Biology U5 PMT

What are the advantages of using Polythene tunnels?

• Protects form pests

• Protects from harsh weather conditions

• Can maintain CO2 levels

• Can maintain temperature

How do we increase the Carbondioxide available and how does increasing the level of CO2 increase the rate of photosynthesis?

• You can increase the amount of CO2 by burning Paraffin lamps

• Increasing the CO2 available allows enzymes to work at their optimum temperature so the rate of photosynthesis incresase

How to Nitrates help plants grow faster?

Nitrates are required to make amino acids for proteins to allow plants to grow

Why is Phosphorous added to fertilisers?

Phosphates are required for respiration and root growth

Why is the Potassium added to fertilisers?

Potassium (absorbed as various compounds of potassium) allows enzyme reactions to take place and increase the growth of flowers and fuit

What are the advantages of using pesticides?

• Quick

• Can kill entire populations

What are the disadvantages of using pesticides?

• Organisms can develip resistance

• Bioaccumulation

• Need to be reapplied continuously

• Can kill useful bacteria

What are the disadvantages of using biological control?

What is the role of pesticides?

To kill pests

What is the role of herbicides?

To kill weeds

What is the role of insecticides?

To kill insects

What is the chemical equation for yeast using anaerobic respiration?

Glucose → Ethanol + Carbon Dioxide

Describe the experiment to investigate the rate of Carbondioxide produces in the anaerobic respiration of yeast

1) Dissolve sugar in boiled water

2) Add yeast and the solution in a boiling tube and add oil to ensure the reaction is anaerobic

3) Connect the boiling tube to a test tube of lime water

4) Count the number of bubbles formed for a specified amount of time

Describe the process of the production of yoghurt

1) Sterilise equipment to kill off unwatered bacteria

2) Pasturise the milk by heating it at 70^oC for 15 seconds

3) Add lactobacillus

4) Place in an incubator at 40^oC, the lactose breaks down to form lactic acid

Describe how bacteria and fungi are produced in fermenters

• The fermenter is sterilised to kill off unwatered bacteria

• The nutrients needed are added

• The culture medium is added

• The paddles stir to distribute heat, nutrients and pH evenly

• The products are then purified

What is genetic modification

Changing the DNA of an organism by removing, changing or inserting genes

What is a recombinant plasmid?

When DNA pieces form two different species are joined together, the plasmid formed is the recombinant plasmid

Describe the process of selective breeding

• Parents with desired characteristics are chosen

• They are bread together

• Offsprings with desired characteristics are bred together

• The process is repeated until all of the offspring have the desired characteristic

What are the disadvantages of selective breeding?

• Inbreeding

• Reduction in gene pool as ther is less variety of alleles produces. This means that if there is a new disease the species would become extinct because they are all genetically similar

• Small gene pool leads to a greater chance of genetic mutations

What is genetic engineering?

Modifying the genome of an organism by introducing a gene from another organism

Describe how Genetic modification can be used to produce human insulin

• The gene that codes of insulin is identified in humans

• That gene is cut using a restriction enzyme

• The same enzyme also cuts into a bacteria’s plasmid to form sticky ends

• The human gene is inserted into the bacteria’s plasmid and the sticky ends are attached using DNA ligase

• The plasmid formed is called a recombinant plasmid

• The plasmid is then inserted back into the bacteria

• The bacteria reproduces

• That makes bacterial culture rich with human insulin, it can be grown in fermenters

Why do we use bacteria specifically for insulin?

• They contain the same genetic code as organism we are taking genes from, allow them to easily ‘read’ the genetic code and produce the same proteins

• There are no ethical concerns

• The presence of plasmids, separate from the main bacterial chromosome allows for easy manipulation of inserting genes and placing them in and out of bacterial cell