A measure of how much change occurs per unit of time.

An exothermic chemical process that transfers energy for life processes, using glucose as fuel.

Apparatus used to measure the rate of respiration in small organisms.

When bonds in an enzyme molecule break and the molecule changes shape.

Explaining the effect of temperature on the rate of cellular respiration

Combined science

Pupils will learn how substances essential for chemical reactions, and the products of the reactions, are transported into, around and out of plants, and about factors affecting the rate of water uptake by a plant.

Pupils learned about photosynthesis in producers, including a two-stage model of the process and the requirements and products of each stage.

Aerobic and anaerobic cellular respiration

Physical activity and equipment requiring safe use

The respirometer shown is used to measure the rate of respiration. What units would the rate of respiration be measured in?

As the temperature increases, the rate of cellular respiration decreases.

As the temperature increases, the rate of cellular respiration increases.

As the temperature increases, the rate of cellular respiration stays the same.

The following table shows results from a respirometer experiment. What conclusion can be drawn from these results?

The rate triples for every 10 °C rise in temperature.

The rate doubles for every 10 °C rise in temperature.

The rate increases by 0.5 mm/min every 10 °C.

The following table shows results from a respirometer experiment. Which statement about the data is true?

Enzymes work as catalysts because the substrate precisely fits into part of the enzyme molecule called the active site. Scientists use the {{}} and key model to describe this precise fit.

Molecules have more effective collisions.

Substrate molecules and enzyme molecules have more energy.

Substrate molecules and enzyme active sites collide more often.

Which of these is the **best** explanation of why the rate of cellular respiration increases with temperature?

At 55 °C, the temperature is so high that it breaks bonds in the enzyme molecule, changing its 3D shape. The enzyme is {{}} and no longer works.

aerobic cellular respiration in animal cells

anaerobic cellular respiration in animal cells

anaerobic cellular respiration in yeast cells

aerobic cellular respiration in yeast cells

What kind of cellular respiration is used to produce alcoholic drinks?

There must be lots of oxygen dissolved in milk.

There must be some oxygen dissolved in milk.

There must be very little oxygen dissolved in milk.

Bacteria that produce lactic acid when they respire are used in the production of yogurt from milk. What can you conclude about the amount of oxygen dissolved in milk?

The simple respirometer shown in the diagram is used to investigate the effect of temperature on the rate of cellular respiration. Match each variable to its correct example.

Oxygen is used and the carbon dioxide produced is absorbed by the soda lime.

Carbon dioxide is used and the oxygen produced is absorbed by the soda lime.

Soda lime absorbs oxygen before it can be used in respiration.

Soda lime absorbs carbon dioxide before it can be used in respiration.

When using this type of respirometer, the water moves up the capillary tube because the pressure inside the test tube falls. Why does the pressure in the tube fall?

Neither of the two dependent variables will affect the rate of respiration.

The two dependent variables will both affect the rate of respiration.

Neither of the two independent variables will affect the rate of respiration.

The two independent variables will both affect the rate of respiration.

A student plans to use a respirometer to investigate the effect of temperature and amount of glucose on the rate of respiration. The investigation will not produce valid results. Why?

A student used the respirometer shown. After 5 minutes at 25 °C, the coloured water moved 8 mm towards tube A and 2 mm towards tube B. How many mm has the water moved because of cellular respiration?

Content guidance

Risk assessment required - equipment

Adult supervision required

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