Edexcell ppt Biology 5.1 - 5.9 Used in lessons to scaffold class teaching and as a revision resource for students

1. Food production
CROP PLANTS
5.1 describe how glasshouses and polythene tunnels can be used to increase the yield of certain crops
5.2 understand the effects on crop yield of increased carbon dioxide and increased temperature in glasshouses
Greenhouses and polythene tunnels raise the temperature, which increases
the rate of photosynthesis, which increases crop yield.
(Yield - The total mass of the edible part of crop.)
1) If the level of CO2 in the greenhouse is increased  the yield will further
increase .
2) Heating units increase temperature and CO2. (combustion)
(remember, CO2 is a limiting factor in photosynethsis)
3) In winter months using artificial lights gives a ‘longer day’ for growing
4) Transparent glass and plastic allow short wave energy in (light) and reflect
long wave energy back (heat) to keep temperature high.

2. Glasshouses and Polythene tunnels
5.1 describe how glasshouses and polythene tunnels can be used to increase the yield of certain crops
5.2 understand the effects on crop yield of increased carbon dioxide and increased temperature in glasshouses

3. What is grown
5.1 describe how glasshouses and polythene tunnels can be used to increase the yield of certain crops
High value crops are grown in polythene tunnels and
greenhouses.
Some examples are:
• Strawberries
• Tomatoes
• Flowers
Only high value crops make sense to grow in this intensive
way.
(Value of crop must exceed cost of production)

4. Fertilizer and Crop Yield
5.3 understand the use of fertiliser to increase crop yield
If fertilizers are added (specifically those that contain
Potasium, Nitrate and Phosphate– KNP fertilisers) then
the yield will increase even more!
Potassium – essential for plant membranes
Nitrate – essential for making plant
proteins
Phosphate – essential for DNA and membranes

5. Fertilizer and Crop Yield
5.3 understand the use of fertiliser to increase crop yield
• Nitrogen is used to make
protiens
• Proteins increase biomass (more
plant)
• Increase in biomass increases
marketable part of the crop
( on a plant)
• Increased crop increases revenue
(the cost of fertilizer must be less
then the increase in value of the
crop)

6. Eutrophication again
Simply but Clearly
5.3 understand the use of fertiliser to increase crop yield
Nitrates >
Algae Grow >
Algae Die >
Algae Decay >
No Oxygen >
Fish &
Animals Die

7. Pest Control
5.4 understand the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with
crop plants
Pest Control can also be used to increase Yield. This can be done
either using pesticides or biological controls.
• Pesticide – a chemical that kills pests (anything that eats your
crop), but does not harm the crop plant
• Biological control – introducing a biological organism which will
eat the pest, but not the crop plant (e.g. birds are sometimes
encouraged inside greenhouses because they eat caterpillars)

8. Name some –cides
5.4 understand the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with crop plants
• Herbicides
• Insecticides
• Fungicides
• Molluscicides
• Fratricides
• Suicides
• Homicide
• Uxoricide
• Matricide
• Patricide
• Vatricide
• Deicide
• Tomeicide
• Mundicide
Plants
Insects
Fungi
Shellfish
Brother
Self
Person
Wife
Mother
Father
Poets
God
Books
Everything

9. Pesticides
5.4 understand the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with crop plants
Disadvantages of using pesticides:
• pesticides may enter and
accumulate in food chains
• pesticides may harm organisms
which are not pests
• some pesticides are persistent.
DDT

10. Biological Control
5.4 understand the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with crop plants
Advantages and disadvantages of
biological control, to include:
• advantages:
– no need for chemical pesticides
– does not need repeated treatment
• disadvantages:
– predator may not eat pest
– may eat useful species
– may increase out of control
– may not stay in the area where it is
needed.

11. Micro Organisms
5.5 understand the role of yeast in the production of beer
Yeast
Remember that yeast are capable of respiring
1) aerobically (producing CO2 and water)
&
2) anaerobically (producing CO2 and ethanol).
Yeast are therefore used in the brewing industry.

12. MAKING BEER
5.5 understand the role of yeast in the production of beer
In order to make beer:
• barley seeds are allowed to germinate by soaking
them in warm water (This is called malting).
• The germinating barley seeds break down their
carbohydrate stores, releasing sugar.
• After a couple of days the barley seeds are gently
roasted (which kills them).
• The dead seeds are put into a fermenter with
yeast.
• The yeast use the sugar for anaerobic respiration
and produce ethanol.

13. Well it’s beer

14. EXPERIMENT
5.6 describe a simple experiment to investigate carbon dioxide production by yeast, in different conditions
You need to know:
An experiment that shows the production of CO2 by yeast, in
different conditions:
IV (choose one and keep the others constant):
a) Type of sugar
b) Concentration of sugar (mass meter/measuring cylinder - %)
c) Temperature of solution (thermometer – 0C)
DV (Measure one):
a) Height of frothy bubbles (ruler - cm)
b) Volume of CO2 produced (gas syringe - mL)
c) Volume of CO2 from delivery tube to inverted container over
water (graduated cylinder – mL)
The best example is to mix a yeast suspension with sucrose
Any CO2 produced can be collected over water or bubbled through
lime water or hydrogen carbonate indicator

15. 5.6 describe
a simple
experiment
to investigate
carbon
dioxide
production by
yeast, in
different
conditions

16. Graphs and Limiting Factors
5.6 describe a simple experiment to investigate carbon dioxide production by yeast, in different conditions
The rate of CO2 production levels off in the
experiments over time.
Reason:
1) Sugar (glucose/sucrose) is a limiting factor
2) Ethanol is produced which is toxic to micro-organisms
(yeast)

17. MAKING YOGHURT
5.7 understand the role of bacteria (Lactobacillus ) in the production of yoghurt (TA)
Lactobacillus bacterium is This bacterium is used to turn milk
into yoghurt.
It uses lactose sugar in the milk to produce lactic acid by
anaerobic respiration.
A. The lactic acid affects the milk proteins, making the
yoghurt curdle (go solid) and giving it the characteristic
tart taste.
B. lowers the pH of milk to inhibit harmful to human
bacterial growth

18. Industrial Fermenters
5.8 interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter,
including aseptic precautions, nutrients, optimum temperature and pH, oxygenation and agitation, for the growth of micro-organisms
(TA)
Fermenters are huge containers that hold up to 200,000dm3 of liquid.
They make it possible to control the environmental conditions such as:
1. Temperature
2. Oxygen
3. Carbon Dioxide concentrations
4. pH
5. Nutrient levels
This allows microorganisms can grow and respire
without being limited and can work as efficiently as
possible
(High Yield)

19. MAKING MONEY FROM BACTERIA
5.8 interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter, including
aseptic precautions, nutrients, optimum temperature and pH, oxygenation and agitation, for the growth of micro-organisms (TA)
It is very important the everything in the
fermenter is sterile, so that only the
microorganisms that are wanted grow in the
culture.
Fermenters are used to produce commercially:
• Penicillin (antibiotic) in aerobic conditions
• Beer (ethanol) in anaerobic conditions
• Yoghurt (lactic acid) in anaerobic conditions

20. FERMENTER
5.8 interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter, including aseptic
precautions, nutrients, optimum temperature and pH, oxygenation and agitation, for the growth of micro-organisms (TA)
Important details:
Water Cooling jacket – keeps the microorganisms at optimum temperature.
They will produce lots of heat through respiration, therefore need to be
cooled!
Paddles – keep stirring the mixture. This stops waste products from building up
and keeps the air evenly mixed
Nutrient medium – supplies the microorganisms with fuel for respiration
Sterile Air supply – supplies clean O2 for respiration (note: this is not required
in anaerobic fermentation processes)
Data-logger – monitors temperature and pH, keeps the fermenter at optimum
conditions

21. Fermenter Diagram
5.8 interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter, including aseptic
precautions, nutrients, optimum temperature and pH, oxygenation and agitation, for the growth of micro-organisms (TA)
You don’t need to be
able to draw this out,
but you could be
asked to label a
diagram of a
fermenter or be
asked to explain the
function of the
various parts of a
fermenter.

22. STOPPING THE O2, RELEASING CO2
5.8 interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter, including
aseptic precautions, nutrients, optimum temperature and pH, oxygenation and agitation, for the growth of micro-organisms (TA)
The valve
• releases CO2 under pressure
• stops Oxygen and
microorganisms from entering

23. Why Fish farming(overview)
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality, control of
intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of selective breeding.
• Control feeding diet quality and frequency
• Control water quality, temperature and waste removal
• Control predation
• Control disease and parasites
• Select for species, size and quality
• No boats needed and a guaranteed harvest
• Less overfishing of natural wild fish stocks
• No risk of catching unwanted (non-marketable species)

24. Fish farming
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality, control of
intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of selective breeding.
Fish are farmed in fish farms because they are a
good source of protein.
1) Fish farms keep lots of fish in very small tanks to
minimize space requirements.
2) To stop the fish fighting with each other these
precautions are taken;

25. Fish farming
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality, control of
intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of selective breeding.
To reduce predation:
• Nets cover tanks
• Barriers separate tanks

26. Basic Points
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including
maintenance of water quality, control of intraspecific and interspecific predation, control of disease, removal of waste
products, quality and frequency of feeding and the use of selective breeding.
- Different fish species are kept in
separate tanks. This stops
competition between species of
fish (interspecific competition)
- Fish of different genders are kept
separately (unless they are being
bred)
- Fish of different ages are kept
separately. This stops competition
between fish of the same species
(intraspecific competition)

27. INCREASING YIELD
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality,
control of intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of
selective breeding.
The fish are fed often and in small amounts, or fed with
protein-rich food
(where does the protein come from?)
Sometimes hormones are added to the water to speed
growth.
Only the biggest and most healthy fish are allowed to
breed.
(The small and unhealthy fish end up as fish food.)
This is an example of selective breeding.

28. INCREASING YIELD, DECREASING DISEASE, MAKING
SUPERBUGS AND AFFECTING CONSUMERS
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality, control of intraspecific and
interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of selective breeding.
The use of antibiotics will increase the rate of growth (yield) &
decrease incidence of disease.
Pesticides decrease the growth and spread of parasites
Negatives:
1. It can also selectively breed antibiotic resistant bacteria.
2. Pesticides can kill other invertebrates
3. Pollution from organic material leads to eutrophication
4. Antibiotics may not degrade and can be passed on to
consumers (humans).

29. DECREASING DISEASE
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality,
control of intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of
selective breeding.
Water is closely monitored.
Fish are continuously supplied with fresh sterile
water so that wastes and excess nutrients are
washed out constantly.
The fish are kept in sterile water to limit disease,
which would spread very quickly in the cramped
ponds.

30. DECREASING DISEASE
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality,
control of intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of
selective breeding.
C:
O:
R:
M:
M:
S:
Question
Answer Notes Marks
C different temperatures / eq;
O same species / size/ age/gender/eq;
R repeat / eq;
M1 mass / length / number / eq;
M2 time period stated;(one day minimum)
S1 and S2 same food type / same food mass /
same oxygen / tank size /
fish density stated / eq;;
6
Total 6