B5 Communicable Diseases Flashcards
What is health?
The state of physical and mental well-being
What are the major causes of ill health?
Communicable and non-communicable diseases
What other factors have an effect on health?
- Diet
- Stress
- Life situations
How can physical ill health affect mental health?
Physical ill health can cause mental health problems
How do different types of disease interact? (4 marks)
- Defects in the immune mean that an individual is more likely to suffer from infectious diseases
- Viruses living in cells can trigger cancer
- Immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma
- Severe physical ill health can lead to depression and other mental illnesses
What are the risk factors linked to non-communicable diseases such as heart, liver lung problems and Type 2 diabetes? ( 2 marks)
- A person’s lifestyle, e.g. diet, obesity, exercise
* Substances in the person’s body or environment
What are pathogens? (1 mark)
Microorganisms that cause infectious disease
Name four types of pathogens
- Virus
- Bacteria
- Fungi
- Protists
How can pathogens be spread?
- By direct contact, e.g. touching
- By exchange of body fluids, e.g. unprotected sex
- Through droplets/spores in air
- Through spores in soil
- Contaminated water
- Contaminated food
How do viruses cause illness? (1 mark)
Viruses enter the body cells damage cells
How do bacteria cause illness? (1 mark)
Bacteria produce toxins and damage the cells
Give two reasons why pathogens make us feel ill. (2 marks)
- Pathogens produce toxins
* Pathogens damage cells
Describe the aseptic techniques used to grow microorganisms (4 marks)
- Sterilise petri dish that is used to grow microorganisms
- The nutrient agar which will provide their food must be sterilised. This will kill of any unwanted microorganisms
- Inoculate the sterile agar with the microorganisms that you want to grow
- Seal the petri dish and incubate at 250C or less (in school) to allow the microorganisms to grow.
How do bacteria multiply? (3 marks)
- By simple cell division called binary fission
- Every 20 minutes
- They need enough nutrient and a suitable temperature
What is an antiseptic? (1 mark)
A chemical applied to skin to kill bacteria
What is a disinfectant? (1 mark)
A chemical applied to surfaces to kill bacteria
How can the spread of disease be prevented? (4 marks)
- Simple hygiene e.g. washing hands
- Destroying vectors e.g. mosquitos
- Isolation of infected person/people
- Vaccination
Name 3 diseases caused by viruses (3 marks)
- Measles
- HIV
- Tobacco Mosaic Virus (TMV)
What is Measles? (5 marks)
- Viral disease
- Symptoms: Fever and red skin rash
- Serious illness that can cause death
- Most children are vaccinated when young
- Measles spreads by inhaling droplets from sneezes and coughs
What is HIV? ( 4 marks)
- Virus that causes flu-like symptoms
- Virus enters lymph nodes and attacks the body’s immune cells
- AIDs occurs when the body’s own immune system cannot deal with other infections
- HIV is spread by sexual contact or exchange of body fluids e.g. blood when sharing needles
What is Tobacco Mosaic Virus (TMV)? (3 marks)
- Plant pathogen
- Affects many plants including tomatoes
- Gives distinct ‘mosaic’ discolouration on the leaves
- Affects the growth of plant due to lack of photosynthesis
Name a fungal disease (1 mark)
Rose Black Spot
What is Rose Black Spot? (5 marks)
- Purple or black spots develop on leaves, and then turn yellow and drop
- Affects the growth of photosynthesis
- Photosynthesis is reduced
- Spreads by water or wing
- Treated by fungicides or removing the affected leaves
Name disease caused by a Protist (1 mark)
Malaria
What is Malaria? (5 marks)
- A disease caused by protists
- The life cycle includes the mosquito that carries it from person to person
- Malaria causes recurrent episodes of fever and can be fatal
- The spread can be controlled by preventing the vectors (mosquitos) from breeding
- Use mosquitos nets to avoid being bitten
Describe how the human body defends itself against the entry of pathogens (4 marks)
- 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.
State three ways by which white blood cells protect us against pathogens (3 marks)
- Produce antibody
- Produce antitoxins
- Phagocytosis (engulfing and ingesting pathogens)
What is antibody? (1 mark)
These are the substances made by white blood cells to kill the pathogens
What can plant diseases be detected by? (7 marks)
- Stunted growth
- Spots on leaves
- Areas of decay
- Growths
- Malformed stems or leaves
- Discolouration
- The presence of pests
How can identification be made? (3 marks)
- Reference to a gardening manual or website
- Taking infected plants to a lab to identify the pathogen
- Using testing kids that contain monoclonal antibodies
List some plant diseases ( 3 marks)
- Tobacco Mosaic Virus (TMV- viral disease)
- Black Spot (fungal disease)
- Aphids (insects)
What ion deficiencies can affect plant growth? (2 marks)
- Stunted growth caused by nitrate deficiency
* Chlorosis caused by magnesium deficiency
Why are nitrate ions needed? ( 2 marks)
- For protein synthesis
* Growth
Why are magnesium ions needed? ( 1 mark)
To make chlorophyll
What defences do plants have to resist invasion of microbes? ( 3 marks)
- Cellulose cell walls
- Tough waxy cuticle on leaves
- Layers of dead cells around stems (or bark on trees) which fall off, taking pathogens with them
What chemical plant defence systems are there? (2 marks)
- Produce antibacterial chemicals, such as mint and witch hazel
- Produce poisons to deter herbivores, such as tobacco plants, foxgloves and deadly nightshade
What mechanical adaptions do plants have? (3 marks)
- Thorns and hairs deter animals from eating or touching them
- Leaves which droop or curl when they are touched
- Mimicry to trick animals into not eating them or not laying eggs on the leaves
