Chapter 20: Biotechnology Flashcards
What is fermentation? (2)
-The term fermentation applies to a wide range of reactions brought about by micro-organisms
-Alcoholic fermentation is a form of Anaerobic respiration.
Fermentation
C6H12O6 —> CO2 + C2H5OH + energy
What is biotechnology? (2)
-Using organisms usually microorganisms to produce required substances.
-It involves using living organisms to carry out processes that make substances that we want.
What are yeast? (2)
-Yeast has been used to make bread and alcohol.
-Bacteria have been used to make yoghurt and cheese.
Why does biotechnology use only microorganisms? (5)
-Bacteria are very small and are easy to grow in a laboratory. They do not take up a lot of space.
-Bacteria reproduce very quickly. They are able to make a huge range of different chemical substances.
-Bacteria can make complex molecules that are useful to humans.
-No one minds what is done to bacteria and fungi. There are a few ethical issues like those that might arise if we used animals.
-As well as their main DNA- their ‘chromosome’- bacteria also have little loops of DNA called plasmids. They are quite easy to transfer from one cell to another. We can use plasmids for moving genes from the cells of one organism to another.
Products of yeast anaerobic respiration
Yeast is able to respire anaerobically. When it does so it produces ethanol and carbon dioxide
glucose —> ethanol + carbon dioxide
Alternative to reduce fossil fuels pt 1
(2)
-One alternative is to use plants to provide sugars which yeast can then break down to form ethanol.
-Ethanol sometimes called bioethanol can then be used as fuel.
M and S process
-Maize and sugarcane are two of the crops that are used in to process.
-Maize is first treated with amylase enzymes which break down stored starch to glucose.
-Sugarcane does not need to be treated with enzymes because it stores most of its carbohydrates as sucrose rather than starch.
-Yeast is then added and allowed to use the glucose in anaerobic respiration.
-The ethanol that is produced can then be extracted from the mixture by distillation.
The disadvantage of plant fuel (2)
-Although alcohol burns well it does not contain as much energy per litre as fossil fuels.
-It is therefore normally mixed with gasoline (petrol) to make biofuel that is used in vehicle engines.
Advantage of biofuel (4)
-It is a sustainable resource
-We can keep growing more maize to make more fuel.
-It also helps to reduce the amount of carbon dioxide that we add to the atmosphere.
-Although carbon dioxide is produced when the biofuel is burnt the plants that are grown to make the fuel will have recently taken in carbon dioxide from the air during photosynthesis using it to make the sugar and starch.
The disadvantage of fossil fuel
-Burning fossil fuels causes us to release co2 into the air that has been stored in the earth for millions of years.
Disadvagde of biofuel (3)
-The crops take up land that could otherwise be used to grow food for people.
-Using large quantities of maize the other crops to make biofuels puts up their price, making it more expensive for people to buy food.
-The land on which the crops are grown may originally have contained a biodiverse natural ecosystem which was cleared to increase the area for growing the monoculture crop.
Biofuel
A fuel that is made by mixing ethanol (made by the anaerobic respiration of yeast) with petrol.
Making bread
-Bread is made from flour which is made by grinding the grains (seeds) of cereal crops. Most bread is made from wheat flour.
-Flour contains a lot of starch and also protein especially a protein called gluten. To make bread the flour is mixed with water and yeast to make dough.
-Amylase enzymes break down some of the starch in the dough to make maltose and glucose which yeast can use in anaerobic respiration. Il produces bubbles of CO2. These get trapped in the dough.
-Gluten makes the dough stretchy so the carbon dioxide bubbles cause the dough to rise.
Pectinase
An enzyme that is used to digest pectin increases the quantity of juice that can be extracted from fruit, and clarifies the juice.
What is pectin? (2 )
-Fruit juices are extracted using an enzyme called pectinase.
-Pectin is the substance which helps to stick plant cells together. A fruit such as an apple or orange contains a lot of pectin. Pectinase breaks down pectin. This makes it much easier to squeeze juice from the fruit.
Why is pectinase used? (3)
-Pectinase also helps to make the juice clear rather than cloudy. The cloudiness in fruit juice is often caused by insoluble carbohydrates that float in the juice.
-Pectinase and other enzymes such as cellulase(which breaks down cellulose) can be added to the cloudy juice.
-They break the insoluble substances to soluble ones so the juice becomes clear.
What do biological washing powders contain? (3)
-Enzymes are found in the biological washing powders and detergents. They remove stains made from animal or plant substances such as blood or egg stains.
-Protease catalyse the breakdown of protein molecules to amino acids. Eg- Blood stains
-Some enzymes are lipases which catalyse the breakdown of fats into fatty acids and glycerol for greasy stains.
Enzymes removing blood stains (2)
-Blood contains the red protein haemoglobin.
-The proteases in biological washing powders break the haemoglobin molecules into smaller molecules which are not coloured and can dissolve easily in water and can be washed away.
How do prevent enzymes digesting protein and fats don’t the skin? (2)
-The enzyme is packed into microscopic capsules.
-The capsules break open when the washing powder is mixed with water.
Reasons for treating milk with lactase. (2)
-For people who don’t make lactase thel\melsves can drink milk or eat products from lactose-free milk. Some people stop breaking down lactase when their adults and hence cannot digest lactose leading them to feel ill when consuming lactose products.
-For producing galactose and glucose for making sweets.
fermenter
a vessel usually made of steel or glass in which microorganisms can be grown in order to produce a required product.
sterilised
treated- eg with steam to destroy all living cells.
culture
a population of microorganisms growing in a nutrient liquid or on agar jelly.
