B2 complete Flashcards
(42 cards)
Name causes of disease. (3)
- Organism may be infected by pathogen.
- Organism’s lifestyle may affect their health.
- A mutation in the organism’s genes.
What is a communicable disease.
eg:
A communicable disease is a disease which can be spread between organisms (bacteria).
What is a non-communicable disease.
eg:
A disease which cannot be passed from one organism to another (cancers).
Name the four pathogens that can cause communicable diseases and a bit about them.
- Bacteria > very small cells reproducing rapidly
- Viruses > Not cells but replicate inside themselves inside the infected organism’s cell
- Protists > Eukaryotic cell usually single celled
- Fungi > Single celled thread like structures called hyphae.
Name the different ways in which communicable disease are transmitted. (5)
- Diseases from dirty water. eg: cholera
- Air, droplets produced when you sneeze or cough can cause the flu.
- On surfaces from touching pathogenic surfaces. eg: athlete’s foot
- Body fluids such as blood being shared could be one transmission. eg: HIV.
- Food that is contaminated with disease. eg: salmonella
Name the three ways humans defend against pathogens.
Physical
Chemical
Microbial
An example of a physical defence?
Skin acts as a barrier to pathogens. If skins gets cut platelets come in to clot the wound to stop potential pathogen entering blood stream.
An example of a chemical defence?
Saliva contains molecules which kill pathogens that enter the mouth, so they do not react in the stomach.
An example of a microbial defence?
If the pathogen does get past the saliva in the mouth they have to compete with immune cells and antibodies in the stomach.
What physical defences do plants have to defend against pathogens? (2)
A waxy cuticle (leaf’s surface) which acts as a waterproof barrier.
Plants surround themselves with cell wall made from cellulose which acts as a physical barrier is the pathogen makes it past the waxy cuticle.
What do plants not have that humans do.
Plants do not have a specialised immune system or antibodies like animals.
What is the most important function of the immune system?
Destroying pathogens.
What is the most important part of your immune system?
Your white blood cells.
What are the three stages of attacking a pathogen?
- Consuming them
- Producing antibodies
- Producing antitoxins
consuming them. What do white blood cells do, and name some features of one that allow them to do this.
Flexible membranes and lots of enzymes enables them to engulf foreign cells and digest them.
producing antibodies. What do the white blood cells do?
White blood cells come across a foreign antigen on a pathogen, and receptors in membrane bind to the antigen. WBC produce proteins called antibodies which are specific and lock on to the antigens invading cell.
producing antitoxins. What do the white blood cells do.
Some white blood cells produce antitoxins which counteract the toxins produced in the pathogen and limit any damage done by invading pathogens.
Name some ways in which disease can be reduced or prevented in ANIMALS. (3)
- Being hygienic
- Living in clean, safe conditions
- Sterilising wounds
- Vaccinations
Name some ways in which disease can be reduced or prevented in PLANTS. (2)
- Crop rotation = pathogens are specific to a particular plant and changing the type of plants grown stops the pathogens becoming established in an area
- Destroying infected plants
- Regulating movement of plant material = infected plants will not come into contact with healthy plants.
Why are you vaccinated?
If you’re infected with a new pathogen it make take your WBC a while to produce antibodies. In this time you may become very ill.
What are big outbreaks of disease called?
Epidemics
Name a pro and a con for a vaccination.
Pros:
Helps to control lots of communicable diseases.
Cons:
Does not always work
Expensive to carry out vaccination programmes
Name a laboratory technique that can be used to identify a disease.
- Counting the number of cells in a sample
eg: some diseases may change the number of red blood cells in a given volume of blood. Also white blood cells outside the normal range could indicate body is fighting infection.
How do you grow bacteria?
- Hot agar jelly pour into petri dish.
- Then set an inoculating loop to transfer microorganisms.
- Then the microorganisms begin to multiply
