Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology Year 2 > cloning and biotechnology > Flashcards

cloning and biotechnology Flashcards

1
Q

define clones

A

genetically identical organisms or cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

define vegetation propagation

A

reproduction from vegetative parts of a plant- usually an over wintering organ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

advantages of natural cloning

A
  • if the conditions fro growth are good for the parent, then they will also be good for the offspring
  • cloning is relatively rapid, so the population can increase quickly to take advantage of the suitable environment conditions
  • reproduction can be carried out, even if there is only one parent and sexual reproduction is not possible
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

disadvantages of natural cloning

A
  • the offspring may become overcrowded
  • there will be no genetic diversity
  • the population shows little variation
  • selection is not possible
  • if the environment changes to be less advantageous , the whole population is susceptible
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

describe plant cloning by vegetative propagation

A

the differentiation of many plant cells is not as complete as that in animals. many parts of a plant contain cells that retain the ability to divide and differentiate into a range of types of cells. this means that plants are able to reproduce by cloning. . natural cloning involves a process called vegetative propagation. this is the process of reproduction through vegetative parts of the plants , rather than through specialised reproductive structures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

plant cloning by vegetative propagation

describe runners, stolons, rhizomes and suckers

A

many plants grow horizontal stems that can form roots at certain points .These stems are called runners or stolens if they grow on the surface of the ground, and rhizomes if they are underground. some rhizomes are adapted as thickened over wintering organs from which one or more new stems will grow in the spring

suckers are new stems that grow from the roots of a plant-these may be close to the base of a older stem or could be some distance away. in all cases , the original horizontal branch may die , leaving the new stem as a separate individual

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

plant cloning by vegetative propagation

describe bulbs

A

over an over wintering mechanism for many perennial monocotyledonous plants. bulbs consists of an underground stem from which grow a series of fleshy leaf bases. there is also an apical bud , which will grow into a new plant in the spring. often a bulb contains more than one apical bud and each will grow into a new plant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

plant cloning by vegetative propagation

describe corms

A

corms are often mistaken for bulbs. however corms are solid rather than fleshy like a bulb. a corm is an underground stem with scaly leaves and buds. corms remain in the ground over winter. in the spring the buds grow to produce one or more new plants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

plant cloning by vegetative propagation

describe leaves

A

the kalanchoe plant reproduces asexually , as clones grow on the leaf margins . the immature plant drops off the leaf and take root.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

plant cloning by vegetative propagation

describe tubers

A

tubers are another type of underground stem. potatoes are tubers. one potato will grow into one or more plants. each new plant can then produce many new tubers later that year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

describe cloning in animals

A

animals do not clone as often as plants. there are, however, a few examples of natural cloning
-mammals clone when identical twins are formed. this occurs when a fertilised egg divides as normal, but the two daughter cells then split to become separate cells. each cell grows and develops into a new individual

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how to make a cutting

A

a stem is cut between two leaf joints( nodes) . the cut end of the stem is then placed in moist soil. new roots will grow from the tissue in the stem- usually from the node , but they may grow from other parts of the buried stem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what helps stimulate root growth

A

dipping the cut stem in rooting hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

cuttings can also be made successfully from what other parts of a plant

A
  • root cuttings- in which a section of root is buried just below the soil surface, and produce new shoots
  • scion cuttings- which are dormant woody twigs
  • leaf cuttings- in which a leaf is placed on moist soil. the leaves develop new stems and new roots. some leaves may produce many new plants from one cutting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

describe tissue culture

A

many commercially grown houseplants are cloned using tissue culture techniques

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

tissue culture is widely used commercially to increase the number of new plants, in micropropagation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

define micropropagation

A

growing large numbers of new plants from meristem tissue taken from a sample plant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

describe the micropropagation steps

A

1-suitable plant material is selected and cut into smaller pieces . these are called explants. explants could be tiny pieces of leaf, stems, root or bud. meristem tissue is often used, as this is always free from virus infection

2- the explants are sterilised using diluted bleach or alcohol. this is essential to kill any bacteria and fungi as these would thrive in the conditions supplied to help the plant grow well

3- the explants are placed on sterile growth mediums containing suitable nutrients such as glucose , amino acids and phosphates. the gel also contains high concentrations of the plant growth substances auxins and cytokines. this stimulates the cell of each explant to divide by mitosis to form callus

4- once a callus has formed , it is divided to produce a larger number of smaller clumps of undifferentiated cells

5- these small clumps of cells are stimulated to grow , divide and differentiate into different plant tissues. this is achieved by moving the cells to different growth media . each medium contains different ratios of auxins and cytokinins.

5- the first medium contains the ratio 100auxins ; 1 cytokinin , and this stimulates roots to form. the second medium contains the ratio 4 axins : 1 cytokinins , which stimulates the shoots to form

6- once the tiny plantlets have been formed, these are transferred to a greenhouse to be grown in compost or soil and acclimatised to normal growing conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

advantages of artificial cloning

A
  • cloning is a relatively rapid method of producing new plants compared with growing plants from seeds
  • cloning can be carried out where asexual reproduction is not possible . plants that have lost their ability to breed sexually can be reproduced . similarly plants that are hard to grow from seeds can be reproduced
  • the plant selected will all be genetically identical to the parent plant. they will therefore display the same desirable characteristics such as high yield , resistance to a common pest or disease, or a particular colour of flower
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

describe artificial cloning in animals

A

some invertebrate species such as greenfly and water fleas have evolved the ability to clone naturally . in order species it is a rare event. therefore most cloning of animals is artificial

successful cloning starts with that are totipotent - such cells can divide and differentiate into all types of cells found in the adult organism. in animals, the only truly totipotent cells are very early embryo cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

reproductive cloning may be useful for

A
  • elite farm animals produced by selective breeding or genetic modification
  • genetically modified animals developed with unusual characteristics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what are the two main techniques to achieve cloning are

A
  • embryo twinning

- somatic cell nuclear transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

define embryo twinning

A

splitting an embryo to create two genetically identical embryos

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

define enucleation

A

removal of the cell nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

describe embryo splitting

A

1- a zygote is created by in vitro fertilisation
2- the zygote is allowed to divide by mitosis to form a small ball of cells
3-the cells are separated and allowed to continue dividing
4- each small mass of cells is placed into the uterus of a surrogate mother

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

define somatic cell nuclear transfer

A

a technique that involves transferring the nucleus from a somatic cell to an egg cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

describe somatic nuclear transfer steps

A

1- an egg is obtained and its nucleus is removed , known as enucleation
2- a normal body cell from the adult to be cloned is isolated and may have the nucleus removed
3-the complete adult somatic cell or its nucleus is fused with the empty egg cell by applying an electric shock
4- the shock also triggers the egg cell to start developing , as through it has just been fertilised
5-the cells undergo mitosis to produce a small ball of cells
6- the young embryo is placed into the uterus of a surrogate mother

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is non reproductive cloning

A

is the production of cloned cells and tissues for purposes other than reproduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

describe therapeutic cloning

A

new tissues and organs can be grown as replacement parts for people who are not well

  • skin can be grown in vitro to act as a graft over burned areas
  • cloned cells have been used to repair damage to the spinal cord of a mouse of a mouse and to restore the capabilities to produce insulin in the pancreas
  • there is the potential to grow whole new organs to replace diseased ones

tissues grown from the patients own cells will be genetically identical and so avoid rejection , which is a problem when transplanting donated organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

describe cloning for scientific research

A

cloned genetically identical embryos can be used for scientific research into the action of genes that control development and differentiation . they can also be used to grow specific tissues or organs for use in tests on the effects of medicinal drug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

arguments for artificial cloning

A
  • can produce a whole herd of animals with a high yield or showing an unusual combination of characteristics
  • produces genetically identical copies of very high value individuals retaining the same characteristics
  • using genetically identical embryos and tissues for scientific research allows the effect of genes and hormones to be assessed with no interference from different genotypes
  • testing medicinal drugs on cloned cells and tissues avoids using animals or people for testing
  • can produce cells and tissues genetically identical to the donor , for use in repairing damage caused by disease or accidents
  • individuals from an endangered species can be cloned to increase numbers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

arguments against artificial cloning

A
  • lack of genetic variation may expose the herd to certain disease or pests
  • animals may be produced with little regards to their welfare , which have undesirable side effects such as meat producing chickens cant walk
  • the success rate of adult cells cloning is very poor and the method is a lot more expensive than conventional breeding. cloned animals may be less healthy and have shorter ethical issues
  • ethical issues regarding how long the embryos survives and whether it is right to create a life simply to destroy it
  • this does not help increase genetic diversity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

define biotechnology

A

the use of living organisms or parts of living organisms in industrial processes. this could be to produce food, drugs or other products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

recent examples of biotechnology include

A
  • the use of bacterium clostridium acetobutylicum to produce acetone , which was needed to make explosives during ww1
  • the manufacturer of penicillin from the fungus penicillium notatum during ww2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what are the four main areas in which microorganisms are used in biotechnology

A
  • food
  • pharmaceutical drugs
  • enzymes
  • other products
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

main areas in which microorganisms are used in biotechnology

-food

A
  • ethanol in beer and wine ( yeast)
  • carbon dioxide used to make bread rise ( yeast)
  • lactic acid used to make yoghurt and cheese ( lactobacillus bacteria )
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

main areas in which microorganisms are used in biotechnology

-pharmaceutical drugs

A
  • penicillin ( penicillium fungus)
  • other antibiotics ( other fungi or bacteria )
  • insulin ( genetically modified bacteria )
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

main areas in which microorganisms are used in biotechnology

-enzymes

A
  • protease and lipase in washing powders (bacteria)
  • pectinase used to extract juice from fruit (aspergillus niger )
  • lactase to make lactose free milk ( A. niger and A orzyae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

main areas in which microorganisms are used in biotechnology

-other products

A
  • biogas, which is a combination of carbon dioxide and methane ( anaerobic respiration)
  • citric acid for food preservation ( A niger fungus )
  • bioremedication ( variety of bacteria and fungi)
39
Q

advantages of using microorganisms in biotechnology

A
  • microorganisms are relatively cheap and easy to grow
  • fewer ethical issues to worry about in using microorganisms
  • microorganisms can reproduce quickly so population can grow rapidly inside the reaction vessel
  • products are released from the microorganism into the surrounding medium. this makes the product easy to harvest
  • production takes place at lower temperatures than that would be required to make the molecules by chemical engineering , this saves fuel and reduced costs
  • production process can take place at atmospheric pressure, which is safer than using chemical reactions that may require high pressure
  • the production process is not dependent on climate, so it can take place anywhere in the world with the resources to build and run suitable equiptment
40
Q

describe using other organisms in biotechnology

A

microorganisms are not the only organisms used in biotechnology . genetically modified mammals such as sheep, goats, and cows can be used to produce useful proteins

in some mammals the proteins are incorporated into the milk and can be easily harvested . for example goats that have been genetically modified to possess the gene for spider milk secrete it into their milk. in other cases the protein may be secreted into the blood. for example cows have been genetically modified to synthesise human antibodies , which can be isolated from their blood

41
Q

what are the other forms of biotechnology

A
  • gene technology
  • genetic modification and gene therapy
  • selective breeding
  • cloning by embryo splitting and micropropagation
  • the use of enzymes in industrial processes
  • immunology
42
Q

microorganisms in food manufacturing

-yoghurt

A
  • yoghurt is milk that has undergone fermentation by lactobacillus bulgaricus and streptococcus thermophiles.
  • the bacteria convert lactose to lactic acid . the acidity denatures the milk protein causing it to coagulate . the bacteria partially digest the milk , making it easy to digest . fermentation also produces the flavours characteristic of yoghurts
43
Q

microorganisms in food manufacturing

  • cheese
A

milk is usually pre treated with a culture of bacteria that can produce lactic acid from the lactose . once it is acidified , the milk is mixed with rennet. rennet contains the enzymes rennin which is found in the stomachs of young mammals . rennin coagulates the milk protein in the presence of calcium ions

1-kappa casein which keeps the casein in solution, is broken down. this makes the casein insoluble
2-the casein is precipitated by the action of calcium ions, which bind the molecules together

the resulting solid called curd is separated from the liquid component by cutting, stirring and heating. the bacteria continue to grow, producing more lactic acid. the curd is then pressed into moulds

44
Q

microorganisms in food manufacturing

-baking bread

A

bread is a mixture of flour , water and salt with some yeast. and involves the following steps

1-mixing - the ingredients are mixed together thoroughly by kneading . this produces dough
2-proving/ fermenting- the dough is left in a warm place for up to three hours while the yeast respires anaerobically . this produces carbon dioxide bubbles, causing the dough to rise
3-cooking- the risen dough is baked. any alcohol evaporates during the cooking process

45
Q

microorganisms in food manufacturing

-alcoholic beverages

A

alcoholic beverages are also the product of the anaerobic respiration of yeast . wine is made using grapes that naturally have yeasts on their skins. grapes contain the sugars fructose and glucose . when the grapes are crushed , the yeast uses these sugars to produce carbon dioxide and alcohol

ale or beer is brewed using barley grains that are beginning to germinate . this process is called malting . as the grain germinates it converts stored starch to maltose, which is respired by the yeast . anaerobic respiration again produces carbon dioxide and alcohol . hop are used to give a bitter taste to the liquid

46
Q

microorganisms in food manufacturing

  • single cell protein
A

microorganisms have been used to manufacture protein that is used directly as food. the microorganisms used most frequently is the fungus fusarium venenatum . the fungal protein or mycoprotein is also known as single celled protein

there is a huge potential in SCP production using such microorganisms as kluyveromyces, sctalidium and candida . these fungi can produce protein with a similar amino acid profile to animal and plant proteins . they can grow on almost any organic substrate , includidng waste material such as paper and whey

47
Q

advantages of using microorganisms in food manufacturing

A
  • production of protein can be many times faster than that of animals or plant protein
  • the biomass produced has very high protein content
  • production can be increased and decreased according to demand
  • there are no animal welfare issues
  • the microorganisms provide a good source of protein
  • the protein contains no animal fat or cholesterol
  • not much land is required
  • can be easily genetically modified to adjust the amino acid content of the protein
48
Q

disadvantages of using microorganisms in food manufacturing

A
  • some people may want to eat fungal protein or food that has been grown on waste
  • isolation of a protein , the microorganisms are grown in huge fermenters and need to be isolated from the material on which they grow
  • the protein has to be purified to ensure it is uncontaminated
  • microbial biomass can have high proportions of nucleic acids which must be removed
  • the conditions needed for the microorganisms to grow are also ideal for pathogenic organisms
49
Q

disadvantages of artificial cloning

A
  • tissue culture is labour intensive
  • it is expensive to set up the facilities to perform tissue culture successfully
  • tissue culture can fail due to microbial contamination
  • all the cloned offspring are genetically identical and are therefore susceptible to the same pests or diseases . crops grown in monocultures allow raid spread of disease or pests between the closely planted crop plants
  • there is no genetic variation ,except that introduced by mutation
50
Q

what are fermenters

A

when commercial drug production uses large stainless steel containers , in which growing conditions can be controlled

51
Q

the conditions that must be controlled in fermenters are

A
  • temperature
  • nutrients available
  • oxygen availability
  • PH
  • concentration of products
52
Q

describe how fermenters are set up

A

must first be sterilised using superheated steam. it can then be filled with all the components required for growth and supplied with a starter culture of the microorganism to be used . the culture will be left and synthesis the products

53
Q

describe batch culture

A

other products are produced only when the cells are placed under stress, such as high population density or limited nutrients availability. these are called secondary metabolites and are produced mostly during the stationary phase of growth . here the culture is set up with a limited quantity of nutrients and allowed to ferment for a specific time. after this time, the fermenter is emptied and the product can be extracted from the culture . this is known as batch culture

54
Q

describe continuous culture

A

some products are synthesised by the microorganism during normal metabolism when they are actively growing. . these are called primary metabolites . such products are continually released from the cells and can be extracted continuously form the fermenting broth. the broth is topped up with nutrients as these are used by the microorganisms . some of the broth is removed regularly to extract the product and remove cells from the broth - otherwise the population becomes close too dense. this is known as continuous culture and keeps the microorganism growing at a specific growth rate

55
Q

describe the importance of asepsis

the nutrient mediums would also support the growth of unwanted microorganisms which could reduce production, because the unwanted microorganisms :

A
  • compete with the cultured microorganisms for nutrients and space
  • reduce the yield of useful products
  • spoil the products
  • produce toxic chemicals
  • destroy the cultured microorganisms and their products
56
Q

what is asepsis

A

is ensuring that sterile conditions are maintained

57
Q

describe the production of penicillin

A

is a secondary metabolite- it is only produced once the population has reached a certain size. therefore, penicillin is manufactured by batch culture

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

58
Q

describe the production of insulin

A

insulin is widely used to treat type 1 diabetes . it was previously extracted from the pancreas of the animal such as cattle or pigs sent for slaughter. insulin from slaughtered animals is not identical to human insulin and so is less effective than human insulin, and expensive to extract

in 1978, synthetic human insulin was developed by genetically modifying a bacterium . the gene for human insulin was combined with a plasmid to act as a vector ,so the gene could be inserted into the bacterium ; the resulting genetically modified bacterium enabled the production of vast quantities of human insulin at relatively low cost. insulin is manufactured by continuous culture

59
Q

describe bioremediation

A

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

60
Q

what conditions are needed for bioremediation

A
  • available water
  • suitable temperature
  • suitable PH

where conditions are not quite suitable , they may be modified by the addition of suitable substances .in some cases, additional nutrients such as molasses may be needed to ensure the microorganisms can grow effectively . it may also be necessary to pump oxygen for aerobic bacteria.

61
Q

advantages of bioremediation

A
  • uses natural systems
  • less labour/ equipment is required
  • treatment in situ
  • few waste products
  • less risk of expose to clean up personnel

however bioremediation is only suitable for certain products , heavy metals such as cadmium and lead cannot be treated

62
Q

define agar

A
  • a polysaccharide of galactose obtained from seaweed, which is used to thicken the medium into a gel
63
Q

define aseptic techniques

A

sterile techniques used in culturing and manipulating microorganisms

64
Q

in the laboratory , microorganisms are usually grown on what two types of growth medium

A
  • a soup like liquid called broth, kept in bottles or tubes

- a set jelly like substance called agar, which is melted and poured into petri dishes

65
Q

describe the standard procedures for aseptic techniques

A

1- wash your hands
2- disinfect the working area
3- have a Bunsen burner operating nearby to heat the air. this causes the hair to rise and prevents air borne microorganisms setting. it also creates a sterile air in which the microbiologist can work
4-as you open a vessel , pass the neck of the bottle over the flame to prevent bacteria in the air entering the bottle. the bottle should also be flamed as closing
5-do not lift the lid of the perti dish off completely - just open it enough to allow introduction of the desired organism
6-any glassware or metal equipment should also be passed through the flame before and after contact with the desired microorganisms

66
Q

growing microorganisms an agar plates involve what three main steps

A
  • sterilisation
  • inoculation
  • incubation
67
Q

describe sterilisation

A

the nutrient agar medium and any equipment to be used must be sterilised

the medium is sterilised by heating an autoclave at 121 degrees for 15 minutes . this kills all living organisms , including any bacterial or fungal spores. when the medium has cooled sufficiently to handle. it is poured into sterile petri dishes and left to set. it is important that the lid is kept on the petri dish to prevent infection

68
Q

define inoculation

A

is the introduction of microorganisms to the sterile medium

69
Q

what are the 4 way inoculation can be achieved

A

streaking- a wire inoculating loop is used to transfer a drop of liquid medium onto the surface of the agar . the drop is drawn out into a streak by dragging the loop across the surface. take care not to break the surface of the agar

seeding-a sterile pipette can be used to transfer a small drop of liquid medium to the surface of the agar or to the petri dish before the agar is poured in

spreading- a sterile glass spreader may be used to spread the inoculated drop over the surface of the agar

a small cotton swab or cotton bud can be moistened with distilled water and used to collect microorganisms from a surface and then carefully wiped over the surface of the agar medium

70
Q

describe incubation

A

the peti dish must be labelled and top taped to the bottom using two stripes of adhesive tape, but not to seal it completely as this can lead to selection of anaerobic bacteria which may be pathogenic. the petri dish is then placed in a suitable warm environment such as an incubator. it should be placed upside down as this prevents condensation falling onto the agar. suitable temperatures depend on the organism

cultures can be examined after 24-36 hours. the petri dish shouldn’t be opened . the bacteria grow into visible colonies.

all petri dishes must be completely sterilised after use and before disposal. thoroughly wash your hands after handling petri dish , as any moisture coming out of a dish could be a source of infection

71
Q

describe using a liquid medium

A

a liquid broth is initially clear but will turn cloudy when bacteria have grown. a liquid broth can be useful to increase the numbers of microorganisms before transferring to agar plates for counting or identification. a liquid broth can be used to investigate population growth

72
Q

define closed culture

A

a culture which has no exchange of nutrients or gases with the external environment

73
Q

define serial dilution

A

a sequence of dilutions used to reduce the concentration of a solution or suspension

74
Q

describe the growth curve

A

a small population of microorganisms in a closed culture that contains all the nutrients required for growth will undergo population growth . the population growth will follow a predictable pattern

these are similar to the conditions set up for batch production in a fermenter. in batch production , however, certain substances such as oxygen may be added to keep the population growing until the nutrients are used up

75
Q

describe the lag phase

A

in the early part of population growth , the population doesn’t grow quickly . this is partly because the population is still small, but also because the organisms are adjusting to their new environments this may involve

  • taking up water
  • cell growth
  • switching on certain genes
  • synthesising specific proteins
76
Q

describe the log phase

A

the organisms have adjusted to their environments . they each have the enzymes needed for survival . each individual has sufficient nutrients and space to grow rapidly and reproduce. the population doubles in size with each generation.

77
Q

describe the stationary phase

A

eventually the increasing number of organisms use up the nutrients and produce increasing amounts of waste products such as carbon dioxide and other metabolites . the rate of population growth declines and the number of individuals dying increases until the reproduction rate equals the death rate . there is no population rate

78
Q

describe the death phase

A

1the nutrients run out and the concentration of waste products may become lethal. more individuals die than are produced and the population begins to fall. eventually all the organisms will die

79
Q

describe primary metabolites

A

produced during the normal activities of the microorganism will be collected from a fermenter during the log phase , in a fermenter , the population is not kept in a closed culture , but conditions are maintained for optimal growth

80
Q

describe secondary metabolites

A

are produced in the stationary phase . the population must be kept in a closed culture and the metabolites can be collected at the end of the stationary phase or during the decline phase

81
Q

define immobilised enzymes

A

an enzyme that is held in place and not free to diffuse through the solution

82
Q

advantages and disadvantages of immobilised enzymes

A
  • enzymes do not mix with the product , so extraction costs are lower
  • the enzymes can be easily reused
  • a continuous process is made easier, as there are no cells requiring nutrients , reproducing and releasing waste products
  • the enzymes are surrounded by the immobilising matrix , which protects them from extreme conditions- so higher temperatures or a wider PH range can be used without causing denature

HOWEVER- setting up the immobilised enzyme process is more expensive , and immobilised enzymes are usually less active than free enzymes, making the process slower

83
Q

what are the methods of immobilise enzymes

A
  • adsorption
  • covalent bonding
  • entrapment
84
Q

describe adsorption ( immobilised enzymes )

A

enzyme molecules are bound to a supporting surface by a combination of hydrophobic interactions and ionic links .suitable surfaces include clay, porous carbon , glass beads and resins . the enzyme molecules are bound with the active site exposed and accessible to the substrate . however the active site may be slightly distorted by the additional interactions affecting enzyme activity

the bonding forces are not always strong, and enzymes can become detached and leak into the reaction centre

85
Q

describe covalent bonding

immobilised enzymes

A

enzyme molecules are bonded to a supporting surface such as clay using strong covalent bonds. the enzymes are bonded using a cross linking agent, which may also link them in a chain

the production of covalent bonding can be expensive and can distort the enzyme active site, reducing activity . however the enzymes are much less likely to become detached and leak into the reaction mixture

86
Q

describe entrapment

immobilised enzymes

A

enzyme molecules are trapped in a matrix that does not allow free movement . the enzyme molecules are unaffected by entrapment and remain fully active . however the substrate molecules must diffuse into the entrapment matrix , and the product molecules must be able to diffuse out . the method is therefore suitable only for processes where the substrate and product molecules are relatively small .

87
Q

describe membrane separation

A

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

88
Q

industrial use of immobilised enzymes

glucose isomerase

A
  • converts to fructose
  • probably the most widely used enzyme , because of the number of application of the syrup produced
  • used to produce high fructose corn syrup , which Is must sweeter than sucrose . as is often used in diet foods as less sugar needs to be added for the equivalent sweetness. it may also be used as a sweetener in food for diabetics. its cheaper than sucrose and so is widely used in the food industry to replace sucrose
89
Q

industrial use of immobilised enzymes

penicillin acylase

A

formation of semi-synthetic penicillin’s, such as amoxicillin and ampicillin , which were first developed during the 1960s. some penicillin resistant microorganisms are not resistant to these semi synthetic pigments

90
Q

industrial use of immobilised enzymes

lactase

A
  • converts lactose to glucose and galactose by hydrolysis . used to produce lactose free milk
  • milk is an important source of calcium , which is needed for strong bones and teeth . people with insufficient calcium in their diet are more likely to develop weak bones or osteoporosis . it is therefore important that people who are lactose intolerant are given calcium supplements or lactose free milk
91
Q

industrial use of immobilised enzymes

aminoacylase

A
  • a hydrolase used to produce pure samples of L-amino acids by removing the acyl group from the nitrogen of an N-acyl-amino acid
  • L amino acids are used as the building blocks for synthesis of a number of pharmaceutical and agrochemical compounds. they may also be used as additives for human food and animal feedstuffs
92
Q

industrial use of immobilised enzymes

glucoamylase

A

converts dextrins to glucose . during the hydrolysis of starch , short polymers of glucose are formed. hydrolysis by glucoamylase can convert these dextrins to glucose . glucoamylase can be immobilised on a variety of surfaces and used to digest sources of starch such as corn and cassava

the enzyme is used in a wide range of fermentation processes, including the conversion of starch pulp to alcohol used to produce gasohol - an alternative fuel for motor vehicles . it is also used within the food industry to make high fructose corn syrup

93
Q

industrial use of immobilised enzymes

nitrile hydratase

A
  • converts nitriles to amides , including acrylonitrile to acrylamide .acrylamide can be polymerised to form polyacrylamide , which is a plastic used as a thickener
  • the most common use of polyacrylamide is in treatment of water. it helps to stick many small contaminants together , so that they are precipitated or are easy to filter out of the water
  • polyacrylamide is also used in paper making and used to make gel for electrophoresis

Biology Year 2 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions