Health, Disease and the Development of Medicines Flashcards
What is physical well-being?
Free from disease, eating and sleeping well, getting regular activity, and limiting the intake of harmful substances such as alcohol and drugs
What is social well-being?
How well you get on well with other people, and also how your surroundings affect you
What is mental well-being?
How you feel about yourself
What is a disease?
A problem with a structure or process in the body that is not the result of an injury
What are pathogens?
Microorganisms that cause diseases
What are communicable diseases?
Diseases caused by pathogens that can be passed from an infected person to other people
What are non-communicable diseases?
Diseases that are not passed from person to person, caused by a fault in the genes or a result our lifestyle
What are possible causes of the correlation between diseases?
- Disease damages immune system (easier for other pathogens to cause disease)
- Disease damages body’s natural barriers and defences
- Disease stops an organ system working effectively
What are genetic disorders caused by?
Faulty alleles of genes
What is malnutrition?
When you get too little or too much of particular nutrients from your food
What deficiency causes anaemia?
Iron
What deficiency causes rickets?
Vitamin D
What deficiency causes scurvy?
Vitamin C
What is ethanol?
A drug found in alcohol, which changes the way the body works. It is broken down by the liver (too much can cause liver disease)
What is obesity?
Where large amounts of fat are formed under the skin around organs like the heart and kidneys
What is cardiovascular disease?
A result of the circulatory system functioning poorly
What are symptoms of cardiovascular disease?
High blood pressure, which can lead to heart pain or a heart attack
How do you calculate BMI?
BMI = MASS/HEIGHT^2
What is a better method of measuring abdominal fat than BMI?
WAIST:HIP ratio
Why can smoking lead to cardiovascular disease?
- Tobacco’s harmful substances are absorbed from the lungs into the blood and are transported around the body which can damage blood vessels
- Increase blood pressure
- Make blood vessels narrower by fat building up in the artery wall
- Increase the risk of blood clots forming in blood vessels
How do you reduce high blood pressure to decrease the risk of cardiovascular disease?
Exercise more and give up smoking; or medicine if the risk is too high
How can a stent treat cardiovascular disease?
- A narrowed blood vessel can be widened by inserting a stent at the narrowest part to hold it open
- It is inflated and opens up the vessel
How can blocked arteries in the heart be bypassed?
-By inserting other blood vessels so the heart tissue is supplied with oxygen and nutrients again
What is the general term for a microorganism that causes a disease?
Bacterium
What are the symptoms of TB?
- Fever
- Weight loss
- Blood-specked mucus after coughing
Why are viruses not true organisms?
Because they do not have a cellular structure
How do viruses multiply?
By infecting a cell and taking over the cell’s DNA-copying processes to make new viruses
What does the HIV (human immunodeficiency virus) do?
Attacks and destroys white blood cells in the immune system
What do people with HIV often develop and why?
AIDS (acquired immune deficiency syndrome) because their immune systems cannot protect them from secondary infections
What is good hygiene?
Keeping things clean to remove/kill pathogens
What is the oral route?
When pathogens enter the body through the mouth
What are vectors?
Organisms that carry pathogens from one person to the next
What do all viruses contain?
One or more strands of genetic material surrounded by a capsid (protein coat)
What is a lysis?
Types of virus that can cause the complete breakdown of a cell
What is the lysogenic pathway?
- Virus infect a cell and consequently behave differently
- Their genetic material inserts into the cell’s genetic material
- Every time the cell divides, the virus’ genetic material is replicated with the cell’s
Describe the lytic cycle
- Virus attaches to cell and injects genetic material
- Viral genetic material forms a circle
- New viral genetic material and proteins are produced and assembled
- Cell lyses, releasing viruses
Describe the lysogenic cycle
- Viral genetic material inserts itself into the bacterial chromosome
- Bacterium reproduces normally, replicating viral genetic material at each cell division
- Occasionally, viral genetic material separates from the bacterial chromosome causing a lytic cycle
What can you use to study the effect of viruses on bacteria?
Bacterial lawn plates
How can you use bacterial lawn plates to study the effect of viruses on bacteria?
- Nutrient agar plates, a thin layer of bacteria grows on top; a solution containing viruses is added to the plate
- After a few days, clear circles can be seen where bacteria have been killed by the viruses (then calculate cross-sectional area of a clear circle)
- The larger the clear area, the more effective the viruses have been at replicating and killing the bacteria
How do you calculate the cross-sectional area of a clear circle?
CROSS-SECTIONAL AREA = Pi X r^2
What is the cuticle?
A waxy layer that covers the outer surfaces of leaves and stems, acting as a physical barrier to reduce pathogens getting to the cells beneath in plants
How do some pathogens penetrate the tough cell walls of plants if they get through the physical barriers of plants?
They release enzymes that soften cell walls or infect parts of plants with weaker cell walls (young shoots or parts that aren’t growing well)
Give an example of a chemical barrier plants use to deter herbivores/pathogens when they are attacked
Wild potato release substance in air when attacked by aphids (similar to alarm substance aphids release when attacked by predator), causing other aphids to fly away
Give an example of a medicine developed from substances that plants use to protect themselves
Aspirin (controls symptoms of pain/fever), produced from salicylic acid from meadowsweet and willow trees
What are aseptic techniques?
Practices that stop tests being contaminated by microorganisms from the air and on equipment (sterilises)
Why is it important for farmers to identify the cause of stress to a plant?
So can treat the crop correctly and prevent loss of yield
Give examples of visible signs of stress on a plant
- Changes in growth
- Changes in colour/blotching of leaves
- Lesions (areas of damage) on stems or leaves
What is distribution analysis?
Looks at where the damaged plants occur
How can lab tests give a diagnosis of a crop disease?
- Try to grow a pathogen from damaged crop plants
- Use technology to identify the presence of genetic material from a pathogen
Name a physical barrier for humans against pathogens
The skin - can only cross through wounds or an animal vector that pierces the skin
Name a chemical barrier for humans against pathogens
Lysozyme - enzyme that breaks down the cell walls of some bacteria (makes pathogens inactive/kills them)
Where is lysozyme secreted?
In tears, saliva and mucus
What are ciliated cells specialised to do?
To move substances such as mucus across their surfaces
How can the transmission of pathogens such as the HIV virus and chlamydia bacterium be reduced?
By using a condom (artificial barrier) during intercourse
What does screening do?
Help to identify an infection so that people can be treated for the disease
What are antigens?
Molecules on the outer surfaces of all cells and virus particles that identify if something inside the body is a cell of the body or has come from outside
Describe how the immune system attacks a pathogen
- Pathogens have antigens on their surface that are unique to them
- A lymphocyte with an antibody that perfectly fits the antigen and lymphocyte is activated
- This lymphocyte divides over and over again to produce clones of identical lymphocytes
- Some of the lymphocytes secrete large amounts of antibodies, which stick to the antigens and destroy the pathogen
- Other lymphocytes remain in the blood as memory lymphocytes, ready to respond immediately if the same antigen ever turns up again
How can immunisation be triggered?
Artificially by a vaccine, which contains weakened/inactive pathogens
What is herd immunity?
When majority of a group are immunised, so the chance of coming into contact with an infected person will be very low
What are antibiotics?
Substances that either kill bacteria or inhibit their cell processes, which stops them growing and reproducing
Why is it important that many different antibiotics are developed?
Different bacteria have different structures that do not all respond in the same way to a particular antibiotic
What is a problem with antibiotics?
Many bacteria are evolving resistance
What is the first step in the development of possible new medicine?
Pre-clinical stage - when it is tested on cells/tissues in the lab
What are side effects?
Causing unintended changes that may be harmful
What happens after the pre-clinical stage in testing?
Test on animals without risk to humans
What happens after animal testing?
Clinical trial - tests on a small number of healthy people to check medicine is safe and harmful side effects are limited
What happens after a clinical trial?
Large clinical trial - many who have the disease are given the medicine to treat to help work out the correct dose
What are monoclones antibodies?
Identical antibodies
How do pregnancy test sticks work?
They detect a hormone in the urine that is only produced during pregnancy
Why can’t normal lymphocytes make monoclonal antibodies in large amounts?
Although a lymphocyte can divide over and over again to make many clones, once it has started to produce antibodies, it cannot divide any more
How do lymphocytes get around the problem of producing antibodies without a limit?
Hybridoma cells are made - fuse lymphocyte that produces right antibodies with cancer cell
Why are cancer cells used to produce a hybridoma cell?
Because cancer cells can divide over and over again
How are monoclonal antibodies made?
- Particular antigen (e.g. human hormone) injected into a mouse who produces lymphocytes that make antibodies against the human hormone
- Cancer cells growing in culture medium
- Lymphocyte from mouse and cancer cell is fused to produce hybridoma cell
What can monoclonal antibodies be made to do?
- Match and stick to any kind of protein (like hormones and enzymes)
- Match antigens on pathogens (so identify pathogen)
- Stick to specific cells in the body such as cancer cells or platelets
What are platelets?
Fragments of blood cells that help to form blood clots
Why are blood clots dangerous?
In the wrong places, if they form in the brain or heart, these clots can kill
How can monoclonal antibodies be used in medical diagnosis?
By making the antibodies slightly radioactive - when they attach to cancer cells, radioactivity can be detected using a PET scanner, so position of cancer can be found
Why is chemo/radiotherapy possibly dangerous?
Can expose healthy cells to the drugs/radiation and can damage them
Why is it good if cancer drugs are attached to monoclonal antibodies?
So that the drugs are delivered just to the cells that need treating, reducing the amount of drug needed to kill the cancer cells and the risk of damaging healthy cells
