Y10 Science Mocks Revision Flashcards
What is a pathogen?
A microorganism that causes disease
What are viruses?
- DNA/RNA surrounded by a protein coat
- Viruses live and reproduce inside cells causing damage
- Examples of viruses: cold, influenza, measles, HIV, tobacco mosaic virus
What is bacteria?
- Made of prokaryotic cells
- No membrane bound organelles (no chloroplasts, mitochondria or nucleus)
- Have a cell wall and are single celled organisms
- Examples of bacteria: tuberculosis (TB), salmonella, gonorrhoea
What are protists?
- Membrane bound organelles
- Usually single celled
- Examples of protists: dysentery, sleeping sickness, malaria
What are fungi?
- Membrane bound organelles
- Cell wall made of chitin
- Single celled or multi cellular
- Examples of fungi: athletes foot, thrush, rose black spot
What are communicable diseases?
Diseases that can be spread from person to person
Give some examples of communicable diseases. Include the method of transmission and how they can be controlled
Disease Pathogens. Symptoms. Method of Control of
Transmission Spread
Measles Virus. Fever, red. Droplet infection Vaccine
skin rash. from sneezes/coughs
HIV. Virus. Flu like symp. Sexual contact/. Anti-retro
-toms, damage. exchange of viral drugs
to immune system body fluids /condoms
Tobacco Mos. Virus Mosaic pattern. Enters wounds. Remove infe
aic Virus. on leaves. in epidermis cted leaves
Salmonella Bacteria Fever, cramps, vo- Food prepared Improve foo
miting, diarrhoea in unhygienic d hygiene
conditions
Gonorrhoea Bacteria Green discharge from. Sexual contact/. Use condo
penis/vagina exchange of body ms/antibo
fluids tics
Malaria. Protists Recurrent fever. By an animal Prevent
vector mosquito br
eeding
Rose Black. Fungus. Purple/Black spots on. Spores from Remove infe
Spot. leaves. wind/water. cted leaves
Name some non-specific defence systems that the body has
- Nose: Nasal hairs, sticky mucus and cilia prevent pathogens entering through the nostrils
- Trachea and bronchus (respiratory system): Lined with mucus to trap dust and pathogens. Cilia move the mucus upwards to be swallowed
- Stomach Acid: Stomach acid (pH 1) kills most ingested pathogens
- Skin: Hard to penetrate waterproof barrier. Glands secrete oil which kill microbes
How are pathogens identified?
Pathogens are identified by white blood cells by the different proteins on their surfaces called antigens
Name the components of white blood cells that fight pathogens and describe how they do so
Phagocytes: Phagocytosis - Phagocytes engulf the pathogens and digest them
Lymphocytes: Antibody Production - Specific antibodies destroy the pathogen. This takes time so an infection can occur. If a person is infected again by the same pathogen, the lymphocytes make antibodies much faster
Antitoxin Production - Antitoxin is a type of antibody produced to counteract the toxins produced by bacteria
Name the different ways plants have of defending themselves from illness
Physical: Thick waxy layers, cell walls stop pathogen entry
Mechanical: Thorns, curling up leaves to prevent being eaten
Chemical: Antibacterial and toxins made by plant
1) What are some symptoms of plant diseases
2) How would you identify plant disease
1) Stunted growth (nitrate ions needed for protein synthesis - lack of nitrate = stunted growth), spots on leaves, area of decay, growths, malformed stem/leaves, discolouration (magnesium ions needed to make chlorophyll - not enough leads to chlorosis - leaves turn yellow), presence of pests
2) Reference using gardening manual or website, laboratory test for pathogens, testing kit using monoclonal antibodies
What are non-communicable diseases
Diseases that can’t be spread from person to person
What is cancer?
- The result of changes in DNA that lead to uncontrollable growth and division
- Some cancers have genetic risk factors
- Carcinogens and ionising radiation increase the risk of cancer by changing/damaging DNA
- Risk factors for cancer include drinking alcohol, diet, obesity and smoking
- These factors can also cause heart/lung disease and effect the brain, liver and health of unborn babies
Name the two types of tumours that cause cancer
Benign tumour - Contained in one area of the body (usually by a membrane) - not cancerous
Malignant tumour - Invade tissues and spread to different parts of the body to form secondary tumours - cancerous
What are antibiotics and painkillers?
Antibiotics: Kill infective bacteria inside the body. Specific bacterial infections require specific antibiotics (eg penicillin)
Painkillers (+ other medicines): Drugs that are used to treat the symptoms of a disease. They don’t kill pathogens (eg aspirin, paracetamol, ibuprofen)
Why can antibiotics not be used to treat viruses?
It’s difficult to develop drugs to kill viruses without harming body tissues because viruses live and reproduce inside cells
How can certain types of bacteria become resistant to antibiotic drugs?
Because bacteria can mutate and in certain cases this has made them resistant to antibiotics and drugs
Define vaccine/vaccination
Used to immunise a large portion of the population to a disease to prevent the spread of a pathogen by injecting people with a small dose of a dead or inactive pathogen
How does vaccination work?
1st infection by pathogen: White blood cells detect pathogens in the vaccine. Antibodies are released into the blood
Re-infection by the same pathogen: White blood cells detect pathogens. Antibodies are made much faster and in larger amounts
This works as a person is unlikely to suffer the symptoms of the harmful disease and it’s spread in a population is prevented
How are drugs made?
Today most new drugs are synthesised by chemists in the pharmaceutical industry. However, traditionally drugs were extracted from plants and microorganisms.
Give some examples of drugs that have been extracted from plants
Digitalis: Extracted from foxgolve plants and used as a heart drug
Aspirin: A painkiller/anti-inflammatory drug that was first found in willow bark
Penicillin: Discovered by Alexander Fleming from the Penicillium mould and used as an antibiotic
What are drugs extensively tested for?
Efficiency: Making sure the drug works
Toxicity: Check that the drug isn’t poisonous
Dose: The most suitable amount to take
What are preclinical trials?
Preclinical trials use cells, tissues and live animals as test subjects before they move onto human trials. Must be carried out before the drug can be tested on humans.
How do drug trials work?
Drugs have to be tested and trialled before to check they’re effective and safe. Clinical trials use healthy volunteers and patients.
Stage 1: Healthy volunteers try a small dose of the drug to check it’s safe and record any side effects
Stage 2: A small number of patients try the drug at a low dose to see if it works
Stage 3: A larger number of patients; different doses are trialled to find the optimum dose
Stage 4: A double blind trial will occur. The patients are divided into groups. Some will be given the drug and others a placebo (a placebo can look identical to the new drug but contain no active ingredients)
What are double blind trials?
A double blind trial is a trial in which both patients and doctors don’t know who receives the new drug and who receives a placebo until the end of the trial. This prevents bias during testing
What are monoclonal antibodies?
Identical copies of one type of antibody produced in a laboratory. They are specific to one binding site on an antigen. Can target specific chemicals or cells in the body.
Describe how monoclonal antibodies work?
1) A mouse is injected with a pathogen
2) Lymphocytes produce antibodies
3) Lymphocytes are removed from the mouse and fused with rapidly dividing mouse tumour cells
4) The new cells are called hybridomas
5) The hybridomas divide rapidly and release lots of antibodies which are then collected
How can monoclonal antibodies be used?
- Diagnosis: pregnancy test - measure hormone levels
- Detecting pathogens: can detect very small quantities of chemicals in the blood
- Detecting molecules: fluorescent dye can be attached so it can be seen inside cells/tissues
- Treatment: bound to radioactive substance, toxic drug or chemical. Cancer cells are targeted too. Normal body cells are unharmed
What’s the problem with using monoclonal antibodies?
They can create more side effects than expected (in some cases they can even be fatal) and are not as widely used as everyone hoped they would be when they were first developed
What is the equation for calculating the magnification of an image?
Magnification = size of image / size of real object
What are the differences between prokaryotes and eukaryotes?
Eukaryotes contain their genetic material in the nucleus whereas prokaryotes don’t. They’re also bigger than prokaryotes
