Uses of biological resources Flashcards
Describe how glasshouses and polythene tunnels can be used to increase the yield of certain crops
Enclosed Environment that Protects Plants from Harmful Weather such as Rain and Thunderstorms
Enclosed Environment Allows Carbon Dioxide Levels to be Controlled to Increase Rate of Photosynthesis for Growth (By Burning Paraffin Lamp)
Plants are Protected from the Outside so Prevents the Entry of Pests that can Damage Plants or Diseases that can Kill Plants
Traps Heat from the Sun so Creates a Warm Climate that is Close to Optimum Temperature of Enzymes in Plants, Increasing Enzyme Activity allowing Rate of Photosynthesis to Increase for Growth
What are the effects on crop yield of increased carbon dioxide and increased temperature in glasshouse?
Glasshouses are Enclosed so Allows Carbon Dioxide Levels to be Controlled
Farmers will Burn Paraffin Lamps to Increase Carbon Dioxide Levels in Glasshouses
When Carbon Dioxide Levels Increases, it is No Longer the Limiting Factor so Rate of Photosynthesis will Increase
As Rate of Photosynthesis Increases, there is More Energy for Growth, Increasing Crop Yield of Plants
Glasshouses are Enclosed so Traps the Heat from the Sun, creating a Warm Climate
Increased Temperature will be Closer to Optimum Temperature of Enzymes in Plants, Increasing Enzyme Activity
Increased Enzyme Activity will Allow Rate of Photosynthesis to Increase
As Rate of Photosynthesis Increases, there is More Energy for Growth, Increasing Crop Yield of Plants
What is the use of fertiliser to increase crop yield?
Fertilisers are Water-Soluble Minerals that Dissolves in Water to be Absorbed through the Roots of the Plants by Active Transport
They contain Minerals and Nutrients such as Nitrates, Phosphates and Potassium that are Essential for the Growth of Plants, Increasing Crop Yield
Describe the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with crop plants
Prevent Organisms such as Insects from Eating or Damaging Plants
PESTISIDES:
Advantages: pesticides are effective in controlling pests, producing fast/instant results.
Disadvantages: pesticides can damage the environment and wildlife, it’s expensive, pests may become resistant to the pesticide, it can leach into the soil. Pesticides are also dangerous to humans, so the amount used in food has to be below a safe level.
BIOLOGICAL:
Advantages: there’s longer lasting effects than spraying pesticides and it’s less harmful to the wildlife.
Disadvantages: doesn’t completely remove pests and the predators may do something unexpected (becoming a major pest themselves).
What is the role of yeast in the production of beer?
Beer is made from grain (usually barley).
Barley grains germinate so starch (in the grains) is broken down into sugar by enzymes.
Grains are dried in the kiln (called malting).
Yeast is added and the mixture is incubated (warmed up). It ferments the sugar into alcohol.
Using the sugars, yeast respires aerobically, then respires anaerobically once the oxygen is used up.
The carbon dioxide contributes to the froth on the surface, which traps oxygen so anaerobic respiration can continue.
The alcohol concentration becomes too high, killing yeast cells. As the yeast dies, fermentation slows down.
Beer is tapped out.
The beer is pasteurised to kill any yeast left in beer.
Describe a simple experiment to investigate carbon dioxide production by yeast
Water is gently boiled in a boiling tube to drive off any air that is dissolved in water. The water is cooled and sugar is dissolved in it. A little yeast is added and the mixture is stirred.
Liquid paraffin is added to the surface of the mixtures using a pipette. The boiled water ensures there is no oxygen and the layer of paraffin stops any oxygen diffusing in from the air.
A control apparatus is set up but boiled yeast is used instead of living yeast.
Both sets are left in a warm place for an hour or two. Gas bubbles form and they pass through the delivery tube and into the solution in the second boiling tube.
If this tube contains limewater, it will turn milky. If it contains hydrogen carbonate indicator it will turn orange to yellow. This shows there is CO2.
What is the role of bacteria (Lactobacillus) in the production of yoghurt? (Paper 2)
Milk is pasteurised at 85-95 for 15-30mins to kill any natural bacteria. It is then homogenised to disperse fat globules. It is cooled to 40-45 and inoculated with lactobacillus and streptococcus. They form lactic acid by fermenting lactose. The culture is kept at this temp for several hours while the pH falls to 4.4. The mixture thickens as the drop in pH causes the milk proteins to coagulate.
The yoghurt is stirred and cooled to 5.
Explain the need to provide suitable conditions in the fermenter (Paper 2)
ASEPTIC PRECAUTIONS
Fermenter is Cleaned by Steam to Kill Microorganisms and Prevent Chemical Contamination, Only allowing Desired Microorganisms to Grow
NUTRIENTS
Nutrients are needed to be Used in Respiration to Release Energy for Growth, allowing Reactions to Take Place
OPTIMUM TEMPERATURE AND pH
Optimum Temperature and pH is Maintained using Probes to Ensure an Optimum Environment for Enzymes to Increase Enzyme Activity (Enzyme Denatures if Temperature and pH is Too High)
OXYGENATION
Oxygen is Needed for Aerobic Respiration to Take Place as Most Reactions are Aerobic
AGITATION
Stirring Paddles Ensures that the Microorganisms, Nutrients, Oxygen, Temperature and pH is Evenly Distributed
Explain the methods which are used to farm large numbers of fish
Big enclosures/tanks are used where fish are raised for food, designed to produce as many fish as possible.
Fish are kept in cages in the sea, to stop fish from using so much energy swimming around, and protects the fish from interspecific predation (being eaten by a different species)
However, being kept in cages makes fish more prone to disease and parasites, e.g. sea lice, which can be killed by pesticides. But to avoid chemical pesticides from polluting, biological pest control is used, e.g. wrasse is used to eat the lice off a salmon’s back.
They’re fed a carefully controlled diet of high energy pellets to maximise the amount of energy the fish get, with the minimum amount of faeces.
Young fish are reared in special tanks to separate them from bigger fish that may eat the infraspecific predation. It ensure as many young fish survive as possible.
The net isn’t anchored to the bottom, because lots of faeces cause localised eutrophication near the bottom, so fish down there may die.
The fish can be selectively bred to produce less agressive and faster-growing fish.
How are plants developed by selective breeding?
Teat off a side shoot from the plant. Dip the side shoot in rooting powder to encourage root formation. Plant it in compost and place it under glass. The mini greenhouse will create a warm environment to speed up growth and a humid one to reduce water loss from the leaves of the cuttings.
How are animals developed by selective breeding?
Parents with Desired Characteristics are Chosen
They will Reproduce, Passing on Gene to Offspring
Best Offspring Animal with Desired Characteristic is Chosen and Selective Breeding Process is Repeated for Future Generations
Describe the use of restriction and ligase enzymes
Restriction enzymes - cut DNA molecules at specific points. They can be used to cut out specific genes from a molecule of DNA
Ligase - join cut ends of DNA molecules
Restriction Enzymes Cut Across the Double Strands at Two Different Places, the Place where they Cut Across the DNA is called the Sticky End
Restriction Enzymes can be used to Cut Out Specific Genes and also Cut Open Places in the Plasmid DNA of a Bacteria
The Sticky Ends will Ensure that the Cut Out Gene (Target Gene) is Able to Fit Exactly in the Plasmid DNA of a Bacteria
Describe how plasmids and viruses can act as vectors
PLASMIDS:
Ligase Enzyme Allows the Cut Out Gene (Target Gene) to be Inserted and Joined into the Plasmid DNA of a Bacteria, Forming a Recombinant DNA
Recombinant DNA is Inserted into a Bacterial Cell
Plasmids will Transfer Recombinant DNA to Other Bacteria when it Reproduces by Binary Fusion
VIRUS:
Ligase Enzyme Allows the Cut Out Gene (Target Gene) to be Inserted and Joined into the Plasmid DNA of a Bacteria, Forming a Recombinant DNA
Recombinant DNA is Inserted into a Virus
Viruses will Carry Recombinant DNA and Infect Organisms that it Comes into Contact with, Inserting Recombinant DNA into Cell
How can human insulin be manufactured?
- Get a human chromosome containing the insulin gene
- Use a restriction enzyme to cut the insulin gene out
- Use the same restriction enzyme to cut the plasmid out from the bacterium
- Mix the plasmid and DNA fragment with the enzyme DNA ligase to produce recombinant DNA
- Mix the plasmid with e-coli (bacteria)
- Open the pores of the bacteria, by applying temporary heat or an electric shock to allow plasmid to enter
- The bacteria can grow in huge numbers in a fermenter
Evaluate the potential for using genetically modified plants to improve food production
Advantages of GM plants:
Manipulated to get desired characteristics
Prevent hereditary diseases which is better for the environment
Can be made for specific environments
Disadvantages of GM plants:
If a plant is herbicide resistant and it escapes and manages to grow, they’re hard to destroy
Natural food chains disrupted
Not scientifically proven that they’re safe for consumption
