Infection and Response

What are the four types of pathogens?

Bacteria (release toxins), Viruses (live inside cells), Protists (eukaryotes, often parasites), and Fungi (hyphae penetrate skin/surfaces).

How do bacteria and viruses cause cell damage differently?

Bacteria divide rapidly and release toxins that damage tissues

What are three ways pathogens can be spread?

By air (droplet infection like flu), direct contact (STIs or skin contact), or water/food (cholera or salmonella).

What are the symptoms and spread of Measles?

Symptoms: Red skin rash and fever. Spread: Inhalation of droplets from sneezes and coughs. (Can be fatal if complications arise).

What is HIV and how does it lead to AIDS?

HIV is a virus that attacks immune cells

What is Tobacco Mosaic Virus (TMV)?

A plant pathogen causing a 'mosaic' pattern of discoloration on leaves, which reduces chlorophyll and stunts growth due to lack of photosynthesis.

How is Rose Black Spot spread and treated?

Spread: Fungal spores carried by water or wind. Treated: Using fungicides and stripping/destroying affected leaves.

What is Malaria and how is it controlled?

Caused by a protist parasite spread by mosquito vectors. Controlled by preventing mosquito breeding and using nets/insecticide to avoid bites.

What are the human non-specific defense systems?

Skin (physical barrier/antimicrobial secretions), Nose (hairs and mucus), Trachea/Bronchi (mucus and cilia), and Stomach (hydrochloric acid).

What are the three roles of White Blood Cells?

Phagocytosis (engulfing/digesting pathogens), Antibody production (targeting specific antigens), and Antitoxin production (neutralizing bacterial toxins).

How do vaccinations work?

They involve introducing small quantities of dead or inactive pathogens into the body to stimulate white blood cells to produce antibodies and develop immunity (memory cells).

What is 'Herd Immunity'?

When a large enough percentage of the population is immune to a disease, the spread of the pathogen is significantly reduced, protecting those who aren't immune.

What are Antibiotics vs Painkillers?

Antibiotics (like penicillin) kill infective bacteria inside the body

Why can't antibiotics kill viruses?

Because viruses live and replicate inside human cells, making it difficult to kill them without damaging the body's own tissues.

What is antibiotic resistance and how does it happen?

Bacteria mutate

Where did the drugs Digitalis, Aspirin, and Penicillin originate?

Digitalis (heart drug) comes from foxgloves

What are the three things tested for in new drug trials?

Toxicity (is it safe?), Efficacy (does it work?), and Dose (how much is needed?).

What is the process of a clinical trial?

1. Preclinical (on cells, tissues, animals). 2. Clinical Phase 1 (low dose on healthy volunteers). 3. Clinical Phase 2/3 (on patients to find optimum dose).

What is a 'Double-Blind Trial'?

A trial where neither the patients nor the doctors know who is getting the real drug and who is getting the placebo, to avoid bias.

What are Monoclonal Antibodies?

Antibodies produced from a single clone of cells, making them specific to one binding site on one protein antigen.

How are monoclonal antibodies produced?

Mouse lymphocytes are stimulated to make a specific antibody, then fused with a tumour cell to create a hybridoma, which divides rapidly to produce clones.

What are three uses of Monoclonal Antibodies?

Pregnancy tests, measuring hormone levels in blood, and treating cancer by attaching toxic drugs to the antibody to target specific cells.

What are the signs of plant disease?

Stunted growth, spots on leaves, areas of decay (rot), growths, malformed stems/leaves, discoloration, and the presence of pests.

How do Ion Deficiencies affect plants?

Nitrate deficiency causes stunted growth (needed for protein synthesis)

What are plant Physical, Chemical, and Mechanical defenses?

Physical: Cellulose cell walls, waxy cuticle, bark. Chemical: Antibacterial chemicals, poisons. Mechanical: Thorns, hairs, leaves that droop/curl, mimicry.