MCQ Flashcards
(578 cards)
1
Q
Is insulin important during the fed state?
A
Yes
2
Q
Why is insulin important during the fed state?
A
Insulin stimulates glycogenesis
3
Q
How is the acetylcholine receptor opened?
A
Rotation of the pore helices
4
Q
What is a potent activator of PFK-1 in liver cells?
A
F-2,6-bisP
5
Q
Does complete oxidation of one molecule of palmitate provide more or less molecules of ATP than complete oxidation of one molecule of glucose?
A
Palmitate produces more
6
Q
Are ketone bodies beneficial for the brain?
A
Yes
7
Q
What oxidises very long chain fatty acids?
A
Peroxisomes
8
Q
What difference can be observed in the circulating fatty acid levels of individuals with type 2 diabetes?
A
Elevated levels
9
Q
What do proteins destined for the plasma membrane pass through?
A
Endoplasmic reticulum and Golgi apparatus
10
Q
What does manose-6-phosphate do to soluble proteins?
A
Directs them to lysosomes
11
Q
What would genomic amplification of the c-MYC gene likely lead to?
A
Development of cancer
12
Q
Are inherited single allele mutations in tumour suppressor genes linked to susceptibility to cancer?
A
Yes
13
Q
What happens to the melting temperature of DNA as length increases?
A
It increases
14
Q
What do histone undergo in their N-terminal sequences?
A
Post-translational modifications
15
Q
What does the binding of the glucocorticoid receptor to its ligand result in?
A
Translocation of the glucocorticoid receptor to the nucleus
16
Q
What is transcription termination coupled to in eukaryotes?
A
mRNA polyadenylation
17
Q
Why does the core RNA polymerase terminate transcription at rho-independent sites in prokaryotes?
A
Due to a GC-rich hairpin and a run of U nucleotides in the RNA
18
Q
What is the significance of the Pribnow box at -10 in prokaryotes?
A
Important determinant of the start site of transcription
19
Q
What is TFIID?
A
A complex of TATA binding protein (TBP) and a number of other
general transcription factors called TAFs
20
Q
What impact will increasing concentration of BH3 only proteins have on a cell?
A
Make the cell more likely to undergo apoptosis
21
Q
What does the spindle assemble checkpoint do?
A
Monitors the proper attachment of chromosomes to microtubules during mitosis
22
Q
What is the action of Humira in rheumatoid arthritis?
A
Blocks the action of TNFα on its receptor
23
Q
How are human antibodies created from transgenic mice?
A
Mice are derived from embryonic stem cells engineered to include the human antibody loci in their genome
24
Q
Does a plasmid produce a circular recombinant molecule in the host cell?
A
Yes
25
Does a bacterial artificial chromosome produce a circular recombinant molecule in the host cell?
Yes
26
Does a yeast artificial chromosome produce a circular recombinant molecule in the host cell?
No
27
Does a cosmid produce a circular recombinant molecule in the host cell?
Yes
28
Does a P1-derived artificial chromosome produce a circular recombinant molecule in the host cell?
Yes
29
Are coding or non-coding regions of genes more conserved between different animal species?
Coding regions are more conserved
30
How many introns do mammalian mitochondrial genes have?
Few or none
31
Are mammalian genes distributed evenly across the genome?
No
32
Is the one gene-one protein assumption true or false?
False
33
What do mutations in genes that are imprinted often alter?
Foetal growth
34
How is mild anaemia of sickle cell trait characterised at the molecular level?
A deleterious gain of function
35
What is the high rate of de novo mutations in Duchenne muscular dystrophy likely related to?
The large size of the dystrophin gene
36
Are most copies of rare mutant alleles found more often in homozygotes or heterozygotes?
Heterozygotes
37
What allows us to predict that male tortoiseshell cats will be sterile?
X-inactivation
38
What hormone is produced by alpha cells in the isle of langehans?
Glucagon
39
What is adrenaline?
A catecholamine derived from tyrosine (the amino acid)
40
What does insulin stimulate muscle to convert glucose into?
Glycogen
41
What do serine proteases use to stabilise the tetrahedral intermediate?
Oxyanion hole
42
What is the amino acid residue at the active site of HIV protease that mediates target cleavage?
Aspartic acid
43
What is targeted by sarin to inhibit acetylcholinesterase?
Serine
44
What intracellular messenger releases Ca2+ from the endoplasmic reticulum?
Inositol-1,4,5-trisphosphate (IP3)
45
What signal stimulates synthesis of phosphatidylinositol-3,4,5-trisphosphate (PIP3)?
Insulin
46
What is released from a G protein when it is activated by a receptor?
GDP
47
What sequence ensure nascent soluble proteins are retained in the endoplasmic reticulum?
KDEL
48
What mediates vesicular transport between endoplasmic reticulum and the Golgi apparatus?
COP II vesicle
49
What mediates the first step in cholesterol uptake?
LDL receptor
50
What chemical interaction holds strands together in a DNA double helix?
Hydrogen bonds
51
What chemical moiety is at the 3'- end of a linear DNA molecule?
Hydroxyl
52
What aromatic base is normally paired with guanine?
Cytosine
53
Is cytosine acidic or basic?
Basic
54
Is cytosine aromatic?
Yes
55
What is a telomere?
The DNA region at each end of a chromosome
56
What enzyme initiates nucleic acid synthesis in DNA replication?
Primase
57
What is a transposon?
A mobile genetic element
58
What is a distinguishing feature of a lariat?
2'-5' phosphodiester bond
59
What part of the antibody is involved in interaction with receptors on effector cells of the immune system?
Fc
60
What is CDR?
A hypervariable loop joining two beta strands
61
What defines the binding specificity of an antibody?
CDR (a hypervariable loop joining two beta strands)
62
What technique involves separation of the products of transcription based upon their lengths, followed by transfer on to a membrane support to allow interrogation with a labelled DNA or cDNA probe?
Northern blotting
63
What is cDNA library construction?
A preparation of a bank of clones from a tissue or a developmental stage that allows further investigation of the genes expressed through sequence analysis or hybridisation to locus specific probes
64
What is restriction fragment length polymorphism analysis?
Digestion of nucleic acids and comparison of the product sizes following gel separation to identify allele specific patterns
65
What is a de novo loss of several adjacent loci from one chromosome, which results in a disease phenotype, an example of?
Contiguous gene deletion syndrome
66
What phenomenon is important for normal development which is often impaired in clinical conditions such as Prader-Willi syndrome?
Imprinting
67
Does muscle require insulin for efficient uptakes and metabolism of glucose?
Yes
68
Does fat require insulin for efficient uptakes and metabolism of glucose?
Yes
69
Does the brain require insulin for efficient uptakes and metabolism of glucose?
No
70
Does the pancreas require insulin for efficient uptakes and metabolism of glucose?
No
71
Does the liver require insulin for efficient uptakes and metabolism of glucose?
No
72
How are serine and alanine similar?
Serine is alanine with another hydroxyl group
73
How are tyrosine and phenylalanine similar?
Tyrosine is phenylalanine with another hydroxyl group
74
What do the amino acid pairs serine+alanine and tyrosine+phenylalanine have in common?
Alanine + -OH = Serine
Phenylalanine + -OH = Tyrosine
75
Is glucose a reducing sugar?
Yes
76
What molecules link to form maltose?
2 α-D-glucose molecules
77
Does starch or glycogen contain more α-1,6 branches?
Glycogen
78
What is cellulose formed from?
A chain of β-D-glucose molecules
79
Are sugars added to proteins in the endoplasmic reticulum?
Yes
80
Where do the side chains point in a β-sheet?
Above and below the plane of the sheet
81
In regular secondary structures, what are all the backbone C=O and N-H atoms forming?
Hydrogen bonds
82
How many of the backbone C=O and N-H atoms form hydrogen bonds in regular secondary structures?
All of them
83
What is an α-helical hairpin mainly held together by?
Hydrophobic interactions
84
In an α-helix, do the side chains point towards the C-terminus?
No
85
What does the Φ angle describe?
Rotation around the bond between the Cα and N atoms
86
What angle describes the rotation around the bond between Cα and N atoms?
Φ
87
What is involved in the humanisation of a murine antibody?
The CDR loops of the murine antibody are grafted onto a human framework
88
Does 1,3-bisphosphoglycerate formation from glyceraldehyde-3-phosphate require ATP?
No
89
Is glucokinase inhibited by glucose-6-phosphate?
No
90
Is the reaction catalysed by aldolase during glycolysis essentially irreversible?
No
91
Does glycerol phosphate formation from dihydroxyacetone phosphate requires NAD+?
No
92
Does AMP interact with glycogen phosphorylase?
Yes, AMP activates glycogen phosphorylase
93
Can more glycogen be stored in liver or muscle?
Muscle
94
How does glucose influence phosphorylation of liver glycogen phosphorylase?
Promotes it
95
What promotes phosphorylation of liver glycogen phosphorylase?
Glucose
96
What reaction does glucose promote in liver glycogen phosphorylase?
Phosphorylation of liver glycogen phosphorylase
97
In liver cells, is the NAD+/NADH ratio lower in the mitochondria or the cytosol?
Mitochondria
98
What reduces pyruvate kinase activity in the liver?
The action of glucagon
99
Do liver tissues use ketone bodies?
No
100
What is the effect of ethanol metabolism in the liver?
It slows down gluconeogenesis
101
How many protons does complex IV pump for each pair of electrons transferred to oxygen?
2 protons
102
Which complexes in the electron transport chain contain tightly-bound iron-sulphur proteins that transfer single electrons?
Complexes I, II, III
103
If the associated entropy change is positive, what will happen as long as the temperature exceeds a certain threshold?
An endothermic chemical reaction will spontaneously proceed
104
What condition must be met for an endothermic chemical reaction to spontaneously proceed if the associated entropy change is positive?
Temperature exceeds threshold value
105
What conditions must be met in order for an endothermic chemical reaction to spontaneously proceed?
The associated entropy change is positive
Temperatures exceeds threshold value
106
What do G-protein-coupled receptors promote?
GDP release from G proteins
107
Do G-protein-couple receptors bind ATP?
No
108
Does the activation of G-protein-coupled receptors require phosphorylation of tyrosine residues?
No
109
Do G-protein-coupled receptors allow ions to pass freely across the plasma membrane?
No
110
Which has a larger phosphorylation potential, adenosine triphosphate or phosphocreatine?
Phosphocreatine
111
How are newly synthesised insulin receptors targeted to the plasma membrane?
Via the Golgi apparatus
112
What cell type do adenocarcinomas originate in?
Glandular epithelial cells
113
Is there a correlation between genome size and organism complexity?
No
114
What do the majority of repeat sequences in our genome derive from?
Transposable elements
115
What do bacteria rely on in DNA mismatch repair?
DNA methylation
116
What do bacteria rely on DNA methylation for?
DNA mismatch repair
117
Is DNA methylation inherited in a Mendelian fashion?
No
118
How is ubiquitin linked to lysine in proteins?
Covalently via a multi-step process
119
Are most genes in mammals spliced or not?
Spliced
120
Is RNA splicing common in yeast?
No, it's rare
121
What does canonical splicing require?
Large ribonucleoprotein
122
During RNA splicing, what does the branch point region base pair with?
US snRNA
123
During RNA splicing, what does US snRNA pair with?
The branch point region base
124
What does alternative splicing increase?
The diversity of the proteome
125
What increases the diversity of the proteome?
Alternative splicing
126
In prokaryotes, does splicing require a unique lariat structure to form?
No
127
What do cells with unrepaired DNA usually undergo?
Apoptosis
128
What does phosphorylation of Cdc6 help prevent?
Re-replication of DNA
129
Can cells with unrepaired DNA damage become senescent?
Yes
130
What effect does cleaving have on a caspase?
Activated when cleaved
131
What caspase cleaves Bid?
Caspase 8
132
Is caspase 7 an initiator caspase?
No
133
Is caspase 8 part of the extrinsic pathway of apoptosis?
Yes
134
What residues to caspases primarily cleave substrates at?
DEVD residues
135
What does giemsa-banding reflect?
Chromatin condensation
136
How often will an aneuploid karyotype be abnormal?
Always
137
How many chromosomes does the mouse karyotype have?
40
138
How does the position of the centromere vary for a given chromosome?
Stays constant
139
What regulates mammalian X inactivation?
Non-coding RNA
140
What proposed random X inactivation?
Mary Lyon's 1961 paper
141
Which is the heterogametic sex in birds?
Female
142
Is the human Y chromosome gene-rich?
No
143
What is the FMR1 gene influenced by?
Trinucleotide repeat expansion
144
What have genome-wide association studies usually identified?
Low risk disease variants
145
What is Down's syndrome generally caused by?
Meiotic defects
146
Why is trisomy 21 common in Down's syndrome?
This chromosome is small and the effects of the increased gene dosage are therefore less serious
147
Is the risk of Down's syndrome correlated to maternal age?
Yes, risk increases with maternal age
148
Is Down's syndrome usually congenital?
Yes
149
Do individuals with Down's syndrome have a lower incidence of dementia?
No, they have a higher incidence of dementia
150
What is biotin a cofactor for?
Acetyl CoA carboxylase
151
What is a cofactor of acetyl CoA carboxylase?
Biotin
152
What is pantothenate involved in?
Transfer of 2-carbon units
153
What is involved in the transfer of 2-carbon units?
Pantothenate
154
What is an electron carrier in cytochrome C?
Haem
155
Is haem found in cytochrome C?
Yes, it acts as an electron carrier
156
What modular domain binds proline-rich sequences?
SH3
157
What nucleotide exchange factor induces conformational change in Ras and release of GDP?
Sos
158
What transcription factor is activated by the MAP kinase pathway?
Fos
159
What enzyme is inhibited via phosphorylation during starvation, thus promoting gluconeogenesis?
Pyruvate dehydrogenase
160
What amino acid provides an important connection between the citric acid cycle and the urea cycle?
Aspartic acid
161
What metabolite inhibits de novo fat synthesis by activating a kinase?
AMP
162
What is an IP3 receptor?
An ion channel
163
What inactivates the signalling properties of cyclic AMP?
Phosphodiesterase
164
What conserved protein domain binds to phosphotyrosine residues?
SH2 domain
165
What is activated by genomic amplification in neuroblastoma?
N-Myc
166
What tumour virus protein is responsible for binding to and inactivating p53?
Human papilloma virus E6
167
What regulates c-Src?
Intramolecular tyrosines with a phosphotyrosine?
168
What is a centromere?
The region of attachment between two sister chromatids
169
What function effect is achieved by X-chromosome inactivation?
Dosage compensation
170
What is a T-loop?
A DNA structure formed by telomeres
171
What enzyme unwinds the parental DNA in replication?
DNA helicase
172
What is the proof reading activity of DNA polymerases?
3'-5' exonuclease
173
What step is required in the maturation of bacterial Okazaki fragments?
Nick translation
174
What is the template of transcription in eukaryotes?
Genomic DNA
175
What is histone acetylase?
A chromatin-modifying enzyme
176
What is an enhancer in transcriptional control?
A cis-regulatory element that can be located far from the gene locus
177
What is a mosaic?
Individual composed of cells with different genotypes
178
What is chiasma?
Point where exchange of genetic information occurs between homologous non-sister chromatids
179
What is the chi-squared test?
Statistical method for determining the significance of observed outcomes against expected results
180
What do glucagon, adrenaline and vasopressin all stimulate?
Cell signalling cascades using cAMP as a common intracellular signal transduction molecule
181
What common intracellular signal transduction molecule do glucagon, adrenaline and vasopressin all use when stimulating cell signalling cascades?
cAMP
182
What regulates protein kinase A catalytic activity?
Binding to cAMP
183
What repulsion is required for calcium ion flow through voltage-gated calcium channels?
Ion-ion repulsion
184
What do voltage-gated calcium channels open in response to?
Plasma membrane depolarisation
185
How many binding sites do voltage-gated calcium channels have for calcium ions?
2
186
How can the response of voltage-gated calcium channels to membrane potential be modified?
Phosphorylation
187
Can disaccharides have reducing ends?
Yes
188
How many chiral centres do glucose and galactose differ at?
1
189
What chiral centre do glucose and galactose differ at?
Carbon 4
190
What bond is the α-1,6 branchpoint in glycogen?
Glycosidic bond
191
How many epitopes does a monoclonal antibody typically recognise on the target antigen?
1
192
How many domains do IgG class antibodies contain?
12 immunoglobulin domains held together by disulphide bonds
193
What allows the antigen binding arms of a single antigen to bind to two antigens?
The hinge region
194
What does the hinge region allow?
The binding arms of a single antigen to bind to two antigens
195
What mediates effector functions of antibodies?
The constant domains
196
What do the constant domains mediate?
Effector function of antibodies
197
What permits the variable domain to form the antigen binding site?
Sequence diversity in three loops
198
What does sequence diversity in three loops allow the variable domain to do?
Form the antigen binding site
199
Does secondary structure always maximise side chain hydrogen bonds?
No
200
What proteins have no disulphide bonds?
Intracellular proteins
201
Is disulphide bonding necessary for all tertiary structures?
No, intracellular proteins have none
202
What sort of protein is haemoglobin?
Globular
203
What makes up the Greek key motif?
4 β-sheets
204
Do cofactors provide functionality?
Yes, ie carrying electrons and oxygen
205
What connects the two nucleotides contained by NAD and FAD?
5'-5' phosphodiester bonds
206
What is tetrahydrofolate essential for?
Adenine production
207
What vitamin is the precursor for a cofactor essential for acyl transfer?
Pantothenate
208
What is the cofactor pantothenate is a precursor for essential for?
Acyl transfer
209
What is MLH1 essential in?
Eukaryotic mismatch repair system -> proof reading -> error frequency x100 increase
210
Do inherited single allele mutations in tumour suppressor genes confer susceptibility to cancer?
Yes
211
What is glucokinase also known as?
Hexokinase IV
212
What is hexokinase IV?
Glucokinase
213
Is hexokinase inhibited by its product?
Yes
214
Is glucokinase inhibited by its product?
No
215
Is hexokinase IV inhibited by its product?
No
216
What is the ΔG·' for the glycolytic reaction catalysed by fructose bisphosphate aldolase?
Highly endergonic
217
How many carbons does acetyl have?
2
218
Is DNA or RNA more stable at alkaline pH?
DNA
219
Can RNA hybridise with DNA?
Yes
220
What does cytosine demethylation produce?
Uracil
221
Are histones basic or acidic?
Basic
222
Can histone tails undergo chemical modifications?
Yes
223
What do chromatin remodellers use for activity?
ATP
224
What does heterochromatin largely consist of?
Repetitive DNA
225
What does histone H! bind to?
Inter-nucleosomal DNA
226
How does DNA replication proceed from the DNA origin?
Bidirectionally
227
What is primase?
A DNA-dependent RNA polymerase
228
How can flux regulation through a pathway be controlled?
Enzyme expression levels
229
What does allosteric control provide?
Rapid regulation of pathways, usually from intracellular cues
230
What prevents accumulation of the products of a given pathway?
Feedback inhibition
231
What inactivates pyruvate dehydrogenase?
Phosphorylation
232
What is the impact of increased concentrations of ATP on citrate synthase?
Inactivates citrate synthase
233
What does the liver take up from the blood stream following exercise?
Lactate
234
What takes up lactate from the blood stream after exercise?
Liver
235
What is the toxic mechanism of dinitrophenol (DNP)?
Uncoupling agent that dissipates the chemiosmotic gradient
236
Does sex chromosome dimorphism occur in birds?
Yes
237
Does sex chromosome dimorphism occur in mammals?
Yes
238
Does sex chromosome dimorphism occur in Drosophila?
Yes
239
In mammals what is the heterogametic sex?
Male
240
In birds, what is the heterogametic sex?
Female
241
What does an IRES facilitate?
CAP-independent translation in eukaryotes
242
What facilitates CAP-independent translation in eukaryotes?
IRES
243
Why does RNA polymerase terminate transcription at rho-independent site in prokaryotes?
Due to a GC-rich hairpin followed by a run of U nucleotides
244
Is RNA polymerase II transcription highly regulated?
Yes
245
What is an important determinant of the transcription start site in prokaryotes?
Pribnow box
246
What is TFIID a complex of?
TATA-binding protein (TBP) and other general transcription factors (TAFs)
247
What inhibits degradation of cyclic AMP?
Caffeine
248
What stimulates protein kinase C activity?
Diacylglycerol
249
What protein is strongly associated with an inherited predisposition to cancer?
Retinoblastoma (look for tumour suppressors)
250
What protein is associated with the development of B-cell lymphoma in chickens infected with the avian leukosis virus?
MYC
251
What protein is strongly associated with tumour angiogenesis?
Vascular endothelial growth factor (VEGF)
252
What are indels frequently caused by?
Polymerase slippage
253
What can unbalanced structural variants cause?
Copy number variant
254
What are transitions and transversions examples of?
Single nucleotide variant
255
What type of repair is coupled to DNA synthesis?
Mismatch repair
256
What is translesion synthesis?
A type of DNA polymerase-dependent DNA repair
257
What type of repair is associated with meiosis?
Homologous recombination
258
What is the peak absorption wavelength of DNA?
260nm
259
What correlates inversely with DNA sequence complexity?
Speed of strand reannealing
260
What assay is used to detect a specific RNA in a nucleic acid sample?
Northern blot
261
What is Turner syndrome?
A sex chromosome aneuploidy condition in females
262
What is Klinefelter syndrome?
A sex chromosome aneuploidy condition in males
263
What is Angelman syndrome caused by?
Paternal uniparental disomy for chromosome 15
264
What method of cell death usually doesn't induce inflammation?
Apoptosis
265
What caspase does pyroptosis often depend on?
Caspase 1
266
What induces ferroptosis?
Toxic lipid peroxides
267
What allosteric modulator regulates the balance between glycolysis and gluconeogenesis acting on PFK1?
Fructose-2,6-bisphosphate
268
What is the product of hexokinase?
Glucose-6-phosphate
269
What is an intermediate in the citric acid cycle and gluconeogenesis?
Oxaloacetate
270
How many ATP molecules are produced from the oxidation of FADH2?
1.5
271
How many ATP molecules are produced from the complete oxidation of acetyl CoA?
10
272
How many ATP molecules are produced from the complete oxidation of palmitoyl-CoA?
108
273
Is tyrosine aromatic?
Yes
274
Is tryptophan aromatic?
Yes
275
Is phenylalanine aromatic?
Yes
276
Is threonine aromatic?
No
277
Can serine be phosphorylated?
Yes
278
Can threonine be phosphorylated?
Yes
279
Can tyrosine be phosphorylated?
Yes
280
Can phenylalanine be phosphorylated?
No
281
What charge are lysine sidechains at pH6?
Positive
282
What charge are arginine sidechains at pH6?
Positive
283
What charge are histidine sidechains at pH6?
Positive
284
Does aspartic acid have positively charged sidechains at pH6?
No
285
Where do secondary structures correspond to on a Ramachandran plot?
2 separate areas
286
What conditions are needed to favour ketone body formation in liver cells?
High ATP levels
High NADH levels
Less active pyruvate dehydrogenase
High acetyl-CoA levels
287
What can ligand-gated ion channels be classified as?
Allosteric receptors
288
Why do SNARE proteins wind around each other?
To force inbound vesicles closer to target organelle membranes
289
What direction does RNA synthesis proceed in?
5'-3'
290
What would make a cell more likely to undergo apoptosis?
Release of cytochrome C from the mitochondria
291
What would make a cell less likely to undergo apoptosis?
Increasing Bcl2 concentration
292
Is it only pro-apoptotic Bcl2 family proteins that have BH3 domains?
No
293
What do Bax and Bak form in the outer mitochondrial membrane?
Pores
294
Is Mcl-1 pro-apoptotic?
No, Mcl-1 is anti-apoptotic
295
What caspase can cleave Bid?
Caspase 8
296
Is Bcl2 a tumour suppressor gene or an oncogene?
Oncogene
297
What does it mean if a meiotic recombination frequency of 50% is observed?
The two genes are likely to be located on different chromosomes
298
If the heterogametic sex of a species is female, what is the sex of the parthenogenetic offspring?
Male
299
Have twin studies shown that genetic factors have a greater role in schizophrenia than in parkison disease?
Yes
300
What equations allows calculation of the genotype frequencies if you know the phenotype frequencies?
Hardy-Weinberg equation
301
Can some oncogenes be characterised by single point mutation?
Yes
302
Does the Bcl2 protein promote cell death?
No
303
When is the v-src protein activated?
Following truncation of its extreme carboxy terminus
304
What gene is involved in chromosomal translocations characteristic of non-AIDS Burkitt's lymphoma?
c-myc
305
What would a point mutation of the intracellular domain of the epidermal growth factor receptor do?
Contribute significantly to the development of cancer
306
Does Magnetic Resonance require ionizing radiation?
No
307
Does Magnetic Resonance require a static magnetic field?
Yes
308
What can Magnetic Resonance be used for?
3D anatomical images
309
Does Magnetic Resonance provide poor soft-tissue contrast?
No, provides excellent soft-tissue contrast
310
Is Magnetic Resonance a relatively insensitive technique?
Only without hyperpolarization
311
What is a PET experiment?
A positron emitting tracer is injected in the patient and gamma radiation is detected from positron-electron annihilation
312
What percentage of the mitochondrial genome makes functional gene products?
95%
313
How are mutations in mitochondrial DNA inherited?
Maternally
314
What are cells with a mixed population of mutant and normal mitochondria known as?
Heteroplasmic
315
What can be used to determine total protein concentration in a solution?
Bradford assay
316
What technique relies on purification on the basis of charge?
Ion exchange chromatography
317
What is isothermal calorimetry used to do?
Measure heat changes when two molecules interact
318
What domain in Grb2 binds to the active receptor tyrosine kinase?
SH2 domain
319
What protein switches off small G proteins?
GTPase activating protein
320
What protein kinase is activated by binding to an active small G protein?
Raf
321
What enzyme catalyses the hydrolysis of triacylglycerol to diacylglycerol in fat cells?
Adipose triglyceride lipase
322
What amino acid is directly involved with the urea cycle?
Arginine
323
What activates phosphorylase kinase?
Calcium ions
324
What inhibits carnitine acyltransferase I?
Malonyl-CoA
325
What activates acetyl CoA-carboxylase?
Citrate
326
What protein is associated with pancreatic cancer?
K-Ras
327
What kinase promotes cell survival?
Akt
328
What scaffold protein directs intracellular co-localization of protein kinase A and other proteins?
AKAP
329
What enzyme hydrolyses phosphatidylinositol-4,5-bisphosphate to generate IP3 and diacylglycerol?
PLC
330
What activates PKA?
Binding of cAMP
331
What is a distinguishing feature of a mRNA 5' CAP in eukaryotes?
5'-5' nucleotide bond
332
What is an RNA mediated mechanism for inhibiting gene expression?
RNAi
333
What is the catalytic core of the spliceosome?
U2 and U6 snRNAs
334
What amino acid forms an isopeptide bond between ubiquitin and a target protein
Internal lysine
335
What is essential for the degradation of long-lived proteins?
Lysosome
336
What is the E3 enzyme?
The ubiquitin ligase
337
What is the ubiquitin ligase?
The E3 enzyme
338
What is a euchromatin?
A gene rich region of DNA
339
What is RNA-dependent DNA polymerase
A reverse transcriptase
340
What is Leber Hereditary Optic Neuropathy (LHON)?
A mitochondrial disease with matrilineal inheritance
341
What is complete insensitivity syndrome?
XY individuals developing as phenotypic females
342
What is chronic myeloid leukaemia commonly caused by?
The presence of the Philadelphia chromosome translocation
343
What does presence of the Philadelphia chromosome translocation often cause?
Chronic myeloid leukaemia
344
What is nuchal translucency?
An ultrasound test contributing to prenatal down syndrome diagnosis
345
What is the initiator of dosage compensation in female mammals?
Xist non-coding RNA
346
What occurs when a new population is established by a small number of individuals from a larger population?
Founder effect
347
During the onset of type 2 diabetes, are blood glucose levels likely to be below 7mM?
No, above 7mM
348
May ketone bodies be present in the blood during onset of type 2 diabetes?
Yes
349
Is the level of insulin in the blood usually low or undetectable during the onset of type 2 diabetes?
No, often very high
350
Is uptake of glucose into fat cells responsive to insulin during onset of type 2 diabetes?
Poor responsive
351
May glucose be present in the urine during the onset of type 2 diabetes?
Yes
352
Which is stronger, the bonding between two strands of an anti-parallel β-sheet or parallel β-sheet?
Anti-parallel β-sheet
353
Why is the bonding between two strands of an anti-parallel β-sheet stronger than two strands of a parallel β-sheet?
Because of the orientation of the hydrogen bonds
354
How can the linkage between two strands of an anti-parallel β-sheet be accommodated?
A short structural loop called a hairpin
355
On their own, what are β-sheet and α-helices held together exclusively by?
Hydrogen bonds
356
What causes scurvy?
Reduced hydroxylation of proline residues, weakening collagen fibres
357
Does glucokinase or muscle hexokinase have a higher km for glucose?
Glucokinase
358
How is genetic diversity altering the peptide sequence of constant domains achieved?
Recombination
359
What is haem?
A prosthetic group
360
How does oxygen bond to an iron ion in oxy-haemoglobin?
Coordinated within a porphyrin ring
361
Kinetically, how does haemoglobin bind to oxygen?
With sigmoidal binding kinetics
362
Where does fatty acid synthesis occur?
In the cytosol
363
What happens to most acetyl-coA in the liver?
Converted into ketone bodies
364
What is insulin made up of?
2 polypeptides
365
Where is insulin produced?
Pancreatic beta cells
366
Does insulin promote glycogen synthesis in muscle?
Yes
367
Do allosteric enzymes obey Michaelis-Menton kinetics?
No
368
Do non-allosteric enzymes obey Michaelis-Menton kinetics?
Yes
369
What do competitive inhibitors do to km and vmax?
Affect km, vmax unchanged
370
What do non-competitive inhibitors do to km and vmax?
Decrease vmax, km unchanged
371
What does the serine protease oxyanion hole do?
Stabilise the transition state
372
What residue do Asp proteases have in their active site?
Aspartic acid residues
373
Can enzymes form covalent bonds with reaction intermediates?
Yes
374
What joins sugar molecules in disaccharides?
Glycosidic bonds
375
What allows the protein backbone to fold?
Rotation around the α-carbon
376
Are phosphodiester bonds present in DNA or RNA?
In both
377
Is L-deoxyribose a building block of DNA?
No, D-deoxyribose is the most naturally occurring one
378
Do all sugars have a reducing end?
No
379
What domains binds to polyproline epitopes?
SH3 domains
380
What do SH2 domains recognise?
Phosphorylated tyrosines
381
How does Sos activate Ras proteins?
Promoting guanine nucleotide exchange
382
What do transcription factors use to recognise specific DNA sequences?
Hydrogen bonds to base pairs down wide groove and sometimes narrow grooves
383
What explains the expansion of gas in a vacuum?
Second law of thermodynamics
384
How can changes in relative concentrations of ATP, ADP and AMP be followed in vivo?
Using 31P nuclear magnetic resonance spectroscopy
385
Does phosphoenolpyruvate have a small or large phosphorylation potential?
It has one of the highest
386
Will the standard free energy change for the hydrolysis of the activated carrier acetyl coenzyme A be positive or negative?
Negative
387
For the reaction A + B ⇌ C + D, is the change in Gibbs free energy under non-standard non-equilibrium conditions is given by: ΔG = ΔGo’ – RT ln {( [A] × [B] ) / ( [C] × [D] )}?
Yes
388
For the reaction A + B ⇌ C + D, what is the change in Gibbs free energy under non-standard non-equilibrium conditions given by?
ΔG = ΔGo’ – RT ln {( [A] × [B] ) / ( [C] × [D] )}
ΔG = ΔGo’ + RT ln {( [C] × [D] ) / ( [B] × [A] )}
389
Do skeletal muscles contain glucose-6-phosphate?
No
390
Do adipocytes contain glycerol kinase?
No
391
Do skeletal muscles contain acetyl-CoA carboxylase?
Yes
392
Do liver cells contain succinyl-CoA:aceoacetate CoA transferase?
No
393
Does heart muscle or skeletal muscle cells contain fructose-1,6-bisphosphatase?
Skeletal muscle does, heart muscle doesn't
394
What causes phenylketonuria?
Failure to breakdown phenylalanine
395
How can leucine and lysine be metabolised?
Only as ketone bodies
396
What is excess ammonia in tissues added to?
Glutamate
397
What carries ammonia from skeletal muscle to the liver?
Alanine
398
What is the activated form of the extender unit in fatty acid synthesis?
Malonyle CoA
399
How does citrate influence acetyl-CoA carboxylase?
Citrate is an allosteric activator
400
Where are fatty acids synthesised?
Cytoplasm
401
How many molecules of CO2 are lost in each extension reaction of fatty acid synthesis?
1
402
Do all G protein-coupled receptors stimulate formation of cyclic AMP?
Some, not all
403
How many transmembrane domains do G protein-coupled receptors have?
7
404
What do G protein-coupled receptors stimulate?
Release of GDP from G proteins
405
What is the nucleus surrounded by?
A double membrane
406
Do nuclear pores allow proteins to pass?
Yes
407
Is the lumen of lysosomes acidic or basic?
Acidic
408
What do the endoplasmic reticulum and nuclear envelope form?
A continuous membrane system
409
Can mitochondria synthesise proteins?
Yes
410
What direction does nucleosomal DNA form a spiral in?
Left-handed spiral
411
Where does eukaryotic DNA replication start?
Multiple origins
412
What do DNA polymerases require for nucleotide polymerisation?
A primer and a template
413
What is primase?
A DNA-dependent RNA polymerase
414
What is DNA polymerase I 3'-to-5' exonuclease activity important for?
Proof reading
415
What is DNA polymerase I 5'-to-3' exonuclease activity important for?
Nick translation
416
What do nuclear hormone receptors form on DNA?
Homo- or hetero- dimers
417
What does activation of the glucocorticoid receptor by cortisol binding involve?
Dissociation of glucocorticoid from Hsp90
418
What are nuclear hormone receptors?
Specific DNA-binding transcription factors
419
Can nuclear hormones influence transcription?
Yes, they can activate and/or repress transcription
420
Where is the mRNA GMP cap methylated?
Position 7
421
What does the poly(A) tail protect RNA from?
3' to 5' exonucleases
422
What does splicing remove?
Introns
423
What is required for splicing?
mRNA cap
424
Does the Ras protein become oncogenic following truncation?
No
425
How does the retinoblastoma protein control the cell cycle?
Inhibiting E2F proteins
426
What is an increase in copy number of the N-myc gene associated with in children?
Childhood neuroblastoma
427
How many somatic mutations do most human cancers have?
1,000-30,000
428
What does the Hardy-Weinberg Law assume?
Mating is random
There is no selection
There is no mutation
There is no genetic drift
429
Do genetics play a greater role in schizophrenia or Parkinson's disease?
Schizophrenia
430
What is often used for the treatment of malignant melanoma?
Drugs that inhibit the mutant B-RAF oncogene
431
What do tumour initiating cells (cancer stem cells) contribute to?
Resistance against radiation therapy
432
Can cells with unrepaired DNA damage become senescent?
Yes
433
What happens during a PET experiment?
Gamma radiation is detected from positron-electron annihilation
434
Why is arganine so basic?
Has a guanido group?
435
What amino acid has a sidechain that attaches to sugars in N-linked oligosaccharides?
Asparagine
436
Is phenylalanine hydrophobic or aromatic?
Both
437
Where is succinate dehydrogenase located?
Inner mitochondrial membrane
438
What is an allosteric activator of pyruvate carboxylase?
Acetyl-CoA
439
What is an allosteric activator of glycogen phosphorylase?
5'- adenosine monophosphate
440
What imports proteins from the cytosol in a fully folded state?
Nucleus
441
What conveys proteins from the Golgi apparatus to the endoplasmic reticulum?
COP I vesicles
442
Where are sugar residues first attached to proteins?
Endoplasmic reticulum lumen
443
What has EF-hands that bind Ca2+?
Calmodulin
444
What inhibits degradation of cyclic AMP?
Caffeine
445
What stimulates release of Ca2+ from the endoplasmic reticulum?
Isonitol-1,4,5-triphosphate (IP3)
446
What are transposons?
Mobile genetic elements?
447
What is replicative transposition?
Chromosomal rearrangement that increases genome size
448
What is a physical measure of DNA complexity?
Annealing rate
449
What is the peak wavelength of ultraviolet absorbance of DNA?
260nm
450
How much DNA is in the human nucleus?
6pg
451
What promotes CAP-independent protein translation?
IRES
452
What signal facilitates digestion in lysosomes?
KFERQ
453
What enzyme is involved in targeted protein degradation?
Ubiquitin ligase
454
What is an oncogene?
Dominantly acting cancer gene
455
What is a spontaneous deamination of 5-methylcytosine?
Endogenous mutational process
456
What is a translocation involving chromosome 1 and chromosome 5?
Structural variation
457
What is an explanation for the high frequency of heterozygous carriers of the HbS autosomal recessive allele for sickle-cell disease in Africa?
Balancing selection
458
What is array-based genomic hybridisation?
Molecular cytogenic method for determining copy number variation in a test sample compared to a reference sample
459
What is variable penetrance?
Less than 100% of individuals with a particular genotype display the expected phenotype
460
What is fMRI?
A method of measuring brain activity using MRI that is sensitive to changes in blood flow and levels of oxygen
461
What is FDG?
A PET tracer that is an analogue for glucose
462
How might inhibitors of phosphotyrosine phosphatases be expected in principal to impact cells responsiveness to insulin?
Increase it
463
What increases the phosphorylase enzyme activity of glycogen phosphorylase b?
Phosphorylation of glycogen phosphorylase b at serine 14
Binding of 5'AMP to phosphorylase b
464
What is oxidised and reduced in the electron transport chain?
Everything up to complex 3 is reduced
Everything after complex 3 is oxidised
465
Complex III of the electron transport chain is inhibited by antimycin. What would happen to the redox state of copper and cytochrome a if antimycin was added to mitochondria that were oxidising NADH?
Copper and cytochrome a both become more oxidised
466
What is the net yield of ATP when glycogen is utilised by contracting muscle?
3 ATP
467
How does carbon derived from carbohydrate and fatty acids enter the citric acid cycle?
Condensation of acetyl-CoA with oxaloacetate
468
What is the absorbance of a compound at a given wavelength equal to?
Its concentration x the width of the sample cuvette x the molar absorbance coefficient
469
Can amino acids be glucogenic?
Most are
470
What can some amino acids be metabolised to to contribute to fatty acid synthesis under appropriate conditions?
Acetyl-CoA and acetoacetate
471
What sort of molecule is urea?
Highly soluble, uncharged
472
What is required as a cofactor by an enzyme that post-translationally modifies collagen?
Ascorbic acid
473
Where do collagen molecules assemble before being secreted?
In the endoplasmic reticulum of fibroblast cells
474
What is the primary sequence of collagen composed of?
Many repeats of the sequence glycine-X-Y where X and Y are often proline and hydroxyproline
475
What is the carbonyl oxygen of each peptide bond hydrogen bonded to?
The amide nitrogen of the amino acid 4 residues towards the C-terminus
476
Can protein alpha helices be amphipathic?
Yes
477
Are protein alpha helices right or left handed?
Right handed
478
Do protein alpha helices tend to maximise hydrogen bonding?
Yes
479
What two amino acids are never found in proteins?
Citrulline
Ornithine
480
What amino acid is involved in the hydrophobic interaction between insulin and its receptor?
Phenylalanine
481
What amino acid is involved in disulphide formation between the A and B chains of insulin
Cysteine
482
What amino acid is involved in a site for regulatory phosphorylation by the kinase activity of the insulin receptor?
Tyrosine
483
Where must insulin be injected?
A site of slow release, ie fat pads but absolutely not a blood vessel
484
What is a recently-developed drug treatment of type 2 diabetes?
Stimulation of the response to the insulin receptor by thiazolidinediones
485
What would be the affect of CO2 reacting with α-amino groups and introducing negative charges that stabilise deoxyhaemoglobin?
Altered affinity of oxygen for haemoglobin
486
How is iron coordinated in haemoglobin?
By N atoms, 4 from the haem ring and one as an axial ligand from histidine
487
What changes occur when oxygen binds to haemoglobin?
O2 binding allows iron to move into the plane of the haem ring accompanied by α-helix movements that lead to a more open structure
488
What metabolic process corresponds with the synthesis of malonyl-CoA?
Fatty acid synthesis
489
What metabolic process corresponds with the donation of the CoA group from succinyl-CoA to a 4-carbon acceptor?
Ketone body utilisation
490
What metabolic process corresponds with the synthesis of glutamate?
Transamination
491
What intracellular enzyme is activated as a result of phosphorylation by protein kinase A and which cleaves its substrate into two products that are both released into the blood for use by other tissues?
Triacylglycerol lipase
492
What enzyme's activity is increased during gluconeogenesis as a result of a fall in the concentration of a potent inhibitor in response to glucagon activity?
Fructose-1,6-bisphosphate
493
What enzyme is require for fatty acid synthesis, is activated by insulin, and inhibited by glucagon via phosphorylation of the enzyme protein at different sites?
Acetyl-CoA carboxylase and fatty acid synthase, but acetyl-CoA is a regulatory point for fatty acid synthesis
494
Where are fatty acids released from during fasting?
Adipose tissue
495
Where are chylomicrons synthesised following the ingestion of a high-fat meal?
Gut epithelium
496
Where is urea synthesised?
Liver
497
What ligand is required for the activation of calmodulin?
Calcium
498
What is a regulator of cytosolic guanylyl cyclase?
Nitrous oxide (NO)
499
What is produced by membrane bound and cytosolic guanylyl cyclase?
3'5' cyclic GMP
500
What enzyme class catalyses geometric or structural changes within one molecule?
Isomerase
501
What enzyme class catalyses oxido-reduction reactions?
Dehydrogenase
502
What enzyme class catalyses bond breaking by means other than hydrolysis and oxidation?
Lyase
503
What is the concentration of the substrate at which the enzyme velocity is half maximal?
Km
504
What is the gradient of the straight line obtained from a Lineweaver-Burk plot?
Km/Vmax
505
What is the intercept on the X axis of a Lineweaver-Burk plot?
-1/Km
506
What guanine nucleotide-binding protein can regulate intracellular vesicle fusion?
Rab
507
What protein is folded in the endoplasmic reticulum and stored in secretory granules?
Insulin
508
What structural coat protein is required for the exit of transport vesicles from the endoplasmic reticulum?
Cop II
509
What amino acid is most positively charged?
Arginine
510
What amino acids are positively charged, from most to least?
Arginine
Lysine
Histidine
511
What amino acids are negatively charged?
Aspartic acid
Glutamic acid
512
What amino acids have hydrophobic side chains?
Tryptophan
Tyrosine
Phenylalanine
Methionine
Leucine
Isoleucine
Valine
Alanine
513
What amino acids have uncharged side chains?
Serine
Threonine
Asparagine
Glutamine
Tyrosine
Cysteine
Proline
Glycine
514
What amino acids have polar uncharged side chains?
Tyrosine
Serine
Threonine
Asparagine
Glutamine
515
What is Arg?
Arginine
516
What is His?
Histidine
517
What is Lys?
Lysine
518
What is Asp?
Aspartic acid
519
What is Glu?
Glutamic acid
520
What is Trp?
Tryptophan
521
What is Tyr?
Tyrosine
522
What is Phe?
Phenylalanine
523
What is Met?
Methionine
524
What is Leu?
Leucine
525
What is Ile?
Isoleucine
526
What is Val?
Valine
527
What is Ala
Alanine
528
What is Ser?
Serine
529
What is Thr?
Threonine
530
What is Asn?
Asparagine
531
What is Gln?
Glutamine
532
What is Cys?
Cysteine
533
What is Pro?
Proline
534
What is Gly?
Glycine
535
What process converts glycogen to glucose?
Glycogenolysis
536
What process converts glucose to glycogen?
Glycogenesis
537
What process converts glucose to pyruvate?
Glycolysis
538
What process converts pyruvate to glucose?
Gluconeogenesis
539
What process converts protein to amino acids?
Proteolysis
540
What converts triacylglycerol to fatty acids?
Lypolysis
541
What process converts fatty acids to triacylglycerol?
Esterification
542
What is the conversion of fatty acids to acetyl CoA?
Beta oxidation
543
What is the conversion of acetyl CoA to fatty acids?
Lipogenesis
544
What is the conversion of ketone bodies to acetyl CoA?
Ketolysis
545
What is the conversion of acetyl CoA to ketone bodies?
Ketogenesis
546
What cyclin-dependent kinases are in G1?
CDK4
CDK6
547
What cyclin-dependent kinases are in G1/S?
CDK2
548
What cyclin-dependent kinases are in S?
CDK2
549
What cyclin-dependent kinases are in M?
CDK1
550
What cyclins are present in G1?
Cyclin D1, D2, D3
551
What cyclins are present in G1/S?
Cyclin E
552
What cyclins are present in S?
Cyclin A
553
What cyclins are present in M?
Cyclin B
554
What inhibits CDK2?
P21
P27
555
What does isocitrate dehydrogenase catalyse?
The decarboxylation of isocitrate to alpha-ketoglutarate
556
What cofactor is used by aminotransferases?
Vitamin B6
557
What do fish excrete nitrogen as?
Ammonium ions
558
What is glycosylation of proteins catalysed by?
Cytosolic enzymes
559
Does an enzyme with a high km have a low or high affinity for its substrate?
Low
560
What does the PH domain bind to?
Inositol phospholipids
561
What does PTB domain bind to?
Phosphorylated tyrosines
562
What is required to initiate fatty acid synthesis?
Acetyl CoA
Malonyl CoA
NADPH
563
What can be added or removed from proteins in the Golgi apparatus?
Add or remove sugar
Add sulphate groups
Add phosphate
564
What is the TTAGGG repeat associated with?
Telomeres
565
Where is purifying selection strongest?
Non-coding regions of genomes
566
What does APC/C CDH1 degrade?
Securin and cyclins from S and M
567
What is the cofactor of succinate dehydrogenase?
FAD+
568
What is the cofactor of the E1 component of PDH complex?
Thiamine Pyrophosphate
569
What inhibits phosphofructokinase 1?
ATP
Citrate
570
What liberates iron from Fe-S clusters?
Superoxide
571
What accepts electrons from complex 1?
Ubiquinone
572
What converts succinate to fumarate?
Succinate dehydrogenase subunit A
573
What accepts electrons from the conversion of succinate to fumarate?
Succinate dehydrogenase subunit B
574
What is dideoxynucleotide (ddNTP)?
A chain terminating nucleotide used in Sanger sequencing
575
What is the difference between type 1 and type 2 topoisomerases?
Type 1 cleave one dna strand
Type 2 cleave two dna strands
576
What is a cluster of defined alleles inherited together?
Haplotype
577
What enzyme regulates centrosome duplication?
CDK2
578
What enzyme is required to remove sister chromatid cohesion?
Separase
