NEUR2201 - All practice questions

The ions most critical to the electrical properties of neurons include:

potassium, which is positively charged; sodium, which is positively charged; and chloride, which is negatively charged.

At the resting membrane potential, the membrane is most permeable to ________, which moves ________ the cell due to its voltage gradient

potassium; into

The movement of K+ across the cell membrane out from the inside of the cell to the extracellular space is _______________

hindered by electrostatic gradient but facilitated by concentration gradient

In a neuron, the conducting regions of the capacitor are represented by the intracellular and extracellular solutions. The non-conducting insulator of the capacitor is represented by what cell element?

Membrane

________ is the uniform motion of electrons through a conductor, while ______ is an accumulated charge formed by either an excess or deficiency of electrons in an object

Electric Current; Static Electricity

Which type of cells in the CNS release proinflammatory factors that can disrupt blood-brain barrier integrity leading to chronic neuroinflammation and subsequent neuronal loss?

Microglia M1

We pass 3 amps through a membrane with a resistance of 17 ohms. What is the resulting change in potential?

51 volts

Which of the following determines the resistance to an ion's movement across a membrane?

ion channels within the membrane

The resting membrane potential can be classified as a form of what kind of electricity?

Static

The blood-brain barrier:

is formed by the tight junctions of astrocytes surrounding capillaries

We measure the potential difference in a membrane as 20 volts and know that the membrane resistance is 5 ohms. What is the amount of current (amps) that was applied to this membrane?

4 amps

Microglia displaying the ________ phenotype attenuate inflammatory and neurotoxic effects supporting neuronal survival, restricting BBB permeability and promoting tissue repair

Microglia M2

________ involves local cell-cell interactions within particular brain regions, while _________ involves projections from one brain region to another

Microcircuits; Macrocircuits

The potential energy stored per unit of charge defines which term?

Voltage

The ___ are the types of neuroglial cells that provide myelin in the central nervous system

oligodendrocytes

The movement of Na+ across the membrane from the extracellular space to the intracellular space is __________________

facilitated by the electrostatic and concentration gradient

________ myelinate ________ in the ________, while _______ myelinate ________ in the __________

Oligodendrocytes; several internodes; CNS; Schwann Cells; a single internode; PNS

If we pass 5 amps of current through a membrane and the resulting change in potential is 10 volts, what is the membrane resistance?

2 Ohms

When an electric force is applied to a lipid, the electron clouds stretch and deform but the electrons do not depart from around the atom making lipids good _____________

insulators

The ___________ potential depends on the relative contributions of the particular ions inside and outside of the neural membrane as described by the Nernst equation

equilibrium

Where do fibrous astrocytic processes contact the axonal membranes in the CNS?

Node

What type of glial cell is present in grey matter and has long processes that send extensions to both blood vessels and neurons?

Protoplasmic astrocytes

Where do fibrous astrocytic processes contact the axonal membranes in the CNS?

The Node

Active transport is primarily responsible for the uneven concentration of ____ions inside and outside a neuron to maintain the resting potential

Na+

During the remission phase of multiple sclerosis (MS), there is a resolution of inflammation, blood-brain permeability is restricted, and tissue repair is promoted. Which type of glial cell mediates this phase of the disease?

Microglia M2

A major factor responsible for the unequal distribution of sodium ions across the membrane during the resting potential is:

the sodium/ potassium pump

With the same voltage, what is the outcome on current if the amount of resistance is doubled?

Decreases by half

What property of a material allows it to be a good conductor?

Atoms in the material have weak bonds to their electrons

When a membrane channel opens, there is a reduction in the membrane _______, allowing ions to enter the neuron increasing the membrane _______, which generates _______, measured by a change in _______

Resistance, capacitance, potential energy, voltage

The movement of ions through the brain parenchyma is a function of what cell type?

astrocytes

With respect to the interconversion between open and condensed chromatin shown, going from open to condensed (closed) (i) would depend on the consequence of which type of chromatin modification?

DNA methylation

Which one condition is required for CREB to facilitate transcription? 

It must be phosphorylated

The outer edges of the nitrogen-containing bases of DNA are exposed and available for which molecule to bond?

Hydrogen

During the process of RNA splicing, _______ are removed and _______ are joined to form a contiguous coding sequence

Introns; exons

What treatment would be used to overcome the methylation of genes after an environmental stressor?

Inhibit histone deacetylation

Synaptic inhibition may be produced by ACh acting through Gi-protein-coupled receptors. This inhibition results from the activation of _______ channels by the Gβγ protein

K+

Which of the following is not one of the ways in which epigenetic mechanisms can influence the expression of a particular gene?

ribosome modification

In the visual system, it is critical to keep a subset of neuronal genes in a repressed state to maintain stability.  Activity of which enzymes contributes to the maintenance of this state of gene repression?

HDAC

Activation of the beta-gamma subunit associated with the Gi protein complex would lead to what outcome?

Postsynaptic hyperpolarization

What arrangement of hydrophobic and hydrophilic amino acids of the CREB protein is most important for its proper functioning in gene expression? 

Hydrophilic surface, hydrophobic core

The process of translation refers to _________

the use of mRNA to organize specific amino acid sequences

Which statement is true regarding the process of protein phosphorylation? 

A reversible posttranslational modification that regulates protein states and functions

Transcription factors are important for opening up DNA packaging during _________

regulated gene expression

Transcription factors bind co-activators which change chromatin structure and facilitate assembly of the pre-initiation complex composed the general transcriptional machinery and what critical enzyme?

RNA polymerase II

What noncoding RNA can bind to complementary target sites on mRNA causing translation repression or cleavage ultimately leading to degradation of mRNA genes?

miRNAs

If there is a toxin that prevents the hydrolysis of GTP to GDP,

The G proteins would remain locked in the "on" position, transmitting signals even in the absence of signaling molecules

One of the critical actions of activated cAMP in the quest to regulate gene transcription is its ability to initiate what step in the membrane to nuclear signaling cascade?

Removal of the PKA regulatory subunit

A protein that interacts with water would have what type of amino acids located on the surface of its structure?

Polar

Which of the following sequences is correct moving from the largest level of organization to the smallest?

chromosome, nucleosome, DNA, genes

What changes occur to the BDNF gene following chronic stress?

Methylation

Genes are tightly packed in a structure of DNA and histones, known as nucleosomes, that form what structure?

Chromatin

How does the CREB protein contribute to chromatin remodeling?

Inhibits HDAC via phosphorylation

Changes in function of which of the following protein by posttranslational modification (such as phosphorylation or acetylation) would be most likely to, in turn, affect the expression of specific genes?

Histone

What type of PTM is used in the ER to facilitate delivery of a protein to its correct destination?

Glycosylation

You have detected that a patient with severe motor deficits has a base-pair substitution whereby the amino acid sequence has a hydrophobic side chain at the 53rd position rather than a hydrophilic side chain.  This alteration is likely to produce what outcome in the protein?

Less stable shape

One potential treatment for addiction is to inhibit the expression of the gene that codes for the dopamine 1 receptor.  Which type of drug would accomplish this goal?

HAT inhibitor

What type of glial cell can only myelinate a single internode on a single axon?

Schwann cell

During development, what type of cell do newborn neurons use as scaffolds to reach their final destinations in the cerebral cortex?

Radialglia

What type of glial cell is present in grey matter and has long processes that send extensions to both blood vessels and neurons?

Protoplasmic astrocytes

What type of glial cell controls extracellular K+ homeostasis and local blood flow, removes excess glutamate, and provides neurons with metabolic support?

Astroglia

What is the traditional role for microglia in brain function?

Secrete factors to modify disease progression

Which of the options is not considered a glial cell

Neuroepithelial cells

Which glial cell type serves as a resident immune cell in the central nervous system?

Microglia

In the mature central nervous system, glial stem cells with the properties of astrocytes can give rise to:

astrocytes, oligodendrocytes, and neurons

Choose the correct progenitor cells of the CNS: 

Radial glial cells and Neuroepithelial cells

What glial cells myelinate axons? Choose the Correct Option: 

Schwann Cells in the PNS

Choose the incorrect option about the M1 Microglia

It restricts the BBB permeability

Astrocyte endfeet wrap around what?

Blood vessels

The Blood Brain Barrier is a semi-selective permeable membrane

False

Please choose the correct option about astrocytes:

Fibrous Astrocytes contact Nodes of Ranvier on singular axon

At the end of cortical development, most radial glia lose their attachment to the ventricles, and migrate towards the surface of the cortex. Most will become neurons during the process of neurogenesis

False

If potassium channels are blocked, the influence on graded potentials will be:

less hyperpolarization

Voltage-sensitive sodium and potassium channels open when the membrane potential reaches ________

-50 millivolts

A major factor responsible for the unequal distribution of sodium ions across the membrane during the resting potential is:

the sodium/potassium pump

If sodium channels are blocked, the influence on the graded potentials will be:

lack of depolarization

Propagation of the action potential (AP) occurs due to what type of ionic movement?

Active and passive

Which statement about Na+ permeability during an action potential is most accurate?

It is responsible for the rising phase of the action potential

Which process(es) underlie(s) the refractory period?

The slow time course of turning off K+ conductance activation and the persistence of Na+ conductance inactivation

Which consequence of Na+ channels staying open, instead of closing after membrane depolarization, is most plausible?

The membrane would not repolarize (return to a negative value of membrane potential) following depolarization

Membrane potential depolarizes, Na+ channels open, Na+ current increases, _______

K+ channels open

Myelin sheath increases the conduction, whereas the Nodes of Ranvier increase conduction speed

False

Which statement correctly differentiates between the passive and active current in a myelinated axon?

The active current flows only in the nodes of Ranvier, unlike the passive current

Practically speaking, how would you determine that Na+ influx into a cell underlies the early current?

Remove Na+ from the extracellular compartment and assess the early current under new conditions

EPSPs and IPSPs contribute to:

All of the above

A summation of excitatory post-synaptic potential lead to depolarization

True

Fill in the blank: The _____ of _____ and the _____ of _____ contribute to the Action potential

influx, Na+, efflux, K+

Synaptic inhibition may be produced by ACh acting through Gi-protein-coupled receptors. This inhibition results from the activation of _______ channels by the Gβγ protein

K+

Which of the following is the most accurate process?

Activation of G protein → change in activity of effector enzyme → change in second messenger levels → activation of protein kinase

If there is a toxin that prevents the hydrolysis of GTP to GDP

The G proteins would remain locked in the "on" position, transmitting signals even in the absence of signalling molecules

Activation of the beta-gamma subunit associated with the Go protein complex would lead to what outcome?

Closing of presynaptic Ca2+ channels

Activation of the beta-gamma subunit associated with the Gi protein complex would lead to what outcome?

Postsynaptic hyperpolarization

The effector molecule at the synapse of an intercellular signal transduction process is a(n)

ion channel

Most enzyme-linked receptors affect the function of the target cell by

phosphorylating intracellular target proteins

Cholera toxin locks the Gs subunit into an active state, in that GTP is bound and cannot be hydrolyzed back to GDP to turn off the subunit. What effect will cholera toxin have in the cell?

Increased cyclic AMP levels will lead to increased protein kinase A activation

Which molecule is an effector directly downstream of an activated G-protein? 

Phospholipase C

Which second messenger originates from both extracellular and intracellular compartments?

Ca2+

Which statement about protein kinases in the brain is most accurate?

They amplify second messenger signals

Which type of signaling do mature neurons most commonly use to communicate with each other?

Chemical only

What is the greatest advantage of the chemical signal transduction scheme?

Signal amplification

The go pathway occurs presynaptically

True