The measles virus is spread by inhalation of droplets from sneezes and coughs. HIV initially causes a flu-like illness. HIV is spread by sexual contact or exchange of body fluids such as blood which occurs when drug users share needles.
Tobacco mosaic virus TMV is a widespread plant pathogen affecting many species of plants including tomatoes. Know that salmonella food poisoning is spread by bacteria ingested in food, or on food prepared in unhygienic conditions. In the UK, poultry are vaccinated against Salmonella to control the spread.
Fever, abdominal cramps, vomiting and diarrhoea are caused by the bacteria and the toxins they secrete. Gonorrhoea is a sexually transmitted disease STD with symptoms of a thick yellow or green discharge from the vagina or penis and pain on urinating.
It is caused by a bacterium and was easily treated with the antibiotic penicillin until many resistant strains appeared. Gonorrhoea is spread by sexual contact. The spread can be controlled by treatment with antibiotics or the use of a barrier method of contraception such as a condom. Rose black spot is a fungal disease where purple or black spots develop on leaves, which often turn yellow and drop early.
It affects the growth of the plant as photosynthesis is reduced. It is spread in the environment by water or wind. Know that the pathogens that cause malaria are protists. The malarial protist has a life cycle that includes the mosquito. Malaria causes recurrent episodes of fever and can be fatal. The spread of malaria is controlled by preventing the vectors, mosquitos, from breeding and by using mosquito nets to avoid being bitten. You should be able to explain the nonspecific defence systems of the human body against pathogens.
The human body defends itself against the entry of pathogens including: The skin is a barrier and produces antimicrobial secretions. The nose traps particles which may contain pathogens. The trachea and bronchi secrete mucus which traps pathogens and cilia waft the mucus to the back of the throat where it is swallowed. The stomach produces acid which kills the majority of pathogens which enter via the mouth.
You should be able to explain the role of the immune system in the defence against disease. If a pathogen enters the body the immune system tries to destroy the pathogen.
White blood cells help to defend against pathogens by: You should be able to explain how vaccination will prevent illness in an individual, and how the spread of pathogens can be reduced by immunising a large proportion of the population. Know that vaccination involves introducing small quantities of dead or inactive forms of a pathogen into the body to stimulate the white blood cells to produce antibodies.
You do not need to know details of vaccination schedules and side effects associated with specific vaccines. If a large proportion of the population is immune to a pathogen, the spread of the pathogen is very much reduced. Be able to discuss the global use of vaccination in the prevention of disease. You should be able to explain the use of antibiotics and other medicines in treating disease.
Antibiotics, such as penicillin, are medicines that help to cure bacterial disease by killing infective bacteria inside the body. It is important that specific bacteria should be treated by specific antibiotics. The use of antibiotics has greatly reduced deaths from infectious bacterial diseases. However, the emergence of strains resistant to antibiotics is of great concern.
Painkillers and other medicines are used to treat the symptoms of disease but do not kill pathogens. You should be able to describe the process of discovery and development of potential new medicines, including preclinical and clinical testing. Know that traditionally drugs were extracted from plants and microorganisms. Penicillin was discovered by Alexander Fleming from the Penicillium mould. Most new drugs are synthesised by chemists in the pharmaceutical industry. However, the starting point may still be a chemical extracted from a plant.
New medical drugs have to be tested and trialled before being used to check that they are safe and effective. New drugs are extensively tested for toxicity, efficacy and dose. Preclinical testing is done in a laboratory using cells, tissues and live animals. Clinical trials use healthy volunteers and patients.
Very low doses of the drug are given at the start of the clinical trial. If the drug is found to be safe, further clinical trials are carried out to find the optimum dose for the drug. In double blind trials, some patients are given a placebo, which does not contain the drug. Patients are allocated randomly to groups so that neither the doctors nor the patients know who has received a placebo and who has received the drug until the trial is complete.
You should understand that the results of testing and trials are published only after scrutiny by peer review. This helps to prevent false claims. Know that monoclonal antibodies are produced from a single clone of cells and be able to describe how they are produced.
The antibodies are specific to one binding site on one protein antigen and so are able to target a specific chemical or specific cells in the body. They are produced by stimulating mouse lymphocytes to make a particular antibody. The lymphocytes are combined with a particular kind of tumour cell to make a cell called a hybridoma cell.
The hybridoma cell can both divide and make the antibody. Single hybridoma cells are cloned to produce many identical cells that all produce the same antibody. A large amount of the antibody can be collected and purified.
You should be able to describe some of the ways in which monoclonal antibodies can be used. In laboratories to measure the levels of hormones and other chemicals in blood, or to detect pathogens. In research to locate or identify specific molecules in a cell or tissue by binding to them with a fluorescent dye. It delivers the substance to the cancer cells without harming other cells in the body. You are not expected to recall any specific tests or treatments but given appropriate information you should be able to explain how they work.
Appreciate the power of monoclonal antibodies and consider any medical or ethical issues. Monoclonal antibodies create more side effects than expected. They are not yet as widely used as everyone hoped when they were first developed. Be able to valuate the advantages and disadvantages of monoclonal antibodies.
HT only Know that plant diseases can be detected by: Plants can be infected by a range of viral, bacterial and fungal pathogens as well as by insects. Know that plants can be damaged by a range of ion deficiency conditions eg. Knowledge of ions is limited to nitrate ions needed for protein synthesis and therefore growth and magnesium ions needed to make chlorophyll.
Appreciate the everyday application of scientific knowledge to detect and identify plant disease AND the understanding of ion deficiencies allows horticulturists to provide optimum conditions for plants.
You should be able to describe physical and chemical defence responses by plants to resist e. Production of antibacterial chemical e. Production of poisons to deter herbivores eg tobacco plants, foxgloves and deadly nightshade.
Physical defence response adaptation to resist microorganisms. Thorns and hairs deter animals from eating or touching them. Mimicry to trick animals into not eating them or not laying eggs on the leaves. Know that sunlight is the ultimate source of energy for all living systems. Both animals and plants use this oxygen to oxidise food in a process called aerobic respiration which transfers the energy that the organism needs to perform its functions.
Conversely, anaerobic respiration does not require oxygen to transfer energy. During vigorous exercise the human body is unable to supply the cells with sufficient oxygen and it switches to anaerobic respiration.
This process will supply energy but also causes the build-up of lactic acid in muscles which causes fatigue. Photosynthesis, importance explained, limiting factors affecting rate Revision Notes. Know that photosynthesis is represented by the word and symbol equations: You should be able to describe photosynthesis as an endothermic reaction in which energy is transferred from the environment to the chloroplasts by light. Know how the rate of photosynthesis may be affected by temperature, level of carbon dioxide, light intensity and amount of chlorophyll.
Be able to explain the effects of temperature, light intensity and carbon dioxide concentration on the rate of photosynthesis and to interpret graphs of photosynthesis rate involving one limiting factor. HT only Know that these factors interact and any one of them may be the factor that limits photosynthesis. HT only You should be able to explain graphs of photosynthesis rate involving two or three factors and decide which is the limiting factor.
HT only You should understand and use inverse proportion — the inverse square law and light intensity in the context of photosynthesis. HT only Limiting factors are important in the economics of enhancing the conditions in greenhouses to gain the maximum rate of photosynthesis while still maintaining profit.
HT only Be able to use data to relate limiting factors to the cost effectiveness of adding heat, light or carbon dioxide to greenhouses. You should have done the practical to investigate the effect of a factor on the rate of photosynthesis. Know that plants, to make proteins, also use nitrate ions that are absorbed from the soil. Know the chemical tests to identify starch, glucose and proteins using simple qualitative reagent tests. You should be able to describe cellular respiration as an exothermic reaction which is continuously occurring in living cells.
The energy transferred supplies all the energy needed for living processes. Respiration in cells can take place aerobically using oxygen or anaerobically without oxygen , to transfer energy. You should be able to compare the processes of aerobic and anaerobic respiration with regard to the need for oxygen, the differing products and the relative amounts of energy transferred. Reactions which transfer energy to the environment are exothermic reactions.
Organisms need energy for chemical reactions to i build larger molecules, ii for movement and iii keeping warm. Know that aerobic respiration is represented by the equations: Anaerobic respiration in muscles is represented by the equation: As the oxidation of glucose is incomplete in anaerobic respiration much less energy is transferred than in aerobic respiration.
Anaerobic respiration in plant and yeast cells is represented by the equations: Anaerobic respiration in yeast cells is called fermentation and has economic importance in the manufacture of bread and alcoholic drink. Know that during exercise the human body reacts to the increased demand for energy. The heart rate, breathing rate and breath volume increase during exercise to supply the muscles with more oxygenated blood. If insufficient oxygen is supplied anaerobic respiration takes place in muscles.
The incomplete oxidation of glucose causes a build up of lactic acid and creates an oxygen debt. During long periods of vigorous activity muscles become fatigued and stop contracting efficiently. HT only Know that blood flowing through the muscles transports the lactic acid to the liver where it is converted back into glucose.
Oxygen debt is the amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells. You should have done an investigation into the effect of exercise on the body. You should be able to explain the importance of sugars, amino acids, fatty acids and glycerol in the synthesis and breakdown of carbohydrates, proteins and lipids.
Metabolism is the sum of all the reactions in a cell or the body. The energy transferred by respiration in cells is used by the organism for the continual enzyme controlled processes of metabolism that synthesise new molecules.
Specifications - syllabuses, past exam papers, specimen practice question papers. For latest updates see https: Enter specific science words or science course e. All copyrights reserved on revision notes, images, quizzes, worksheets etc.
Copying of website material is NOT permitted. Exam revision summaries and references to science course specifications are unofficial. Cameron , a professor of biochemistry and molecular biology, and holder of the Eberly Chair in Biochemistry and Molecular Biology, studies viruses and looks for ways to cure diseases caused by them. The viruses he studies all contain a common bond—RNA is their genetic material.
His work has contributed to the conceptual and practical development of strategies to treat and to prevent viral infection. Cameron knew that although he wanted a career where he could help people using science, there were paths aside from being a doctor.
Watching the devastation caused by this viral parasite inspired me to enter a career that would facilitate annihilation of viral pathogens. This image illustrates a human cell during a normal viral infection. Craig Cameron lab, Penn State University.
He discovered that the mitochondrial RNA polymerase POLRMT is an off-target for therapeutic ribonucleosides, especially those developed to treat hepatitis C virus infection that exhibited adverse effects during clinical trials. Using poliovirus, and its RdRp 3Dpol as their model system, the team has.
The objective of their work with picornaviruses is to reconstruct picornavirus genome replication in vitro from purified components. Viruses multiply quickly with the help of an enzyme, polymerase, which makes more copies of the viral genetic material. Once a virus infects a cell, the immune system kicks in and triesobtained new insight into the chemical mechanism for nucleotidyltransfer. They have discovered a link between RdRp incorporation fidelity and pathogenesis and a connection between RdRp dynamics and incorporation fidelity.
These discoveries have led Cameron and his team to hypothesize that RdRp incorporation fidelity is a target for antiviral and vaccine development.
Cameron and his team, consisting of postdoctoral scholars, research assistants, graduate students, and undergraduate students, are currently working on severalprojects, including: RdRp mechanism; viral attenuation and vaccine to control the spread. If the immune system is unsuccessful at stopping the spread of the virus, it can cause disease or even death. However, if the body has been exposed to a vaccine — a weakened form of the virus — the body can respond more rapidly when it is exposed to the virulent strain.
The key to developing vaccines is finding the mutation that will prime the immune system without causing disease. He studied the kinetic, thermodynamic and structural basis need to be cleared in order to show that it is a promising strategy for the future. Vaccination is the only known approach to prevent viral infection, with the most effective vaccines being live, weakened virus strains. There are no side effects involved with this method, unlike potential side effects that could arise when using different types of birth control.
There are few disadvantages to using abstinence, other than the fact that it takes personal restraint and responsibility to avoid sexual activity, as well as an open dialogue with partners who must be compliant with this personal choice.
After speaking with her nurse practitioner, Jennifer decides that engaging in a sexual relationship with her boyfriend is important to her. She does not think that abstinence is the right choice for her at this time, meaning she could not commit to the responsibility of avoiding sexual play and intercourse, nor is she comfortable with the risks associated with hormonal birth control and implants.
Jennifer decides using a barrier method of birth control and disease prevention, such as condoms, is the best choice for her. In this lesson, we discussed a method of pregnancy and disease prevention called abstinence. Abstinence means to refrain from sexual play or sexual intercourse. It is the most effective way of preventing pregnancy, and sexually transmitted diseases, without the possible side effects of hormonal birth control or implants.
It is a personal choice that many individuals and couples make for many diverse reasons. The information on this site is for your information only and is not a substitute for professional medical advice. To unlock this lesson you must be a Study. Login here for access.
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Want to watch this again later? In this lesson, you will learn about a medical term called abstinence. We will also learn facts, surrounding the practice of abstinence, in relation to sexuality, pregnancy, and sexually transmitted infections. Questions About Intimacy Jennifer is in a serious relationship with her boyfriend and he has asked her about her feelings towards taking their relationship to the next level, sexually. What Is Abstinence The nurse practitioner explains to Jennifer that abstinence means to refrain from doing something, which in her case means to restrain from having sexual activity.
There are many reasons why an individual may wish to abstain from sexual activity: To prevent pregnancy To prevent contracting sexually transmitted diseases For religious reasons For medical reasons For personal reasons such as the desire to wait for the right partner, grieving the death of a partner or the end of a relationship, or to concentrate on other things like career, education etc.
Try it risk-free No obligation, cancel anytime. Want to learn more? Select a subject to preview related courses: A Decision After speaking with her nurse practitioner, Jennifer decides that engaging in a sexual relationship with her boyfriend is important to her. Lesson Summary In this lesson, we discussed a method of pregnancy and disease prevention called abstinence.
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NEW AQA GCSE Trilogy () Biology - Preventing & Treating Disease Homework This task is designed for the NEW AQA Trilogy Biology GCSE, particularly the ‘Infection & Response’ SoW. For more resources designed to meet sp. BIOl Quizzes Unit Assessment 1: Biology, The Science of Life. Question 1. Points: 10 out of 10 Some of the chemicals that make up living organism have only few structures (like DNA) other have many different structures (like proteins).