SB5 - Health, Disease and the Development of Medicines Flashcards
Define ‘health’
Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity
What is a ‘disease’?
A disease is a condition where part of an organism doesn’t work properly
What are communicable diseases?
A disease that can spread between individuals
What are communicable diseases usually caused by?
Bacteria, viruses, fungi and parasites
What are non-communicable diseases?
Diseases that cannot be spread from person to person
What are two types of causes for non-communicable diseases?
Genetics and lifestyle factors
What type of disease, communicable or non-communicable, generally lasts a long time and gets worse slowly?
Non-communicable
True or False: If a person has AIDS, they have an increased chance of suffering from diseases like flu
True
Explain why a person that has AIDS has an increased chance of suffering from diseases like flu
A person with AIDS is less able to fight off the pathogen that causes flu because their immune system is weakened by the HIV virus
What do we call organisms that cause disease?
Pathogens
What is meant by the term ‘sexually transmitted infection’?
A pathogen that is transmitted through bodily fluids during sexual intercourse / activity
True or False: Both animals and plants can be infected by organisms that cause diseases
True
Explain why bacteria such as ‘Salmonella’ make you feel ill
They produce toxins (poisons) inside the body that damage cells and tissues
What communicable disease is caused by ‘Helicobacter pylori’ bacteria?
Stomach ulcers
True or False: Viruses are cells
False
How do viruses replicate?
They live inside body cells and replicate using the cell’s machinery to produce many copies of themselves
How do viruses spread within the body?
Infected cells eventually burst and release the new viruses into the tissue and / or blood
What makes you feel ill when you have a viral infection?
The cell damage caused by infected cells bursting
Name the virus that infects and destroys the white blood cells that normally help fight infections
HIV
What are protists?
Eukaryotic organisms that are usually unicellular
What are parasites?
Organisms that live on or inside other organisms and can cause them damage
What disease is caused by a protist that lives inside a mosquito through part of its life cycle?
Malaria
How do fungi, made up of hyphae (thread-like structures), cause disease in animals and plants?
The hyphae grow and penetrate the skin or surface of plants causing disease. The hyphae can produce spores which can be transferred to other plants and animals
Give an example of a plant disease caused by fungi
Chalara ash die-back disease
Give an example of a human disease caused by fungi
Athlete’s foot, thrush, ringworm
State five methods that pathogens are spread
- Drinking and bathing in dirty water
- Airborne (carried in the air)
- Swallowing contaminated water or food
- Bodily fluids (e.g. blood, vomit, saliva)
- Animal vectors transmit pathogens
What disease is caused by ‘Mycobacterium tuberculosis’?
Tuberculosis (TB)
Which bacterial disease causes symptoms of coughing, lung damage, weight loss and coughing up blood?
TB
How is the bacteria ‘Mycobacterium tuberculosis’ spread?
Through the air in droplets that are sprayed out when a person coughs and sneezes
What could infected individuals do to reduce the spread of a pathogenic bacteria?
- Isolate themselves
- Avoid crowded public spaces
- Sleep alone
- Practice good hygiene - cover mouth and nose with tissue when coughing and sneezing, disposing of tissues in a bin
- Good ventilation can reduce likelihood of transmission
What disease is caused by the bacterium “Vibrio Cholerae”?
Cholera
What are the main symptoms of an infection caused by “Vibrio cholerae”?
Diarrhoea that lasts for a few days leading to severe dehydration and ultimately, if untreated, death
How is the pathogen “Vibrio cholerae” spread?
Through contaminated water sources
Explain why most cases of cholera occur in developing countries
Clean water is not widely available in many developing countries
How can the spread of cholera be reduced?
By making sure that everyone has access to clean water supplies
How does the “Heliobacter pylori” bacteria cause stomach ulcers?
It inflames the stomach lining which can lead to the lining becoming damaged. The damage allows stomach acid to penetrate the stomach lining, creating a hole (the ulcer) that exposes the tissue underneath
What are the symptoms of stomach ulcers?
Stomach pain, nausea and vomiting
How can the transmission of “Heliobacter pylori” be reduced?
Clean water supplies, hygienic living conditions: disinfecting food preparation areas, washing hands before eating or handling food, keep toothbrushes separately, infected people should not prepare or serve food, through cleaning of utensils
What is Ebola and what does it cause?
Ebola is a virus that causes haemorrhagic fever
How is Ebola spread?
Through contact with bodily fluids of an infected individual
Describe the symptoms caused by Ebola
A fever that causes internal bleeding and bleeding from the eyes, nose or mouth often leading to death
How was the spread of West African Ebola reduced during the 2013 - 2016 epidemic?
Infected individuals were isolated from others, bodies were left untouched until they could be collected by officials wearing protective clothing covering the whole body. Medical staff wore protective clothing covering the whole body, sterilising areas where the virus may be present. Treatment centres were set up where infected individuals were isolated, bodies buried in mass graves by people wearing full body protective clothing. Community awareness campaigns about the protective factors individuals could take, (e.g. avoiding contact with infected people and hand washing using soap and water)
Describe the symptoms of Chalara ash dieback
Loss of leaves and bark lesions (wounds) leading ultimately to the death of the tree - directly or because the tree is weakened so much that it cannot defend itself from other pathogens
How is the fungus that causes Chalara ash dieback transmitted?
Through the air by the wind - spores. By the movement of infected ash trees from one area to another
How can the spread of Chalara ash dieback be slowed down?
Removing young infected ash trees and replanting with another species of tree. Putting restrictions on the import and the movement of ash trees
What are the vectors of the malaraia parasite?
Mosquitos
How do the mosquito vectors become infected?
The mosquitos suck up the malarial protist when they feed on infected animals
How do the mosquito vectors infect other animals?
The malarial protist does not affect mosquitos. When mosquitos feed on an animal they introduce the protist into the animals bloodstream
What are the symptoms of malaria?
Repeated episodes of fever, hot and shivery, lethargy, sweating, headaches, vomiting, diarrhoea, muscle pains and ultimately it can lead to death
What damage can the malaria protist do to the body?
Damage reed blood cells, damage to the liver
What preventative measures can be taken to protect people from mosquitos?
Removing sources of standing water where mosquitos breed, upturning containers that are used to collect rain water, spraying insect repellent onion skin and clothes, sleeping under a mosquito net
What type of pathogen is “Chlamydia”?
A bacterium
What are the symptoms of “Chlamydia”?
There are usually no symptoms caused by Chlamydia
What can be the result of an untreated case of “Chlamydia”?
Infertility in women and in men
True or False: “Chlamydia” can be passed on from a woman to her child during childbirth
True
How can the transmission of “Chlamydia” be reduced?
By wearing a condom during sexual contact, avoiding sexual contact if infected and getting treatment - antibiotics
How can a person find out if they have been infected with “Chlamydia”?
Screening is available - medics can carry out a test for the presence of Chlamydia
What does HIV stand fro?
The Human Immunodeficiency Virus
What cells are attacked by HIV?
White blood cells
True or False: HIV can be controlled - treatment leads to a zero viral load which means individuals cannot pass on the virus
True
If untreated, what will HIV lead to?
AIDS (Acquired Immune Deficiency Syndrome)
How is HIV spread?
Exchanging infected bodily fluids such as blood, semen and vaginal fluids. Exchange of bodily fluids usually occurs during sexual intercourse / contact and by sharing needles when taking drugs
How can couples reduce the spread of HIV?
Wearing a condom. Getting themselves tested and if positive getting and maintaining treatment (medication) to ensure their viral load reaches and stays zero
True or False: A pregnant HIV + mother with a zero viral load can infect her unborn foetus with HIV
False
Describe the structure of viruses
A protein coat around a strand of genetic material
What is the start of the life cycle of a virus?
When the virus infects a new host cell
Name the type pathways that a virus can reproduce through
The lytic pathway and the lysogenic pathway
Which pathway is when the virus is incorporated into the genome (DNA) of the host cell?
Lysogenic pathway
Which pathway is when the viral genetic material gets replicated along with the host DNA every time the host cell divides?
Lysogenic pathway
Which pathway is when the virus uses protein and enzymes in the host cell to replicate its genetic material and create the components of new viruses?
Lytic pathway
Which pathway produces host cells that split open once full of new viruses?
Lytic pathway
Which pathway requires a trigger such as the presence of a specific chemical causes the genetic material to leave the genome and Exeter the other pathway?
Lysogenic pathway
Which pathway leads to the release of new viruses?
Lytic pathway
During which pathway are new viruses assembled
Lytic pathway
During which pathway does the virus lay dormant
Lysogenic pathway
Describe two examples of physical plant defences
Plant leaves and stems have waxy cuticles which are a barrier to prevent entry by pathogens or damage by pests. Waxy cuticles repel water reducing the risk of pathogens transmitted in water. Plant cell walls are made of cellulose which act a barrier to pathogens, hairy plant leaves and stems prevent pests from reaching the leaf surface to eat them
Describe what chemical defences plants can employ
Produce antiseptics which kill bacteria and fungi. Produce poisons which deter pests
How would a plant pathologist determine if a symptom of disease is due to a nutrient deficiency?
Observe the leaves and determine which nutrient the plant may be deficient in. Add that nutrient to the soil and observe any changes in plant symptoms
How would a plant pathologist determine if a symptom of disease is due to a pathogen?
Analyse the distribution of diseases plants. Use monoclonal antibodies to detect antigens unique to a specific pathogen. Take a tissue sample, then analyse the DNA to detect any pathogen DNA
Give two examples of the bodies physical barriers against pathogens
Skin is a barrier which can create a scab to seal any cuts to keep pathogens out. Hair and mucus in the nose physically trap particles. Trachea and bronchi cells secrete mucus to trap pathogens. Ciliated cells in the trachea and bronchi waft the mucus and any trapped particles and pathogens up to the throat to be swallowed
Give two examples of the body’s chemical barriers against pathogens
Stomach produces hydrochloric acid kills pathogens. Produce enzymes called lysozymes which kill bacteria - found in tears and mucus
Name the cells found in the blood that are involved in the body’s immune system
White blood cells
What is phagocytosis?
When a white blood cell engulfs foreign cells and digests them - consuming pathogens
How are B-lymphocytes involved in the body’s immune system?
They produce antibodies
Name the proteins found on the surface of pathogens
Antigens
