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| Pregunta | Respuesta |
| Explain how data can be very precise, but not accurate. What kind of error could account for this? | -SYSTEMATIC ERROR -for example, if your instrument was not calibrated properly, it could give very precise results, but wrong every time -ZERO ERROR -for example, if your spring scale always reads 1 gram before you put anything on it, all your results will be 1 gram too heavy. |
| A student prepares a slide with a sample of onion cells and places it on the stage of a light microscope. Describe the steps she should take to get a focused image of the cells. (4 marks) | 1. Select the LOWEST-POWERED OBJECTIVE LENS (1) 2. Move the STAGE up, so the SLIDE is just underneath the objective lens (1). 3. Looking through the LENS, move the stage downwards until the specimen is nearly in focus (1). 4. Adjust the height of the stage with the FINE ADJUSTMENT KNOB until the image is in focus (1). |
| Name two subcellular structures found in a prokaryotic cell. | chromosomal DNA plasmid DNA |
| Name two ways you can reduce risk when using a bunsen burner. | 1. Stand it on a heat proof mat. 2. Do not leave it unattended. |
| Discuss why, when designing a scientific study, it is better to use a large sample size than a small sample size. | 1. A sample should REPRESENT THE WHOLE POPULATION, ie, share as many of he characteristics in the population as possible. The bigger the sample size, the better it will represent the population. 2. It's harder to recognize ANOMALIES if the sample size is too small |
| Scientific results need to be REPEATABLE, REPRODUCIBLE, and VALID. Explain what each of these terms means in the context of scientific evidence. | REPEATABLE - If the experiment is done again by the same person, using the same methods and the same equipment, they will get the same or similar results. REPRODUCIBLE - If the experiment is done again by a different person, or using a different method or piece of equipment, the results will still be similar. VALID - Valid results are both repeatable and reproducible, they answer the original question, and the experiment used is a FAIR TEST, with a sufficient sample size and CONTROLLED VARIABLES. |
| What is a flagellum and what does it do? | FLAGELLA (singular flagellum) are long, hair-like structures that rotate to make a cell move - away from harmful things like toxins or predators and towards beneficial things like nutrients or oxygen. |
| What do all plant and animal cells have? Name five structures and their functions. | 1. NUCLEUS (contains genetic material, organized into CHROMOSOMES, that controls the activities of the cell) 2. CELL MEMBRANE (holds the cell together, and determines what goes in or out) 3. CYTOPLASM (gel-like substance where most of the chemical reactions happen, w enzymes) 4. MITOCHONDRIA (where RESPIRATION takes place) 5. RIBOSOMES (where translation of genetic material and synthesis of proteins takes place) |
| What is the difference between CORRELATION and CAUSATION? Give an example of correlation not due to causation. | CORRELATION just means that there is a relationship between two variables. CAUSATION means that the change in one variable caused the change in the other. Correlation could also be due to chance or a 3rd variable not controlled for in the study. For example, there is a correlation between shark attacks and warmer water. This isn't because the warmer water causes sharks to attack more. There is a 3rd variable - the number of people swimming where the water is warm - that explains the increase in shark attacks. |
| Name three structures plant cells have, that animal cells don't have. Describe their functions. | 1. Rigid CELL WALL - made of CELLULOSE, supports and strengths the cell 2. Large VACUOLE - contains CELL SAP, a weak solution of sugar and salts. It maintains the internal pressure to support the cell 3. CHLOROPLASTS - where PHOTOSYNTHESIS occurs, which makes food for the plant. They contain green CHLOROPHYLL. |
| Explain four ways in which sperm cells are adapted to their functions. | The function of a sperm is to transport the male's DNA to the female's egg. 1. LONG TAIL - to help it swim to the egg. 2. LOTS OF MITOCHONDRIA - lots of respiration to provide lots of energy need to swim this distance 3. ACROSOME at the front of the head, where it stores ENZYMES needed to digest its way through the membrane of the egg cell. 4. HAPLOID NUCLEUS to store the DNA. |
| Explain three ways in which egg cells are adapted to their function. | The main functions of an EGG cell are to carry the female DNA and to nourish the developing embryo in the early stages. 1. It contains nutrients in the cytoplasm to feed the embryo. 2. It has a nucleus holding haploid DNA 3. Immediately after fertilisation, its membrane changes structure to stop any more sperm getting in, to ensure offspring have right amount of DNA. |
| Explain what ciliated epithelial cells do, where they are found, and how they are adapted to their function. | EPITHELIAL CELLS line the surfaces of organs, and their function is move materials, such as moving mucus in the airways upward away from the lungs. CILIATED epithelial cells have cilia, or hair-like structures, on the top surface of the cell, which help to move the mucus. |
| Describe what MITOSIS is, its end result, and its phases. | GENERAL: Mitosis is cell division (1) • Two cells are produced (1) • Both are diploid (1) • Both cells are genetically identical (1) INTERPHASE cell is performing its normal functions, not dividing PROPHASE The nuclear envelope disintegrates. Each chromosome doubles and becomes a pair of chromatids joined together by a centromere. Spindle fibres start to form at either side of the cell. METAPHASE The chromatid pairs line up in the middle of the cell and are held there by the spindles. ANAPHASE The chromatid pairs split and each chromatid is dragged to one side or the other by the spindles TELOPHASE The chromatids assemble at either end of the cell and two new nuclear envelopes form around them. The overall cell creases and then cleaves in two. |
| How is meiosis different from mitosis? | MEIOSIS -has two cell divisions, instead of one, resulting in four "daughter" cells (1) -daughter cells are genetically different (1) -daughter cells are haploid (instead of diploid) (1) -daughter cells are gametes (instead of somatic/body cells) (1) |
| Describe how some cells in an embryo become specialized cells. | The cells in the embryo are called STEM or MERISTEMATIC cells (1) They DIFFERENTIATE (1) by changing their shape, size or metabolic ability(1) to become a named cell - for example, a root hair cell, muscle cell, or neurone (1) |
| Scientists are researching if it's possible to use embryonic stem cells to produce insulin-secreting cells, which could potentially be implanted in a patient in order to cure them of type 1 diabetes. Discuss two potential risks of using stem cells to cure type 1 diabetes. (4 marks) | 1. If the rate of division can't be controlled (1), a tumour may develop (1). 2. If viruses have infected the stem cells of the donor (1), they could infect the recipient and make them sicker. (1) 3. There may be a risk that the new cells will trigger an immune response by the recipient (1), as they have not been grown using the patient's own stem cells (1). |
| Describe two structural differences between a motor neurone and a sensory neurone. (2 marks) | SENSORY NEURONS have one large DENDRON, while MOTOR NEURONES have many short DENDRITES. (1) Sensory neurones have a CELL BODY located in the middle of the neurone, while motor neurons have a cell body at one end. (1) Sensory neurones have a short AXON, while motor neurons have a long axon. |
| What does the myelin sheath do? | The MYELIN SHEATH speeds up the electrical or nervous impulse along the neurone. |
| Explain how a mutation in DNA may result in a different protein. (3 marks) | The mutation may cause one (or more) bases to change on the DNA. (1) This will result in a change in the amino acid in the protein, (1) resulting in a change of shape in the protein. (1) |
| Describe the structure and function of a RELAY NEURONE. | A RELAY NEURONE works within the CNS. It has many short DENDRITES which carry nerve impulses from SENSORY NEURONES to the cell body. An AXON carries nerve impulses from the cell body to motor neurones. |
| Why are some reasons why species go extinct? | • Predation / disease • change in environmental conditions • loss of reduced food source • increased competition • limited adaptations /survival of the fittest • unable to reproduce /reproduce less |
| Explain Darwin's theory of evolution by natural selection. | 1. VARIATION AND COMPETITION most organisms produce more young than can survive to adulthood populations have organisms with genetic variation - individuals differ (slightly) from one another the struggle for existence means that these organisms compete with each other to survive they compete for resources e.g. food, shelter, mates SURVIVAL OF THE FITTEST AND INHERITANCE those organisms with the most advantageous characteristics survive those organisms less well adapted die those organisms that survive will reproduce the advantageous characteristics will be passed onto their offspring 3. GRADUAL CHANGE over time, more organisms will express the advantageous characteristics/alleles non-advantageous characteristics will be lost species will evolve over time |
| Explain why smoking tobacco increases the risk of developing lung cancer. | Tobacco/tar contains carcinogens (cancer forming chemicals, or chemicals which encourage mutations of normal lung cells into cancerous ones). In addition, the nicotine in tobacco is addictive, which makes it difficult to give up, and causes people to smoke for longer. |
| Explain how stimulants affect neurotransmission. | Stimulants act at the synapse, increasing neurotransmitters, which speeds up neurotransmission. |
| A chef touches a hot tray. A reflex reaction causes him to immediately move his hand away. Describe the pathway of the reflex arc, from receptors to effector. (5 marks) | Impulses are sent from RECEPTORS in his hand along a SENSORY NEURONE to the CNS (1). The impulse is transferred, via the release of NEUROTRANSMITTERS (1), across a SYNAPSE to a RELAY NEURONE (1). It is then transferred across another synapse to a MOTOR NEURONE (1) and travels along the motor neurone to the EFFECTOR (a muscle in his arm) (1). |
| How has microscope technology changed, and how have these changes affected our understanding of the world? | Changes in microscope technology, including electron microscopy, have enabled us to see cell structures increased resolution and increased magnification than in the past, and thereby increased our understanding of the role of sub-cellular structures |
| The human genome contains over 20000 genes. Explain what is meant by the term 'gene.' (1 mark) | A gene is a section of DNA on a chromosome that codes for a particular protein. |
| Name the bonds that break when a DNA molecule denatures. How are its complementary base pairs joined together? | weak hydrogen bonds |
| Describe how to extract DNA from a fruit. (4 marks) | 1. Begin by breaking up the fruit, making a mash. 2. Add an extraction solution of DETERGENT and SALT to the fruit pulp. The detergent will help break down the cell and nuclear membranes and release the DNA. The salt will make the DNA stick together. 3. FILTER the mixture to get the froth and large insoluble bits out. 4. Add some ICE-COLD ALCOHOL to the filtered mixture. DNA is not soluble in cold alcohol, so it will form a PRECIPITATE. 5. Fish out the precipitate with a glass rod. |
| Name at least three reasons why a species may become extinct | Predation / disease (1) • change in environmental conditions (1) • loss of / reduced food source (1) • increased competition (1) • limited adaptations (1) • unable to reproduce / reproduce less (1) |
| Describe three possible causes of variation of traits in a population. | Variation of traits can be due to GENETIC VARIATION (1) Genetic variation can be due to MUTATION (1) or HYBRIDISATION with another population (1) Trait variation can also be due to new combinations of alleles in offspring, the result of SEXUAL REPRODUCTION (1) ENVIRONMENTAL VARIATION can be responsible for trait variation - eg a plant grown in sun with plenty of water will look lush and green, a plant grown in dark or dry conditions with poor soil will look spindly, weak, and/or yellow (1) |
| How could information from the Human Genome Project be used to help prevent individuals from developing certain diseases? | A person's genes can be used to help predict what diseases they're most at risk of developing (1). This means that they could be given periodic checks to catch the disease early, lifestyle and diet advice to help prevent them from getting the diseases (1). |
| Explain why smoking is a major risk factor associated with cardiovascular disease, and can lead to a heart attack or stroke. (4 marks) | The NICOTINE in cigarette smoke increases the heart rate and blood pressure (1). HIGH BLOOD PRESSURE damages artery walls, which contributes to the buildup of FATTY DEPOSITS in the arteries (1). These deposits RESTRICT BLOOD FLOW which increases the risk of a heart attack or stroke (1). Smoking increases the risk of blood clots forming in arteries, which can restrict or block blood flow to the heart, leading to a heart attack, or to the brain, leading to a stroke. (1) |
| Explain how stimulants affect neurotransmission. | • (stimulants) act at the synapse (1) • more neurotransmitters (1) • so speeds up neurotransmission(1) |
| CHALARA ASH DIEBACK What pathogen causes it? What are the symptoms? How does it spread? How to prevent it? | CHALARA ASH DIEBACK What pathogen causes it? A fungus that infects ash trees. What are the symptoms? Leaf loss and bark lesions (wounds) How does it spread? Carried through the air by the wind, also when diseased ash trees are moved between areas. How to prevent it? Remove infected ash trees and replanting with different species. Restrict the import or movement of ash trees. |
| Explain how a bacterial population could become less affected by a particular antibiotic. (3 marks) | Bacteria with the antibiotic resistance allele are more likely to survive than bacteria without the allele (1) and are able to reproduce many more times (1). This leads to the allele for antibiotic resistance being passed on to lots of offspring, and so it becomes more common in the population (1). |
| State the SELECTION PRESSURE involved when bacteria evolve to develop resistance to an antibiotic. | The SELECTION PRESSURE for the bacteria is the exposure to the antibiotic. |
| Why is DNA called a "design for life"? Describe how a section of DNA determines the structure of a protein. (6 marks) | A section of DNA is a gene, which codes for protein. (1) • The sequence of bases in the DNA determines sequence of amino acids (1) • There is one code , or 3 bases for one amino acid (1) • Several amino acids make up a protein (1) • In the first stage, or transcription - DNA base pairs copied to mRNA (1) •In the second stage, translation- mRNA base pairs used to line up amino acids into protein (1) |
| Draw the structure of an amino acid. | |
| Are most phenotypic features the result of multiple genes or a single gene? | multiple |
| What is homeostasis? | Homeostasis is the maintenance of a stable internal environment. |
| Explain how sweat glands can help the human body to cool down. | Sweat glands release water to the surface of the skin. The water evaporates, and heat energy is removed. |
| What is the World Health Organization's definition of health? | According to WHO, health is a state of complete physical, mental, and social well-being, **not merely the absence of disease or infirmity.** |
| What is selective breeding? Give an example. Describe the steps involved. | SELECTIVE BREEDING is when humans ARTIFICIALLY SELECT the plants or animals that are going to reproduce, so that the genes for particular characteristics remain in the population, and those characteristics are strengthened. Organisms are selectively bred to develop features that are useful or attractive. For example, dogs may be bred to have a good, gentle temperament. 1) From existing stock, select the individuals which have the desired characteristics. 2) Breed them with each other. 3) Select the offspring which most demonstrated the desired characteristic, and breed them together. 4) Repeat over several generations. Eventually, all the offspring will have the desired characteristics. |
| What is cancer? What is a carcinogen? What is a tumour? | Cancer is the result of MUTATIONS in cells that lead to rapid and UNCONTROLLED cell division. Carcinogens are substances that cause such mutations. Smoking tobacco is a known CARCINOGEN. TUMOURS are growing lumps of cells that can damage the body and result in death. |
| What are the problems associated with selective breeding?(3 marks) | 1. Because only certain individuals are allowed to reproduce, selective breeding reduces the gene pool - the number of different ALLELES in a population. Selective breeding can lead to a state where all individuals are closely related - INBREEDING. 2. Inbreeding can cause health problems because there's more chance of individuals inheriting genetic DEFECTS when the gene pool is limited. 3. If a new disease appears, the limited gene pool gives less chance of RESISTANCE ALLELES being present. All the stock are closely related to each other, so if one is going to be killed by a new disease, the others are also likely to perish. |
| Describe how malaria is transmitted. | The (female Anopheles) mosquito is a vector for malaria (1) The mosquito sucks blood from her host and injects (1) a Plasmodium, or malarial protozoan (1) |
| Describe how vectors can be used to insert DNA into other organisms. Give one example. | A VECTOR is something that is used to transfer DNA into a cell. PLASMID DNA and VIRUSES can both be used as vectors. 1. The desired gene (for example, the gene for producing human insulin) is cut out using a RESTRICTION ENZYME. The vector DNA is then cut open using the same restriction enzyme. 2. The restriction enzyme leaves the cut DNA with sticky ends. 3. LIGASE ENZYMES join the pieces of DNA together to make RECOMBINANT DNA. 4. The recombinant DNA is then inserted into other cells, for example bacteria. 5. These cells can now use the gene you inserted to make the desired protein, for example, insulin. The engineered cell can reproduce and its offspring will also be able to make the desired protein. |
| Explain one benefit of being able to genetically engineer herbicide-resistant crops. (2 marks) | It can improve the yield of the crop (1) because herbicides can be sprayed on the field to kill weeds, without damaging the crops. (1) |
| CHOLERA What pathogen causes it? What are the symptoms? How does it spread? How to prevent it? | CHOLERA What causes it? A bacterium called Vibrio cholerae. What are the symptoms? Diarrhoea How does it spread? via contaminated water sources How to prevent it? make sure people have access to clean water supplies. |
| What are the two major factors that contribute to the form and function of an organism? | 1. GENETIC information passed on from parent to offspring 2. ENVIRONMENT - the conditions that affect that organism during its lifetime - eg climate, diet, etc |
| What mechanism drives evolution? | natural selection |
| What is the evidence for evolution? | 1. GENETIC ANALYSIS - comparing genomes of different organisms 2. studying EMBRYOS and their similarities 3. looking at changes in fast-reproducing species in modern times - eg, the development of antibiotic resistance in bacteria 4. comparing the ANATOMY of different forms 5. the FOSSIL record |
| Explain how whales may have evolved from a horse-like ancestor that lived in swampy areas millions of years ago. Use the evidence of whales' pentadactyl limbs, and Darwin's theory of natural selection. | 1. The horse-like ancestor with PENTADACTYL LIMBS was adapted to its swampy environment , but MUTATIONS IN GENES allowed some individuals to develop more flipper-like limbs 2. Flipper-like limbs were a SURVIVAL ADVANTAGE in the aquatic environment, allowing greater mobility to COMPETE for food resources or avoid predators 3. INHERITANCE - The flippered individuals survived to pass on the flipper trait to their offspring. 4. EVOLUTION - Over millions of years, other successful mutations led to form of modern whale 5. Pentadactyl bone structure is still evident inside whale's flippers.. very unlike what is inside a fish's flippers. |
| How are fossils formed? How do we find them? | 1. When an animal or plant dies, the processes of decay usually cause all the body tissues to break down. In rare circumstances, the organism's body is rapidly covered and OXYGEN IS PREVENTED from reaching it. Instead of decay, fossilisation occurs. 2. Over hundreds of thousands of years, further SEDIMENTS are laid down and COMPRESS the organism's remains. 3. Harder parts of the organism, such as bones and teeth, are REPLACED BY MINERALS from solutions in the rock. SOFT-BODIED organisms are not preserved well as fossils. 4. Earth upheavals, such as those caused by TECTONIC PLATE MOVEMENT, bring sediments containing the fossils nearer to the earth's surface. 5. EROSION of the rock by wind, rain, and rivers exposes the fossil, so that PALEONTOLOGISTS may find them. |
| Name two significant finds of fossils that give clues to human evolution. | 1. Ardi - 4.4 million years old. Ardi may have been able to walk upright, but still had long arms and toes well adapted for climbing trees 2. Lucy - 3.2 million years old - one of the first skeletons to show a fully upright walking stance and toes similar to modern humans although more curved. |
| Describe the structure of DNA. | Points relating to DNA structural features: • two strands • double helix • bases A, T, C, G • adenine / A paired with thymine / T • guanine / G paired with cytosine / C • hydrogen / H bonds joining bases |
| You feel hot and you start to sweat. Describe what is happening in your nervous system for this reaction to occur. | The stimulus is heat. The RECEPTORS in your skin detect the heat and send a nerve signal to the SENSORY NEURONS, which carry the signal to RELAY NEURONS in the CENTRAL NERVOUS SYSTEM. The HYPOTHALAMUS in the CNS sends a nerve signal to MOTOR NEURONS, which carry the signal to the EFFECTORS - in this case causing your sweat glands to produce sweat, which helps reduce your body temperature through EVAPORATIVE COOLING. |
| When receptors detect pain stimuli, imulses are passed to the spinal cord and then to the brain. Opioid drugs relieve pain by preventing the release of neurotransmitters from certain sensory neurons. With reference to synapses, explain how opioids can reduce pain. (3 marks) | By preventing the release of the neurotransmitters, opioids prevent information being transmitted across synapses (1) between sensory neurons and relay neurons in the spinal cord (1). This means the information about the stimulus doesn't reach the brain, so no pain is felt (1). |
| MALARIA What pathogen causes it? What are the symptoms? How does it spread? How to prevent it? | MALARIA What pathogen causes it? A protist What are the symptoms? Damage to red blood cells and in severe cases, to the liver. How does it spread? Mosquitoes act as animal vectors - they pass on the protists to humans through injecting their saliva into the human bloodstream. They don't get the disease themselves. How to prevent it? Use of mosquito nets and insect repellent to prevent mosquitos carrying the pathogen from biting people. |
| TUBERCULOSIS What pathogen causes it? What are the symptoms? How does it spread? How to prevent it? | TUBERCULOSIS What pathogen causes it? A bacterium called Mycobacterium tuberculosis. What are the symptoms? Coughing and lung damage - eventually coughing up blood and death How does it spread? Through the air when infected individuals cough. How to prevent it? Infected people should avoid crowded public spaces, practice good hygiene, and sleep alone. Their homes should be well-ventilated. |
| If you are affected by one disease, are you more susceptible to other diseases? | Yes, because your body may become weakened by the first disease, so it's less able to fight off others. |
| HIV What pathogen causes it? What are the symptoms? How does it spread? How to prevent it? | HIV What pathogen causes it? A virus called the Human Immunodeficiency Virus What are the symptoms? may cause no symptoms until the HIV infection develops into AIDS, when the body's immune system deteriorates and fails, and the body succumbs to other pathogens. How does it spread? Via bodily fluids - blood, semen, and vaginal fluids. These are shared through sexual activity and shared drug needles How to prevent it? Use condoms and do not share needles. Also, medication can reduce the risk of a known infected individual infecting others during sex, so screening is important. |
| CHLAMYDIA What pathogen causes it? What are the symptoms? How does it spread? How to prevent it? | CHLAMYDIA What pathogen causes it? Chlamydia is a kind of bacterium, but it behaves in a similar way to a virus because it can only reproduce inside host cells. What are the symptoms? It doesn't always cause symptoms, but it can result in INFERTILITY in men and women. How does it spread? Sexual contact How to prevent it? Wear a condom. |
| According to the World Health Organisation (the WHO), what is the definition of health? | "a state of complete physical, mental and social well-being, and not merely the absence of disease or infirmity". |
| Name the pathogen that causes cholera, its symptoms/effects, how it spreads, and how to reduce/prevent transmission of the disease. | The pathogen is a bacterium called Vibrio cholerae, a symptom/effect is diarrhoea, and it spreads via contaminated water sources. Its transmission can be reduced or prevented by making sure that people can have access to clean water supplies. |
| What are STIs? | STIs are infections that are spread through sexual contact, including sexual intercourse. Two examples of them are HIV, and Chlamydia. |
| Health, Disease and STIs (p. 39-40) 1) Explain why being healthy doesn't just mean not being sick. 2) What is a 'non-communicable' disease? 3) How can the transmission of malaria be prevented? 4) How can the spread of Chlamydia be reduced? 5) Why does HIV eventually lead to AIDS? | Check the book |
| Fighting Disease (p. 41-42) 6) Give two types of chemical defence that prevent pathogens from infecting humans. 7) What is an antigen? 8) What does a B-lymphocyte do when it recognizes a pathogen? 9) How do vaccines prepare the immune system against infection by a particular pathogen? | Check the book |
| Being healthy is a combination of which three types of well-being? | Physical, Mental, and Social. |
| Antibiotics and Other Medicines (p. 43) 10) Which type of pathogen can antibiotics be used to kill? 11) What is the placebo effect? | Check the book |
| What are B-lymphocytes, and how do they work? | B-lymphocytes are a type of white blood cell that are involved in the specific immune response – this is the immune response to a specific pathogen. Here's how it works: 1) Every pathogen has unique molecules (e.g. proteins) on its surface called antigens. 2) When your B-lymphocytes come across an antigen on a pathogen, they start to produce proteins called antibodies. (Memory lymphocytes are also produced here.) Antibodies bind (lock on) to the new invading pathogen, so it can be found and destroyed by other white blood cells. The antibodies produced are specific to that pathogen, they won't lock onto any other pathogens. 3) The antibodies are then produced rapidly and flow all round the body to find all similar pathogens. |
| What is the function of white blood cells? | The most important part of your immune system is the white blood cells. They travel around in your blood and crawl into every part of you, patrolling for pathogens. |
| What happens when pathogens make it into your body? | Your immune system kicks in to destroy them. |
| Draw a graph of the concentration of the right antibody in the blood versus time. Make sure to include two exposures to the same antigen, and include explanations. |
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| How is the BMI calculated? | (weight (kg))/((height (m))^2) |
| What is the waist-to-hip ratio? | (waist circumference)/(hip circumference) Make sure both measurements use the same unit. |
| Non-Communicable Diseases (p.44-46) 12) Describe how smoking can increase the risk of a heart attack or stroke. 13) Give a risk factor related to lifestyle for the development of liver disease. 14) Write the equation for finding the body mass index of an individual. 15) Give three examples of lifestyle changes that can help to prevent cardiovascular disease. | Check the book |
| What happens in preclinical testing of a drug? | 1) In preclinical testing, drugs are first tested on human cells and tissues in the lad. However, you can't use human cells and tissues to test drugs that affect whole or multiple body systems, e. g. a drug for blood pressure must be tested on a whole animal. 2) The next step is to test the drug on live animals. This is to test that the drug works (produces the effect you're looking for), to find out how toxic (harmful) it is and to find the best dosage. |
| What happens in clinical testing of a drug? | 1) If the drug passes the tests on animals then it's tested on human volunteers in a clinical trial. 2) First, the drug is tested on healthy volunteers to make sure that it doesn't have any harmful side effects when the body is working normally. 3) If the results of the tests on healthy volunteers are good, the drugs can be tested on people suffering from the illness. The optimum dose is found – this is the dose of drug that is most effective and has the fewest side effects. 4) Patients are randomly put into two groups. One is given the new drug, the other is given a placebo (a substance that looks like the drug being tested but doesn't do anything, e.g. a sugar pill). This is to allow for the placebo effect (when the patient expects the treatment to work and so feels better, even though the treatment isn't doing anything. |
| Do the patients or doctors in a clinical trial know which pill is being served? | 5) Clinical trials are blind – the patient in the study doesn't know whether they're getting the drug or the placebo. In fact, they're often double-blind – neither the patient nor the doctor knows until all the results have been gathered. This is so the doctors monitoring the patients and analyzing the results aren't subconsciously influenced by their knowledge. |
| After clinical and preclinical testing, can a drug be used to treat patients? | No. It still has to be approved by a medical agency before it can be used to treat patients. All of this means that drugs are as safe and effective as possible. |
| Kwashiorkor is caused by a deficiency of what nutrient? What are its symptoms, and what foods help prevent it? | Protein; enlarged belly, small muscles, failure to grow properly; meat, fish, dairy, eggs, pulses (e. g. lentils) |
| Scurvy is caused by a deficiency of what nutrient? What are its symptoms, and what foods help prevent it? | vitamin C; swelling and bleeding gums, muscle and joint pain, tiredness; citrus fruits (e. g. oranges) and some vegetables (e. g. broccoli) |
| Rickets is caused by a deficiency of what nutrient? What are its symptoms, and what foods help prevent it? | Vitamin D and/or calcium; soft bones, curved leg bones; Oily fish provide vitamin D, while dairy products provide calcium |
| Osteomalacia is caused by a deficiency of what nutrient? What are its symptoms, and what foods help prevent it? | Vitamin D and/or calcium; soft bones, curved leg bones; Oily fish provide vitamin D, while dairy products provide calcium |
| Anaemia is caused by a deficiency of what nutrient? What are its symptoms, and what foods help prevent it? | Iron; red blood cells that are smaller than normal and in reduced number, tiredness; red meat, dark green leafy vegetables, egg yolk |
| Rank these countries by death rates from liver disease. USA UK Russia Brazil Australia | Russia (48.7 per 100000 people) Brazil (28.8 per 100000 people) UK (16.0 per 100000 people) USA (14.9 per 100000 people) Australia (6.8 per 100000 people) |
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