Responses To Pathogens PDF

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Responses To Pathogens Inquiry Question: How does a plant or animal respond to infection? 

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Investigate the response of a named Australian Plant to a named pathogen through practical and/or secondary-sourced investigation, for example:  Fungal pathogens  Viral pathogens Analyze responses to the presence of pathogens by assessing the physical and chemical changes that occur in the host animal’s cells and tissues.

Plant Reponses to Pathogens 

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Plants are proficient in avoiding infectious disease and responding to pathogenic threats.  They have, in both natural and cultivated environments, inherent disease-resistant strategies. These defences may be:  Passive (Physical and Chemical barriers)  Active (Once the pathogen is recognized) If a plant is able to prevent a pathogen from invading its tissue, or from reproducing, the plant will be resistant to that pathogen.

Passive Defences Physical Barriers: Barrier Thick Cuticle

How It Defends Against Pathogen Invasion › ›

Cell Walls

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Small Stomata

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Able to withstand enzymes secreted by pathogens Provides protection as thick layer makes it difficult for pathogen entry into the plant Provides protection as thick layer makes it difficult for pathogen entry into the plant. Small size prevents larger pathogen entry into the organism.

Chemical Barriers: Active   

Defences: When the passive barriers are breached, plant is at risk of harm from pathogen. Active defences are more targeted responses from plants There are three major group of responses in Active Defences:  Recognition  Rapid Response  Delayed Response

Pathogen Recognition:  Plants are able to recognize pathogens by detecting certain physical and chemical signals, including fragments from the cell walls of bacteria and fungi.  Genes within the cells of the plant are thought to regulate plant responses.

Responses To Pathogens Rapid Active Response (minutes to hours):  Recognition of pathogen by proteins on the surface of cells in plants causes changes in the permeability of the plant cell membrane.  This allows movement of certain ions (calcium ions in particular) into the cell and triggers defence responses by activating the expression of certain genes. ...