keep our lungs clean: 1. Mucus is produced and traps dust, bacteria etc 2. The mucus is swept upwards to the mouth by cilia (cells with tiny hairs)

White blood cells If microbes enter our body they need to be neutralised or killed. This is done by WHITE BLOOD CELLS: White blood cells do 3 things: 1) They eat the microbe (these white blood cells are called “phagocytes”) 2) They produce antibodies to neutralise the microbe (“lymphocytes”) 3) The produce antitoxins to neutralise the poisons produced by microbes (lymphocytes again) 10/20/2021

Producing antibodies 10/20/2021 You’re going down Step 1: The lymphocyte “sees” the pathogen (microbe) Step 2: The cell produces antibodies to “fit” the pathogen Step 3: The antibodies fit onto the pathogens and cause them to “clump” Step 4: The pathogens are “eaten” by the white blood cells. Some memory cells stick around!

Specific antibodies Antibodies are specific – they will neutralise the microbe they have been made for. 10/20/2021

Fighting disease 10/20/2021 Immunisation Can be done in two ways: 1) A vaccine with dead microbes is injected – the body is “tricked” into producing antibodies ready for the real thing. This is called ACTIVE IMMUNISATION 2) The antibodies made by another organism are injected directly into the body – this is called PASSIVE IMMUNITY Name two differences between passive and active immunity. Active has a lasting effect but may take a few weeks to become effective

Vaccinations 10/20/2021 Some people argue that the MMR vaccine is a good idea, others think it is a bad idea. Briefly summarise each side of the argument: For Against MMR vaccine

Using Antibiotics 10/20/2021 Antibiotics can be used to kill bacteria. However, there are two problems: 1) Overuse of antibiotics can lead to bacteria becoming resistant (e. g. the MRSA “superbug”). This means that antibiotics must be used sparingly. 2) Antibiotics have no effect on a virus, like the common cold. It is difficult to kill a virus without damaging body tissue. A virus is usually allowed to “run its course” or with the use of antivirals

Now try these! 10/20/2021 1) Fill in the gaps! Antibodies are made by our ____. Antibodies lock onto ______ on the surface of a _______. Antibiotics do not kill pathogens such as ______. A ____ is a harmless pill that can have a positive psychological effect. A ______ is where volunteers don’t know which treatment they’re receiving A____ is where the doctors don’t know either White blood cells, passive, blind trial, antigens, pathogen, double blind trial, active, viruses, placebo

The Nervous System 10/20/2021 The CENTRAL NERVOUS SYSTEM (CNS) enables us to react to our surroundings. It consists mainly of the brain, the spinal chord, nerve cells (“neurones”) and receptors. Types of receptor: 1) Light receptors in the eyes 2) Sound receptors in the ears 3) Taste receptors on the tongue 4) Smell receptors in the nose 5) Touch, pressure and temperature receptors in the skin 6) Changes of position receptors in the ears (balance)

Conscious actions 10/20/2021 A conscious action is one where the brain makes a considered response. Here’s what happens: 4) The brain decides to move 3) Here another sensory neurone away the hand carries the signal to the brain 5) This impulse is sent by MOTOR NEURONES to the hand muscles (the effectors) via the spinal chord… 2) The impulse is carried by SENSORY NEURONES to the spinal chord 1) Receptors in your skin detect a stimulus Stimulus 6) Which then moves the hand away Receptor Motor Neurone Sensory Neurone Effector Coordinator Response

Examples of reactions Stimulus Bright light Sour taste Losing balance Sit on a drawing pin Receptor (i. e. the thing that detects the stimulus) Effector (i. e. the thing that will do the reaction) 10/20/2021 Response (i. e. action taken)

Types of nerve cell Nucleus Cell body 10/20/2021 Muscle strands (effector) Dendrites Nerve cells (neurones) are elongated with branched endings to connect to many muscles fibres. 1) Motor neurone 2) Sensory neurone Impulse 3) Relay neurone

Synapses - higher 10/20/2021 Neurones never ____ each other – there is a small gap between them called a _____. A signal is sent from one _______ to the next by a _______ transmitter across the synapse. These transmitters are then ____. Words – chemical, synapse, neurone, touch, destroyed

Reflex actions 10/20/2021 Sometimes conscious action is too slow to prevent harm, e. g… In situations like this the body bypasses the brain to produce a quicker response. Here’s how it works…

Reflex actions 2. Sensory neurone 1. Receptor 10/20/2021 3. Relay neurone in the spinal chord 4. Motor neurone 5. Effector

6 mark question - Higher 10/20/2021 The quality of written communication will be assessed in your answer to this question. Describe how neurones are adapted to carry and pass on nerve impulses quickly from one neurone to the next.

10/20/2021 Level 3 Answer correctly applies knowledge of how and why neurones are adapted being long, having branched endings and insulated by a fatty sheath There should be reference to the synapse and how this allows impulses to travel in one direction (see diagram). All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5– 6 marks) Level 2 Answer applies knowledge of how neurones are adapted and how the synapse is the gap between two neurones to allow nerve impulses to travel in one direction. For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3– 4 marks) Level 1 An incomplete answer, states simple neurone and synapse description. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1– 2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)

10/20/2021 6 marker question - Foundation The quality of written communication will be assessed in your answer to this question. Explain why active immunity is used for an outbreak of a disease over passive immunity.

10/20/2021 Level 3 Answer correctly applies knowledge of active immunity to give a well-reasoned explanation of how dead or inactive pathogens are injected into the body and how they trigger your immune system to make their own antibodies and that this is usually permanent. There should be reference to passive immunity and how this is only temporary involving injecting antibodies directly. All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5– 6 marks) Level 2 Answer applies knowledge of active and passive immunity to give a partial explanation of how immunity is different and why active is better in this case. For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3– 4 marks) Level 1 An incomplete answer, states simple immunity description, recognising that active immunity is different to passive immunity. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1– 2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)

Vision “Binocular vision” 10/20/2021 “Monocular vision”

The Eye Iris Lens 10/20/2021 Sclera Retina Pupil Optic nerve Cornea Ciliary muscles Suspensory ligaments

Seeing things Rays of light are refracted (bent) first by the cornea and then by the lens. They focus on the retina. 10/20/2021

Focussing on different distances For distant objects the ciliary muscles relax and the suspensory ligaments pull tight making the lens pull thin – the light doesn’t bend as much. When an eye focuses this is known as accomodation For close objects the ciliary muscles contract allowing the lens to go fat, thus bending the light more. 10/20/2021

Correcting eye sight problems 10/20/2021 Long sighted people are unable to focus on ______ objects. The eyeball is too ____, so the image of near objects are brought into focus behind the retina. You can use glasses or contact lens with a ____ lens to correct it Short sighted people are unable to focus on _______ objects. The eyeball is too _____, so the image of distant objects are brought into focus in front of the retina. You can use glasses or contact lens with a _____ lens to correct it. Concave, convex, short, long, near, close

Drugs 10/20/2021 Depressant Build muscle to allow athletes to train harder Asprin Hallucinogen Distort what is heard or seen Alcohol, solvents Stimulant Decrease activity of the brain Anabolic steroids Painkiller Increase the activity of the brain Nicotine, ecstasy Reduce no. of painful stimuli LSD Performance enhancer

Try these 10/20/2021 • 1. Which class of drug is the most dangerous, give some examples. • 2. Higher – Explain how the effects of alcohol are different from nicotine. • 3. Why do people get smokers cough? • Class A – heroin, LSD, ecstasy, cocaine • Nicotine is a stimulant so more neurotransmitter will cross to the next neurone, whereas alcohols a depressant so binds to receptors to block impulses/slow down • Smoke stops cilia from moving and makes goblet cells produce more mucus. Dust collects and irritates

Smoking 10/20/2021 Cigarettes contain 3 harmful things: 1. NICOTINE, which is an ______ drug that raises the heart beat, narrows the arteries and so causes _____. This leads to heart _____. 2. TAR, which coats the lining of the _______ making them less able to take in oxygen. It also contains carcinogens which cause _______. 3. CARBON MONOXIDE, which is a _______ which joins up with ____ blood cells making them incapable of transporting _______ around the body. In pregnant women it can cause oxygen deprivation, leading to low birth ______. Words – high blood pressure, oxygen, red, addictive, disease, poisonous gas, lungs, cancer, mass

Homeostasis 10/20/2021 Homeostasis means “controlling internal conditions”: Waste products that need to be removed + how CO 2 Produced by respiration, removed via lungs Urea Produced by liver breaking down amino acids, removed by kidneys and transferred to bladder Internal conditions that need controlling + how Temperature Increased by shivering, lost by sweating Ion content Increased by eating, lost by sweating + urine Water content Increased by drinking, lost by sweating + urine Blood glucose Increased and decreased by hormones

Maintaining Body Temperature 10/20/2021 Cold Hot Vasodilation Vasoconstriction

6 marker -Foundation 10/20/2021 The quality of written communication will be assessed in your answer to this question. • It is important to keep the body temperature at 37 o. C as this is the optimum temperature for many enzymes. • Explain what would happen if a person gets too hot and how homeostasis helps us to cope with this.

10/20/2021 Level 3 Answer correctly applies knowledge of dangers of overheating, such as heat stroke and dehydration. Understanding shown that blood flowing at the surface of skin increases heat loss and explanation of how sweating cools the skin down by evaporation. All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5– 6 marks) Level 2 Answer applies knowledge of overheating and brief explanation of sweating. For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3– 4 marks) Level 1 An incomplete answer, states simple description that people sweat to cool down and brief description of dangers of overheating. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1– 2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)

6 marker -Higher 10/20/2021 The quality of written communication will be assessed in your answer to this question. • Explain using negative feedback how the hypothalamus helps to maintain body temperature.

10/20/2021 Level 3 Answer correctly applies knowledge of increased temperature of blood detected by hypothalamus so increased sweat production and vasodilation in an attempt to lose more heat. This increases concentration of blood which results in less urine production to conserve water. Understanding of negative feedback – change in environment trigger a response that counteracts the changes. All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5– 6 marks) Level 2 Answer applies knowledge of how the hypothalamus helps to keep our body in balance by detecting when the blood is too hot or cold. For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3– 4 marks) Level 1 An incomplete answer, states simple description that hypothalamus detects blood temperature change. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1– 2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)

Hormones 10/20/2021 Hormones are “chemical messengers” produced by endocrine _____. They control the way in which parts of the body work and are transported to their target organs in the _______. Some examples. . . Words – testosterone, glands, bloodstream, insulin, adrenaline

Controlling Blood Sugar levels 10/20/2021 We need glucose in our bodies to help our cells to respire and produce energy. What happens if we have too much glucose? If blood sugar is too high the pancreas releases insulin The liver then converts glucose into insoluble glycogen and is removed from the blood

Diabetes 10/20/2021 Diabetes is a ____ in which a person’s blood sugar (i. e. glucose) level may rise to a _______ level. This is because the ______ doesn’t produce enough _____. Type 1 diabetes is when the pancreas doesn’t produce insulin. Glucose is removed from the blood by the kidneys glucose is excreted in the urine. It usually occurs in teenagers. Type 2 diabetes occurs when the body either produces too little or the cells won’t react to insulin. It is more common in older people and is linked to obesity. Diabetes can be treated by _____ carefully or by injecting extra insulin when needed. Diabetics have to test their blood sugar level before they decide how much insulin to _______ themselves with. A new technique is the insulin pump, its constantly changed for you.

Defining tropisms

Higher - Hormones and phototropism

Uses of plant hormones 10/20/2021 Describe 4 uses of plant hormones • Take a cutting - A cutting is taken from the plant and dipped in this powder. This stimulates the roots to grow quickly and enables gardeners to grow lots of exact copies of a particular plant. • Selective weedkillers -They kill the weeds by making the weed grow too fast, so it dies off faster. • Seedless fruit - Synthetic auxins are sprayed on unpollinated flowers. The auxins make the sterile flowers produce fruit. The fruits produced will have no seeds (pips) e. g. Seedless grapes • To ripen fruit in transport - Bananas are picked when they are green and unripe and less easily damaged. Application of a hormone ensures that when they arrive at the shops they are yellow and ripe.

Sexual Reproduction 10/20/2021 We have similar characteristics to our parents due to genetic information being passed down in genes through gametes: The human egg and sperm cell (“GAMETES”) contain 23 chromosomes each. When fertilisation happens the gametes fuse together to make a single cell called a ZYGOTE. The zygote has 46 chromosomes (23 pairs) and contains information from each parent.

Sexual vs. Asexual reproduction 10/20/2021 Sexual reproduction: • 2 parents are needed • Offspring will have “pairs” of chromosomes • This will cause genetic variation Asexual reproduction: • Only 1 parent needed • Offspring are GENETICALLY IDENTICAL to parent (“clones”) “Snuppy” – the first cloned dog (Aug 05)

Mother Boy or Girl? 10/20/2021 Son Father Daughter

Eye colour 10/20/2021 In eye colour the brown eye allele is dominant, so we call it B, and the blue eye is recessive, so we call it b: BB Bb bb Homozygous brown-eyed parent Heterozygous brown-eyed parent Blue-eyed parent What would the offspring have?

Eye colour Example 1: A homozygous brown-eyed parent and a blue -eyed parent: X BB Parents: Gametes: 10/20/2021 Example 2: 2 heterozygous brown-eyed parents bb Bb X Bb B B b b B b Bb Bb BB Bb b. B bb (FOIL) Offspring: All offspring have brown eyes 25% chance of blue eyes

Another method Example 3: A heterozygous brown-eyed father and a blue-eyed mother: B b b Bb bb Father Mother 10/20/2021

Example questions 10/20/2021 1) In mice, white fur is dominant. What type of offspring would you expect from a cross between a heterozygous individual and one with grey fur? Explain your answer with a genetic diagram. 2) A homozygous long-tailed cat is crossed with a homozygous short-tailed cat and produces a litter of 9 long-tailed kittens. Show the probable offspring which would be produced if two of these kittens were mated and describe the characteristics of the offspring (hint: work out the kitten’s genotype first).

Inherited diseases 10/20/2021 1) Cystic fibrosis – a disease that causes thick and sticky mucus to coat the lungs, gut and pancreas. It’s caused by recessive alleles: Cc X Cc

Gamete Zygote Key words 10/20/2021 • This allele determines the development of a characteristic • This is formed when an egg is fertilised by a sperm Allele • This allele will determine a characteristic only if there are no dominant ones Dominant • This word refers to a pair of chromosomes being made of two different alleles of a gene Recessive • An egg or a sperm are called this Homozygous • This word refers to a pair of chromosomes being made of two of the same alleles of a gene • An alternative form of a gene Heterozygous