Food and Energy – Post Lesson Practice.

 

Copy and complete the following sentences.

 

1.         Living organisms need energy for many activities. In humans for example

            energy is needed for growth and for maintaining our body

            temperature.                                                                                                               (2)

 

2.         Energy in food is stored as chemical energy which can be changed into heat energy

 and measured. This energy is measured in units called kilojoules.

 4.2kJ is the quantity of heat energy required to raise the temperature of

 1000g of water by 1oC.                                                                                              (4)

 

3.         The energy content of food can be measured most accurately by using a 

 food calorimeter.                                                                                                       (1)

            Fat has twice as much energy as either carbohydrate or protein.                           (3)

 

                                                                                                Total = 10 marks

 

 

Adenosine Triphosphate – Post Lesson Practice.

 

Copy and complete the following sentences.

 

1.         ATP  is a molecule which is used as a temporary energy

store in living cells. It is made up from one adenosine molecule

 and three inorganic phosphate groups.                                                                    (3)

 

2.         When ATP is made from ADP and Pi, the energy required

            for its formation comes from the breakdown of glucose.                                         (3)

 

3.         When ATP is broken down, energy is released and ADP and

            Pi are produced.                                                                                                         (2)

 

4.         When ATP is added to muscle it causes the fibres to contract.

For example, a piece of muscle measuring 90mm might measure only

 72mm after the addition of ATP. This would be a 20%

decrease in length.                                                                                                     (2)

 

 

 

 

 

 

Aerobic Respiration – Post Lesson Practice

 

Copy and complete the following sentences.

 

1.         During aerobic respiration, energy is released from  glucose/food

            in the presence of oxygen.                                                                                         (2)

 

2.         At the beginning of this process, glucose is broken down into

            pyruvic acid in a series of steps controlled by enzymes.

            This part of the process is called glycolysis.                                                            (3)

 

3.         The breakdown of pyruvic acid requires the presence of oxygen.

The products of this breakdown are carbon dioxide and water.                              (2)

 

4.         The energy released from the breakdown of one molecule of glucose

            allows 2 molecules of ATP to be formed. The subsequent breakdown of

 pyruvic acid allows a further 36 molecules of ATP to form.

 Thus, during the aerobic respiration of 120 molecules of glucose,

             4560 molecules of ATP would be produced.                                                            (3)

 

                                                                                                Total = 10 marks.

 

 

 

 

Anaerobic Respiration in Animals – Post Lesson Practice

 

1.         Anaerobic respiration in animals takes place when oxygen

 is not available. Under these conditions, glucose is not completely

 broken down into carbon dioxide and water, instead lactic acid is

 formed. When this substance builds up in muscle cells it makes them ache.

 This is called muscle fatigue.                                                                                   (4)

 

2.         During the recovery period after anaerobic respiration, the depth

            and rate of breathing continue at greater than normal levels.

            This allows the oxygen debt to be repaid. The oxygen is used to convert

 lactic acid back to pyruvic acid.                                                                               (4)

 

3.         During the anaerobic respiration of one molecule of glucose in an animal,

            the number of ATP molecules produced from glycolysis is 2 and the number

 of ATP molecules produced from the breakdown of pyruvic acid is 0.                  (2)

 

                                                                                                Total = 10marks

 

                                                                                                           

           

Anaerobic Respiration in Plants and Yeast – Post Lesson Practice

 

Copy and complete the following sentences.

 

1.         In anaerobic respiration in plants and yeast, glucose is broken down to

pyruvic acid which is further broken down to carbon dioxide and the liquid

ethanol. Because carbon dioxide is a gas which is given off, this is a

pathway which is irreversible/not reversible.                                                           (5)

 

2.         The anaerobic breakdown of one glucose molecule results in the formation

of 2 molecules of ATP from the process of glycolysis.                                            (2)

 

3.         In an experiment to demonstrate anaerobic respiration in yeast, a layer

            of oil can be used to keep oxygen out of the mixture and the gas

            given off can be verified by testing it with lime water/bicarbonate indicator.

The product of the process which remains in the solution is ethanol.                     (3)

 

                                                                                                Total = 10 marks.