Chapter 20:biotechnology and genetic modifications

Question 1

Define biotechnology

Answer 1

using organisms,usually microorganisms,to produce required substances

Question 2

Define genetic modification

Answer 2

changing the genetic material of an organism by removing,changing or inserting individual genes

Question 3

Why does biotechnology and genetic modification make use of microorganisms like bacteria

Answer 3

-bacteria are very small and are easy to grow in a laboratory as they don’t take a lot of space
-bacteria reproduce very quickly as they are able to make huge range of difficult chemical substances
-bacteria can make complex molecules that are useful to humans
-no one minds what is done to bacteria and fungi.there are few ethical issues like those that might arise if we used animals
-bacteria has little loops of DNA called plasmids,these are easy to transfer from one cell to another.so we can use plasmids to move genes from one organism to another

Question 4

How does yeast respire

Answer 4

Yeast respires anaerobically.
Glucose —> ethanol + carbon dioxide

Question 5

State 2 uses of anaerobic respiration in yeast

Answer 5

-making bread rise
-making ethanol for biofuels

Question 6

How does yeast make ethanol for biofuels

Answer 6

1.Maize and sugar cane are used
2.maize is first treated with amylase enzymes which breaks down stored starch to glucose
-sugar cane does not need to be treated with enzymes because it stores most of its carbohydrate as sucrose rather than starch
3.yeast is then added and allowed to use the glucose in anaerobic respiration
4.the ethanol that is produced can then be extracted from the mixture by distillation
5.even though alcohol burns well,it does not contain much energy so it is mixed with gasoline to make biofuel that is used in vehicle engines

Question 7

Advantage of making biofuels using maize and sugar cane

Answer 7

-sustainable source
-we can keep growing maize to make more biofuel
-reduces the amount of carbon dioxide that we add to the atmosphere

Question 8

Disadvantages of making biofuels using maize and sugar cane

Answer 8

-the crops take up land that can be used to make food for people
-makes it more expensive

Question 9

Define biofuels

Answer 9

a fuel that is made by mixing ethanol (made by anaerobic respiration of yeast)with patrol

Question 10

Describe the role of anaerobic respiration in yeast during bread making

Answer 10

1.to make bread,the flour is mixed with water and yeast to make dough
2.amylase enzyme break down some of the starch in the dough to make maltose and glucose,which the yeast can use in anaerobic respiration.
3.it produces bubbles of carbon dioxide p,these get trapped in the dough.
4.gluten makes the dough stretchy,so the carbon dioxide bubbles cause the dough to rise

Question 11

Define pectinase

Answer 11

An enzyme that is used to digest pectin,increasing the quantity of juice that can be extracted from fruit and clarifying the juice

Question 12

What’s pectin

Answer 12

Pectin is a substance which helps to stick plant cells together

Question 13

Describe the use of enzyme pectinase in producing fruit juice

Answer 13

-pectinase is an enzyme that breaks down pectins in the cell wall of fruits
-by breaking down the cell walls,it realises the juice from within the cells

Question 14

how are fruit juices clear

Answer 14

the cloudiness in fruit juices are often caused by insoluble carbohydrates that float in the juice.pectinase and other enzymes such as cellulase (breaks down cellulose ) can be added to the cloudy juice.they break down the insoluble substances to soluble ones,so the juice becomes more clear

Question 15

What do biological washing powders contain :

Answer 15

-protease - this helps with the removal of stains caused by proteins :such as blood stains
-lipase -good for removing greasy stains

Question 16

How do protease get rid of blood stains

Answer 16

The protease in biological washing powders break the haemoglobin molecules into smaller molecules which are not coloured and which dissolve easily in water and can be washed away

Question 17

What is lactase

Answer 17

Lactase is a enzyme which breaks down lactose to glucose and galactose

Question 18

What is a fermenter

Answer 18

a vessel,usually made from steel or glass in which microorganisms can be grown in order to procure a required product

Question 19

how do fermenters produce large scale production

Answer 19

1- before the fermentor is used, It is thoroughly washed and sterilised. This is done by passing steam through it. This kills all the microorganisms that are in the form and teaser so that it will not contaminate the culture.
2-Water and the nutrients (amino acid and sugar) that the micro organism need for growth are added to the fermentor
3- If the micro organisms respire aerobically air bubble through the contents of the fermenter,this provides oxygen.
4-A motor turns paddles that keep the contents mixed.this makes sure that the microorganisms in every part of the fermenter are supplied with nutrients and oxygen
5-microorganisms are added
6-a probe measures the conditions inside the fermenter
7- When the micro organisms have had time to produce the required product, the contents of the fermenter can be harvested

Question 20

what happens when mixing contents when the fermenter is being used to grow a fungus made up of long hyphae

Answer 20

If the fermenter is being used to grow fungus made of hyphae there are usually no pedals because they will get tangled up with the hyphae

Question 21

What are the products produced using fermenters

Answer 21

1- insulin by genetic modified bacteria
2- penicillin produced by the fungus penicillium
3- myroprotien produced by a fungus called fusarium

Question 22

process of genetic modification

Answer 22

1- DNA is extracted from human cells.The DNA is cut into small pieces using restriction enzymes
2-Restriction enzymescut DNA at different places on the two strands,which leaves short lengths of unpaired bases at each end.These are called sticky ends.
3-The same restriction enzymes are used to cut plasmids in the bacteria. This opens up the circular plasmids again leaving sticky ends.plasmids have complementary bases to one another
4-The cut human DNA and the cut plasmid are mixed together.the complimentary bases on the two lots of sticky and join together.
5-DNA ligase is mix with the human DNA and plasmids.this enzyme joins the plasmids back together again into complete circles.these become recombinant plasmids and are put into bacteria.
6-The bacteria put into Fremington allowed to reproduce.

Question 23

Name 4 examples of genetic modification

Answer 23

1- the insertion of human genes into bacteria to produce human proteins
2- the insertion of genes into crop plants to confer resistance to herbicides
3-the insertion of genes into crop plants to confer resistance insect pests
4-the insertion of genes into crop plants to improve natural qualities

Question 24

advantages of genetically modifying crops

Answer 24

1-having extra vitamin A in rice makes it more nutritious
2-crop plants that make their own toxin ps to kill insect pests do not need to be sprayed with insecticides
3-if the crop plants are resistant to herbicides,farmers can kill weeds in the crops using that herbicide

Question 25

Disadvantages of genetically modifying crops

Answer 25

1-seeds if genetically engineered crops can be more expensive than the normal seeds
2-requires high skilled people and high quality laboratory facilities
3-makes people ill