B5. Communicable Diseases Flashcards
Define the term communicable disease
A communicable disease is an illness caused by pathogens that can be spread between individuals within a population
What are pathogens?
Pathogens are microorganisms that cause disease
Name the different types of pathogen
Bacteria
Viruses
Fungi
Protists
How do bacteria cause damage to the body?
Bacteria cause damage to the body by reproducing rapidly and producing toxins which damage tissues
What are the main ways that pathogens are transmitted
Direct contact
Contaminated water
Droplets carried in the air
Contaminated food
Where do viruses live and reproduce?
Viruses live and reproduce inside living cells of a host organism
What is measles?
Measles is a viral infectious disease with symptoms including a fever and a rash. It spreads easily and can be fatal if complications arise
How is measles transmitted between people?
The measles virus is spread by inhalation of droplets that contain the virus
How does HIV cause harm?
HIV can damage the immune system, eventually leading to acquired immune deficiency syndrome
What are the initial symptoms of HIV infection?
The initial symptoms of HIV infections are flu-like symptoms
How is HIV transmitted?
HIV is spread by exchange of body fluids. It can also pass across the placenta during pregnancy
Why do plants infected with TMV have reduced growth
The ‘mosaic’ pattern caused by the virus discolours the leaves; this affects the growth of the plant due to lack of photosynthesis
What is Salmonella?
Salmonella is a bacterial pathogen that causes food poisoning
symptoms include:
fever
Abdominal cramps
Vomiting
Diarrhoea
What is the main way that Salmonella infection can spread?
Through ingestion of contaminated fold
What is gonorrhoea?
Gonorrhoea is a sexually transmitted disease caused by a bacterial pathogen. Symptoms include discharge from the sex organs and pain on urinating
How is gonorrhoea transmitted?
Gonorrhoea is transmitted through sexual contact
How can the spread of gonorrhoea be prevented?
Treating infected individuals with antibiotics
The use of barrier contraception e.g. Condoms
What is rose black spot?
Rose Black spot is a fungal disease of plants where purple or black spots develop which often turn yellow and drop warly
How does rose black spot affect plants?
Rose black spot affects the growth of the plant as photosynthesis is reduced
How does rose black spot spread?
By water or wind
How can rose black spot be treated?
Rose Black spot can be treated using fungicides and/or removing and destroyed the affected leaves
What type of pathogen causes malaria?
Protists
How do malarial protists infect humans?
Malarial protists infect humans when infected mosquitoes bite. The protists pass from the mosquito saliva into the human blood
Define the term vector in the context of infectious disease.
A vector is an organisms that transfers pathogens from one host to the next
What are the symptoms of malaria?
Malaria causes recurrent episodes of fever and can be fatal
How is the spread of malaria controlled?
Controlling the mosquito vectors by preventing the mosquitoes from breeding or using misquote nets to avoid being bitten
What is the role of the trachea and bronchi in non-specific immune defence?
The role of the trachea and bronchi are to trap pathogens, dirt and dust using ciliated epithelial cells and mucus
What is the role of antibodies in the immune response?
Antibodies attach to antigens on pathogens binding the pathogens together. This can prevent them from infecting cells, and make it easier for phagocytes to engulf them
What is the role of antitoxins produced by white blood cells?
Antitoxins neutralise toxins released by pathogens, preventing them from causing harm to the body
What is the difference between antigen, antibody and antitoxin?
An antigen is a protein molecule found on the surface of a cell
An antibody is a protein produced by lymphocytes that binds to specific antigens on pathogens
An antitoxin is a protein that neutralises toxins released by pathogen
Give three symptoms that may indicate disease in plants
Stunted growth
Spots on leaves
Areas of decay (rot)
Growths
Malformed stems or leaves
Discolouration
The presence of pests
Give one example of a viral disease in plants
Tobacco mosaic virus
What type of pathogen causes black spot disease in plants
Black spot disease is caused by a fungal pathogen
How can aphids can acts as a vector for plant disease?
Aphids acts as a plant disease vector when they transfer pathogens between plants as they feed
Why does a magnesium deficiency result in stunted growth of plants?
Magnesium is required for chlorophyll production and chlorophyll is required for photosynthesis
If there is a lack of magnesium then there will be a lack of chlorophyll and this will mean photosynthesis will not be happen as quickly resulting in stunted growth
Define the term chlorosis
The yellowing of leaves that occur when chlorophyll is lacking as a result of low magnesium levels
Which mineral ion is required in the production of amino acids and proteins?
Nitrates are required by plants to build amino acids and therefore proteins
Give examples of physical defences against disease in plants
Cellulose cell walls
Tough waxy cuticle on leaves
Deas cells that form a layer around the outside of stems
What is an example of a chemical defence response in plants?
Antibacterial chemical
Poisons to deter herbivores
How does mimicry function as a mechanical defence in plants
Plants use mimicry to put off animals that may otherwise eat them, e.g. plants may droop to mimic diseased plants or resemble large insects to scare away threats
How might a plant protect itself from herbivores?
Physical defences e.g. Cellulose cell wall
Chemical defences e.g. antibacterial chemicals
Mechanical defences e.g. thorns and hairs
