Biology PAG 6: Physiology, responses, respiration

Suggested Activity 2: Physiology, responses, respiration

Instructions and answers for teachers & techniciansThis practical activity is composed of two parts; a teacher/technician section and the learner activity which can be found on page 10. This Practical activity supports OCR GCSE Biology.

When distributing the activity section to the learners, either as a printed copy or as a Word file, you will need to remove the teacher instructions section.

This is a suggested practical activity that can be used as part of teaching the GCSE (9-1) Gateway Science (A) and Twenty First Century Science (B) specifications.

These are not controlled assessment tasks, and there is no requirement to use these particular activities.

You may modify these activities to suit your learners and centre. Alternative activities are available from, for example, Royal Society of Biology, Royal Society of Chemistry, Institute of

Physics, CLEAPSS and publishing companies, or of your own devising.

Further details are available in the specifications (Practical Skills Topics), and in these videos.

OCR recommendations:

Before carrying out any experiment or demonstration based on this guidance, it is the responsibility of teachers to ensure that they have undertaken a risk assessment in accordance with their employer’s requirements, making use of up-to-date information and taking account of their own particular circumstances. Any local rules or restrictions issued by the employer must always be followed.

CLEAPSS resources are useful for carrying out risk-assessments: (http://science.cleapss.org.uk).

Centres should trial experiments in advance of giving them to learners. Centres may choose to make adaptations to this practical activity, but should be aware that this may affect the Apparatus and Techniques covered by the learner.

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IntroductionThe topic of physiology covers a vast range of processes. This Practical activity focuses on the

anaerobic respiration of microorganisms.

Anaerobic respiration is a type of respiration that does not use oxygen. Anaerobic respiration in

plant cells and some microorganisms (such as yeast), produces ethanol and carbon dioxide, as

opposed to lactic acid.

glucose → ethanol + carbon dioxide (+ energy)

The experiment illustrates the production of carbon dioxide and the requirement for glucose in

anaerobic respiration. Additionally, pupils gain an understanding of the necessity for a control test.

This practical activity can be done as a teacher demonstration, as a simple class experiment to see

observe the production of carbon dioxide or a more complex investigation to see the impact of other

variables such as temperature impact on respiration.

DfE Apparatus and Techniques coveredThe codes used below match the OCR Practical Activity Learner Record Sheet (Biology / Combined Science) and Trackers (Biology / Combined Science) available online. There is no requirement to use these resources.

1 [1]: Use of appropriate apparatus to make and record a range of measurements accurately, including: v) temperature, vi) volume of liquids

2 [2]: Safe use of appropriate heating devices and techniques including use of: ii) a water bath

3 [3]: Use of appropriate apparatus and techniques for the: i) observation of biological changes and/or processes

Could additionally include

5 [5]: Measurement of rates of reaction by a variety of method including: i) production of gas

Aim Recall ideas about aerobic respiration and compare the concepts with ideas about anaerobic

respiration

Appreciate the basic concepts of anaerobic respiration

Describe practical investigations into the effect of different substrates on the rate of respiration in

yeast

Evaluate the purpose of a control test

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Intended class timeThis activity will take 30 minutes.

Links to Specifications: Twenty First CenturyB4.1.1 Compare the processes of aerobic and anaerobic respiration, including conditions under which they occur, the inputs and outputs, and comparative yields of ATP.

B4.1.2 Explain why cellular respiration occurs continuously in all living cells.

B4.1.5 describe practical investigations into the effect of different substrates on the rate of respiration in yeast

GatewayB1.3a Describe cellular respiration as a universal chemical process, continuously occurring that supplies ATP in all living cells.

B1.3c Compare the processes of aerobic respiration and anaerobic respiration.

Mathematical Skills coveredUnderstand and use the symbols: =, <, <<, >>, >, ∝, ~

Twenty First Century IaS references covered IaS1.1 in given contexts use scientific theories and tentative explanations to develop and justify

hypotheses and predictions

IaS1.9 In given contexts evaluate data in terms of accuracy, precision, repeatability and

reproducibility, identify potential sources of random and systematic error, and discuss the

decision to discard or retain an outlier

IaS2.10 Evaluate an experimental strategy, suggest improvements and explain why they would

increase the quality (accuracy, precision, repeatability and reproducibility) of the data collected, and

suggest further investigations.

IaS2.11 In a given context interpret observations and other data (presented in diagrammatic,

graphical, symbolic or numerical form) to make inferences and to draw reasoned conclusions, using

appropriate scientific vocabulary and terminology to communicate the scientific rationale for findings

and conclusions.

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Gateway Working scientifically references coveredWS1.2a use scientific theories and explanations to develop hypotheses

WS1.2e evaluate methods and suggest possible improvements and further investigations

WS1.3e interpreting observations and other data

WS1.3g being objective, evaluating data in terms of accuracy, precision, repeatability and reproducibility

WS1.3h identifying potential sources of random and systematic errorWS1.4ause scientific vocabulary, terminology and definitions

WS2a Carry out experiments with due regard to the correct manipulation of apparatus, the accuracy of measurements and health and safety considerations, and following written instructions.

WS2b Make and record observations and measurements using a range of apparatus and methods keeping appropriate records.

WS2d communicating the scientific rationale for investigations, methods used, findings and reasoned conclusions presentations through paper-based and electronic reports and presentations using verbal, diagrammatic, graphical, numerical and symbolic forms

EquipmentPer group:

Boiling tube

Boiling tube rack

2 spatulas dried yeast

2 spatulas sugar

1 balloon, that will stretch over the top of the boiling tube

Measuring cylinder

Spatula

For the class: Access to a water bath at 37- 40 oC

If extending the practical to observe and measure the impact of variables such as temperature

(recommended as a teacher demonstration), a method of gas collection will be required:

Either

A gas cylinder

Or

Ice cream tub

50ml measuring cylinder

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Delivery tube

With water baths at varying temperatures (15oC and 60oC recommended)

Health and SafetyTeachers will need to carry out a suitable risk assessment for each practical. The following may

assist you in the preparation of your risk assessment:

The water bath will be over 30oC, students could burn themselves.

The food products used in the experiment, sugar and yeast, should not be consumed in the Science

laboratory.

Method Observing the production in carbon dioxide

Students

1. Add two spatulas of yeast to a boiling tube

2. Add two spatulas of sugar to the boiling tube

3. Use a measuring cylinder to measure 15ml of water

4. Add the 15ml of water to the boiling tube

5. Put the balloon over the top of the boiling tube – making sure that no air can get in.

6. Place the boiling tube, with the balloon on it, in the water bath

7. After 5 minutes gently swirl the mixture in the boiling tube and place it back in the water bath

8. Leave the boiling tube in the water for 10 minutes more, until the balloon rises

Teacher – control test

1. Add two spatulas of yeast to a boiling tube

Sugar is not added, as this is the control test

2. Use a measuring cylinder to measure 15ml of water

3. Add the 15ml of water to the boiling tube

4. Put the balloon over the top of the boiling tube, making sure no air can get in

5. Place the boiling tube, with the balloon over it, in the water bath

6. After 5 minutes gently swirl the mixture in the boiling tube and place it back in the water bath

7. Leave the boiling tube in the water for 10 minutes more

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Measuring the production of carbon dioxide

1. Add two spatulas of yeast to a boiling tube

2. Add two spatulas of sugar to the boiling tube

3. Use a measuring cylinder to measure 15ml of water

4. Add the 15ml of water to the boiling tube

5. Connect the delivery tube, or gas cylinder, to the boiling tube

6. Stand the boiling tube, in a water bath

7. After 5 minutes gently swirl the mixture in the boiling tube and place it back in the water bath

8. Measure the volume of gas collected over 10 minutes

9. Repeat in water baths at two difference temperature

Technician NotesObserving the production in carbon dioxide

For this practical the teacher will require for a class of 30, working in pairs: 15 x Boiling tube

15 x Boiling tube racks

30 x spatula dried yeast

30 x spatulas sugar

15 x balloon, that will stretch over the boiling tube (would be helpful to have spares available

in case of snapping/ripping)

15 x Measuring cylinder

30 x Spatulas

For the teacher’s control test Boiling tube

Boiling tube rack

2 spatulas dried yeast

1 balloon, that will stretch over the top of the boiling tube

Measuring cylinder

Spatula

For the class: Access to a water bath at 37- 40 oC

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Measuring the production of carbon dioxide

If extending the practical to observe and measure the impact of variables such as temperature

(recommended as a demonstration), a method of gas collection will be required:

Either

A gas cylinder

Or

Ice cream tub

50ml measuring cylinder

Delivery tube

With water baths at varying temperatures (15oC and 60oC recommended)

Sample photos for the experiment:

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Starter Quiz - Answers True or false starter activity

1. The word equation for respiration is Carbon dioxide + Oxygen Glucose + Water FALSE

2. Anaerobic respiration is when there is oxygen present FALSE

3. The word equation for respiration is Oxygen + Glucose Carbon Dioxide + Water TRUE

4. Respiration is only carried out by humans FALSE

5. Respiration is the same as breathing FALSE

6. Respiration results in energy being released TRUE

Activity Sheet – answers Before the experiment

1. Make a prediction - what do you expect to observe during and after the reaction?

Student’s own answer.

During the experiment

2. Explain the purpose of the control test

To compare what would happen without the presence glucose. It increases the reliability of the results.

After the experiment

3. Record your observationsa. What changes did you see in the glucose sample and control test?

Glucose sample: Student’s own answer – should see balloon inflate, bubbles produced in solutionControl test: Student’s own answer – should not see a change.

b. Was your prediction correct?

Student’s own answer.

c. Explain your findings – why do you think this happened?

In the glucose sample, the balloon inflates and bubbles are produced because of the production of carbon dioxide.

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In the control sample, there should be no changes as glucose is not present

d. What modifications would you make to this test to improve its accuracy?

Repeat the testMore than one control test Use a gas syringe to measure how much carbon dioxide is produced Use varying amounts of sugar (glucose)

Challenge question 1: What would happen if you increased the temperature of the water bath to 50oC?

Nothing – respiration will not take place, as the enzymes will denature

Challenge question 2: Why is yeast used in bread making?

Yeast is used in bread making becuase it makes the bread rise. As carbon dioxide is produced during respiration, the bubbles in the dough make it rise.

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Biology PAG 6: Physiology, responses, respiration

Suggested Activity 2: Physiology, responses, respiration

Learner Activity

Physiology, responses respirationIntroductionIn this practical activity, you will observe the results of anaerobic respiration of microorganisms.

Anaerobic respiration is a type of respiration that does not use oxygen. Anaerobic respiration in

plant cells and some microorganisms (such as yeast), produces ethanol and carbon dioxide, as

opposed to lactic acid.

Aim Recall ideas about aerobic respiration and compare the concepts with ideas about anaerobic

respiration

Appreciate the basic concepts of anaerobic respiration

Describe practical investigations into the effect of different substrates on the rate of respiration in

yeast

Evaluate the purpose of a control test

Starter QuizTrue or false;

1. The word equation for aerobic respiration is Carbon dioxide + Oxygen Glucose + Water

2. Anaerobic respiration is when there is oxygen present

3. The word equation for aerobic respiration is Oxygen + Glucose Carbon Dioxide + Water

4. Respiration is only carried out by humans

5. Respiration is the same as breathing

6. Respiration results in energy being released

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Equipment Boiling tube

Boiling tube rack

2 spatulas dried yeast

2 spatulas sugar

1 balloon, that will stretch over the boiling tube

Measuring cylinder

Spatula

There will be a water bath for the class to share.

Health and SafetyThe water bath will be over 30oC, be careful not to burn yourself.

The food products used in the experiment, sugar and yeast, should not be consumed in the Science

laboratory.

Method1. Add two spatulas of yeast to a boiling tube

2. Add two spatulas of sugar to the boiling tube

3. Use a measuring cylinder to measure 15ml tap water

4. Add the 15ml tap water to the boiling tube

5. Put the balloon over the top of the boiling tube, - making sure that no air can get in

6. Place the boiling tube, with the balloon on it, in the water bath

7. After 5 minutes gently swirl the mixture in the boiling tube and place it back in the water bath

8. Leave the boiling tube in the water for 10 minutes more, until the balloon rises

Version 1.1 – January 2018 11 © OCR 2018

Activity SheetBefore the experiment

1. Make a prediction - what do you expect to observe during and after the reaction?

During the experiment

2. Explain the purpose of the control test

After the experiment

3. Record your observationsa. What changes did you see in the glucose sample and control test?

Glucose sample:

Control test:

b. Was your prediction correct?

c. Explain your findings – why do you think this happened?

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d. What modifications would you make to this test to improve its accuracy?

Challenge question 1: What would happen if you increased the temperature of the water bath to 50oC?

Challenge question 2: Why is yeast used in bread making?

DfE Apparatus and Techniques coveredIf you are using the OCR Practical Activity Learner Record Sheet (Biology) you may be able to tick off the following skills:

Biology1-v 1-vi 2-ii 3-i 5-i

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