Respiration
Lesson Description
The following would be covered:
Define cellular respiration
Discuss the role of glycolysis, Kreb’s cycle and Oxidative phosphorylation in aerobic respiration
Define anaerobic respiration
Explain Alcoholic fermentation and
Lactic acid fermentation in muscles
Look at the role of anaerobic respiration in industry
Compare aerobic respiration and anaerobic respiration
Respiration – the process
Why do organisms need to respire?
All living things need energy
Energy in the form of…
Food=chemical energy
Cell use energy in the form of ATP
Cells recycle ATP
Where does all this take place?
Mitochondria
Explain this organelle structurally suited for respiration.
Double membrane which is permeable to gases and water
Inner membrane folded to increase surface area for attachment of respiratory enzymes
What is respiration?
Cellular Respiration is the process that releases energy by breaking down food molecules in
the presence of oxygen.
6O2 + C6H12O6 6CO2 + 6H2O + Energy
Oxygen + Glucose Carbon Dioxide + Water + Energy
There are three stages in aerobic respiration –
1. Glycolysis
2. Kreb’s Cycle
(Citric Acid Cycle)
3. Electron
Transport Chain
Glycolysis: This occurs in the cytoplasm of the cell. Glucose is broken down into pyruvic acid
and energy-rich
rich hydrogens are given off.
The hydrogens move into the mitochondria to be used in oxidative phosphorylation.
Two ATP molecules are produced during glycolysis.
The Krebs cycle breaks down the pyruvic acid completely into energy-rich hydrogen and
carbon dioxide. The hydrogen will be used in oxidative phosphorylation and the carbon
dioxide will be released eventually from the lungs.
Oxidative phosphorylation: takes the energy from the energy-rich hydrogens to make ATP
The energy depleted hydrogens combine with oxygen to make water. This is either released
as water vapour or excreted with the urine.
A Summary of the process:
Anaerobic Respiration
What happens if oxygen does not reach the mitochondria?
Anaerobic respiration occurs when glucose is broken down and there is no oxygen present. Very
little energy is produced.
There are two types of anaerobic respiration :-
Question One
Why is respiration important to organisms?
Maintains the oxygen balance in the atmosphere.
Maintains the carbon dioxide balance in the atmosphere.
Providing energy to heterotrophs.
2. Draw a labelled diagram to illustrate the general structure of the mitochodria.
3. Study the diagram below and then answer the questions that follow.
(Nated SG p1 2010)
1. State ONE function of the rubber stopper in tube A. (1)
2. Name the
(i)
biochemical process that is taking place in tube A.
(ii)
(iii)
3.
4.
5.
6.
gas bubbles in tube B.
liquid X in tube B.
Name THREE products formed in the biochemical process that is taking place in tube A. (3)
Describe how you would set up a control for this investigation. (2)
Give ONE reason why the process illustrated in the diagram is economically important. (1)
State ONE reason why it would have been better to use a thermos flask instead of a test tube. (2)
1 - Prevents atmospheric air from entering/escape the test tube/make test tube airtight
2 (i) anaerobic respiration/fermentation
(ii) carbon dioxide
(iii) lime water /bromothymol blue solution
3 - alcohol
- carbon dioxide
- ATP /energy
4 Set up the apparatus as shown but do not put in yeast in test tube A
5 - beer making/wine making/produce alcohol
- baking/form CO2 (mark first ONE only)
6 - to keep temperature constant
(Nated HG p1 2012)
4. A group of learners investigated whether all organisms release carbon dioxide.
They set up the experiment as shown in the diagram below. All the test tubes were kept in light
and they used an indicator to show the different concentrations of carbon dioxide.
The following colour changes of the indicator revealed the levels of carbon dioxide present:
Normal amount of carbon dioxide: Indicator turns orange
Low amount of carbon dioxide: Indicator turns purple
High amount of carbon dioxide: Indicator turns yellow
The table below shows the results obtained in each test-tube.
1.
2.
3.
4.
5.
6.
What is the purpose of test tube C in the investigation?
Give ONE reason why it was necessary to seal each test tube with a rubber stopper.
What gas do you think would increase in concentration in test tube A? Explain your answer.
Explain the results of each test tube after a few hours of the investigation.
Predict what colour the indicator would be if the learners set up a fourth test tube with worms and leaves.
Explain your answer to 5 above.
Anaerobic Respiration in Industry
Yeast is used widely in Biotechnology. It is used in the fermentation of alcohols and the
production of bread.
5. Define cellular respiration
Process whereby organic compounds are broken down using oxygen to release energy in the
form of ATP
6. List the reactants and the products of cellular respiration in both chemical equation and words.
6O2 + C6H12O6 6CO2 + 6H2O + Energy
Oxygen + Glucose Carbon Dioxide + Water + Energy
7. Tabulate the differences between respiration and photosynthesis.
Respiration
Occurs in cytoplasm and mitochondria
Oxygen consumed
Catabolic –uses energy
Energy, CO2,H2O produced
Light not essential
Photosynthesis
Occurs in chloroplast
Carbon dioxide confused
Anabolic – makes energy
Organic molecules produced
Light essential
8. Compare aerobic and anaerobic respiration.
Aerobic respiration occurs in the presence oxygen and creates a maximum of 38 ATP, while
anaerobic respiration occurs in the absence of oxygen and creates a maximum of 2 ATP.
The products of aerobic respiration are CO2, energy and water vapour while the products of
anaerobic respiration are CO2, little energy and alcohol
al
or lactic acid
June Exam 2013 Ahmed Timol Secondary
9. The following diagram shows the apparatus used in an experiment. Seeds of the pea plant were
soaked in water and placed into 3 identical glass bottles. A fourth empty bottle was also used. A
Carbon dioxide sensor was placed into each of the bottles. One bottle with seeds was place into a
freezer, room and oven. Answer the questions that follow.
1 What process is being investigated in this experiment?
(1)
2 Write down an aim for this experiment
(2)
3 Is light necessary for this process?
(1)
4 Why was one bottle left empty (without seeds?)
(1)
5. Why was it necessary to soak the seeds in water?
(1)
6. The table below indicates the results of the experiment. Use this data to draw a graph.
CONDITION
AMOUNT OF CO2 IN AIR (%)
No seeds
0.03
Freezer
0.04
Room temperature
0.1
Oven
0.03
(10)
1 Cellular respiration
1
2 To show/determine the effect of temperature on respiration
2
3 No
1
4 As a control
/to know the normal amount of CO2 in air
1
5 So that the seeds start to germinate/grow/respire
1
6
Amount of CO2 in bottles put under
different conditions.
AMOUNT OF CO2 IN AIR (%)
0.12
0.1
0.08
0.06
0.04
0.02
0
No seeds
Freezer
Room
temperature
CONDITION CRITERION
MARKS
Axes labels
2
y-axis scale
1
Labelling of bars/key
1
Heading
1
Oven Plotting
4
Type of graph
1 (TOTAL =10)
.