Physiology: Biology Combined Science 8464 : Past Paper Questions AQA GCSE

Why does a conscious action take longer than a reflex action?

Because higher brain processes and more processing stages are involved, conscious actions take longer than reflex actions. Compared to the quick, involuntary nature of reflex actions, conscious actions involve more complexity and need a longer reaction time since the cerebral cortex is involved in information processing, decision-making, and initiating motor orders.

Why are reflex reactions important?

Because they enable quick, instinctive responses to potentially dangerous stimuli, reflex reactions are crucial for defending the body from harm or injury.

Define the term homeostasis.

Homeostasis is fundamental to the survival of living things because it maintains vital physiological parameters like the body's temperature, pH levels, and nutrient concentrations roughly constant.

A student set up a model to represent the digestion and absorption of food molecules in the digestive system. This is the method used. -Fill a test tube with water at 37°C -Test the water for starch and for sugar. -Mix together starch and enzyme solution and immediately test it for starch and for sugar. -Fill some partially permeable tubing with the starch and enzyme mixture. -Seal the tubing and place it in the test tube of water. -Place the test tube in a water bath at 37°C -After 30 minutes, test the mixture inside the partially permeable tubing and test the water in the test tube for starch and for sugar. Suggest which parts of the body the partially permeable tubing and the water in the test tube represent.

In the set-up of the model for digestion and absorption, the partially permeable tubing represents the small intestine, while the water in the test tube represents blood.

Which two processes are regulated by homeostasis? A) Controlling water output in urine B) Defending the body against pathogens C) How quickly you walk D) Keeping cool on a hot day E) Waking up in the morning

Sweating on a hot day is one regulation brought about by homeostasis to keep cool and regulate body temperature in a hot environment. Controlling water output in urine also helps maintain the fluid balance in the body.

Before eating a sugar-coated cereal a person had a blood glucose concentration of 5.2 mmol/dm3. Soon after eating the cereal the person had a blood glucose concentration of 8.4 mmol/dm3. Calculate the increase in the blood glucose concentration.

The increase in the blood glucose concentration can be calculated by this formula: increase in concentration ​= blood glucose after eating − blood glucose before eating = 8.4 mmol/dm3 − 5.2 mmol/dm3 = 3.2 mmol/dm3​ The increase in the blood glucose concentration in the person eating the cereal is 3.2 mmol/dm3.

The heart is often described as a double-pump. Describe why.

The pulmonary and systemic circulations are the two distinct but linked pumping circuits that make up the heart, frequently referred to as a double pump. Because of the heart's dual pumping activity, blood is circulated efficiently throughout the body, with each side of the organ performing a different but crucial function in preserving appropriate blood flow and oxygenation.

A scientist investigated the effect of exercise on the breathing rate of four people. The scientist concluded that person B was the fittest. Give two reasons that support the scientist’s conclusion.

Two reasons that support the conclusion that person B is the fittest would be that person B had the lowest resting breathing rate and the lowest increase in breathing rate among the four individuals. Fit individuals are characterised to have lower body fat and higher muscle mass, which contributes to more efficient and lower metabolic rates.

Information travels at 120 metres per second in neurons. Calculate the time it would take for the information to travel 1.6 m along a neuron.

We may use the following formula to get the amount of time information would need to travel 1.6 metres along a neuron: Time = Distance ÷ Speed Considering that the distance is 1.6 metres and the speed is 120 metres per second, Time = 1.6 ÷ 120​ Time=0 .01333 s Since 1 second is equivalent to 1000 milliseconds, we can convert this to milliseconds: Time = 0.013333 x 1000 Time=13.33 ms Consequently, information would travel 1.6 metres along a neurone in 13.33 milliseconds.