Response to exercise Flashcards – AQA GCSE Combined Science: Trilogy (8464) — Biology — Higher

What happens to glucose when exercising muscles have insufficient oxygen?

It is incompletely oxidised during anaerobic respiration, and lactic acid accumulates.

What is an oxygen debt after exercise?

The extra oxygen needed to support removal and processing of accumulated lactic acid and a return towards resting conditions.

What can happen to breathing and heart rates during recovery from exercise?

They can remain elevated.

How do elevated breathing and heart rates help during recovery from exercise?

They help supply the additional oxygen needed.

Why do muscles need more oxygen during exercise?

They need more energy for contraction, increasing their demand for oxygen for aerobic respiration.

How does heart rate change during exercise, and what does this help deliver to muscles?

Heart rate increases, helping deliver more oxygenated blood to the muscles.

How do breathing rate and breath volume change during exercise?

Both increase: more breaths are taken each minute, and more air is moved in each breath.

What is the combined effect of increased heart rate and breathing during exercise on oxygen supply?

They increase oxygen uptake and delivery to active muscles.

What is muscle fatigue?

A temporary reduction in the ability to sustain effective muscle contractions.

Under what conditions can muscles become fatigued?

During long periods of vigorous activity.

What can happen to fatigued muscles with rest?

Their ability to contract can recover.

What is anaerobic respiration?

Chemical reactions in cells that break down nutrient molecules and release energy without using oxygen.

How does the energy released per glucose molecule compare between anaerobic and aerobic respiration?

Anaerobic respiration releases much less energy per glucose molecule than aerobic respiration.

What two products are formed when yeast breaks down glucose by anaerobic respiration?

Alcohol and carbon dioxide.

What product is formed when muscles break down glucose by anaerobic respiration during vigorous exercise?

Lactic acid.

Which process produces lactic acid in exercising muscles?

Anaerobic respiration.

How does lactic acid from exercising muscles reach the liver?

It is carried in the blood.

What does the liver convert lactic acid into?

Glucose.

What role does extra oxygen play during recovery from exercise?

It supports the removal and processing of accumulated lactic acid.