What is a communicable disease?
A communicable disease is a disease that can be spread from one person to another.
What is a pathogen?
A pathogen is a microorganism that causes infectious disease.
Name the four types of pathogens.
The four types of pathogen are:
Describe three ways in which pathogens can be spread.
Pathogens can be spread by:
- Direct contact (including skin, blood and by vectors e.g. insects)
- By water/food
- By droplets (including sneezing, coughing)
Explain how bacteria make us feel ill.
Bacteria reproduce rapidly inside the body and produce toxins that damage tissue.
Explain how viruses make us feel ill.
Viruses live and reproduce inside cells, causing cell damage.
What type of pathogen causes measles.
Measles is caused by a virus.
Describe 2 symptoms of the measles.
Two symptoms of the measles are:
- Red skin rash
Describe how the measles is spread between people.
The measles virus is spread by the inhalation of droplets from sneezes and coughs.
What type of pathogen causes HIV?
HIV is caused by a virus.
Describe how HIV is spread.
HIV is spread by sexual contact or exchange of bodily fluids eg blood.
What type of pathogen causes Tobacco Mosaic Virus (TMV)?
Tobacco Mosaid Virus is caused by a virus.
Describe the symptoms of Tobacco Mosaic Virus.
Tobacco Mosaic Virus causes discoloured leaves.
Explain why Tobacco Mosaic Virus affects the growth of plants.
Tobacco Mosaic Virus damages the chloroplasts in the leaves. This means that the plant is unable to absorb sunlight and can therefore not photosynthesis and produce glucose for growth.
What type of pathogen causes Salmonella?
Salmonella is caused by bacteria.
Describe how Salmonella is spread.
Salmonella is spread by eating contaminated food and by preparing food in unhygeinic conditions.
Describe the symptoms of salmonella.
The symptoms of salmonella are:
- Abdominal cramps
What type of pathogen causes Gonorrhoea?
Gonorrhoea is caused by bacteria.
Describe how gonorrhoea is spread.
Gonorrhoea is a sexually transmitted disease which is spread by having unprotected sex.
Describe the symptoms of Gonorrhoea.
The symptoms of Gonnorhoea are:
- thick yellow discharge from vagina / penis
- pain urinating
Describe how Gonnorhoea can be treated.
Gonnorhoea can be treated by using antibiotics (eg penicillin).
Describe how Gonnorhoea can be prevented.
Gonnorhoea can be prevented by using a barrier method of contraception eg a condom.
What type of pathogen causes Rose Black Spot Disease?
Rose Black Spot Disease is caused by a fungus.
Describe the symptoms of Rose Black Spot Disease.
Rose black spot disease causes purple or black spots on leaves which often turn yellow and drop off early.
Describe and explain the effect of Rose black spot on the growth of plants.
Rose black spot causes stunted growth because photosynthesis is reduced.
Describe how Rose black spot is spread.
Rose black spot is spread in the environment by wind or water.
Describe how Rose black spot can be treated.
Rose black spot can be treated by:
- Using fungicides
- Removing or destroying the affected leaves
What type of pathogen causes Malaria.
Malaria is caused by protists.
Describe how the spread of malaria can be controlled.
The spread of malaria can be controlled by:
- Preventing mosquitos from breeding
- Using mosquito nets to avoid being bitte,
Describe & explain four non-specific defence systems of the human body.
Four non-specific defence systems of the human body are:
- Skin - acts as a barrier to prevent the entry of pathogens.
- Nose - lined with hair and mucus to trap pathogens
- Trachea & Bronchi - lined with cilia to trap pathogens
- Stomach - contains acid to kill pathogens
Which type of blood cell helps to defend against pathogens?
White blood cells help defend against pathogens.
Describe 3 ways in which white blood cells defend against pathogens.
White blood cells defend against pathogens by:
- Phagocytosis - phagocytes engulf and destroy pathogens
- Antibody production - lymphocytes produce antibodies which bind to pathogens
- Antitoxin production - antitoxins neutralise the toxins produced by pathogens
Explain how vaccination prevents illness.
Vaccinations contain an inactive or dead form of the pathogen which is injected in to the body.
White blood cells produce antibodies against the pathogen.
Some white blood cells become memory cells. If the pathogen enters the body in the future, the memoery cells "remember" which antibody to produce.
What are antibiotics used to treat?
Antibiotics are used to treat infections caused by bacteria.
Describe what painkillers are used for.
Painkillers are used to treat the symtoms of a disease eg pain.
Explain why it is important that people finish a course of antibiotics even if they are feeling better.
People should finish the course of antibiotics to prevent the development of antibiotic resistant bacteria.
From what plant does the heart drug Digitalis originate?
Digitalis originates from foxgloves.
From what plant does the painkiller Aspirin originate?
Aspirin originates from willow.
Who discovered the antibiotic penicillin?
Penicillin was discovered by Alexander Feleming.
Describe the process of pre-clinical testing.
Pre-clinical testing involves testing in the laboratory using cells, tissues and animals.
Why are new drugs extensively tested?
New drugs are tested for toxicity, efficacy and dose.
What is a placebo?
A placebo is a dummy drug that does not contain the active ingedient being tested.
Explain what is meant by a double blind trial?
In a double blind trial some patients are given the real drug and the others are given a placebo. Neither the doctors or the patients know which drug they are receiving.
What is a monoclonal antibody?
Monoclonal antibodies are produced from a single clone of cells. The antibodies are specific to one binding site on one protein antigen and are so and so are able to target a specific chemical or cells in the body.
Describe how monoclonal antibodies are produced.
Monoclonal antibodies are produces 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 divide and produce the antibody. Single hycridom cells are cloned to produce many identical cells that all produce the same antibody.
Describe four uses of monoclonal antibodies
Monoclonal antibodies can be used to:
- For diagnosis such as in pregnancy tests.
- 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.
- To treat some diseases
Explain how monoclonal antibodies can be used to treat cancer.
The monoclonal antibody can be bound to a radioactive substance, a toxic drug or a chemical
which stops cells growing and dividing. It delivers the substance to the cancer cells without harming other cells in the body.
Give a disadvantage of using monoclonal antibodies.
Monoclonal antibodies create more side effects than expected.
They are not yet as widely used as everyone hoped when they
were first developed.
Name 7 ways in which plant diseases can be detected.
Plant diseases can be detected by:
• stunted growth
• spots on leaves
• areas of decay (rot)
• malformed stems or leaves
• the presence of pests.
Describe 3 ways in which plant diseases can be identified.
Identification can be made by:
• reference to a gardening manual or website
• taking infected plants to a laboratory to identify the pathogen
• using testing kits that contain monoclonal antibodies.
Describe and explain what would happen to a plant with a nitrate deficiency.
Plants with a nitrate deficiency would have stunted growth.
Nitrate ions are needed for protein synthesis.
Describe and explain what would happen to a plant with a magneisum deficiency.
A plant with a magensium deficiency would cause chlorosis (yellow leaves).
Magnesium is needed to produce chlorophyll.
Name three physical defence responses of plants to resist invasion of microorganisms.
Three physical defence responses of plants are:
- Cellulose cell walls
- Tough waxy cuticle on leaves
- Layers of dead cells around stems (or bark) which fall off
Name two chemical plant defence responses.
Two chemical plant defence responses are:
- Antibacterial chemicals
- Poisons to deter herbivores
Name 3 mechanical adaptations of plants.
Three mechanical adaptations are:
- Thorns and hairs to deter animals
- Leaves which droop or curl when touched
- Mimicry to trick animals