SB5g-h, j-l, SB3a-ci Flashcards
What are the physical barriers for plants?
- Cuticle (thick waxy waterproof layer that covers surface of leaves)
- Thick layer of bark
What are 2 ways pathogens can overcome a plant’s physical barrier?
- Using enzymes to hydrolyse the walls of the plant to enter
- Finding other parts of the plant with weaker cell walls
What are the chemical barriers for plants?
- Poisons
- Insect repellents
How do plants use their chemical barriers?
They produce chemical substances that are toxic to pests so once the pest bites the plant they get poisoned.
What is another use for plants?
Used in production of medicine to treat diseases.
What is the medicine and source of medicine for malaria?
Artemisinin - found in Wormwood trees
What is the medicine and source of medicine for pain/fever?
Salicylic acid (aspirin) - found in Willow trees and Meadowsweet trees
How are medicines made free from contamination in labs?
Usage of aseptic techniques ensures the destruction of any pathogens that can contaminate the medicines.
How are medicines sterilised in labs?
Autoclave.
How do farmers check for diseased crops?
Drones.
How do plants get infected?
- Fungal disease spread by spores
- Pests and pathogens in the soil
What are some problems that plants could have?
- Lack of water/ too much water
- Lack of nutrients in the soil
- Pests
- Diseases
What are some symptoms of plant diseases?
- Changes in growth
- Changes in colour of leaves
- Blotching in leaves
- Lesions on stem and leaves
What are 2 ways of identifying problems in plants?
- Distribution analysis - checking the environment of crops (flooding, droughts, lack of nutrients, pests, pathogens)
- Diagnosis - soil and plant samples are sent to labs to test and determine cause of problem
How is plant diagnosis done?
- Pathogens are taken from the plant and grown in agars to check their DNA and identify them
- They check the soil for lack of nutrients and toxins
What are the 2 types of white blood cells involved in fighting off pathogens and treating infections?
- Macrophages/phagocytes
- Lymphocytes
What is the job of macrophages/phagocytes?
- Ingest any pathogen and try to destroy it by phagocytosis
- Release hydrolytic enzymes which digest the pathogen
What is the job of lymphocytes?
- Secrete antibodies to fight off the pathogens
- Destroy the pathogens
What are antigens and what do they do?
Antigens are proteins found on pathogens.
The immune system recognises the antigen and tries to destroy the pathogen. If a body cell gets infected by a pathogen it attaches the antigen on its surface to be seen by the immune system.
What are antibodies and what do they do?
Antibodies are proteins secreted by lymphocytes to destroy pathogens.
It binds on the antigen in order to destroy the pathogen. They are specific.
How does the body fight off pathogens?
- The pathogen invades the body
- The antigen on the pathogen is recognised by the immune system
- The white blood cells that recognise the antigen of the pathogen will send a signal to the specific lymphocyte that produces the specific antibodies for the specific antigen
- The antibody binds on the antigen and destroys the pathogen
- The specific lymphocyte will multiply by mitosis and produce memory cells
What are the 2 types of immune responses?
- Primary immune response
- Secondary immune response