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Alevel Biology > 6.4 > Flashcards

6.4 Flashcards

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1
Q

what are clones

A

genetically identical copies

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2
Q

how are clones produced

A

by asexual reproduction in which the nucleus is divided by mitosis, mitosis creates 2 identical copies of the DNA, whihc are then separated into 2 genetically identical nuclei befire the cell divides to form 2 genetically identical cells, these cells may not be physically or chemically identical as after divisoin they may differentiate to form different cell types

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3
Q

where are clones formed

A

in nature, any organism that reproduces asexually will produce clones of itself (e.g. bacteria divided by binary fission involving exacrt replication of DNA, so cells produced are geneticslly identical)

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4
Q

What are the advantages of reproduction by cloning

A

if conditions for growth are good for parent, they’ll be good for offspring too, cloning os relatively rapid (so population can increase quickly when environment suitable), reproduction can be carried out even if only 1 parent and sexual reproduction isn’t possible

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5
Q

what are disadvanatges of natural cloning

A

offspring may become overcrowded, no genetic diversity, population shows little variation, selection not possible, if environment changes whole population may be wiped out

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6
Q

What do many parts of a plant contain and what does this mean

A

cells that retain ability to differentiate into range of cell types meaning that plants are able to reproduce by cloning

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7
Q

what dies natural cloning involve

A

vegetative propagation

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8
Q

what is vegitative propagation

A

process of reproduction through vegetative parts of the plant, rather than through specialsied reproductive structures

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9
Q

What are runners/stolens/rhizomes

A

horizontal stems that can form roots at certain points, runners and stolens grow on grouds surface, rhizomes grow undergroud

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10
Q

how are some rhizomes adapted

A

as thickened organs from which one or more new stems will grow from in spring time

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11
Q

What are suckers

A

new stems that grow from roots of a plant, these may be close to the base of an old stem or could be some distance away. In all cases, the original branch may die, leaving new stem as a separate individual

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12
Q

what are bulbs (e.g. onions)

A

an over-wintering mechanism for many perennial monocotyledonous plants, they consist of undergroynd stem which grows a series of fleshy leaf bases. There’s also an apical bud which will grow into new plant in spring, often bulb contains more than 1 apical bud and each will grow into a new plant

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13
Q

What are corms

A

solid rather than fleshy like a bulb, it is an underground stem with scaly leaves and buds, corms remain in the ground over winter, in spring buds grow to produce 1 or more new plants

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14
Q

how does the Kalanchoe plant reproduce

A

asexually, as clones grow on leaf margins, immature plants drop of leaf and take root

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15
Q

what are tubers

A

another type of underground stem (e.g. potatoes), 1 potato will grow into 1 or more plants, each new plant can then rpoduce many new tubers later in the year

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16
Q

do animals clone as often as plants

A

no

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17
Q

what is an example of when mammals clone

A

identical twins, the zygote divides as normal but the 2 daughter cells spit to become 2 separate cells, each cell grows and develops into a new individual

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18
Q

what is the easiest ways for garderns to make clones

A

by making cuttings

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19
Q

how are cuttings made for clones

A

a stem is cut between 2 leaf joints (nodes), the cut end of stem is plased into moist soil, new roots will grow from tissues in the stem (usually from the node), but they may grow from other parts of the buried stem

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20
Q

what do gardeners do when some plants don’t take root easily

A

they need further treatment, by dipping the cut stem in rooting hormone helps stimulate root growth, may also help to remove bark from cut end of the stem as it encourgaes the plant to produce as callus

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21
Q

why is making cuttings a good technique

A

can be used to produce large number of plants very quickly

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22
Q

where in teh plant can cuttings be made sucessful (3 other examples)

A

root cuttings (section of root is buried just below soil surface and produces new shoots), scion cuttings (dormant woody twigs), leaf cuttings (leaf is placed on moist soil, leaves develop new stems and new roots, some leaves may produce many new plants from one cutting)

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23
Q

what is a less time consuming and more reliable method of cloning plants

A

tissue culture techniques

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24
Q

what is tissue culture

A

a series of techniques used to grow cells, tissues or organs from a small sample of cells of tissue, it is carried out on a nutirent medium under sterile conditions, application of plant growth substances at correct time can encourage cells in growing tissues to differentiate

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25
Q

when is tissue culture widely used

A

commercially to increase number of plants, in micropropagation

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26
Q

what does micropropagation involve

A

taking a small piece of plant tissue (explant) and using plant growth substances to encourage it to grow and develop into a whole new plant

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27
Q

what is steps 1-2 of micropropagation

A
  1. suitable plant material is selected and cut into new pieces called explants, they can be tiny pieces of leaf, stem, root or bud, meritem tissue often used as it is always free from virus infection 2. explants are sterilised using dilute bleech or alcohol, essential to kill any bacteria and fungi, as these would thrive in conditions supplied to help plant grow well
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28
Q

what is steps 3-4 of micropropagation

A
  1. explants placed on sterile growth medium (agar gel) containing suitable nutrients like glucose, aminno acids and phosphates and plant growth substances like auxin and cytokinin which stimulates cell of each explant to divide by mitosis to form a callus (mass of totipotent cells), 4. once callus formed, it is divided to produce a larger number of small clumps of undifferentiated cells
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29
Q

what is steps 5-6 of micropropagation

A

these small clumps of cells are stimulated to grow, divide and differentiate into different plant tissues, achieved by moving the cells to different growth media, each medium contains different ratios of auxin and cytokinin, first medium contins 100 auxin:1 cytokinin stimulating roots to form, 2nd medium contains ratio 4 auxin: 1 cytokinin stimulating shoots to form 6. once tiny platelets have been formed, these are transfered to a greenhouse to be grown in compost or soil and acclimatised to normal growing conditions

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30
Q

what are first 3 advantages of artifical cloning

A

relatively rapid method compared with growing plants from seeds, carried out where asexual reproduction not possible or plants that are hard to grow from seeds, plants will be genetically identical to parents so will have same desirable traits like high yield, disease resistance or certain flower colour,

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31
Q

what are last 3 advantages of artifical cloning

A

if original plant had n unusual combination of characteristics due to selective breeding or genetic modification it can be retained without risk of losing combination through sexual reproduction, new plants have same phenotype so easier to grow and harvest, using meristem as explant for tissue culture ensures new plants are free from viruses

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32
Q

what are 5 disadvantages of artifical cloning

A

tissue culture is labour intensive, it’s expensive to set up facilities to do it successfully, can fail due to microbial contamination, all offspring are identical so susceptible to same pests and diseases, no genetic variation unless mutations occur

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33
Q

what have some species like greenfly and water fleas done

A

have evolved the ability to clone naturally, in other species this is rare, so most animal clonign is artifical

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34
Q

where does successful cloning in animals start

A

in totipotent cells, these cells can divide and differentiate into all different types of cell found in the adult organism (in animals very early embryonic stem cells are the onnly totipotent ones)

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35
Q

what can reproductive cloning do

A

produce large numbers of genetically identical animals

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36
Q

what may reproductive cloning be useful fro (2)

A

elite farm animals produced by selective breeding or genetic modification, genetically modified animals developed with usual characteristics (e.g. goats milk w spider silk)

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37
Q

what are the 2 main techniques for reproductive cloning

A

embryo twining and somatic cell nuclear transfer (SCNT)

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38
Q

what happens if a embryo splits very early in developement

A

a twin is produced

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39
Q

what is embryo twinning technique (4 steps)

A
  1. zygote is created in vitro fertilisation (IVF) 2. zygote allowed to divide by mitosis to form small ball of cells 3. cells are separated and allowed to continue dividing 4. each small mass of cells placed into uterus of surrogate mother
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40
Q

what has embyro twinning technique been used for

A

clone elite farm animals or animals for scientific research, but, precise genotype and phenotype on offspring depends on sperm and egg used, so precise phenotype unknown till animal is born

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41
Q

What is an advanatge of somatic cell nuclear transfer (SCNT)

A

only way to clone an adult, phenotype is knwon before cloning starts

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42
Q

how does SCNT work (6 steps)

A
  1. egg obtained and nucleus is removed, known as enucleation 2. somatic cell from adult to be cloned is removed and may also have nucleus removed 3. complete adult somatic cell or just its nucleus is fused with empty egg cell by applying electric shock 4. shock triggers egg cell to start developing as tho it had just been fertilised 5. cell undergoes mitosis tp produce small ball of cells 6. young embryo placed into uterus of a surrogate mother
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43
Q

what is non-reproductive cloning

A

production of cloned cells and tissues for purposes other than reproduction

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44
Q

what is therapeutic cloning (type of non-reproductive cloning)

A

new tissues and organs can be grown as replacement parts for ill patients, skin can be grown in vitro as a graft over burns, cloned cells could repair damage to spinal cord and restore ability for pancreas to produce insulin, potential to grow new organs to replace diseased organs

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45
Q

why could therapeutic cloning work to produce new tissues/organs

A

it’s grown from paitent’s own cells so avoids rejection, which is an issues in organ transplants

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46
Q

what is non-reproductive cloning for scientific research

A

cloned gebetically identical embryo used for research into action of genes that control development and differentiation, also used to grow specifc tissue or organs for use in tests on effects of medicinal drugs

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47
Q

what is pro and con of using artfiical cloning to produce elite farm animals

A

can produce whole herds of animals with high yields of milk or showing usual combinations like silk in their milk, but, lack of genetic variation may expose herd to certain diseases or pests and animals may be produced w little welfare regard

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48
Q

what is pro and con of using artfiical cloning to produce high value animals

A

produces genetically identical copies of very high value individuals retaining the same characteristics, but, success rate of adult cell cloning is poor and more expensive than conventional breeding, these cloned animals may be less healthy and have shorter life span

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49
Q

what is pro and con of using artfiical cloning for scientific research

A

using genetically identical embryos and tissue for research allows effects of genes and hormones to be assessed with no interference from different genotypes, but, ethical issues about making and then destroying embryos

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50
Q

what is pro of cloning for testing medicinal drugs

A

avoids use of testing in people or animals when done on cloned cells and tissues

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51
Q

what is pro of cloning for organ transplant

A

can produce genetically identical cells and tissues to donors for use in preparing damage due to disease or accidents

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52
Q

what is pro and con of cloning for helping endangered species

A

individuals from endangered species can be cloned to increase numbers, but, this does not help increase genetic diversity

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53
Q

what was the term biotechnology first used to describe

A

any technological process that made use of living organisms or parts of living organisms to manufacture useful products or provide useful services, including domestication of animals, crop planting and selective breeding of plant and animals over generations

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54
Q

what are 2 recent examples of biotechnology

A

use of bacterium Clostridium acetobutylicum to produce acetone needed to make explosives in WW1, manufacture of penicillin from fungus Penicillin Notatum in WWll

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55
Q

what has led to a huge expansion in biotechnology

A

new science of DNA technology, our current underdtanding of genetics and genetic engineering, and ability to manipulate living conditions of living organisms

56
Q

what is biggestest expanison of biotechnology

A

use of microorganisms in industrial processes

57
Q

how are microorganismed used in biotechnology for food

A

ethanol in beer and wine (Yeast), CO2 to make bread rise (yeast), lactic acid for cheese and yogurt, mycoprotein (filamentous fungus protein to make vegitarian food, soya (soya beans fermentated to produce soy sauce)

58
Q

how are microorganismed used in biotechnology for pharmaceutical drugs

A

penicillin, other antibiotics, insulin (genetically modified bacteria)

59
Q

how are microorganismed used in biotechnology for enzymes

A

protease and lipase in washing powders (bacteria), sucrase used to make sweeteners (yeast), protease used to tenderise meat, lactase for lactose-free milk

60
Q

how are microorganismed used in biotechnology for other produccts

A

bioremedification (clean water taste), uses a variety of fungi and bacteria

61
Q

what are first 4 advanatges if using microgranisms in biotechnology

A

microorganisms cheap and easy to grow, production process occurs at low temps so saves fuel and reduces cost, can occur at normal atmospheric presure which is safer than chemical reactions that require high pressure, production is not cliamate depend(can occur anywhere in the world)

62
Q

what are first 4 advanatges if using microgranisms in biotechnology

A

microorganisms cheap and easy to grow, production process occurs at low temps so saves fuel and reduces cost, can occur at normal atmospheric presure which is safer than chemical reactions that require high pressure, production is not cliamate depend(can occur anywhere in the world)

63
Q

what are next 3 advanatges if using microgranisms in biotechnology

A

microorganisms fed bi-products from other industries, microorganisms have short life and reproduce quickly, microorganisms can be genetically modiifed easily allwing specific process to be achieved

64
Q

what are last 3 advanatges if using microgranisms in biotechnology

A

less ethical issues with microorganisms, products released from microorganism to surrounding medium making product easy to harvest, product easier to isolate than in chemical engineering

65
Q

apart from microorganisms what is also used for biotechnology

A

fenetically modififed mammals like sheep, goats and cows used to produce useful proteins (e.g. goats GM to posses gene for spider silk in their milk)

66
Q

apart form biotechnology for production process, what other forms are there (7)

A

gene technology, genetic modification, gene therapy, selective breeding, cloning by embryo-splitting, use of enzymes in industrial processes, immunology

67
Q

how are microorganisms used in food production of yogurt

A

yogurt is milk that undergoes fermentation by Lactobacillus bulgarius and streptococcus thermopiles. These bacteria convert lactose to lactic acid, the acidity denatures the milk proteins causing it to coagulate, bacteria partially digests the milk, making it easy to digest. Fermentation produces the flavour characteristic to yogurt. Other bacteria can also be added as probiotics (bacteria which may improve human healthy by improving lactose digestion, helping gastronomical functions and stimulating immune system)

68
Q

how are microorganisms used in food production of cheese (1/2)

A

milk is pre-treated with culture of bacteria that can produce lactic acid from lactose. Once it is acidified, milk is mixed with rennet which contains enzyme rennin which is found in stomach of young mammals. Rennin coagulates milk protein (casein) in presence of calcium ions: 1. Kappa-casein, which keeps casein in solution, broken down making caesin insoluble 2. caesin is precipitated by action of calcium ions which bind molecules together

69
Q

how are microorganisms used in food production of cheese (2/2)

A

resulting solid (curd) is separated from liquid component by cutting, stirring and heating. The bacteria continue to grow, producing more lactic acid, cured then pressed into moulds. Treatment which making and pressing the curd determines cheese characteristics. Flavour determined during later maturing process and it can also have additional flavour by inoculation with fungus (e.g. blue cheese)

70
Q

how are microorganisms used in food production of bread

A

Bread is flour, water, salt and yeast. 1. Mixing-ingredients are mixed together thoroughly by kneading to produce dough 2. proving/fermentation-dough left in warm place whilst yeast anaerobically respires to produce carbon dioxide bubbles causing dough to rise 3. cooking-risen dough is backed, any alcohol evaporates during cooking process

71
Q

how are microorganisms used in production of alcohlolic beverages

A

use product of anaerobic respiration of yeast, wine made using grapes that naturally have yeast in their skin, grapes contain sugars fructose and glucose when grapes are crushed, yeast uses these sugars to produce carbon dioxide and alcohol. Beer brewed using barley grains beginning to germinate, a process called malting. As grain germinates it converts stored starch to maltose, which is respired by the yeast, anaerobic respiration produces carbon dioxide and alcohol.

72
Q

how are microorganisms used in production of single-cell protein (SCP)

A

microorganisms can e used to make proteins directly used as food, most often using fungus. SCP also known as mycoprotein/fungal protein (e.g. Quorn, meat substitute for vegitarians, contains no animal fat or cholesterol). Using microorganisms for SCP can produce a protein with similar amino acid profile to animal and plant proteins, they can grow on almost any organic substrate, including waste materials like paper

73
Q

what are advantages of using microorganisms in food production (10)

A

protein production alot faster than in animal/plant protein, biomass produced has very high protein content, production can be increased or decreased according to demand, no animal welfare issues, microorganism good source of proteins, these proteins have no animal fat or cholesterol, microorganisms can be GM to adjust amino acid content of the protein, SCP could be combined with removal of waste products, production is idenpendant of seasonal variation, little land required

74
Q

what are disadvantages of using microorganisms in food production (7)

A

people may not want to eat fungal protein grown on waste, microorganisms grown in huge fermentaters and need to be isolated form material they grow on, protein has to be purified to ensure uncontaminated, microbial biomass can have high proportion of nucleic acids which must be removed, amino acid profile may be different from traditional animal protein, conditions that microorganisms grow in are ideal for pathogenic organisms so need to ensure culture doesn’t get infected, protein doesn’t have taste or texture of traditional protein sources

75
Q

what does commerical drug production use to do what

A

steel containers called fermenters where growing conditions can be controlled to ensure best possible yeild of product

76
Q

what conditions must be controlled in commerical drug production (5)

A

temp(too hot enzymes will denature, too cool growht limited), avaliable nutrients (microorganisms require nutrient to grow and synthesise product, sources of carbon, nitrogen, minerals and vitamibns are needed), oxygen avaliability (most microorganisms respire aerobically), pH (enzyme activity, growth and synthesis affected by extreme pH), concentration of product (if product is allowed to build up may affect synthesis process)

77
Q

what must occur to fermenter before its used for commercial drug production

A

sterilised using superheated steam, then filled will all necessary components for growth and supplied with a starter culture of microorganisms to be used. Culture will be left to grow and synthesise the products

78
Q

what are primary metabolities in batch and continuous culture

A

some products synthesised by microorganism during normal metabolism when they are actively growing, these are continously released from cells and can be continuosly extracted from fermenting broth, broth is topped up with nutrients as these are used by microorganism

79
Q

what is some of the broth removed regularly in continuous ulture

A

to extract product and remove cells from broth so population doesn’t become too dense, known as continuous culture and keeps microorganism growing at a specific growth rate

80
Q

what are secindary metabolities in continous culture

A

other products produced when cells placed under stress like high population density or limited nutrient availability. They are produced mostly in stationary phase of growth, culture is set up with a limited quantity of nutrients and allowed to ferment for specfifc time, after this, fermenter is emtied and product can be extracted from culture known as batch culture

81
Q

what is asepsis

A

ensuring sterile conditions maintained, nitrient medium would also support growth of unwanted microorganisms which would reduce production as unwanted microorganisms: compete with cultured microorganisms for nutrients and space, reduce yield of useful products, soil product, produce toxic chemicals, destroy cultured microorganisms ad their products

82
Q

when food or mediicnal chemicals produced what must happen if unwanted contamination

A

discarded

83
Q

what was Florey and Chain process to mass produce pennicillin through fermentation of fungus (3)

A
  1. fermentation run for 6-8 days, culture is then filtered to remove the cells 2. antibiotic is precipitated as crystals by addition of potassium compounds, the antibiotic may be modified by action of other microorganisms or by chemical means 3. antibiotic is mixed with insert substances and prepared for administration in tablet form, as a syrup or in a form suitable for injection
84
Q

what does it mean that penicillin is a secondary metabolite

A

it is only produced once popuklation has reached certain size, so, penicillin manufactured by batch cukture

85
Q

how was synthetic human insulin developed

A

by genetically modifying a bacterium, the gene for human insulin was combined with a plasmid to act as a vector, so gene could be inserted in bacterium E. Coli. The resulting genetically-modified bacterium enabled production of vast quantities of human insulin at relatively low cost, insulin is manufactured by continuous culture

86
Q

what is bioremediation

A

use of microorganisms to clean soil and underground water on polluted sites, the organisms convert toxic pollutants to less harmful substances

87
Q

when did idea of bioremidication start

A

found a modified bacterium enabled breakdown of crude oil, can treat oil spills, bioremediation also used for solvents and pesticides

88
Q

what does bioremedication invovle

A

stimulating growth of suitable microbes that use contaminants as source of food, it requires right conditions for microorganism growth which are available water, suitable temp, suitable pH

89
Q

what happens if condiitons not suitable for bioremedication

A

modified by additon of suitable substances such as nutrients so microorganism can grow or oxygen for aerobic bacteria, if conditions in situ not suitable soil may be removed and treated ex situ

90
Q

what are advanages of bioremedication (5)

A

uses natural systems, less labour required, treatment in situ, few waste products, less risk of exposure to clean-up personnel

91
Q

disadvantage of bioremedicaion

A

only suitble for certain producta, heavy metals like lead can’t be treated

92
Q

what will microorganisms grow on

A

almost any materiel that provides carbon compumds for respiration and source of nitrogen for protein synthesis

93
Q

in a lab what are the 2 options of growht mediums microorganisms can be grown in

A

soup like liquid called a broth, kept in bottles or tubes, a set jelly like substance called agar which is melted and poured into a petri dish

94
Q

what does typical nutrient agar contain

A

peptones (from enzyme breakdown of gelatine), yeast extract, salts and water, may also contain glucose or blood

95
Q

what are aseptic techniques

A

developed to reudce likelyhood of contaminating medium with unwanted bacteria or fungi

96
Q

what is the standard procedure in aseptic techniques (6)

A
  1. wash hands 2. disinfect work area 3. have busen burner near to heat the air (causes air to rise and prevents air born microorganisms settling and creates an area of sterile air to work in) 4. As open vessel pass neck of bottle over flame to prevent bacteria in air entering bottle, bottle should be flamed as its closed too 5. don’t lift lid of petri dish completly off, just enough to introdce desired microorganism 6. any glassware or metal equipment should be passed through flame before and after contact with desired microorganisms
97
Q

what are the 3 main steps to ensure the microorganism grows on the growht medium and it isn’t others that have infected it

A

growing microorganisms on agar plates involves 1. sterilisation, 2. inoculation 3. incubation

98
Q

what is sterilisation in techniques for microorganism culture

A

nutrient agar medium and any equipemnt must be sterilised by heating it in an autoclave at 121 degreesC for 15mins killing all living organisms, including bacterial or fungal spores. When medium sufficiently cooled, its poured into sterile petri dish and left to set. It is important lid is kept on pertri dish to stop infection

99
Q

what is inoculation in techniques for microorganism culture

A

introduction of microoragnisms to sterile medium achieved in number of ways, streaking, seeding, spreading, small cotton bud moistened

100
Q

what is streaking in inoculation

A

wire inoculation loop used to trabsfer drop of liquid medium onto surface of agar, drop is drawn out into a streak by dragging loop across the surface, take care not to break agar surface

101
Q

what is seeding in inoculation

A

sterile pipette used to transfer small drop of liquid meidum to surface of agar or pertri dish befire agar poured in

102
Q

what is spreading in inoculation

A

sterile glass spreader may be used to spread inoculated drop over agar surface

103
Q

what is moistened cotton bud in inoculation

A

moistened with distilled water amd used to collect microorganisms from a surface and then carefully wiped over surface of agar medium

104
Q

4 steps to inoculkating an agar plate

A
  1. heat inoculating loop in blue flame and let it cool briefly 2. remove cap from broth culture and flame mouth of bottle, dip cool sterile inoculating loop in broth, flame and recap bottle 3. spead a streak of culture over surface of agar and cover with lid, reheat inoculating loop in blue flame 4. use adhesive tape to hold lid on petri dish and incubate at 25degrees C
105
Q

what is incubation in techniques for microorganism culture (1/3)

A

petri dish must be labelled and top taped to bottom using 2 strips of adhesive tape, don’t seal dish completly, as can lead to pathogenic anaerobic bacteria. Petri dish then placed in warm environment like incubator upside down to prevent consenstaion drops falling onto agars surface and prevent agar medium drying out too quickly

106
Q

what is incubation in techniques for microorganism culture (2/3)

A

suitable temp dpends on organism type being grown, cultures can be examined after 24-36h, don’t open petri dish as bacteria that grows in colonies may grow round the edge of the dish. Colonies can be shiney or dull and range in colours, each colony results from single bacterium

107
Q

what is incubation in techniques for microorganism culture (3/3)

A

filamentous fungi grow into a mass of hyphae, which may also be circular but mass is not shiney and looks like cotton wool with fluffy areil hyphae . Single celled fungi grow as circular colonies. All petri dishes must be completely sterilised after use and before disposal, thoroughly wash your hands after handling petri dish, as any moisture out of dish could be source of infection

108
Q

why is a liquid meidum used to grow microoragnisms

A

liquid broth is intiially clear but will turn cloudy when bacteria have grown. A liquid broth can be useful to increase numbers of microorganisms before transferring to agar plates for counting or identification. Aseptic techniques must also be used when using a broth, liquid broth can be used to investigate population growth

109
Q

what is a liquid broth used to measure

A

growth rate of a microorganism

110
Q

what happens to a sterile broth when measuring microogranism growth rate

A

inoculated and population size measured at regualr intervals during incubation, population size can be measured by transfering small sample onto agar plate and incubating agar culture (each individual microorganism will produce a visible colony)

111
Q

why is it essential to reduce population density and how is it achieve when counting individual microorganisms in a brooth

A

if broth used to inoculate agar plate, may be too many colonies which merge together making count impossible, to investigate growth rate of population of microorgansims its essential to reduce population density, achieved by serial dilution

112
Q

how does serial dilution work for broth culture

A

at each step broth is diluted by factor of 10. take 1cm3 sample of broth and add 9cm3 distilled water (10-1), then take 1cm3 of 10-1 and 9cm3 distilled water to make 10*-2) and so on until enough serial dilutions

113
Q

what happens once seial dilutions done to measure number of colonies

A

drop of each dilution used to incoluate agar plate, 1 of them will produce a culture plate where number of colonies can be counted, when recording population density, do not forget to multiply your count by dilution factor and by volume added to plate

114
Q

what is closed culture

A

culture which has no exchange w gas or nutrients from external environment1

115
Q

when does population gorwth in closed culture occur

A

when microogranisms have all required nutrients for growth, population growth will follow predictable pattern

116
Q

difference between closed culture and batch production

A

in batch production some substances like oxygen mmay be added to keep population growing till nutrients used up

117
Q

what is lag phase in population growth

A

in early pop growth, pop doesn’t grow quicjly as population is still small and as organisms are adjusting to their new environment which may involve taking up water, cell growth, activating certain genes, synthesising specific proteins (enzymes)

118
Q

what is log (exponential) phase in population growth

A

organnisms have adjusted to their environment and have enzymes needed to survive, each individual has sufficient nutrients and space to grow rapidly and reproduce (population doubles in size with each generation)

119
Q

what is stationary phase in population growth

A

increrasing number of organisms use up nutirents and produce increasing amounts of waste products like co2 and other metabolites, rate of population growth declines and number of individuals dying increases until reproduction rate equals death rate. This is stationary phase, no pop growth

120
Q

what is death (decline) phase in populaiton growth

A

nutrients run out and concentration of waste products becomes lethal, more individuals die than are produced and population begins to fall, eventually all organisms will die

121
Q

what are primary metabolites

A

PM produced during normal activities of microorganisms will be collected from fermenter during log phase. In a fermenter, pop not in closed culture but conditions maintained for optimal growth

122
Q

what are secondary metaboloites

A

produced during stationary phase, population must be kept in closed culture and metaboloites collected at end of sttaionary phase or in decline pahse

123
Q

how can some biotechnological processes be simplified

A

by taking enzymes out of microorganisms, enzymes are large proteins that act on subtrates to generate product. Enzymes aaren’t used up in reaction and remain in suspension when reaction has been completed. In industrial process, means that product must be isolated from enzyme befire use which could be expensive

124
Q

what are immoblised enzymes

A

enzymes taken out of suspension and held so they don’t freely mix with substrate

125
Q

what are 4 advantages of immobilised enzymes

A

enzymes don’t mix w product so lower extraction costs, enzymes easily reused, continous processes easier as no cells requiring nutrients, reproducing and releasing waste products, enzymes surrounded by immobilising matrix which protect them from extreme conditions so high temp or pH used without denaturing them

126
Q

what is disadvantage of immobilised enzymes

A

setting them up is more expensive and immobilised enzymes are usually less active than free enzymes, making process slower

127
Q

how can enzymes be immobilised

A

by binding them to a surface or trapping them so they can’t enter substrate solution

128
Q

what is adsorption as method for immobilising enzymes and a limitation of this

A

enzyme molecules are bound to supporting face by combination of hydrophobic interactions and ionic links. Suitable surfaces include clay, glass beads and resins. Enzyme molecules are bound w active site exposed and accessible to substrate but active site may be slightly distorted by additional interactions affecting enzyme activity. Bonding forces are not always strong and enzymes can become detached and leak into reaction mixture

129
Q

what is covalent bondign as method for immobilising enzymes and a limitation of this

A

enzyme molecules bonded to supporting surface like clay using strong covalent bonds, enzymes are bonded using cross-linkage agent, which may also link them in a chain. But, Production of covalent bonding can be expensive and can distort enzyme active site, reducing reactivity. But, enzymes much less likely to detach and leak into reaction mixture

130
Q

what is entrapment as a method for immobilising enzymes and a limittion

A

enzyme molecules trapped in matrix that doesn’t allow free movement, enzyme molecules are unaffected by entrapment and remain fully active. But, substrate molecules must diffuse into entrapment matrix and product molecules must be able to diffuse out. This method therefore only works for processes where substrate and product molecules are relatively small. Calcium alginate beads often used in schools to immoblise enzymes by entrapment but industiel processes may use cellulose mesh.

131
Q

what is membrane separation as method for immobilising enzymes and a limitation of this

A

enzyme molecules separated from reaction mixture by partially permeable membrane. As in entrapment, substrate and product molecules must be small enough to pass through partially permeable membrane by diffusion, this access to enzymes may limit reaction rate

132
Q

what is industrial use of glucose isomerase

A

converts glucose to fructose, many applications for the syrup produced, can produce high fructose corn syrup (HFCS), replaces sucrose in many things and makes artificial sweatners for those on diet or w diabetes, widely used in food industry in soft drinks, jams, yogurt

133
Q

what is industrial use of penicillin acylase

A

formation of semi-synthetic penicillins like amoxicillin and ampicillin first developed in 1960s, some penicillin-resistant microorganisms not resistant to these semi-synthetic penicillins

134
Q

what is industrial use of lactase

A

converts lactose to glucose and galactose by hydrolysis, used to produce lactose free milk, lactose free milk necessary for those with lactose intolerance to ensure they still receive enough calcium to have strong teeth snd bones

135
Q

what is industrial use of aminoacylase

A

produces pure saamples of L-amino acids by removing acyl group from nitrogen of N-acyl-amino acid, L-amino acids sued a building blocks for pharmaceutical compounds and can also be used as additives for human food

136
Q

what is industrial use of glucoamylase

A

converts dextrins to glucose, during startch hydrolysis dextrins (short polymers of glucose) are formed. Hydrolysis by glucoamylase can convert them to glucose, glucoamylase can be immobilised on many surfaces and used to digest sources of starch like corn, enzyme used in many fermentation processes like production of gashol (altnertive fuel for motor vehicles)

137
Q

what is industrial use of nitrile hydratase

A

converts nitriles to amides, like acrylamide which can by polymerised to form polyacrylamide which thickens plastics, most common use of polyacrylamide is in water treatment (helps to stick many small contaminants toetehr so they filter out of water, polyacrylamide also used in paper making and making gel for electrophoresis

Alevel Biology (25 decks)

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