A plasmid-encoded beta-lactamase gene (bla) is used to:
A. Calculate beta-sheets
B. Measure GFP fluorescence
C. Maintain the plasmid through antibiotic selection
D. Atomic Force Microscopy
E.Measure lactate metabolism
When environmental conditions change, gene expression of how many genes can change bacteria (e.g. Salmonella enterica) within minutes?
A. Approximately hundreds
C. Very few (1-10 genes)
D. Exactly 100 genes
E. No genes will change in their expression; it takes much longer.
The K-OH test is used to differentiate bacteria into two groups as an alternative of the:
A. Oxidative-Fermentative (O-F) Test
B. Catalase test
C. Gram staining method
D. Smell test
E. Oxidase test
The optimal growth temperature for Escherichia coli is:
Which is NOT part of the Gram-negative cell envelope
A. Outer membrane
B. Inner membrane
C. Lipoteichoic acid
D. Thin cell wall
What is the chemical reaction of the catalase test?
A. 2 H2O = H2O + H2O
B. CO2 = C + O2
C. 2 H2O = 2 H2 + O2
D. 2 H2O2 = 2 H2O + O2
E. 2 H2O2 = 2 H2 + 2 O2
An established technique to measure gene expression in bacteria uses:
A. A plasmid
B. Bright-field microscopy
C. Atomic force microscopy
D. Gram staining
The oxidase test is carried out to test for the presence of:
A. Cytochrome C oxidases
B. Cytochrome E oxidases
C. Cytochrome D oxidases
D. Cytochrome A oxidases
E. Cytochrome B oxidases
Increasing turbidity of growth medium over time inoculated with bacteria indicates:
A. GFP expression
B. Extensive cell death
C. Cell aggregation
D. Cells growing to high density
E. The pH of the medium is changing
Bacteria expressing GFP can be monitored using:
A. Transmission electron microscopy
B. Fluorescence microscopy
C. Atomic force microscopy
D. Gram staining
E. Bright-field microscopy
Action potential, which of the following statements are correct?
A. All of the options given are true
B. Membrane potential reverses from approximately -65mV to +35mV when an action potential occurs.
C. The influx of Na^+ into the cell, causes a depolarisation, moving the neuron's voltage towards neutral. i.e. making it less negative
D. Depolarisation always leads to an action potential
What happens to the simulated neuron (on Metaneuron) when a stimulus depolarises the neuron by 4 to 5 mV ?
A. A failed initiation occurs and action potential does not occur.
B. The neuron enters a refractory period.
C. The neuron becomes hyperpolarised.
D. An action potential is achieved.
What happens when tetrodotoxin is applied to the squid giant axon preparation?
A. Calcium channels are blocked
B. The Neuron becomes hyperpolarised
C. Sodium channels are blocked
D. Potassium channels are blocked
Using a stimulus intensity of 65 µA, produce an action potential in the simulated neuron on Metaneuron. What happens when tetrodotoxin is applied?
A. the neuron becomes hyperpolarised
B. an action potential occurs
C. No depolarisation occurs
D. a small depolarisation, but no action potential occurs
Depolarisation & repolarisation in metaneuron - put the following events in order (from 1 to 4).
A. Membrane potential crosses the threshold potential and an action potential is achieved.
B. Depolarisation occurs when the applied current is sufficient to move membrane potential towards neutral.
C. The neuron’s membrane potential drops below the initial resting membrane potential and temporarily becomes refractory to further action potentials.
D. Membrane quickly repolarises by opening of K+ channels, allowing K+ ions to leave the cell and charge separation to be re-established.
1. Depolarisation occurs when the applied current is sufficient to move membrane potential towards neutral.
2. Membrane potential crosses the threshold potential and an action potential is achieved.
3.Membrane quickly repolarises by opening of K+ channels, allowing K+ ions to leave the cell and charge separation to be re-established.
4. The neuron’s membrane potential drops below the initial resting membrane potential and temporarily becomes refractory to further action potentials.
Many neurotransmitters trigger depolarisation by binding their receptors and gating an ion channel that allows Na+ influx.
What happens if a neurotransmitter such as GABA, binds its receptor, gating a chloride channel (Cl-)?
A. The membrane potential does not change
B. The neuron fires an action potential
C. The neuron becomes depolarised.
D. The neuron becomes hyperpolarised
Ion flux and depolarisation - select the TWO CORRECT statements.
A. Efflux of K+ is the electrical signal for repolarisation
B. Influx of Ca2+ is the electrical signal for the depolarisation
C. Influx of Na+ is the electrical trigger for depolarisation
D. Efflux of K+ is the electrical signal for depolarisation
Potassium leak is a major determinant of resting membrane potential.
What happens to the resting membrane potential when the intracellular concentration of potassium is increased to 120 mM?
A. The resting membrane potential collapses
B. The resting membrane potential becomes more positive
C. The resting membrane potential becomes more negative
D. It has no impact on the resting membrane potential
If membrane potential became more negative how would this affect its ability to fire an action potential?
A. A larger stimulus intensity would be required to achieve an action potential
B. A smaller stimulus intensity would be required to achieve an action potential
C. It has no impact on ability to fire an action potential
D. The membrane would become permanently depolarised
What are the main factors influencing the intra- and extracellular ion concentrations?
A. electrical gradients, chemical gradients
B. electrical gradients, chemical gradients, membrane permeability and leak channels
C. chemical gradients, membrane permeability and leak channels, electrical gradients and Na/K-ATPase
D. chemical gradients, membrane permeability and leak channels, Na/K-ATPase
what effects does the reagent Tetradotoxin (TTX) have on action potentials?
A. TTX causes an action potential by causing a depolarisation.
B. TTX prevents action potential, it blocks sodium channels so depolarisation is insufficient to trigger the magnitude of voltage changed required to make an action potential.
C. TT causes repolarisation after an action potential has occurred due to depolarisation.
D. TTX prevents action potential, it blocks potassium channels so depolarisation is insufficient to trigger the magnitude of voltage changed required to make an action potential.
What happens to the membrane potential and equilibrium potential when you increase the extracellular concentration of potassium (K^+)?
A. Increasing extracellular K^+ depolarises the resting membrane potential
B. It has no effect on resting membrane potential.
C. Increasing extracellular K^+ repolarises the resting membrane potential.
D. Increasing extracellular K^+ causes hyperpolarisation of the resting membrane potential
It is altered in this way because the electrical gradient required to maintain the resting membrane potential at the usual -65mV is being dissipated by increasing extracellular potassium ions.
What happens to the membrane potential and equilibrium potential when you decrease the intracellular concentration of potassium (K^+)?
A. Decreasing intracellular K^+ depolarises the resting membrane potential
B. It has no effect on resting membrane potential.
C. Decreasing intracellular K^+ repolarises the resting membrane potential.
D. Decreasing extracellular K^+ causes hyperpolarisation of the resting membrane potential
A change in a membrane potential from +30 mV to -70 mV is an
E. zero potential
The negative charge established along the cytosolic border a
nerve cell membrane is due to:
a. movement of sodium ions into the cell
b. movement of proteins out of the cell
c. higher permeability of K+ relative to Na+
d. movement of proteins through membrane channels
e. both b and d
Which of the following is/are found in all cells of excitable
and nonexcitable tissues?
a. a threshold potential
b. a resting membrane potential
c. gated ion channels
d. all of the above characteristics
e. mechanically-gated channels
Which term best describes an excitable cell when a resting
membrane potential is present?
A threshold potential is:
a. the potential achieved when two opposing forces acting upon an ion (concentration and electrical gradients) achieve a state of equilibrium
b. the peak potential achieved during an action potential
c. the point at which there is an explosive increase in Na+ or Ca2+ permeability
d. the potential at which K+ permeability increases
e. always a positive potential
A change in a membrane potential from -70 mV to -60mV is an
e. zero potential
a. are local changes in membrane potential that occur in varying degrees of magnitude
b. are weak action potentials
c. serve as long-distance signals
d. are only depolarizations
e. always lead to action potentials
During the rising phase of the action potential:
a. PK+ is much greater than PNa+
b. PNa+ is much greater than PK+
c. PK+ is the same as P Na+
d. Na+ efflux occurs
e. b and d are true
Which of the following is not a graded potential?
a. end-plate potential
b. action potential
c. slow-wave potential
d. receptor potential
e. postsynaptic potential
Which of the following is responsible for the falling phase of
an action potential?
a. opening of Na+ gates
b. Na+-K+ pump restoring the ions to their original locations
c. greatly increased permeability to Na+
d. Na+ efflux
e. none of these
In most excitable cells, the rising phase of the action
potential is due to:
a. calcium efflux
b. potassium efflux
c. chloride influx
d. potassium influx
e. sodium influx
The falling phase of the action potential is due to:
a. calcium influx
b. potassium efflux
c. chloride influx
d. sodium efflux
e. the action of Na+-K+ pumps
Binding of an excitatory neurotransmitter to a postsynaptic
a. voltage-gated Na+ channels open
b. voltage-gated K+ channels open
c. chemically-gated Na+ channels open
d. voltage-gated Cl- channels open
e. chemically-gated Cl- channels open
When chemically-gated Na+ channels open, the
d. becomes more negative
e. is inhibited
Opening either a chemically-gated Na+ channel or a
chemically-gated K+ channel during the resting potential would
a. an impulse to be propagated
b. a graded potential
c. an action potential
d. the membrane's potential to becomes more negative
e. threshold voltage will be reached
An action potential on a neuron develops when:
a. threshold voltage is reached on an axon
b. voltage-gated Na+ channels open
c. spatial or temporal summation of graded potentials occurs to a great enough degree
d. the axon hillock reaches threshold voltage
e. any of the above events occur
Myelinated axons conduct impulses much faster
a. the myelin insulates the axon
b. ion channels only have to open at the nodes
c. voltage is not lost along myelinated areas
d. saltatory conduction occurs
e. all of the above are true
At the peak of an action potential:
a. the diffusion of Na+ through voltage-gated channels ceases
b. the concentration gradient for K+ promotes the movement of this ion out of the cell
c. K+ permeability greatly increases
d. the electrical gradient promotes the diffusion of K+ out of the cell
e. all of the above are true
Which statement is not accurate about the absolute refractory
a. Another stimulus, regardless of its strength, cannot initiate another action potential during this period
b. During this period, voltage-gated Na+ channels open, then close but are inactivated
c. Immediately following this period, the membrane can experience another action potential if the stimulus is strong enough
d. This period occurs during the after hyperpolarization phase of the action potential
e. This period ensures a unidirectional spread of the action potential down a nerve fiber
Because of the presence of both activation and inactivation
gates, voltage-gated Na+ channels can:
a. be closed but capable of opening
b. be activated
c. be closed and not capable of opening
d. exhibit all of the above events
e. exhibit only the a and b events
What is responsible for development of the resting membrane
a. Leak channels
b. Gated channels
c. Ion pumps
d. both a and b
e. both a and c
When is a plasma membrane more permeable to K+ than to
a. During the resting potential
b. During the rising phase of an action potential
c. During the rising phase of a graded potential
d. Both a and b
e. Both b and c
When the membrane potential is +15 mV, that portion of the
a. is at the normal resting potential
b. has a positively-charged inside border
c. is more permeable to Ca2+ than normal
d. is in the after hyperpolarization phase of an action potential
e. is in a hyperpolarized state
Local current flow:
a. occurs only on dendrites of neurons
b. causes impulses to move from the axon hillock toward the neuron's cell body
c. involves current flowing between active and adjacent inactive areas, thereby bringing the inactive areas to threshold
d. occurs only on axons of neurons
e. does not occur on all excitable membranes
a. occurs in unmyelinated nerve fibers
b. is slower than contiguous conduction because myelin acts as an insulator to slow the impulse
c. involves the impulse jumping from one node of Ranvier to the adjacent node
d. refers to the action potential spreading from one Schwann cell to the adjacent Schwann cell
e. occurs along dendrites and axons of certain neurons
The oxidative fermentative tests:
(a) Only if bacteria can grow in the presence of oxygen
(b) Only if bacteria can grow in the absence of oxygen
(c) If bacteria can ferment oxygen
(d) If bacteria can undergo fermentation under oxidation conditions
(e) If bacteria can grow in the presence or absence of oxygen
A subject attempts to sustain a maximum hand grip on a dynamometer for 60 seconds while keeping their eyes closed. Their lab partner monitors the force generated in N and the EMG amplitude in mV
During the 20-40 second time frame they would expect to see:
(a) A decrease in force and a decrease in EMG activity
(b) A decrease in force and an increase in EMG activity
(c) A decrease in force and no EMG activity
(d) An increase in force and a decrease in EMG activity
(e) An increase in force and an increase in EMG activity
How does tetrodotoxin affect neurotransmission?
(a) It blocks voltage-gated Sodium channels, thus preventing the firing of an action potential
(b) It blocks voltage-gated Potassium channels, thus preventing depolarisation
(c) It blocks voltage-gated Calcium channels, thus preventing neurotransmitter release
(d) It blocks the sodium/potassium ATPase, thus disrupting the resting membrane potential
How can a rough phenotypic differentiation of bacteria be obtained ?
A. The source of bacteria, Cell shape and colony colour and
B. Gram status, Metabolic features, Phenotypic tests for presence of characteristic genes
C. The source of bacteria, Cell shape and colony colour and
Gram status, Metabolic features, Phenotypic tests for presence of characteristic genes
D. The source of bacteria, Cell shape and colony colour and
Gram status, Metabolic features
E. Cell shape and colony colour and morphology
Gram status, Metabolic features
What can potassium hydroxide do to bacteria ?
A. Quickly lyse gram negative cells as they have a weaker cell envelope and liberate DNA
B. Quickly lyse gram positive cells as they have a weaker cell envelope and liberate DNA
C. Quickly lyse gram negative cells as they have a stronger cell envelope and liberate DNA
D. Quickly lyse gram negative cells as they have a weaker cell envelope and store DNA
What is the composition of LPS ?
A. O-antigen, Lipid A, teichoic acid
B. O-antigen, Core saccharide, Lipid A
C. Core saccharide, lipid A, lipid B
D. Core saccharide, Lipid A, wall teichoic acid
What may gram negative bacteria be further characterised by ?
A. Whether or not the are catalase positive/negative
B. Only if they possess the ability to grow in presence of oxygen
C. Whether they possess the ability to grow in the presence or absence of oxygen
D. Only is they possess the ability to grow in the absence of oxygen
A. Coocus shaped
B. Rod Shaped
C. Coccoid/Coccobacillus shaped
D. Comma shaped
A. Rod shaped
B. Coccus shaped
C. Comma shaped
D. Coccoid/Coccobacillus shaped
What is the positive control of oxidase production test?
B. Staphyloccus Aureus
C. Acinetobacter baumannii
A. rod shaped
B. comma shaped
C. coccus shaped
D. coccoid/ coccobacillus shaped
A. rod shaped
B. comma shaped
C. coccus/coccobacillus shaped
D. coccoid shaped
What does purple after gram staining mean:
A. gram negative
B. gram positive
A. comma shaped
B. coccoid shaped
C. rod shaped
D. coccus/coccusbacillus shaped
Where does nervous system arise from?
D. Germ layers
Where does heart and somites arise from?
Where do the lungs arise from?
What is organogenesis?
A. The interaction of cells within and across the germ layers to form organ systems. Establishment of body plan at appropriate position within the embryo
B. It is local interactions between cells
C. It is when neural plates form upwards making neural folds and fuse together to enclose an internalised neural tube.
D. The interaction of cells across the germ layers to form tissues. Establishment of body plan within the embryo.
What is organogenesis characterised by?
A. Interaction of cells across germ layers to make organ systems
B. Local interactions superimposed on the information laid down with the basic body plan, to allow definition and development of tissues.
C. Local interactions superimposed on the information laid down with the basic body plan, to allow definition and development of an organ. Morphogenetic changes in tissue and cell shape.
D. Morphogenetic changes in tissues and cell shapes to make organ systems.
What does organogenesis involve ?
A. The making of organs from germ layers
B. The interaction and rearrangement of cells to produce tissues and organs
C. The interaction and arrangements of cells to make tissues.
D. The interaction and rearrangement of germ layers to make tissues
How does neural tube form?
A. Neural plates begin to fold upwards forming neural folds which then fuse together and enclose an internalised neural tube.
B. Neural plates fold upwards forming neural folds.
C. Rod like structure of mesoderm cells fuse
D. Neural plates begin to fold downwards forming neural folds which then fuse and open an internalised neural tube.
What causes the ectoderm to form the neural plate?
A. Ligands from ectoderm cells
B. Signalling molecules secreted by the heart and other organs
C. Signalling molecules secreted by the notochord and other tissues
D. Signalling molecules from neural folds
Processes causing formation of neural plate?
A. Induction using sonic hedgehog
B. Induction using desert hedgehog
C. Induction using Indian hedgehog
What happens as neural fold and fuse?
A. The adjacent surface ectoderm fuses to enclose the neural tube which becomes the circulatory system
B. The adjacent surface endoderm fuses to enclose the neural tube which becomes the brain and spinal cord
C. The adjacent surface mesoderm fuses to enclose the neural tube which becomes the brain and spinal cord
D. The adjacent surface ectoderm fuses to enclose the neural tube which becomes the brain and spinal cord
What happens after the neural tube forms?
A. Neural crest cells migrate away from the dorsal aspect of the tube to central locations where they give rise to the central nervous system
B. Neural crest cells migrate away from the dorsal aspect of the tube to peripheral locations where they give rise to the peripheral nervous system
C. Neural crest cells stay where they are
D. Neural crest cells migrate away from the dorsal aspect of the tube to peripheral locations where they give rise to the circulatory system
What are neural crests cells formed by ?
A. Interactions between germ layers
B. Interactions between surface and neural mesoderm
C. Interactions between surface and neural ectoderm
D. Interactions between outer surface and neural endoderm.
What is the peripheral system made up of?
A. Motor system and autonomic nervous system
B. Sensory system, motor system, and autonomic nervous system
C. Sensory system and nervous system
D. Sensory system and autonomic nervous system
What is the first event in organogenesis?
B. Making of germ layers
What forms in 1st step in neurulation?
B. Neural tube
C. Neural folds
D. Brain and spinal cord
3 Principles for use of animals in research:
A. Reduction and Replacement
B. Reduction, Refinement and Replacement
C. Refinement, Reduction and Ramifiaction
D. Replacement and Refinement
Signals sent from notochord to overlying ectoderm initially form:
A. Brain and spinal cord
B. Neural folds
C. Neural tube
D. Neural plate
What is neurogenesis?
A. Formation of neurons
B. Making of brain and heart
C. Formation of peripheral nervous system
D. Formation of central nervous system
A. Mesoderm cells that reduces either side of the neural tube
B. Endoderm cells that form into blocks on either side of the neural tube
C. Mesoderm cells that form into blocks on either side of the neural tube
D. Ectoderm cells that form into blocks on either side of the neural tube
What must the flat chick and mammalian embryo do to enclose the gut and form the tube within a tube structure ?
A. Must fold ventrally
B. Must fold distally
C. Must fold upwards
D. Must not fold evenly
What does a dual circulatory system connect ?
a. With the extra mesodermic structure during development and another with the lungs after birth
b. With the extra embryonic structure during development and another with the lungs after birth
c. With the extra endodermic structure during development and another with the lungs after birth
d. With the extra ectodermic structure during development and another with the lungs after birth
What are the steps of the circulatory system building ?
a. Mesenchymal to epithelial transition
b. Extensive branching morphogenesis
c. Mesenchymal to epithelial transition, extensive branching morphogenesis
Where does the blood production switch from at day 11 in the mouse ?
a. The yolk sac to early ventricles
b. The yolk sac to the angioblasts
c. The yolk sac to the aorta-gonad neural plate
d. The yolk sac to the aorta-gonad mesonephros
What is the notochord?
A. The formation of a rod like structure of mesoderm cells along the dorsal midline of the future embryo
B. The formation of a rod like structure of mesoderm cells along the ventral midline of the future embryo
C. The formation of a rod like structure of ectoderm cells along the dorsal midline of the future embryo
D. The formation of a rod like structure of endoderm cells along the dorsal midline of the future embryo