MBB165 Flashcards
(260 cards)
1
Q
A. nidulans is a homothallic species. What does this mean?
A
There are no mating type differences.
2
Q
Where is the centromere found in a paracentric inversion?
A
Outside the inverted segment.
3
Q
What special mycelium is grown when A. nidulans goes through asexual reproduction?
A
Dikaryon.
4
Q
Dipolids in yeast can undergo asexual reproduction by mitosis. This allows for dominance and complementation tests. What happens to allow gene segregation, gene interactions and linkage to be studied?
A
Sporylation of diploids.
5
Q
A. nidulans have an asexual and sexual cycle. What one of these is longer?
A
The sexual cycle which lasts 14 days. The asexual cycle last 2 days.
5
Q
What life cycles does yeast contain?
A
Haploid and diploid life cycles.
5
Q
What can the YsxC protein bind?
A
GTP.
7
Q
What is increased through the use of a slope culture?
A
Surface area.
7
Q
What are the characteristics of mutant/recessive corn kernals?
A
Sweet and yellow.
7
Q
What type of inheritance is shown with Brachdactyly disorder?
A
Autosomal dominance.
8
Q
Conidia are ____ nucleate and are usually ____. These can give rise to _____ which grow by apical extension and laternal branching to make ______.
A
Uni, haploid, hypthea, mycelium.
9
Q
What type of colour blindness is this describing? The part of the spectrum normally seen as green is grey or indisitinct.
A
Deutan.
10
Q
What would you call a chromosome that has its centromere in the middle?
A
Metacentric.
10
Q
All enzyme activity in soil comes from enzymes associated with micro-organisms. True or false?
A
False.
11
Q
What do temperature sensitive mutants allow you to identify?
A
Genes essential for survival.
11
Q
What is plotted on the Y axis of a Lineweaver-Burk plot?
A
1/v.
12
Q
Malt contains a large number of simple and complex sugars. What is the most common complex sugar found in malt?
A
Maltose.
13
Q
Do gram positive or gram negative bacteria have a thin cell wall?
A
Gram negative.
13
Q
Is pink sarafranin also used as a counterstain when looking at endospores?
A
Yes.
13
Q
What is the cross linking like in the G75 beads?
A
Medium. Above 80kd is excluded?
14
Q
The dipolid nuclei found in the sexual reproduction in A. nidulans have a relatively short life. What can they not undergo that yeast can?
A
Mitotic division.
14
Q
How are sulphatses classified?
A
Depending on the type of sulphate ester they hydrolyse.
14
Q
What colour is the DCPIP dye when it is reduced?
A
Colourless.
15
Q
Damage to the cell wall caused by heat shock is irreversible. True or false?
A
False. When the cells have returned to a normal temperature the pores can reseal.
16
Endospores do not effect the staining procedure of bacteria. True or false?
False. They make them harder to stain.
16
How do you work out the relative length of a chromosome?
(Length of chromosome/ total length of haploid set of autosomes) x 100
17
What do single gene disorders tend to show that complex disorders do not?
Regular and predictable inheritance patterns.
18
What are the five stages that prophase can be split into?
1. Leptotene 2. Zygotene 3. Pachytene 4. Dipolotene 5. Diakinesis
19
What is the 'void volume' in gel filtration?
The molecules that are excluded from the beads as they have been eluted first. The volume of their elution is equal to the amount of liquid outside of the beads.
20
A. niger, A. oryzae and P. chrysogenum all have economic importance, however they do not have a sexual cycle. What can not be done as a result of this?
The genes can not be mapped.
20
What three temperatures are used in PCR?
94, 50, 72.
21
What stain will be taken up by endospores?
Macahite green.
22
Where is the centromere in a telocentric chromosome?
At one end.
22
What buds of conidiophores?
Chains of uninucleate conidia through successive mitotic divisions.
24
What is a Helber slide used to do?
Count cells. It is made of 1mm^2 of 400 small squares.
25
In what stage of mitosis do chromosomes become visible?
Prophase.
25
What are Ishihara test cards used for?
To test colour blindness.
25
The total volume of the beads is equal to Vt-Vo. What else does it also equal?
Vi+Vs.
26
What washed methyl violet from gram negative bacteria?
Alcohol/ acetone.
27
What does the Km value show?
How much of the rate is dependent on substrate concentration.
28
What enzyme can break down lactose into glucose and galactose?
Lactase.
29
Through measuring the amount of CO2 produced in fermentation what can you determine?
The ability of alcohol dehydrogenase to act on different substrates and reactions optimum conditions.
30
How many break points does an inversion need?
2.
30
When prepping tissue extracts to measure the effect cofactors have on respiration how do you remove the oxygen to ensure that the reaction happens anaerobically?
Gas the tube with nitrogen.
31
What type of culture is being described here? 10ml of agar solution is solidified upright and is then inoculated in the middle with a needle.
Stab culture.
32
Does staining and light microscopy allow the visulisation of individual chromosomes?
No.
32
Why will supercolied DNA move further through the gel in electrophoresis?
Because it is more compact.
33
What is the difference between pour plates and overlay cultures?
Less melted agar is used in overlay cultures.
34
What do you need to know for affinity chromatogr
A specific binding property such as the presence of an insulin receptor.
35
What are three purposes of gel filtration
1. Desalting/ buffer exchange. 2. Purification of buffer macromolecules. 3. Analysis of the oligomeic state or proteins.
36
Is BG synthasised when glucose is present?
No. This is because there would be no cAMP present.
37
A proton is produced when lactate is broken down by lactate dehydrogenase. How is this removed?
Through a glycine containing buffer ( an alkaline reaction medium).
38
How many times should you pass a slide through a flame in heat fixation?
3.
38
What leads to a colour change in phenol red at high pH's?
The dissociation of a H+ ion.
39
Sulphur in the soil mainly comes from sulphate ions but can also come from organic sulphate esters. True or false?
False, 90% of the sulphur comes from organic sulphate esters.
40
What can phenylketonuria lead to?
A mental defect.
41
What stain is commonly used in a gram stain?
Methyl/ crystal violet.
41
What shape is an ascus, which holds 8 ascospores?
Spherical.
42
What is flanked by the primers in the buccal smear sample test?
The DYZ region found on the Y chromsome and not on the X.
43
What stage of prophase is being described here? Bivalents contain two homologous chromosomes that include centromeres. Still held together at a few points called chiasmata where crossing over has occurred. Sister chromatids are attached at centromeres.
Dipolotene.
45
The human karyotype can be divided into 7 groups, named A-G. What are these groups based on?
The size and the position of the centromere.
47
Is agar needed in broth culture?
No.
47
What sort of inheritance is shown with phenylketonuria?
Autosomal recessive.
49
What type of culture is being described here? A cool medium is allowed to set into an even, smooth layer. The inoculation is then streaked over the plate.
Streak plate.
50
What type of medium is used in a broth culture?
Liquid medium.
51
When NaOH is added to the reaction between aryl sulphatase and p-nitrocatechol substrate it stops the reaction. What else does it do?
Deprotanates the nitrocatechol so it can be assasyed spectrophotometrically.
52
What are MDR-TB and CRE?
Antibiotic resistant strains.
53
What two buffers do E.coli cells need to be washed in to render them component?
TFB1 and TFB2.
53
What does this equation show? Vo+Vi+Vs?
The total voume inside the column. Vs is the volume of the solid beads. This is normally between 5% and 15% of the total volume.
55
What are general stains used for?
To visualise morphology.
55
Many bacterial species contain the YsxC protein. If an antibiotic was created to target this protein what would it be classed as?
A broad spectrum antibiotic.
56
What charge do acidic amino acids have at a pH of greater than 4?
A negative charge. Basic amino acids tend to have a positive charge.
56
There was a delay in BG activity after IPTG was added. Why is this?
Because the IPTG needed to react/ be metabolised before the reaction could start.
57
What does aryl sulphatase catalyse?
The hydrolysis of synthetic substrate p-nitrocatechol sulphate into nitocatechol and sulphate.
59
Specific patterns on chromosomes given by G stain is not sufficient to distinguish between different chromosomes. True or false?
False.
60
Why does a heatshock cause pores in the membrane of a bacterial cell?
Due to pressure difference between the inside and the outside of the cell.
61
Why can the level of ethanol, NAD+ and carbon dioxide all show how much fermentation has taken place?
As they are all made in a 1:1:1 ratio.
62
What do sulphatases hydrolyse?
Sulphuric acid esters.
63
When the concentration equals 0, what does It equal?
I0.
64
Beta galactosidase can cleave ONPG. What colour is ONPG?
Colourless.
65
What two strains of S. cerevisiae are used in brewing?
1. Ale yeast 2. Larger yeasts
66
What do Aspergillus niger, Aspergillus oryzae and Penicillum chrysogenum all have?
Economic importance.
67
Colourless substances do not absorb visible wavelengths of light. What can they absorb instead?
UV light on infra red radiation.
67
What is the advantage of using a Lineweaver-Burk plot over a Michaelis-Menton plot?
It is easier to determine Km and Vmax.
67
What does anion exchange chromatography separate proteins by?
Charge. Resin is positive.
67
What does Duniella use as a compatible solute?
Glycerol.
69
What stage of prophase is being described here? Condensation begins. Each chromosome becomes paired and can be visulised as chromatids.
Leptotene.
70
When dipolid zygotes in yeast sporulate each nuclei divides to form what?
A tetrad.
70
Compounds at a low potential are _______ by those at a higher potential.
Oxidised.
71
What fixative is made up of Orcein, latic and acetic acid?
Clarkes fixative.
71
Why are readings above 1 from a spectrophotometer not ideal?
As the spectrophotometer does not read these readings accurately.
72
Do gram positive or gram negative bacteria have a thin outer membrane?
Gram positive.
72
How does sexual reproduction occur in A. nidulans?
Two haploid spores come together.
73
What is the cross linking like in G25 beads?
Tight. Anything about 5kd is excluded.
74
Does isolating plasmid DNA require acid or alkaline hydrolysis?
Alkaline.
75
What do acidic amino acids have in their side chain?
A carbonyl group.
75
When making a brain tissue extract the tissue is homogenised with ice cold hypotonic solution containing potassium bicarbonate and nicotinamide. How is undistrupted tissue then removed?
Centrifugation.
77
What type of culture is being described here? 10ml of agar is heated and melted. This is then set on a slanted position to increase the surface area. This is ideal for small amounts of bacteria.
Slope.
78
What is the significance of Mata and Matalpha in yeast?
They are 'sexes' as they contain unlike alleles at the mating type locuses.
78
The Michaelis-Menton plot shows the relationship between Km and Vmax- it is a curved graph. This graph is often replotted into a linear graph, what is this graph called?
Lineweaver-Burk plot.
79
What occurs to allow a teratype to form?
A single crossover between the two alleles.
80
What two polymer matrices are normally used in electrophoresis?
Polyacrylamide and agarose.
81
What does the Y intercept show on a LB plot?
1/vmax.
81
What does Vi show in gel filtration?
The amount of liquid in the beads. this is equal to VI-V0.
83
What stage of mitosis are mammalian chromosomes most easily seen in?
Metaphase.
84
Asperigullus has no economic importance however related fungi do. True or false?
True.
86
The diploid nuclei in A.nidulans can not undergo mitotic divison. What process happens instead?
Meiosis and the mitosis, giving rise to 8 ascospores.
87
What does the X intercept show on a LB plot?
-1/km.
88
How much bacteria can be grown on a slope culture?
A small amount.
89
Labs typically use 1% agarose gels. What size DNA fragments can be resolved trough these?
1-10kb.
91
When genes are far apart what can you say the PD class equals?
The NPD as they would segregate independently.
91
Can the buccal smear test be used on its own to establish sex?
No, as it can give rise to false positives and negatives.
91
What two properties can be changed in anion exchange chromatography?
pH and salt.
93
What plating method is prepared the same way as a streak plate apart from the fact that the innoculant is a drop liquid culture?
Spread plate.
93
What temperature should the primers used in PCR melt at?
Around 60 degrees.
94
In gel filtration what are particles separated according to?
Their size.
96
In a human pedigree do Arabic numbers or roman numerals identify the generation?
Roman numerals.
97
What is IPTG?
An inducer of the lac operon.
98
What was the purpose of the ethanol validation assay carried out in the industrial biotechnology practical?
It allowed the level of NADH to be determined also allowing the determination of the amount of ethanol produced by fermentation.
99
What happens at a high pH to basic amino acids?
They loose the proton so are not charged.
99
What can small changes in the pH of the blood result in?
Coma or death.
100
How long does it take for the mycelium to differentiate into conidiophores in A. nidulans?
2 days.
100
Can yeast be manipulated in similar ways to prokaryotes?
Yes.
101
How does yeast reproduce?
Asexually through budding.
102
Conidia are normally green. What two colours can they be when they are mutant?
White- no pigment is present. Yellow - incomplete pigment synthesis
104
What colour is the carbonyl fuchsin/ safranin?
Pink/ red.
105
Why do you need to degrease slides?
As even strong oxidizing agents will not degrease the slides. Flames need to be used.
106
Why would you use a pour plate? (2 reasons)
1. Isolation of bacterial cultures from a mix media. 2. When lawn cultures are needed.
108
What sort of taste can phenylthiocarbamine be described as?
Bitter.
109
What is the cross linking like in the G200 beads?
Loose. Above 600kd is excluded.
110
What type of DNA moves the slowest through the gel?
Supercolied dimers.
111
You can measure growth of a microorganim by counting the number of cells and by measuring biomass. What other way can you use?
Measuring the turbidity/ optical density of a culture.
112
What method is used to distinguish between individuals in a population?
DNA profiling.
113
What can fermentation be described as?
An anaerobic cellular process in which organic compounds are converted into simple molecules which chemical energy being produced.
115
What can areas of polymorphism be used as ?
Genetic markers.
115
At a high pH what colour is phenol red?
Red.
117
What organism is random spore analysis carried out on?
Aspergillus nidulans.
117
Why are very low OD readings, such as ones below 0.3 not ideal?
As error from inaccurate measurements will have a large effect.
118
Is the counter stain taken up by all cells?
Yes, but in gram positive bacteria the methyl purple stain will predominate.
120
What do general stains act on?
All bacteria.
121
What does barbitone inhibit?
NADH dehydrogenase. In the experiment we carried out this had no effect on the rate of electron transport as we were looking from complex 2 onwards (succinate dehydrogenase).
122
You can measure respiratory activity by measuring the uptake of oxygen. What other method can you use which is experimentally convenient?
Using a a different terminal electron acceptor. Dyes can be used which tap of the reducing equivalents from the respiratory chain.
123
When counting spores do you ignore the spores which appear on the lines?
Some of them. Count the spores on the top line and the left boundary.
123
Where is the YsxC protein found?
In Bacillus subtilis.
124
Proliferating mico-organisms can release enzymes into the soil. True or false?
True.
125
How would you remove cofactors from a brain tissue extract?
You would pour the tissue through a sausage shape bag of a semi permable membrane. This bag is dialysed against a bicarbonate/nicotinamide solution.
126
Does nicked DNA or linear DNA move further through the gel?
Nicked.
127
What stage of prophase is being described here? The bivalents become shorter and thicker. Crossing over occurs also they are not visible.
Pachytene.
128
What size gel bead is used in desalting or in buffer exchange?
G25.
128
Is the role of YsxC known?
No.
130
What type of inheritance is shown with Zea mays/ corn?
Dihybrid. Each kernal is a result of an individual fertilisation.
131
Why can gram positive bacteria maintain stains?
Because they have a thick cell wall and a thin outermembrane.
132
What causes phenylketonuria?
An enzyme deficiency.
133
What is the purpose of a streak plate?
To isolate separate colonies.
134
When a sample is placed into the column to allow for gel filtration it occupies the 'narrow zone'. How much of the column volume does this occupy?
1-5%.
136
Where is it easiest to visualise mitosis?
Root tips.
137
What is plotted on the X axis of a Lineweaver-Burk plot?
1/s.
138
what does I0/It show?
Change in absorbance. By logging this number you can get A.
140
Inversions normally happen in a gene. True or false?
False. They normally happen between genes.
141
Why does brain tissue need to be kept on ice?
To allow the glycolytic enzymes originally found in the cytoplasm to retain their activity.
143
Do gram positive or gram negative bacteria have a thick cell wall?
Gram positive.
144
Where is the centromere on a acrocentric chromosome?
Near one end.
145
When isolating plasmids does the plasmid or chromosomal DNA form a 'white gloop' with the SDS/lipid/protein percipitate?
The tangled chromosomal DNA.
147
What does the pKa show?
What pH the protein has a 'buffering' action at.
149
Are proteins or substrates more commonly coloured?
Substrates. Proteins are rarely coloured.
150
What molecules can enter the beads in gel filtration?
Small molecules.
151
What colour is the stain toluidine used in chromosome visulisation?
Blue.
152
How many nuclei are found in a dikaryon?
Two, one from each parent.
153
The distance a molecule travels in a gel is plotted on a arithmetic scale. What scale is the size of the molecule plotted on?
Log10 scale.
155
If you determine the pH in which [A-] equals [HA} what can you determine?
pKa.
156
Why is EDTA included in the buffer used in the reaction of lactate and lactate dehydrogenase?
It chelates any divalent metal ions that could catalyse the production of NADH from NAD+.
157
Why did we have to compare the NADH reading with and without alcohol dehydrogenase?
As there is a basel level of NADH in the cells.
159
Are conidia involved in the asexual or sexual reproduction of A. nidulans?
Asexual.
160
Broth culture can produce a large number of bacteria. What can it not produce?
Discrete colonies.
161
When plasmid DNA is lysed with NaOH do the strands remain intertwined?
Yes.
162
What colours are confused in the comments congenital case of colour blindness?
Red-green.
164
What are the characteristics of pure breeding corn kernals?
Starchy and purple.
165
As the cell density increases what else increases?
The optical density reading.
166
What can be observed in flower buds, grasshopper testes and locuses?
Meosis.
167
What type of beads can the histidine affinity tags bind to?
Na2+ beads.
168
What can phase contrasting microscopes do?
Allow the visualisation of chromosomes without staining.
169
Why is it a negative thing to gave too much mitrochondria in the curvette when measuring electron transport?
As it can adust the OD readings.
170
What are the three steps to produce slides?
1. Degrease slides 2. Preparation of flims 3. Heat fixation
171
What enzyme can break down starch into smaller disaccharide and trisaccharide sugars such as maltose?
Alpha amylase.
172
What does random spore analysis involve?
Squashing a single cleisothecium to obtain random prodgeny as it is difficult to dissect out individual asci.
173
Where is the centromere in a pericentric inversion?
In the inverted segement.
174
What stage of prophase is being described here? Further shorting and thickening of chromosomes.
Diakinesis.
175
What is the name given to a chromosome when its centromere is between the middle and the end?
Submetacentric.
176
What can absolute ethanol do to nucleic acids?
Catalyse them to form ppt.
177
What three things can you abstract from Duniella?
1. Glycerol 2. B carotene 3. Neutral lipids.
178
What are the two types of linear molecules often joined in a cloning experiment?
A vector molecule or a insert molecule, such a fragments of chromosomal DNA cut with the same restriction enzyme.
181
Can spectrophotometry be used to identify chemical bonds and establish purity?
Yes.
181
What is glycerol often described as ?
A commodity chemical. This is because it is used in foods, cosmetics, plasmids and explosives.
182
After the addition of the SDS phase chromsomal DNA will form a white gloop which can be removed. Apart from plasmid DNA what else is found in the remaining solution?
rRNA and tRNA. Some chromosomal DNA may also be present due to shearing.
184
When are endospores produced by some bacteria?
In unfavorable conditions.
185
Thousands of asci are formed at the same time in a single structure called a \_\_\_\_\_\_\_\_\_.
Cleistothecium.
187
What is malonate a competitive inhibitor to?
Succiante in the succinate dehydrogenase enzyme.
189
Why is the agar cooled to roughly 50 degrees on a plate culture?
To stop the plate from cracking and to prevent antibiotics being inactivated.
189
What does the buccal smear sample test?
The presence of a Y chromosome.
190
Why is the actual length of the nuclei not useful when determining chromosome length?
Some chromosomes made be more or less elongated.
192
What can lactic acid do to foodstuffs?
Improve their flavor and storage properties.
193
What are the two forms of red-green colour blindness?
1. Protan. 2. Deutan.
194
What can you describe the side chains of a neutral amino acid to be?
Non-ionisable.
195
Why is glycerol contained in the buffer involved in gel loading?
It is heavy and allows the sample to sink to the bottom of the gel.
196
What stage of prophase is being described here? Homologous chromosomes become associated in bivalents by a process of synapsis.
Zygotene.
197
Do positive or negative stains colour the organism?
Positive, negative colour the background.
198
After the DAN is lysed with NaOH potassium acetate is added to bring the pH back to neutral. What does this do to the DNA?
It allows the strands to renature. Long chromosomal stands can not rehybridise correctly and instead form a partially hybridized tangle. Shorter plasmid DNA can correctly rehybridise.
200
What colour blindness is this describing? Caused by alleles on two linked genes for colour sensitive pigements of cone cells in the retina. This causes a restriction at the visable red end of the spectrum also causing blue/green to appear as grey or indistinct.
Protan.
202
Is the amount of NADH produced equivalent to the amount of lactate produced in anerobic respiration?
Yes.
203
Where does the agar solidify in overlay cultures?
On the top.
204
What does a ocular eyepiece allow?
The determination of the size of the object being studied.
205
What is the purpose of the SDS when isolating plasmid DNA?
It dissolves the lipid compnents of the cell membrane and cellular proteins.
206
What is special about exoenxymes and endoenzymes?
They are both free living and are found in soil. Exoenzymes are released from living cells and endoenzymes are released from disintegrating cells.
208
Inversions always cause a mutant phenotype. True or false?
False. There is only a mutant phenotype if the break is in the gene.
209
What was used to carry out original DNA profiling experiments?
DNA fingerprinting. This involves the analysis of polymorphisms across the genome which are roughly 10-100 nucleotides long and are called microsatellites.
210
Inversions always cause inversion loops.True or false?
False. They will not if the inversion is small.
212
What is the purpose of iodine in the gram staining procedure?
It traps the stain in the peptidoglycan cell wall.
212
What stage of growth should the gram stains been used on?
Exponentially growing bacteria.
213
Is lactose or IPTG a more effect inducer of BG synthasis?
Lactose.
214
What is the intermediate made when pyruvate is made into ethanol?
Acetyl aldehyde.
216
Why is glycolysis dependent on added glucose in brain tissue?
As there is a very low glycogen content.
217
What bond is formed during ligation?
Covalent/ phosphodiester bond.
218
What are dilute carbonyl fuchsin or safranin used as?
A counterstain.
219
When lactate and NAD+ is added to lactate dehydrogenase what is produced?
Pyruvate and NADH.
219
What is a plasmid defined as?
An independently replicating extra chromosomal element of DNA.
221
Why does cyanide massively accelerate the electron transport chain?
It blocks the electrons from reaching O2 meaning more are given of by succinate.
223
70% ethanol is used when plasmids are being isolated. What is its purpose?
It washes salts and removes any remaining SDS which can interfere with the restriction digest.
224
Is the clockwise or anticlockwise hair whorl dominant?
Clockwise.
225
What can Brachdactyly disorder be characterised by?
Short fingers.
226
What is Beta carotene a precursor for?
Vitamin A.
227
What are roots placed into to allow the visualise of chromosomes?
HCl and distilled.
229
Do DNA ligases need ATP?
Yes.
230
Glycolysis is essential in muscles. What other system is it vital in the functioning of?
The nervous system.
231
Chloramphenicol is an antibiotic that can inhibit protein synthesis. What is the purpose of adding this with IPTG when inducing the synthesis of BG?
It will help determine if the induction of BG requires the synthesis of the BG enzyme. (Results show that it does involve the synthesis of the enzyme.)
232
When genes are closely linked do you get more parental or more recombinant classes?
More parental.
233
What type of bacteria can be grown with a stab culture?
Anerobic.
234
Being able to taste phenylthiocarbamide requires the recessive genotype. True or flase?
False. Non tasting is recessive.
235
Beta galactosidase can cleave ONPG into o-nitrophenol. What colour is o-nitrophenol (under alkaline conditions)?
Bright yellow.
236
What equation could you use to work out the melting point of a primer?
4 (G+C) + 2(A+T).
238
What do basic amino acids have in their side chain?
A group which is able to bind H+.
239
What is stored in Clarkes fixatives for 4 degrees for three weeks , squashed and dipped in liquid nitrogen to allow the visulisation of chromosomes?
Grasshopper testes.
240
The cdc mutant can grow at 25 degrees. What temperature can it not grow at?
36 degrees.
241
What two processes can allow for accurate analysis of the human karoytype?
1. FISH 2. G banding
242
Do gram positive or gram negative bacteria have a thick outermembrane?
Gram negative.
244
When [A-] equals [HA] what does pKa equal?
pH.
245
What is the cause of smearing in gel lane?
Nuclease enzymes such as DNases degrading left over fragments of sheared DNA.
246
Is A.nidulans filamentous?
Yes.
247
At a low pH what colour is phenol red?
Yellow.
248
What type of culture is being described here? 20ml solid medium is grown in a 9 inch petri dish. This is melted and cooled to roughly 50 degrees.
Plate culture.
249
At a alkaline pH the colour of aryl sulphatases substrate it yellow. What is the colour of p-nitrocatechol at a alkaline pH?
Red.
251
Why do the products of the reaction between lactate and lactate dehydrogenase have to be removed for the reaction to reach completion?
Because the equilibrium lies far to the left.
252
What type of stain is methylene blue?
A positive stain.
253
What dye is used in electrophoresis?
Midori green.
254
The smallest molecules that can completely penertrate the beads elute with a volume equal to the whole volume of liquid in the column. Is this known as VI or Ve?
Vi. Ve are different sized beads that have a specific elution volume.
255
What colour is the DCPIP dye when it is oxidised?
Deep blue.
256
What does karyogamy involve?
The fusion of the two hapolid nuclei in A. nidulands to form a diploid nuclei in sexual reproduction.
257
What type of culture is being described here? The innoculum is added to a melted and cooled agar medium which is then poured into plates. The petri dish is then rotated to ensure an even distribution.
Pour plate.
258
Why are E.coli cells washed with TFB1 and TFB2 when they are made competent?
It allows the outer membrane to become permeable to Ca2+ and Rb2+.
259
What region of the chromosome does the G stain stain?
The heterochromatin ie the gene poor regions,
260
Why are sulphatases found in the soil in Canada very important?
As the soil lacks sources of sulphur.
