Ecology

Question 1

Describe What is Meant by Habitat

Answer 1

The place where an organism lives.

Question 2

Describe What is Meant by Population

Answer 2

All the members of a single species that live in a habitat.

Question 3

Describe What is Meant by Community

Answer 3

The populations of all the different species living in the same habitat.

Question 4

Describe What is Meant by Ecosystem

Answer 4

The interaction of a community of living organisms with the non-living parts of the environment.

Question 5

Describe What is Meant by Interdependence

Answer 5

Organisms in an ecosystem depending on each other.

Question 6

Describe What is Meant by a Stable Community

Answer 6

A community where all the species and environmental factors are in balance so that population sizes remain fairly constant.

Question 7

Describe What is Meant by a Biotic Factor

Answer 7

The living organisms in an ecosystem e.g. new predators, competition, new pathogens and availability of food.

Question 8

Describe What is Meant by an Abiotic Factor

Answer 8

The non-living parts of an ecosystem e.g. light intensity, temperature and soil pH.

Question 9

Describe the Different Types of Adaptations

Answer 9

-A structural adaptation is an adaptation of body shape or body structure.

-A functional adaptation is an adaptation to the body functions of an organism.

-A behavioural adaptation is an adaptation to an organism’s lifestyle or behaviour.

Question 10

Describe the Structural Adaptations of a Camel

Answer 10

-Thick coat on upper surface of body: this protects the upper surface of the camel from the intense heat of the sun.

-Leathery interior of mouth: this allows the camel to eat desert plants which may be tough or have thorns. These plants can be a useful source of water for the camel.

-Long eyelashes: these protect the camel’s eyes from dust or sand.

-Wide feet: these help the camel to walk on sand by spreading the camel’s weight.

Question 11

Describe the Functional Adaptations of a Camel

Answer 11

-Camels produce very concentrated urine and dry faeces. This helps to reduce water loss.

-Camels can tolerate very large changes to their body temperature. This helps them to cope with the intense heat of the desert.

Question 12

Describe the Structural Adaptations of an Arctic Fox

Answer 12

-In winter, the fur of the Arctic Fox turns white. This provides camouflage, making it easier for the Arctic Fox to hunt its prey (and avoid predators).

-Thick fur on body: This insulates the fox’s body and reduces loss of heat to the air.

-Fur on soles of feet: This reduces heat loss to the ice and snow.

-Very small ears: The reduces the surface area of the fox, reducing heat loss to the air.

Question 13

Describe the Adaptations of Cacti

Answer 13

Water stored in stem. This allows cacti to survive for months without rain.

Extensive and shallow roots: a cactus can capture as much water as possible before it evaporates or drains into the ground.

-Very small leaves or spines. Plants lose water vapour through their leaves. Cacti often have very small leaves which reduces the surface area for water loss.

-In many cases, cacti have no leaves at all only spines. This protects the cactus from being eaten by desert animals (which value the water stored in the cactus).

Question 14

Describe the Adaptations of Microorganisms

Answer 14

-Some microorganisms are adapted to live in very extreme conditions. They are known as extremophiles.

-Extreme conditions include very high temperature, high pressure and a high concentration of salt.

Question 15

Describe the Features of a Food Chain

Answer 15

-Producer: This carries out photosynthesis, using energy from sunlight to make glucose.

-Primary consumer: This is an animal which eats a producer.

-Secondary consumer: This is an animal which eats a primary consumer.

-Tertiary consumer: This is an animal which eats a secondary consumer.

Question 16

Describe What a Food Chain Shows

Answer 16

Every food chain starts with a producer. This can be a green plant such as grass or it could be an algae such as seaweed.

-All producers carry out photosynthesis to produce the complex molecule glucose. To do this, they use the energy from sunlight.

-Scientists call molecules such as glucose biomass. This is passed along the food chain.

Question 17

Explain the Results of a Predator-Prey Cycle

Answer 17

-The population of any species is often limited by the amount of food available.

-If the population of prey increases, then so will the population of predators.

-However, as the population of predators increases, the number of prey will decrease.

-Predator-prey cycles are always out of phase. This is because it takes a while for one population to respond to changes in the other population.

Question 18

Describe a Method For Carrying out Sampling Along a Transect

Answer 18

-Select the habitat that you are going to sample. Place a tape measure across the habitat.

-Place a quadrat at the start of the tape measure. Identify the species in the quadrat using a guide. Count the numbers of the different species present.

-Move the quadrat 1m along the tape measure. Count the number of each species again.

-Repeat until you reach the end of the tape measure. Move the tape measure along the habitat and repeat.

Question 19

Describe a Method For Carrying out a Sampling Using a Quadrat

Answer 19

-Place two tape measures at right angles along the edge of the habitat. Write the numbers 1-20 on pieces of paper and place in a bag.

-One student selects a number and moves to that position on the first tape measure. Another student selects a number and moves to that position on the second tape measure.

-A third student places a quadrat at the point where the numbers meet. This ensures the quadrat is placed randomly. The student counts and records the number of each species in the quadrat.

-Repeat this ten times then repeat the whole experiment in the second sample area. Compare the results for each sample area by calculating a mean for each location.

Question 20

Explain why the Quadrat is Placed Randomly

Answer 20

-Plants are never spread perfectly evenly over an area but are often found in patches or clusters.

-If we select areas to sample, we might choose areas with a particularly large number of dandelions or areas with a very low number.

-So to avoid this bias, we throw the quadrat randomly

Question 21

Explain why the Quadrat is Placed a large Number of Times

Answer 21

-Plants are never spread perfectly evenly over an area but are often found in patches or clusters.

-If we threw a quadrat once and counted the number of dandelions, this might not represent the entire area.

-To get a more accurate idea of the number of dandelions, we would need to throw the quadrat a large number of times so that the area was thoroughly sampled.

Question 22

Describe the Role of Decomposers

Answer 22

-Decomposers are microorganisms such as bacteria and fungi that breakdown waster droppings and dead animals and plants.

-When these decomposers respire they release carbon dioxide back into the atmosphere.

-Decomposers are also important because they release mineral ions back into the soil.

Question 23

Describe the Role of Detritivores

Answer 23

-Detritivores are invertebrates that often start the process of decay.

-They eat dead animals and plants and produce waster material into smaller pieces.

-The decomposers then digest everything.

Question 24

Describe the Factors Affecting the Rate of Decay

Answer 24

-Temperature: warmer temperatures make things decompose quicker because they increase the rate that the enzymes involved in decomposition work at.

-However, if the temperature is too high, decomposition slows down because the enzymes become denatured.

-Oxygen availability: many organisms need oxygen to respire which they need to survive. Microorganisms involved in anaerobic decay do not need oxygen.

-Water availability: decay takes place faster in moist environments because the organisms involved in decay need water to carry out biological processes.

Question 25

Explain how Biogas is Produced

Answer 25

-Biogas is mainly made up of methane which can be burned as fuel. Lots of microorganisms are used to produce biogas. They decay plant and animal waste anaerobically. -This type of decay produces methane gas. Sludge waste is used to produce biogas on a large scale. -Biogas is made in a simple fermenter called a generator or digester. They need to be kept at a constant temperature to keep the microorganisms respiring. -Biogas can't be stored as a liquid (it needs too high a pressure) so must be used immediately- for heating, cooking and lighting.

Question 26

Compare the Different Biogas Generators

Answer 26

-Batch generators make biogas in small batches. They are manually loaded with waste which is left to digest and the by-products are cleared away at the end of each session. -Continuous generators make biogas all the time. waste is continuously fed in and biogas is produced at a steady rate. they are more suited to large scale projects. -Both methods need an inlet for waste material to be put in, an outlet for the digested material to be removed through and an outlet so that the biogas can be piped out to where it is needed.

Question 27

Explain why Compost Heaps remain Naturally Warm

Answer 27

-Decomposing microorganisms carry out aerobic respiration to release energy. -Some of this energy is in the form of heat (thermal energy). This makes compost heaps warm

Question 28

Explain why Farmers Water Their Compost Heaps

Answer 28

-As well as aerobic respiration, decomposition involves other chemical reactions. Many of these reactions require water. -Watering the compost heap provides this and speeds up decomposition.

Question 29

Explain why Farmers Turn Their Compost Heaps

Answer 29

-Decomposers carry out aerobic respiration and this requires a supply of oxygen. By turning the compost, we expose it to oxygen in the atmosphere. -Turning the compost also breaks up large clumps. This provides a greater surface area for the decomposing microorganisms to act on.

Question 30

Describe the First Stage in the Carbon Cycle

Answer 30

-The combustion of wood and fossil fuels releases carbon dioxide into the air. -Carbon dioxide also enters the atmosphere from the respiration of organisms.

Question 31

Describe the Second Stage in the Carbon Cycle.

Answer 31

-Carbon dioxide is removed from the atmosphere by green plants and algae during photosynthesis. -The carbon is used to make glucose, which can be turned into carbohydrates, fats and proteins that make up the bodies of the plants and algae. -When plants and algae respire, some carbon is returned to the atmosphere as carbon dioxide.

Question 32

Describe the Third Stage in the Carbon Cycle

Answer 32

-When the plants and algae are eaten by animals, some carbon becomes part of the fats and proteins in their bodies. The carbon then moves through the food chain. -When the animals respire, some carbon is returned to the atmosphere as carbon dioxide.

Question 33

Describe the Fourth Stage in the Carbon Cycle

Answer 33

-When the plants and animals die, detritus feeders and microorganisms feed on their remains. -When these organisms respire, some carbon is returned to the atmosphere as carbon dioxide. -Animals also produce waste that is broken down by detritus feeders and microorganism and releases carbon into the atmosphere as carbon dioxide. -Under certain conditions, for example when there is not enough oxygen, decomposers cannot function. -Now the carbon in dead remains is slowly converted to fossil fuels. When these are combusted the carbon is returned back to the atmosphere as carbon dioxide.

Question 34

Describe the Stages in the Water Cycle

Answer 34

-Energy from the Sun makes water evaporate from the land and sea, turning it onto water vapour. Some water also evaporates from plants through the transpiration stream. -After evaporation water vapour cools and condenses, forming clouds. The water now falls to the ground as precipitation. -Once the water hits the ground, some of the water evaporates back to water vapour in the air and some drains through rocks into aquifers. -A lot of water drains into the sea or forms streams and rivers.

Question 35

Describe a Method for the Decay Practical

Answer 35

-First, label one test tube 'lipase' and another as 'milk'. Then, add 5cm^3 of the enzyme lipase to the first test tube. -To the test tube labelled 'milk', add 5 drops of phenolphthalein. Then, add 5cm^3 of milk and 7cm^3 of sodium carbonate to the 'milk' test tube. -Place a thermometer into the 'milk' test tube and place both test tubes into a water bath at the first temperature, 20°C. Leave the test tubes for ten minutes. -Now, add 1cm^3 of lipase to the 'milk' test tube and start timing. Gently stir the contents until the pink colour disappears. -Finally, repeat the experiment for a range of different temperatures and plot all the results on a graph.

Question 36

Explain why the Test Tubes are Left for Ten Minutes in the Decay Practical

Answer 36

-Once we have placed our test tubes in the water bath, we need to allow some time for the liquids to reach the desired temperature

Question 37

Explain why the Colour Change Takes Place in the Decay Practical

Answer 37

-Milk contains lipid molecules. -Lipase is an enzyme which breaks down lipids, producing glycerol and fatty acids. -Fatty acids cause the solution to become acidic, changing the colour of the indicator.

Question 38

Explain why Clean Test Tubes Need to be Used for Each Repeat in the Decay Practical

Answer 38

Any traces of lipase on the test tube will start breaking down the lipid molecules in the milk. To avoid this we need to use clean test tubes each time.

Question 39

Explain how to reduce the Effect of Error in the Decay Practical

Answer 39

-We can reduce errors due to judging the colour change by asking several people to say when they think the solution has changed colour. -We can then take a mean of their answers. -We can also compare our data with other groups.

Question 40

Describe what is Meant by Biodiversity

Answer 40

Biodiversity is the variety of all the different species of organisms on Earth or within an ecosystem.

Question 41

Explain why the Loss of Rainforests is Damaging to the Planet

Answer 41

-Rainforests are extremely biodiverse. There are many thousands of species living in these habitats. -If the tropical rainforests are destroyed then these species are at risk of becoming extinct.

Question 42

Explain how Intensive Agriculture Leads to Deforestation

Answer 42

-One of the major causes of tropical deforestation is to provide land for grazing cattle such as cows for beef. -If more people reduced their meat consumption, then this would help to prevent deforestation.

Question 43

Explain how the Production of Biofuels Leads to Deforestation

Answer 43

-Biofuels contribute to climate change less than regular fossil fuels. However, biofuels are made using crops such as sugar cane. -Large areas of tropical rainforest are being cleared to grow the crops needed to make biofuels.

Question 44

Describe the Impact of Untreated Sewage on Biodiversity

Answer 44

-Untreated sewage is accidentally released into rivers or streams. -Bacteria use the molecules in the sewage as a source of nutrients and reproduce. -Bacteria use large amounts of oxygen for aerobic respiration. -Dissolved oxygen levels in the water fall sharply. -Aquatic organisms die due to lack of oxygen in the water.

Question 45

Describe the impact of Fertilisers on Biodiversity

Answer 45

-Nutrients from fertilisers are flushed into rivers and lakes. -These pollutants cause aquatic plant growth e.g. algae. -Algae bloom prevents sunlight reaching other plants. The plants die and oxygen in the water is depleted. -Dead plants are broken down by decomposers, using up even more oxygen in the water. -The water becomes more anoxic so life is no longer possible and the ecosystem dies.

Question 46

Describe what is meant by Bioaccumulation

Answer 46

Bioaccumulation is the collection of a substance (such as a toxic chemical) in a living organism at a rate faster than it is metabolised or excreted.

Question 47

Explain how Polluting the Air can Reduce Biodiversity

Answer 47

-When some fuels are burnt, they release sulfur dioxide into the air, When sulfur dioxide dissolves in rainclouds, it makes the rainwater acidic. This then falls as acid rain. -Acid rain damages the leaves, flowers and fruits of plants. It can also soak into the soil and damage the roots. -When the acid rain falls into lakes, the water becomes slightly acidic. If the concentration of acid gets too high, plants and animals can no longer survive. -Some fuels release smoke into the air. Smoke can cause breathing problems in people.

Question 48

Explain how Polluting the Land can Reduce Biodiversity

Answer 48

-Most household rubbish is buried in landfill sites. Not all of this material is safe, for example, batteries contain toxic chemicals. -Herbicides kill weeds that compete with crops for light and space. Pesticides kill the insects that might eat the crops. -These chemicals are poisonous. They can pass into food chains and kill animals.

Question 49

State the Causes of the Three Main Greenhouse Gases

Answer 49

Carbon Dioxide, CO2- caused by the burning of fossil fuels and deforestation. Methane, CH4- caused by intensive agriculture. Water Vapour, H2O- caused by evaporating oceans and lakes.

Question 50

Describe the Enhanced Greenhouse Effect

Answer 50

-The Sun radiates light and heat (short wavelength radiation- UV and visible light). -This light and heat reaches the Earth. The heat that reaches the Earth warms its surface. -The Earth emits some heat back (longer wavelength radiation- infrared). Most of the radiation returns to space. -Greenhouse gases absorb some of the radiation, increasing the amount of thermal energy within the atmosphere. -This causes an increase in global temperatures.

Question 51

Explain why the Greenhouse Effect has Been Essential for the Development of the Earth

Answer 51

-Without the greenhouse effect, the temperature of the atmosphere would be much colder and most living organisms would not be able to survive. -Because of the greenhouse effect, the temperature of the atmosphere is high enough to allow the Earth to support a massive range of living organisms.

Question 52

Describe the Consequences of Global Warming

Answer 52

-Global warming will lead a reduction in biodiversity. Habitats are being destroyed. Some organisms will decrease in number or may become extinct. -Animals such as insects may extend their range to find cooler conditions. These include mosquitoes which can transmit malaria. -As the Earth's temperature increases, animals such as birds may migrate at different times or to different countries. -Plants may flower earlier. Crops may grow in the UK that do not grow now. Some countries may be too hot to grow crops they need.

Question 53

Describe the Purpose of Deforestation

Answer 53

-Deforestation is the cutting down of trees in a forest. -It is done to clear land for farming (e.g. cattle or rice crops) to provide more food. -It is also done to grow crops from which biofuels based on ethanol can be produced.

Question 54

Explain how Deforestation Leads to a Reduction in Biodiversity

Answer 54

-Biodiversity is the variety of different species in the world or a certain ecosystem- the more species, the greater the biodiversity. -Habitats like forests can contain a huge number of different species of pants and animals so when they are destroyed there is a danger of many species becoming extinct. -This means biodiversity is reduced.

Question 55

Explain how Deforestation Leads to a Reduction in Carbon Dioxide Intake

Answer 55

-Cutting down lots of trees means that the amount of carbon dioxide removed from the atmosphere during photosynthesis is produced. -Trees 'lock up' some of the carbon that they absorb during photosynthesis in their wood, which can remove it from the atmosphere for hundreds of years. -Removing trees means that less is locked up.

Question 56

Explain how Deforestation Leads to an Increase in Carbon Dioxide in the Atmosphere

Answer 56

-Carbon dioxide is released when trees are burnt to clear land. -Microorganisms feeding on bits of dead wood release carbon dioxide as a waste product of respiration.

Question 57

Describe the Properties of Peat Bogs

Answer 57

-Bogs are areas of land that are acidic and waterlogged. -Plants that live in bogs don't fully decay when they die because there is not enough oxygen. -The partly-rotted plants gradually build up to form peat. -This means the carbon in the plants is stored in the peat instead of being released into the atmosphere. -Peat is used to make compost for gardens and burned to release energy.

Question 58

Describe the Impact of the Destruction of Peat Bogs

Answer 58

-When peat is drained, it comes into more contact with air and some microorganisms start to decompose it. -When these microorganisms respire, they use oxygen and release carbon dioxide, contributing to global warming. -Carbon dioxide is also released when peat is burned as fuel. -Destroying the bogs also destroys the habitats of some of the organisms that live there so reduces biodiversity.

Question 59

Describe what is Meant by a Rich Biodiversity

Answer 59

A rich biodiversity means that any species is less dependent on any other species so the ecosystem is more stable.

Question 60

Explain how Breeding Programmes can Maintain Biodiversity

Answer 60

-Breeding programmes have been set up to help prevent endangered species from becoming extinct. -These are where animals are bred in captivity to make sure the species survive if it dies out in the wild. Individuals can be released into the wild to boost or re-establish a population.

Question 61

Explain how Habitat Protection Programmes can Maintain Biodiversity

Answer 61

-Programmes to protect and regenerate rare habitats like mangroves, heathland and coral reefs have been started. -Protecting these habitats helps to protect the species that live there- preserving the ecosystem and biodiversity in the area.

Question 62

Explain how Field Margin Programmes can Maintain Biodiversity

Answer 62

-There are programmes to reintroduce hedgerows and field margins around fields on farms where only a single type of crop is grown. -Field margins are areas of land around the edges of fields where wild flowers and grasses are left to grow. -Hedgerows and field margins provide a habitat for a wider variety of organisms that could survive in a single crop habitat.

Question 63

Explain how Government Action can Maintain Biodiversity

Answer 63

-Some governments have introduced regulations and programmes to reduce the level of deforestation taking place. Governments can reduce deforestation by establishing national parks. In these areas, forests are protected from destruction. -They also reduce the amount of carbon dioxide being released into the atmosphere by businesses. -They can reduce carbon dioxide emissions by encouraging the use of renewable sources of electricity and reducing the amount of electricity generation from burning fossil fuels -This could reduce the increase of global warming.

Question 64

Explain how Individuals can Maintain Biodiversity

Answer 64

-Recycling household waste reduces the amount of waste that is dumped in landfills. This means that landfills will take longer to fill up. -Fewer new landfill sites will be needed and this will preserve habitats for plants and animals, preserving biodiversity.

Question 65

Describe the Different Trophic Levels in a Food Chain

Answer 65

-Trophic level one contains producers. Producers are named as such because they make their own food by photosynthesis using energy from the Sun e.g. plants and algae. -Trophic level two contains primary consumers. This level consists of herbivores. -Trophic level three contains secondary consumers. This level consists of omnivores and carnivores. -Trophic level four contains tertiary consumers. This level consists of carnivores. -Carnivores that have no predators are at the top of the food chain so are in the highest trophic level. They are apex predators.

Question 66

Describe the Role of Decomposers in the Food Chain

Answer 66

-Decomposers such as bacteria and fungi break decompose any dead plant or animal material left in an environment. -They can do this by secreting enzymes into the environment. The enzymes digest the molecules in the waste or dead remains. The small soluble products of digestion now diffuse back into the decomposer. -Decomposers are important in ecosystems because when they break down waste or dead remains, they return mineral ions back to the soil. These can then be taken up and used by plants.

Question 67

Describe what is Meant by Biomass

Answer 67

Biomass is the amount of biological material that makes up a living material.

Question 68

Explain why Biomass is Lost Between Levels in a Food Chain

Answer 68

-Organisms don't always eat every single part of the organism that they are consuming. For example, some material is inedible such as bone so not all biomass is passed on. -Organisms don't absorb all of the stuff in the food they ingest. Some of it is egested as faeces. -Some of the biomass taken in is converted into other substances that are lost as waste. -For example, organisms use a lot of glucose in respiration to provide energy rather than making more biomass. This process produces waste products such as carbon dioxide. -Urea is another waste substance released in urine with water when the proteins in the biomass are broken down.

Question 69

Explain why a Shorter Food Chain is More Efficient than a Long Food Chain

Answer 69

-Short food chains are more efficient because there are fewer trophic level. -Longer food chains have more trophic levels so there are more places where biomass is lost through respiration, egestion and decomposition.

Question 70

Explain why More Active Animals Lose More Biomass

Answer 70

-Active animals carry out lots of respiration as active muscles respire more. -Biomass is used (in cellular respiration) to provide energy for movement to supply energy and raw materials (such as protein) needed for building new biomass. -More of the biomass eaten is broken down and more energy is transferred to surroundings as heat as muscles warm up.

Question 71

Explain why eating More Plants May Increase Biomass Transfer Efficiency

Answer 71

-Earth has a limited surface area for plant growth. -Biomass is lost at each stage of the food chain. -If people ate plants instead of feeding plants to animals and then eating animals, food chains would be shorter. -Shorter food chains are more efficient. -Plants biomass would be used to produce human biomass directly.

Question 72

Explain how Increasing Populations Affect Food Security

Answer 72

-The global population is growing at a very fast rate. -This means that countries will need to produce more food or import more food to feed their populations in the future. -if not, food security could be threatened.

Question 73

Explain how Changing Diets Affect Food Security

Answer 73

-As diets in developed countries change, the demand for certain foods to be imported from developing countries can increase. -This increases food security in the developed country as food is imported and they have access to a more balanced diet. -However, enough high quality food may not be available for the exporting country's population. -Food prices in that country may increase too as growers produce less crops for their own population and export more crops

Question 74

Explain how Pests and Pathogens Affect Food Security

Answer 74

-Pests such as insects can damage crops by eating them. -Pathogens such as fungi can infect plants, reducing the yield of crops produced.

Question 75

Explain how Farming Resources Affect Food Security

Answer 75

-The high input costs of farming can make it too expensive for people in some countries to start or maintain food production. -This means that sometimes there are not enough people producing food in these areas to feed a population.

Question 76

Explain how Conflict Affects Food Security

Answer 76

Wars can disrupt farming for example by damaging transport infrastructure required to get crops to market or by damaging water supplies. -Imports of food may not be possible during times of war.

Question 77

Describe the Advantages of Intensive Farming

Answer 77

-Animals are kept in a temperature controlled environment. This reduces the energy used by the animal to keep their body temperature constant. The energy saved is used for growth. -Animal movement is restricted. This means the energy used for movement is minimal. The energy saved is used for growth. -Animals are fed a high protein diet to further promote growth.

Question 78

Describe the Disadvantages of Intensive Farming

Answer 78

-Animals are in close confinement. This increases the risk of disease spreading. -Animals are treated with antibiotics to prevent infections. However, these can accumulate in the food chain and end up in meat that humans eat-we do not know the effects of this. -By using antibiotics when we do not have to, we also increase the risk that antibiotic-resistant bacteria could develop -Some also believe intensive farming is unethical.

Question 79

Describe the Effects of Overfishing

Answer 79

If fish are caught faster than they reproduce, fish stock decrease and some species may go extinct.

Question 80

Describe how Fishing Quotas and Increasing Mesh Size can Preserve Fish Stocks

Answer 80

-Fishing quotas place limits on the number and size of fish that can be caught in certain areas. this prevents certain species from being overfished. -Using a bigger mesh size will mean that 'unwanted' species can escape. Young fish can also escape, allowing them to reach breeding age.

Question 81

Describe how Bacteria can be Genetically Engineered to Produce Human Insulin

Answer 81

-A plasmid is removed from a loop of bacterium. The insulin gene is cut out of a human chromosome using a restriction enzyme. -The plasmid is cut open and the insulin gene is inserted. The recombinant DNA is inserted into the bacteria. -The bacteria reproduces rapidly so makes a lot of human insulin to treat diabetes.

Question 82

Describe the Advantages of GM Crops

Answer 82

-GM crops generally produce a greater yield than normal crops or bigger or better fruit. -GM crops can also be resistant to disease or insect attack. -GM crops could be engineered to contain more nutrients.

Question 83

Describe the Disadvantages of GM Crops

Answer 83

-Some say that growing GM crops will affect the number of wild flowers that live in and around the crops- reducing farmland biodiversity. -Not everyone is convinced that GM crops are safe to eat and some people are concerned that we do not fully understand the effects of eating them on human health. -Transplanted genes may also get out into the natural environment.

Question 84

Describe the Production of Mycoprotein

Answer 84

-Mycoprotein is a low fat meat substitute. -It is made from the fungus 'fusarium'. -This is grown in aerobic conditions. -It is grown on glucose syrup (cheap), which it uses as food. -It is produced on an industrial scale under controlled conditions in fermenters. -The mycoprotein is then harvested and purified.

Question 85

Describe how a Mycoprotein Fermenter Works

Answer 85

-The pH and temperature are maintained at the optimum. -The temperature is controlled by a water jacket that surrounds the whole fermenter. -Sterile oxygen is added to make sure that aerobic respiration occurs. -A food source like glucose syrup is added. -The mixture inside is stirred to make sure all the oxygen and nutrients are equally distributed.

Question 86

Describe the Advantages of Mycoprotein

Answer 86

-Easy to handle- grown in fermenters rather than taking up space in a field. -Grown using waste material. -Can be grown in any part of the world, under any weather conditions. -Faster than waiting for livestock to grow.

Question 87

Explain why Mycoprotein is a More Efficient Source of Protein than Eating Animals

Answer 87

-Mycoprotein is made from glucose which is produced from plants. -Because of this, a much greater percentage of the initial biomass is transferred to protein compared to getting protein by consuming animals.