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Plants and animals are both susceptible to infection - VCE - SSCE Biology - Question 7 - 2006 - Paper 1
Question 7
Plants and animals are both susceptible to infection. a. i. Name one feature of plants that inhibits the entry of infective organisms. ii. Name one feature of h... show full transcript
Worked Solution & Example Answer:Plants and animals are both susceptible to infection - VCE - SSCE Biology - Question 7 - 2006 - Paper 1
Step 1
a. i. Name one feature of plants that inhibits the entry of infective organisms.
Answer
One feature of plants that inhibits the entry of infective organisms is the presence of a thick cuticle on the leaves and stems. This waxy layer acts as a physical barrier, preventing pathogens from penetrating the plant tissues.
Step 2
a. ii. Name one feature of humans that inhibits the entry of infective organisms.
Answer
One feature of humans that inhibits the entry of infective organisms is the skin, which serves as a protective barrier. It has multiple layers that help to keep pathogens out, along with producing antimicrobial substances.
Step 3
b. Outline one way in which a plant responds to minimise damage to its tissues.
Answer
One way a plant responds to minimize damage is by producing phytoalexins, which are antimicrobial compounds that inhibit the growth of pathogens at the site of infection, helping to isolate the infected area.
Step 4
c. Outline two general features of inflammation that minimise the impact of the infection.
Answer
Feature 1: Increased blood flow to the affected area enhances the delivery of immune cells, nutrients, and oxygen, facilitating a more effective immune response.
Feature 2: Swelling and pain restrict movement and encourage rest, which helps prevent further injury and allows the body to focus on healing.
Step 5
d. Explain how cells of the immune system determine self from non-self molecules.
Answer
Cells of the immune system determine self from non-self molecules through the recognition of specific markers known as antigens. Self-cells possess unique markers (such as MHC molecules) that signal they belong to the host, while non-self molecules, such as those found on invading pathogens, have different antigens that trigger an immune response.
Step 6
Step 7
f. Explain the relationship between an allergen, mast cells and histamines.
Answer
An allergen is a substance that triggers an allergic reaction. When exposed to an allergen, the immune system mistakenly identifies it as harmful, leading to the activation of mast cells. These cells release histamines, which cause symptoms such as inflammation, itching, and increased mucus production as part of the allergic response.