Cognitions
What does Identify mean? (1mark)
Recognise and name something or someone specific.
Usually 2 word response
Define thermoregulation. (1mark)
Thermoregulation is the process by which an organism maintains a stable internal body temperature.
What is a virulence factor?(1mark)
A feature or product of a pathogen that helps it establish an infection or cause damage to its host.
What are the specialised signalling cells of the nervous system, and what chemical messengers are released by endocrine glands? (1 marks)
Nervous system: neurons. Endocrine glands: hormones.
What is the main difference between infectious and non-infectious diseases? (2 marks)
Infectious diseases are caused by pathogens. Non-infectious diseases are not caused by pathogens; causes may include inherited conditions, nutritional deficiencies and environmental or lifestyle factors.
What does Describe mean ?(1mark)
Provide an account of a characteristic, feature or event.
Describe one way the body responds to cold temperature. (1mark)
The body responds by shivering, which generates heat through muscle activity.
How do adherence factors help bacteria cause an infection? (1mark)
They allow bacteria to attach to host cells or tissues, helping them resist removal and establish a population.
Contrast between a sensory neuron and a motor neuron (2 marks)
A sensory neuron carries information from receptors towards the central nervous system. A motor neuron carries information from the central nervous system to an effector, such as a muscle or gland.
Classify influenza, measles, type 2 diabetes and scurvy as infectious or non-infectious.(1mark)
Infectious: influenza and measles. Non-infectious: type 2 diabetes and scurvy.
What does Explain mean? (1mark)
To make something clear by revealing a cause, reason, context or relationship.
Has a because statement involved
Contrast between vasodilation and vasoconstriction in terms of thermoregulation. (2mark)
Vasodilation is the widening of blood vessels to release heat, while vasoconstriction is the narrowing of blood vessels to retain heat.
Explain the roles bacterial toxin in causing disease. (1mark)
A toxin damages host cells or disrupts their normal functions, contributing to disease symptoms.
Compare nervous and endocrine communication in terms of signal transmission. (2 marks)
Nervous: electrical impulses travel along neurons. Endocrine: hormones travel through the circulation to target cells.
Define Vector and provide an example (1 mark)
An organism (such as a mosquito, tick, or fly) that transmits a pathogen or parasite from one host to another.
What does Compare mean? (1mark)
To examine similarities and differences between two or more things.
A person enters a cold room and their core temperature begins to fall. Explain how negative feedback helps restore their temperature. (3mark)
Thermoreceptors detect the decrease, and the hypothalamus coordinates a response. Shivering generates heat through muscle contractions, while vasoconstriction reduces blood flow to the skin, conserving heat. As temperature returns towards its normal range, these responses decrease.
A bacterium produces an enzyme that breaks down material between host cells. Identify the type of virulence factor and explain how it contributes to disease. (2mark)
It is an invasion factor. Breaking down material between cells allows the bacterium to penetrate tissues and spread, increasing the extent of infection and damage
Compare nervous and endocrine communication in terms of signal speed and duration. (4 marks)
Nervous: Responses are generally rapid and brief. Endocrine: Responses generally develop more slowly and last longer.
Several students develop vomiting after a camp. One student concludes that it must be an infectious disease because many people have the same symptoms. Explain why this conclusion is insufficient and identify two types of evidence that would help. (2 marks)
Shared symptoms could result from an infection or a shared non-infectious exposure, such as a chemical contaminant. Useful evidence includes testing for a pathogen in affected students and comparing food, water and contact histories of sick and unaffected students.
What does Contrast mean? (1mark)
To examine differences between two or more things.
Two runners exercise at the same intensity and air temperature. One runs in dry conditions and the other in very humid conditions. Predict which runner is more likely to experience a greater rise in body temperature and explain why, even if both sweat heavily. (1mark)
The runner in humid conditions is likely to experience a greater rise. High humidity reduces sweat evaporation, so less heat is removed from the skin. Sweat that drips off provides little evaporative cooling. Heat may therefore accumulate despite heavy sweating.
Two bacterial strains are identical except that strain A has a capsule and strain B does not. After equal numbers are exposed to phagocytes, 80% of strain A survives compared with 20% of strain B. Explain the results and predict what would happen if strain A lost its capsule.(1 mark)
The results support the conclusion that the capsule protects strain A against phagocytosis. Without its capsule, strain A would likely be engulfed and destroyed more readily, reducing its survival towards that of strain B under the same conditions. This would likely reduce its ability to establish infection.
Explain how a signal passes across a chemical synapse from one neuron to another. (3 marks)
An action potential reaches the presynaptic axon terminal, triggering vesicles to release neurotransmitter. It diffuses across the synaptic cleft and binds to specific receptors on the postsynaptic membrane. This changes ion movement and may trigger a new action potential if the threshold is reached.
In a hypothetical outbreak, 18 of 20 people who drank untreated water became ill, compared with 2 of 20 who did not. The same pathogenic bacterium was detected in the water and affected people. Calculate the illness percentages, infer the likely transmission route and justify one control measure.(2 marks)
Water drinkers: 18 ÷ 20 × 100 = 90%. Non-drinkers: 2 ÷ 20 × 100 = 10%. The higher illness percentage among water drinkers, together with the matching bacterium, supports waterborne transmission. Providing a safe, treated water supply would interrupt exposure to the pathogen and help prevent further cases.