5) Use of biological resources Flashcards
Glasshouses
-conditions can be manipulated to increase the rate of photosynthesis:
-artificial heating
-artificial lighting
-increased CO2 content of the air
-regular watering
Polythene tunnels
-large plastic tunnels that cover crops
-protect crops grown outside from the effects of the weather - excessive wind, rain, extreme temperatures
-also increase the temperature slightly inside
-prevent the entry of pests
Fertilizers
Contain minerals that plants require to grow - nitrates, phosphates, potassium
-nitrates - make proteins (what plant cells are made of)
-phosphates - involved in respiration and growth
-potassium - must be present for enzymes to work (plants carry out reactions)
Threats to crop yield
-pests - damage crops by eating them
-weeds - outcompete crop plants for space, water and soil nutrients
-fungi - infect crop plants and spread disease
–can be controlled by pesticides (chemical control) or by introducing another species (biological control)
Advantages to chemical control
-efficient
-immediate effect
-targets and kills the whole population
Disadvantages to chemical control
-pests can develop resistance
-may kill other organisms - non specific chemicals
-toxic to food chain - bioaccumulation
-need for continuous application
Advantages of biological control
-natural method
-no resistance
-ability to target specific species
-long lasting
-efficient as minimal effort is required
Disadvantages of biological control
-may kill other organisms - non specific
-time lag in effect
-cannot kill the entire population
-organism may be unadaptable to new environment and die
Yeast
Yeast - a single celled fungus that can carry out both aerobic and anaerobic respiration.
Yeast - anaerobic respiration
-When yeast carries out anaerobic respiration, it produces an alcohol (ethanol) and carbon dioxide
-Yeast will respire anaerobically if it has access to plenty of sugar, even if oxygen is available
-This is taken advantage of in bread making, where the yeast is mixed with flour and water
glucose –> ethanol + carbon dioxide
C6H12O6 –> 2C2H5OH + 2CO2
Process of making bread
- Yeast produce enzymes, break down starch in flour to sugar for respiration
- CO2 produced is trapped in air pockets in dough, rise, increase in volume
- Dough baked in hot oven
- Ethanol evaporates, yeast killed - no further respiration
- Cooled, eaten
Investigating how temperature affects yeast
- Mix yeast + sugar solution
- Add oil (prevent O2, aerobic respiration)
- Connect boiling tube with capillary tube into another bt with limewater
- Place bt 1 into water bath at set temp
- Count bubbles produced in fixed time in limewater
- Change temp, repeat
Bacteria in food production
-bacteria are useful -they are capable of producing complex molecules
-reproduce rapidly - the amount of chemicals they can produce can also rapidly increase
-used to make yoghurt - lactobacillus
Process of making yoghurt
- all equipment is sterilised
- Milk pasteurised (heated) at 85-95°C to kill unwanted bacteria - other bacteria slows production by competing with the Lactobacillus for the lactose in the milk
-It could also spoil the taste of the yoghurt - The milk to 40-45°C, bacteria is added
- The mixture is incubated at temp for several hours,bacteria digest milk proteins, ferment (digest) the lactose
- convert the lactose into lactic acid, increased acidity, sours, thickens milk - yoghurt
-This lowering of the pH helps to prevent the growth of other microorganisms that may be harmful - preservative - kept for longer time - The yoghurt stirred, cooled to 5°C, stop activity of lactobacillus
- Flavourings, colourants and fruit may be added before packaging
Industrial fermenters
Containers used to grow (culture) microorganisms like bacteria and fungi in large amounts
-used for brewing beer, making yoghurt, mycoproteins, producing genetically modified bacteria and moulds that produce antibiotics (penicillin)
-conditions can be carefully controlled to produce large quantities of the exact right type of microorganism:
-aseptic precautions, nutrients, temperature, pH, oxygenation, agitation
Industrial fermenters - aseptic precautions
-fermenter is cleaned by steam to kill microorganisms and prevent chemical contamination
-ensures only desired microorganisms
Industrial fermenters - nutrients
-nutrients are needed for respiration to release energy for growth
-ensure the microorganisms are able to reproduce
Industrial fermenters - optimum temperature
-temperature is monitored using probes and maintained using the water jacket to ensure an optimum environment for enzymes to increase enzyme activity
-if temp is too high - enzymes denature
-if temp is too low - enzyme activity is too slow
Industrial fermenters - optimum pH
-pH is monitored using a probe to check if it is at the optimum value for the microorganism being grown
-pH can be adjusted if necessary using acids, alkalis
Industrial fermenters - oxygenation
-needed for aerobic respiration to take place
Industrial fermenters - agitation
-Stirring paddles
-ensures that microorganisms, nutrients, oxygen, temperature and pH are evenly distributed throughout the fermenter
Methods of fish farming
-maintaining water quality
-controlling intraspecific
-controlling interspecific predation
-controlling disease
-removing waste products
-controlling the quality and frequency of feeding
-selective breeding
Fish farming - maintaining water quality
-water filtered to remove waste and harmful bacteria to prevent diseases
-water cleaned to maintain high levels for aerobic respiration
Fish farming - control of intraspecific predation
Predation within the same species
-fishes separated by size and age so they don’t eat each other or fight
Fish faming - control of interspecific predation
Predation between different species
-different species of fishes separated by fences, nets, tanks to prevent fighting
Fish farming - control of disease
-Antibiotics are given to fish to prevent disease which might spread quickly due to close confinement, increasing chances of survival
-kept in small numbers to minimise the spread of diseases
Fish farming - removal of waste products
-Water can be filtered to remove waste products such as faeces and sewage
-fences, nets, tanks are cleaned
-location of fish changed to ensure clean water
Fish farming - quality and frequency of feeding
-fish are fed food that is high in nutrients to ensure fast growth
-fed frequently but in small amounts so they don’t overeat or start eating each other
Fish farming - use of selective breeding
-fish are separated by gender so selective breeding can be used by farmers to only allow fish with desired characteristics to reproduce
-ensures fish is fast growing as genes passed on more frequently
Selective breeding of plants
Plants are selectively bred by humans for development of many characteristics, including:
-Disease resistance in food crops
-Increased crop yield
-Hardiness to weather conditions (eg. drought tolerance)
-Better tasting fruits
-Large or unusual flowers
Problems of selective breeding
-Selective breeding can lead to ‘inbreeding’
-results in a reduction in the gene pool
-increases chance of organisms inheriting harmful genetic defects
-Organisms being vulnerable to new diseases (there is less chance of resistant alleles being present in the reduced gene pool)
Process of selective breeding
- Individuals with the characteristics you want are bred together
- Offspring that show the desired characteristics are selected and bred together
- This process is repeated for many successive generations until all offspring have desired characteristics
Natural selection
-occurs naturally
-results in development of population with features that are better adapted to their environment and survival
-usually takes a long time to occur
Artificial selection
-only occurs when humans intervene
-results in development of populations with features that are useful to humans, not necessarily to survival of the individual
-takes less time as only individuals with the desired features are allowed to reproduce
Vectors
Plasmids and viruses can act as vectors for genetic engineering
-take up pieces of DNA and insert recombinant DNA into other cells
Virus: transfer DNA into human cells or bacteria
Plasmids: transfer DNA into bacteria or yeast
Process of manufacturing insulin
- Restriction enzymes used to isolate human insulin gene, leaving it with ‘sticky ends’
- A bacterial plasmid cut by the same restriction enzyme leaving it with corresponding sticky ends
- enzyme + plasmid joined together by DNA ligase enzyme
- recombinant plasmid inserted into a bacterial cell
- When bacteria reproduce, plasmids copied as well, recombinant plasmid spread as the bacteria multiply
- all express the human insulin gene and make the human insulin protein
- placed in a fermenter to reproduce quickly in controlled conditions and make large quantities
Why are bacteria useful for genetic engineering?
-They contain the same genetic code as the organisms we are taking the genes from, meaning they can easily ‘read’ it and produce the same proteins
-There are no ethical concerns over their manipulation and growth
-The presence of plasmids in bacteria makes them easy to remove and manipulate to insert genes into them and then place back inside the bacterial cells
Genetically engineered plants
-resistant to insects
-improve crop yields
-resistant to herbicides
-produce additional vitamins
improve nutritional value
Advantages of GM plants
-reduced use of chemicals such as herbicides/ pesticides - better for the environment
-cheaper/ less time-consuming for farmers
-increased yields from the crops as they are not competing with weeds for resources
Disadvantages of GM plants
-increased dependency on certain chemicals
-reduced biodiversity
-some research has shown that plants that have had genes inserted into them do not grow as well as non-gm plants
Genetic engineering definition
The manipulation of the DNA sequences of an organism
Micropropagation
Tissue culture is a process where small (micro) pieces of plants (tissue) are grown (culture) using nutrient media
-grown in petri dishes on nutrient agar (in vitro) - outside living organism
Process of micropropagation
- Cells scraped from parent plant (explants)
- Surface of explants sterilized
- Transferred to sterile petri dish containing nutrient agar
- Growth medium encourages explant cells to grow and divide into small masses of cells (callus)
- Callus transferred to fresh growth medium that contains a range of plant growth regulators (hormones) that causes callus to develop roots, stems, leaves (plantlets)
- Plantlets transferred to individual potting trays, develop into plants
Advantages of micropropagation in commercial uses
-cheaply produced
-greater yield
-quicker yield
-at any time of the year
-identical to each other
-disease-free
Disadvantages of micropropagation in commercial uses
-trained personnel and sterile laboratory needed
-all plants produced are genetically identical
-vulnerable to same diseases and pests
Cloning animals (Dolly the Sheep)
- Nucleus removed from unfertilised egg cell (Sheep A)
- Nucleus from adult body cell inserted into egg cell (Sheep B)
- Electric shock stimulates egg cell to divide to form an embryo
- Embryo develop into a ball of cells, inserted into womb of adult female (Sheep C)
- Clone of A
Transgenic definition
Organism which genome has been altered artificially by the introduction of foreign DNA sequences from another species
