Cell Respiration (SL IB Biology)

ATP is a chemical substance generated in cellular respiration; it is an immediate source of energy for the cell.  ATP can easily be hydrolysed or re-synthesised. 

State two products created when ATP is hydrolysed by water.

Cells hydrolyse ATP to provide energy for other reactions, or to add phosphate to other substances to make them more reactive. However, ATP needs to be re-synthesised to provide energy for future reactions.

Describe how ATP may be re-synthesised.

Give two ways in which the properties of ATP make it a suitable source of energy for biological processes. 

Each day, the human body synthesises more than its weight in ATP during aerobic respiration.

Explain why it is necessary to synthesise such large amounts of ATP.

The following apparatus was set up to measure the rate of aerobic respiration by a student. 

Suggest what solution X might be and its function within the experiment.

Describe what ethical concerns the student should consider during this experiment.

The student found the water droplet had moved by 2 cm in 24 hours. The diameter of the lumen of the tube is 1 mm.

The volume of the tubing is given by the equation πr²l ;
Use the value of 3.14 to represent π and note that l refers to the length.

Use the equation to calculate the volume of gas produced in cm³ hour⁻¹, give your answer in standard form.

The diagram below shows the respirometer apparatus used by a teacher for measuring the rate of oxygen consumption of seeds during aerobic respiration.

For the first 12 minutes, the tap attached to tube 1 was left open and the syringe from tube 2 was taken away.

Suggest two reasons why this was done.

A temperature of 25 ^oC was used during the experiment. The teacher explained it was very important to keep the temperature constant. 

Explain why it is important to keep the temperature constant.

After 12 minutes, the tap connected to tube 1 was closed and the syringe was attached to tube 2. Every 60 seconds, the syringe plunger was moved to make the levels in the U-tube identical. The reading on the volume scale of the syringe was then recorded. The results are shown in the table below.

Predict, with a reason, whether the coloured liquid in the U-tube would move towards tube 1 or tube 2 during the experiment.

The mass of the seeds was 1.8 g. 

Using the information provided in the table, calculate the rate of oxygen consumption cm³ g^–1 hour^–1 by the seeds. Show your working.

Compare and contrast aerobic respiration and anaerobic respiration.

A Sports Scientist was investigating aerobic respiration in an athlete. The equation below summarises how ATP is produced, using energy from the oxidation of glucose, for this particular athlete.

      glucose + oxygen + (ADP + Pi) → carbon dioxide + water + ATP

               170 g    124.4 dm³     17.25 kg          124.4 dm³         107 g     17.25 kg

Calculate the mass of ATP produced per dm³ of oxygen for the athlete.

The Sports Scientist then decided to measure the volume of oxygen consumed and the mass of ATP produced by the athlete when they ran different length races.

Some of the results for the athlete are shown in the table below.

Complete the table by calculating the missing values.

A group of researchers wanted to investigate ATP production in the preparation of isolated mitochondria taken from a person with mitochondrial disease. They suspended the mitochondria in an isotonic solution and added ADP, phosphate and a respiratory substrate. Oxygen was supplied throughout the preparation.

Explain why the solution used was isotonic.

Researchers measured the rate of CO₂ production by three groups of insects of the same species at 15 °C, 25 °C and 35 °C. The mean mass of each group of insects was also recorded. Their results can be seen in the table below.

Calculate the rate of carbon dioxide release per gram for each temperature in the table. Give your answer to two decimal places.

[1]

[2]

[1]

[2]

The researcher then wanted to measure and compare the rate of aerobic respiration in different species of beetle (with different masses) using the experimental set-up shown below.

[4]

[1]

Explain how temperature influences the rate of ATP production in respiration.

A group of scientists measured the mean rate of respiration in soil found under trees and soil that was not from under trees within the same woodland. The mean rate of photosynthesis in leaves was also measured. The measurements were taken throughout a 24 hour period during the summer.  

The diagram below shows the scientists' results. 

Suggest an explanation for the mean rate of respiration in soil not under the trees between midday and sunset. 

The mean rate of respiration is higher in soil under the trees throughout the 24hours. The scientists suggested the mean rate of photosynthesis was the cause of this. 

Suggest how the rise in the mean rate of photosynthesis could lead to the rise in the mean rate of respiration in soil under trees.

State the measurements needed for the scientists to calculate the rate of carbon dioxide production.