Biology 2: Keeping Healthy Flashcards
Pathogens
Harmful organism which invades the body and causes disease
What are microorganisms that cause disease is called
Microorganisms that cause disease and make us feel ill are called pathogens. Pathogens include bacteria and viruses
Give the symptoms and example of diseases caused by bacteria
- symptoms: release of poisons all toxins by the bacteria
* example: bacterial meningitis, tetanus, salmonella, food poisoning, tuberculosis (TB)
Symptoms and examples of diseases caused by viruses
- symptoms: damage to the cells as the viruses reproduce
* examples: influenza (three), the common cold, measles and chickenpox
Toxins
Poison or hazardous substances
Binary fission
Simple cell division
How do bacteria reproduce
- bacteria reproduce by dividing into, which is a type of a sexual reproduction called binary fission
- bacteria reproduce rapidly (this is called exponential growth) in the ideal conditions of the human body
How viruses reproduce
- viruses neither ‘host’ cell to reproduce. They enter the host cell and ‘hijack’ The cells mechanisms for making DNA and proteins, and make copies of themselves
- The copies of the virus are released in very large numbers from the infected cells and go on to infect other cells and other people
Explain Growth of bacteria in culture Graph
- During the initial ‘ Lag phase’ there is no reproduction. The bacteria are copying DNA and proteins within their single cells
- The exponential growth phase is followed by the ‘ stationary phase’ where resources begin to become scarce and bacteria are dying at the same rate as being produced
3 The final ‘’ comes about because bacteria begin to be poisoned by their own toxins
An increase then stays stationary then decreases over time
Name the bodies external defences
Skin, saliva and tears, and acid in the stomach
Name the bodies internal defence
Immune system
Immune system
A body system which acts as a defence against pathogens, such as viruses and bacteria
Properties of white blood cells
White blood cells:
• are made in the bone marrow
• are found as several types: some in golf and I just invading microorganisms while others produce antibodies, which recognise and destroy invading microorganisms
How does the immune system defend the body
White blood cells
White blood cells
Blood so that defend the body against disease
Antigen
Harmful substance that stimulates the production of antibodies in the body
How do white blood cells antibodies and antigens relate
Different white blood cells carry different types of antibody on their surface. An antibody is specific to one antigen
Describe this series of events when invading cells are detected
- The antibody corresponding to an antigen locks onto it
- The white blood cell divides to produce many copies
- Each white blood cell produces many antibody molecules that lock on to invading cells
Describe the different types of antibody
- destroy the invading microorganism
- enable white blood cells to recognise the organism as being foreign
- cause the micro organism to client together, meaning it is easier to engulf white blood cells
Memory cells
White blood cells that form antibodies in response to a particular antigen and retain the ability to make the that antibody should re-exposure to the antigen occur later in life
What Happens after the infection clears up
- After the infection clears up, memory cells remain in the blood stream.
- These can produce large numbers of antibodies very quickly if the micro organism we enters the body again.
- At this point the person said to be immune to that particular pathogen
Immune
When a person has resistant to a particular disease
Vaccine
Weekend microorganism that are given to a person to produce immunity to a particular disease
Vaccination
Medical procedure, usually an injection, that provides immunity to a particular disease
Why do vaccinations undergo
- vaccination programs protect children against diseases that are preventable
- babies and children undergo a course of vaccinations in their first year or so
- some pathogens do not change over time, so the same vaccine can be used against these, year after year
- other pathogens, such as influenza (flu virus), change rapidly, so new vaccines must be developed
Describes what is called as herd immunity
- and epidemic occurs if the disease spreads rapidly through population, for example in the city or country
- to avoid an epidermic, it is necessary to vaccinate a high percentage of the population – this leads to what is called ‘ herd immunity’
- widespread vaccination has eradicated one disease – smallpox – from the world. It is also reduced childhood diseases such as measles, mumps and rubella
- The longer term aim is to eradicate certain diseases all together
Side-effects
Unwanted affects produced by medicine
How do scientists make vaccine safe
- scientists test new vaccines very carefully as there are developed to check for any side-effects
- Side effects can be more severe than some people than in others, because of genetic variation
- no type of medical treatment can ever be completely risk-free (but people often think that the risk is high that it is)
Why do vaccinations need to be checked
- vaccinations are extremely safe, and millions of people have benefited from them
- occasionally, a child may develop a minor adverse reaction (such as a rash or fever). In very rare cases, this reaction can be more serious. Any adverse reactions are recorded and followed up.
- any risks of vaccination must be considered against the benefits. Any vaccine generating an unusual number of adverse reaction will be quickly withdrawn
Antimicrobials
Substance that act to kill bacteria
Antibiotic
Therapeutic drug acting to kill bacteria taken into the body
What are Antimicrobials effective against
Are used to inhibit (low) microorganisms grace. They are effective against bacteria, viruses and fundi
What are antibiotics effective Against
Are effective against bacteria but not against viruses. They allow doctors to treat illnesses caused by bacteria, such as tuberculosis
Resistance
Ability of an organism to resist death/disease/harm, for example resistance may develop in some microorganisms against Antimicrobials
How are microorganisms becoming resistance
• Studies show that some microorganisms are developing resistance to these antimicrobials because of their very wide use
- resistance to antimicrobials means that some strains of bacteria infections are now difficult to control
- antimicrobial-resistant microbes can be a particular problem where Antimicrobials are use frequently, such as hospitals
Give examples of antimicrobials
- antibiotics against bacteria are; antivirals against viruses; antifungals against fungi
- many cleaning products, along with antiseptics and disinfectants
How do I population of microorganisms react to the resistance of antimicrobials
- in a population of microorganisms, some may be resistant to their antimicrobial.
- these will survive the use of antimicrobial and pass on their resistance
- The resistance spreads through the population of microorganisms
Superbugs
Harmful microorganisms that have become resistant to antimicrobials
Because of the overuse of certain antibiotics what 2 things should antibiotics be
- prescribed only four more serious infections, when they are really needed
- completed, so that bacteria causing the infection or killed completely
Mutations
A change in the DNA in a cell
How has antibiotic resistance becomes a huge problem in many hospitals
- Random changes in jeans – call me patience – give some bacteria resistance to antimicrobials
- because of the rapid reproduction mate of bacteria, antimicrobial resistance genes spread through the population
- antibiotic resistance has led to some strains of bacteria that are very difficult to read it out. These include MRSA, which is a problem in many hospitals