B5(Communicable Diseases) Flashcards
What are the type of plant defences
-Physical
-Chemical
-Mechanical
What are the physical defences in plants
-cellulose cell walls—> to strength plant cells and to help resist microorganism invaders
-Tough waxy cuticle—>barrier to pathogens
-Bark on trees—>layer of dead cells—>protective layer
-Leaf fall—> trees lose their leaves in autumn—> infected leaves fall off
What are the Chemical defences in plants
-Antibacterial chemicals
-poisons to deter herbivores
What are the mechanical defences in plants
-thorns
-hairy stems
-leaves that or droop or curl when touched
-mimicry to trick animals
What are the 2 mineral deficiencies in plants
Magnesium and nitrate
What does the magnesium deficiency affect in plants
The production of chlorophyll which limits photosynthesis
What does the nitrate deficiency affect in plants
The production of amino acids for protein synthesis which limits growth in the plant
What are the common plant diseases
-TMV(tobacco mosaic virus)
-Rose black spot(fungal disease)
-Aphids as pests
-Mineral deficiencies
What is a pathogen
Disease causing microorganism
What is an antigen
Substance that causes an immune response
What is a antibody
Protein produced by white blood cells that attaches to the antigens on pathogens and destroys the pathogens
What do viruses do in the body
Disrupt chemical processes like cell wall production
What does bacteria do in the body
Produce toxins that make you feel ill
How can pathogens spread
Direct contact, air, water
What are the human defence responses
-Skin
-Respiratory and digestive system
How does skin protect us from pathogens
Produces antimicrobial secretions to destroy pathogens
How does the respiratory and digestive system protect us from pathogens
-Nose hairs, trachea and bronchi produce mucus which traps particles in the air that may contain pathogens
-Stomach produces hydrochloric acid which destroys the microorganisms in the mucus and foods you swallow
What are phagocytes
A type of white blood cell which ingests pathogens
What are Lymphocytes
-Another type of white blood cell which recognises antigens on pathogens and produces antibodies and antitoxins
-The antibodies produced cause pathogens to stick together to make it easier for the phagocytes to engulf them
How does the immune system protect us from pathogens
-Lymphocytes recognise antigens on the pathogens and detect that these are foreign and produce antibodies,the antibodies cause pathogens to stick together and make it easier for phagocytes to engulf them
-Lymphocytes can also produce antitoxins to neutralise the toxins produced from pathogens
-Memory B cells are created and produce a quick response if the antigen is encountered again
