N4 Unit 1 Part B Flashcards
Give two useful properties of microorganisms.
They grow quickly and they can use a wide range of materials as a food source
What three food products rely on the activities of yeast?
Beer, wine and bread
Give the word equation for fermentation in yeast.
Sugar → alcohol + carbon dioxide + some energy
Which of the products of fermentation are useful to a brewer and why?
Alcohol makes the beer alcoholic and carbon dioxide makes it fizzy
Which of the products of fermentation are useful to a bread maker and why?
Carbon dioxide makes the bread dough rise.
What is a biofuel?
A renewable fuel that can be made from biomass
Name three types of biofuels.
Bioethanol, biodiesel and biogas
Describe how bioethanol is produced.
Once the plant (corn or sugar cane for instance) have been harvested, yeast are allowed to digest it. Oxygen levels are kept low, they carry out fermentation and produce bioethanol.
How is biodiesel produced?
A type of bacteria has been modified to allow it to produce biodiesel. It feeds on sugar from plant material and secretes the biodiesel into the vat it is growing in.
What is biogas used for?
Can be used to generate electricity or for cooking.
Give one advantage for biofuels.
They emit up to 70% less carbon than fossil fuels
Give one disadvantage for biofuels.
Ethanol is much less efficient than other fuels and gets only about 70% of the mileage of petrol.
Name two food products made using bacteria.
Cheese and yoghurt
When making yoghurt, why is the milk heated before adding the starter culture of bacteria?
To kill off any unwanted microorganisms.
Describe the lactic acid fermentation process.
The bacteria feed on the sugars in the milk and convert the lactose into lactic acid
What is bioremediation?
Any process where a living organism (such as bacteria) is used to remove pollutants from the environment.
What is sewage?
Wastewater that comes from homes, businesses, and other facilities.
Describe how bacteria are involved in the sewage treatment process.
Bacteria feed on the sewage and break it down.
What is radioactive waste?
Waste filled with unstable elements or radionuclides
Describe how bacteria can be used for bioremediation of radioactive waste.
Bacteria can convert toxic mercuric ions to elemental mercury, which is less harmful to humans
What is oil spill bioremediation?
A process that uses microorganisms to break down toxic substances in oil spills.
What is photosynthesis?
A chemical reaction which allows plants to make their own food using light energy.
What are the raw materials of photosynthesis?
Carbon dioxide and water
What are the requirements of photosynthesis?
Light and chlorophyll
What are the products of photosynthesis?
Glucose and oxygen
Describe the role of chlorophyll.
Absorbs light energy.
Describe the energy conversion which takes place during photosynthesis.
light energy → chemical energy
How is the sugar made during photosynthesis stored?
Turned into starch
What is a limiting factor?
A factor that can limit the rate of photosynthesis if it is absent or in short supply.
What are the four limiting factors of photosynthesis?
Light, water, carbon dioxide and suitable temperature
What are the raw materials of respiration?
Glucose and oxygen
What are the products of respiration?
Carbon dioxide, water and energy
What piece of equipment can be used to measure the rate of respiration in an organism?
Respirometer
Name three factors which could affect the rate of respiration.
Concentration of oxygen, concentration of glucose and temperature
What is fermentation?
A type of respiration which takes place in the absence of oxygen
Give the word equation for fermentation in animal cells.
glucose → lactate + some energy
What condition is caused by a build-up of lactate in the muscles?
Muscle fatigue
What is an oxygen debt?
The amount of oxygen required to break lactate down
Give the word equation for fermentation in plant and yeast cells.
glucose → carbon dioxide + alcohol + some energy
What does aerobic mean?
In the presence of oxygen
Which type of respiration releases the most energy?
Aerobic respiration
Why is stem cell technology used?
To cure diseases
Why is stem cell technology controversial?
It involves the destruction of embryos
