use & growth of organisms

Question 1

define ‘biotechnology’

Answer 1

applying biological organisms to the synthesis, breakdown or transformation of materials in the service of people

Question 2

what are the most commonly used microorganisms is biotechnology?

Answer 2

fungi
- particularly yeast & bacteria

Question 3

why are microorganisms used in biotechnology?

Answer 3

• no welfare issues, only optimum conditions need to be considered
• range of organisms capable of carrying out chemical reactions
• genetic engineering allows us to manipulate organisms to produce things such as insulin
• short life cycle and rapid growth rate
• nutrient requirements cheap & simple
• conditions for microorganisms to grow are low temp - cheap

Question 4

what is indirect food production?

Answer 4

the actions of the micro organisms on other foods is important
- eg making bread/cheese

Question 5

what are the disadvantages of indirect food production?

Answer 5

• conditions must be ideal for micro organisms to work/grow properly
• could cause food to go off / cause disease so conditions must be sterile
• ethical issues of genetic engineering

Question 6

what type of micro organism is involved in baking?

Answer 6

yeast

Question 7

what are the main stages of baking?

Answer 7

• active yeast added to other ingredients, left to rise
• dough knocked back & kneaded
• cooked in hot oven, carbon dioxide bubbles expand and yeast cells killed

Question 8

what type of micro organism is involved in brewing?

Answer 8

yeast - respires anaerobically to produce ethanol

Question 9

what are the main stages of brewing?

Answer 9

• malting = enzymes produced by barley break down starch into sugars, seeds killed by slow heating but enzymes retained to produce malt
• mashing = malt mixed with hot water, enzymes break down starch to wort, wort is sterilised and cooled
• fermentation = wort is inoculated with yeast, yeast inhibited by falling pH, ethanol build up and lack of oxygen
• beer is filtered and pasteurised

Question 10

what type of micro organism is involved in cheese making?

Answer 10

bacteria
- feed on lactose in milk
- inhibits growth of bacteria which makes milk go off

Question 11

what are the main stages of cheese making?

Answer 11

• milk is pasteurised and homogenised
• mixed with bacterial cultures until milk separates
• strained through moulds / cheesecloth
• left to mature, dry & ripen

Question 12

what type of micro organism is involved in yoghurt making?

Answer 12

bacteria
- from ethanal and lactic acid
- produces extracellular polymers to give smooth texture

Question 13

what are the main stages of yoghurt making?

Answer 13

• milk powder added to milk, pasteurised & homegenised
• milk mixed with bacteria and incubated
• mixed and fermented

Question 14

what is direct food production?

Answer 14

using micro organisms to produce proteins you eat

Question 15

foods produced in direct food production are known as …. …… …..

Answer 15

single cell protein

Question 16

what is quorn made from?

Answer 16

a single celled fungus grown in large fermenters using glucose syrup as a food source

Question 17

describe how quorn is produced

Answer 17

microorganisms combined with egg white, compressed and formed into meat substitutes

Question 18

what do humans increasingly use SCP for?

Answer 18

• yeast, algae and bacteria are used to grow proteins
• single cell proteins to feed animals that we prefer to eat

Question 19

how is penicillin produced?

Answer 19

• by mould/fungus
• fungus is grown in fermenters, stirred with oxygen and nutrients and then purified

Question 20

how is insulin produced?

Answer 20

• by GM bacteria
• using a human insulin gene and plasmids

Question 21

what is bioremediation?

Answer 21

• micro organisms are used to digest pollutants / contaminants eg sewage
• encourages microbial growth
• increased population size to break down pollution

Question 22

state 5 advantages of using microorganisms

Answer 22

• microbes grow rapidly
• can be GEd
• flavoured to taste
• no ethical concerns
• rich in protein, low in fat

Question 23

state 3 disadvantages of using microorganisms

Answer 23

• can produce toxins if growing conditions aren’t controlled
• conditions must be aseptic
• no natural flavour, requires additives

Question 24

describe the growing conditions for culturing microorganisms

Answer 24

• growth medium (agar) with water and nutrients
• requires oxygen
• incubates at 25 degrees for growth and avoid pathogen growth
• aseptic to prevent contamination

Question 25

describe what is meant by aseptic conditions

Answer 25

• sterilise equipment
• sterilise surface
• wash hands
• work near bunsen burner
• petri dish only slightly open and when necessary