Cloning and biotechnology Flashcards

Question

Describe the process of cheese making

Answer 1

* MILK PASTURISED: heated to 95 for 20 seconds to kill natural bacteria * MILK HOMOGENISED: fat droplets evenly distributed, bacteria and chymosin enzyme added so milk separates into solid curds and liquid whey * COTTAGE CHEESE: curds packaged and sold * HARDER CHEESE: curds cooked in whey and strained through cheese cloth and may be pressed/matured * WHEY: used in animal feeds

Answer 2

* Equipment sterilised (heated to 71 for 20 seconds) * Milk pasteurised * Add bacteria culture and incubate (lactobacillus) * Sampling * Addition of flavours, colours, packaging * Quality control and take some culture to add to next batch

Answer 3

* Production of a protein can be much faster than if made by an animal/plant * Production can be controlled according to demand * No animal welfare issues * Protein contains no animal fat or cholesterol * Microorganisms can be GM to adjust amino acid of the protein * Not affected by seasonal variations * Not much land needed

Answer 4

* Some may not want to eat fungal protein or food grown waste * Need to isolate the protein from the medium its grown in * Protein must be purified * Culture can become infected easily due to optimum growing conditions * Different taste/texture to traditional protein sources

Answer 5

* Includes washing hands, disinfecting working area, Bunsen burner on near (heats air causing it to rise and prevent airborne microbes settling), flaming necks of bottles as they’re opened and closed to prevent bacteria entering * Autoclave: nutrient medium and all equipment put in to be sterilised by being heated to 121 for 15 minutes killing all living organism * Streak plating: way to spread individual bacteria and colonies

Answer 6

population of one type of microorganism that’s been grown under controlled conditions (fermentation vessels)

Answer 7

microorganisms are grown in individual batches in a fermentation vessel so when one culture ends another batch of different microorganisms is grown in the vessel

Answer 8

microorganisms are continually grown in a fermentation vessel without stopping – nutrients are put in and waste products are taken out at a constant rate

Answer 9

if a bioprocess is contaminated by microorganisms from the air or workers it can affect yield so bioreactor is sealed creating aseptic units

Answer 10

* In a closed culture, such as batch fermentation, a population of microorganisms follows a standard growth curve with 4 phases * Lag phase: when bacteria adapting to environment, making enzymes they need * Exponential (log) phase: when the rate of bacterial reproduction is close to or at its theoretical maximum as culture conditions are at their most favourable for reproduction (lots of food and little competition) * Stationary phase: total growth rate is zero as death rate = reproductive rate * Death/decline phase: Population size falls as death rate is higher than reproductive rate due to scarce food and waste products are at toxic levels

Answer 11

* Number of cells in population = initial number of cells x 2n * N = number of divisions

Answer 12

when the substance wanted is formed as an essential part of the functioning of a microorganism e.g. ethanol, ethanoic acid and a range of amino acids and enzymes

Answer 13

• when the substance wanted is not essential for organism’s normal growth but are still used by the cells e.g. many pigments, and the toxic chemicals plants use to protect themselves o Penicillin and many other antibiotics are an example of this

Answer 14

* Immobilised enzymes used to avoid having to separate normal enzymes out of the mixture which can be complicated and costly * Immobilised enzymes: enzymes attached to an insoluble material so they can’t become mixed with the products • Three main ways enzymes are immobilised: 1. Encapsulated in jelly-like alginate beads which act as semi-permeable membrane 2. Trapped in silica gel matrix 3. Covalently bonded to cellulose or collagen fibres

Answer 15

* Columns of immobilised enzymes can be washed and reused – reduces cost * Product isn’t mixed with enzymes – no money or time spent separating them * Immobilised enzymes are more stable and less likely to denature than free enzymes

Answer 16

* Extra equipment required – expensive to buy * Immobilised enzymes more expensive to buy so coupled with equipment cost they aren’t always economical for smaller-scale production * Immobilisation of the enzymes can sometimes lead to reduction in enzyme activity as they can’t freely mix with their substrate

Answer 17

* Conversions of lactose to glucose to galactose: used to produce lactose-free milk * Production of semi-synthetic penicillin: used to combat penicillin resistant organisms * Conversions of dextrins to glucose: used to sweeten and thicken foods * Conversion of glucose to fructose: used as a sweetener in foods as fructose is sweeter but contains less sugar * Production of pure samples of L-amino acids: used to separate L and D amino acids as L amino acids used more * Conversion of acrylonitrile to acrylamide: used to produce synthetic polymers (plastics) for a wide range of uses