The following are true about rods in darkness: a. there is tonic release of neurotransmitters b. the sodium ion channels are open c. the potassium ion channels are shut d. there is a net influx of sodium ions

The following are true about rods in darkness:
a. there is tonic release of neurotransmitters
b. the sodium ion channels are open
c. the potassium ion channels are shut
d. there is a net influx of sodium ions
by

1 Answer

Answer :

there is a net influx of sodium ions
by

Related questions

Which of the following statements is not correct? (a) An action potential in an axon does not move backward because the segment behind is in a refractory phase. (b) Depolarisation of hair cells of cochlea results in the opening of the mechanically gated potassium-ion channels. (c) Rods are very sensitive and contribute to daylight vision. (d) In the knee-jerk reflex, stimulus is the stretching of muscle and response is its contraction.

Description : Which of the following statements is not correct? (a) An action potential in an axon does not move backward because the segment behind is in a refractory phase. (b) Depolarisation of hair cells ... d) In the knee-jerk reflex, stimulus is the stretching of muscle and response is its contraction.

Last Answer : (c) Rods are very sensitive and contribute to daylight vision.

Stomata of a plant open due to (a) influx of potassium ions (b) efflux of potassium ions (c) influx of hydrogen ions (d) influx of calcium ions.

Description : Stomata of a plant open due to (a) influx of potassium ions (b) efflux of potassium ions (c) influx of hydrogen ions (d) influx of calcium ions.

Last Answer : (a) influx of potassium ions

Which of the following statement(s) is/are true concerning cellular ion channels? a. Ion channels are transmembrane proteins that form pores that can conduct ions across the plasma membrane b. Ion channels are formed by membrane-spanning peptides that are arranged so that polar moieties line a central core c. Ion channel proteins undergo conformational changes between open states and closed states d. Ion channels can be blocked

Description : Which of the following statement(s) is/are true concerning cellular ion channels? a. Ion channels are transmembrane proteins that form pores that can conduct ions across the plasma membrane b. ... undergo conformational changes between open states and closed states d. Ion channels can be blocked

Last Answer : Answer: a, b, c, d Ion channels are transmembrane proteins that form pores that can conduct ions across the plasma membrane. Ion channels are formed by membrane-spanning peptides that are arranged ... be blocked by ions or organic compounds that enter the channel, bind there, and occlude the pore

The effect of calcium ions on neurotransmitter release at synapses include: a. vesicular fusion b. tonic depolarization of the presynaptic neurone c. post-tetanic potentiation d. all above

Description : The effect of calcium ions on neurotransmitter release at synapses include: a. vesicular fusion b. tonic depolarization of the presynaptic neurone c. post-tetanic potentiation d. all above

Last Answer : all above

During the nerve impulse transmission, following ion or ions may play significant roles D A. Sodium B. Potassium C. Chloride D. All of these

Description : During the nerve impulse transmission, following ion or ions may play significant roles D A. Sodium B. Potassium C. Chloride D. All of these

Last Answer : All of these

During the nerve impulse transmission, following ion or ions may play significant roles D A. Sodium B. Potassium C. Chloride D. All of these

Description : During the nerve impulse transmission, following ion or ions may play significant roles D A. Sodium B. Potassium C. Chloride D. All of these

Last Answer : All of these

Human urine is usually acidic because (a) potassium and sodium exchange generates acidity (b) hydrogen ions are actively secreted into the filtrate (c) the sodium transporter exchanges one hydrogen ion for each sodium ion, in peritubular capillaries (d) excreted plasma proteins are acidic.

Description : Human urine is usually acidic because (a) potassium and sodium exchange generates acidity (b) hydrogen ions are actively secreted into the filtrate (c) the sodium transporter exchanges one hydrogen ion for each sodium ion, in peritubular capillaries (d) excreted plasma proteins are acidic.

Last Answer : (b) hydrogen ions are actively secreted into the filtrate

Which of the following molecules or ions is NOT formed when K metal reacts with liquid CH3OH? Is it: w) potassium ion x) hydrogen ion y) methoxy ion z) hydrogen molecule

Description : Which of the following molecules or ions is NOT formed when K metal reacts with liquid CH3OH? Is it: w) potassium ion x) hydrogen ion y) methoxy ion z) hydrogen molecule

Last Answer : ANSWER: X -- HYDROGEN ION

A striking feature of living cells is a marked difference between the composition of the cytosol and the extracellular milieu. Which of the following statement(s) concerning the mechanisms of maintenance of these differences is/are true? a. The cell membrane is able to maintain a 10,000 fold gradient between the extracellular concentration of ionized calcium and the intracellular concentration b. The key to these differences is the fact that the plasma membrane is normally impermeable to sodium, potassium and calcium c. The selectivity of biologic membranes is highly consistent and seldom changes d. The selectivity of cell membranes relates only to ions and not organic compounds

Description : A striking feature of living cells is a marked difference between the composition of the cytosol and the extracellular milieu. Which of the following statement(s) concerning the mechanisms of maintenance ... d. The selectivity of cell membranes relates only to ions and not organic compounds

Last Answer : Answer: a The survival of the cell requires that cytosolic composition be maintained within narrow limits, despite the constant influx of nutrients and the simultaneous outflow of waste. A ... be altered drastically as a result of regulatory or signaling processes that occur within the cell

The most probable mechanism of anticonvulsant action of phenytoin is: A. Facilitation of GABAergic inhibitory transmission B. Hyperpolarization of neurones C. Interaction with Ca2+ channels to promote Ca2+ influx D. Prolongation of voltage sensitive neuronal Na+ channel inactivation

Description : The most probable mechanism of anticonvulsant action of phenytoin is: A. Facilitation of GABAergic inhibitory transmission B. Hyperpolarization of neurones C. Interaction with Ca2+ channels to promote Ca2+ influx D. Prolongation of voltage sensitive neuronal Na+ channel inactivation

Last Answer : D. Prolongation of voltage sensitive neuronal Na+ channel inactivation

The primary mechanism of action of benzodiazepines is: A. Dopamine antagonism B. Adenosine antagonism C. Opening of neuronal chloride channels D. Facilitation of GABA-mediated chloride influx

Description : The primary mechanism of action of benzodiazepines is: A. Dopamine antagonism B. Adenosine antagonism C. Opening of neuronal chloride channels D. Facilitation of GABA-mediated chloride influx

Last Answer : D. Facilitation of GABA-mediated chloride influx

What disease is described by: "the toxin acts at the neuromuscular junction, preventing the release of neurotransmitters needed to inhibit muscle contraction." a. Botulism b. Tetanus c. The Plague d. A-C Are Correct

Description : What disease is described by: "the toxin acts at the neuromuscular junction, preventing the release of neurotransmitters needed to inhibit muscle contraction." a. Botulism b. Tetanus c. The Plague d. A-C Are Correct

Last Answer : b. Tetanus

When a photon strikes the rhodopsin: a. bleaching occurs b. retinal molecules are bound to rhodopsin c. the intracellular cGMP is increased d. the sodium ion channels are closed

Description : When a photon strikes the rhodopsin: a. bleaching occurs b. retinal molecules are bound to rhodopsin c. the intracellular cGMP is increased d. the sodium ion channels are closed

Last Answer : the sodium ion channels are closed

Which of the following atoms or ions would be the smallest? w) sodium atom x) magnesium atom y) singly charged sodium ion z) doubly charged magnesium ion

Description : Which of the following atoms or ions would be the smallest? w) sodium atom x) magnesium atom y) singly charged sodium ion z) doubly charged magnesium ion

Last Answer : ANSWER: Z -- DOUBLY CHARGED MAGNESIUM ION

The pain sensation a. arises from stimulation of free nerve endings b. is transmitted to the central nervous system by unmyelinated C fibres c. is transmitted to the brain via the spinothalamic tracts d. is reduced by local anaesthetics through reduction of the potassium influx into the nerve fibres

Description : The pain sensation a. arises from stimulation of free nerve endings b. is transmitted to the central nervous system by unmyelinated C fibres c. is transmitted to the brain via the ... d. is reduced by local anaesthetics through reduction of the potassium influx into the nerve fibres

Last Answer : is transmitted to the brain via the spinothalamic tracts

Which one gives the most valid and recent explanation for stomatal movement? (a) Starch hydrolysis (b) Guard cell photosynthesis (c) Transpiration (d) Potassium influx and efflux

Description : Which one gives the most valid and recent explanation for stomatal movement? (a) Starch hydrolysis (b) Guard cell photosynthesis (c) Transpiration (d) Potassium influx and efflux

Last Answer : (d) Potassium influx and efflux

The symptoms of allergen-mediated asthma result from which of the following? (a) Increased release of mediators from mast cells (b) Increased adrenergic responsiveness of the airways (c) Inceased vascular permeability of bronchial tissue (d) Decreased calcium influx into the mast cell (e) Decreased prostaglandin production

Description : The symptoms of allergen-mediated asthma result from which of the following? (a) Increased release of mediators from mast cells (b) Increased adrenergic responsiveness of the airways (c) ... bronchial tissue (d) Decreased calcium influx into the mast cell (e) Decreased prostaglandin production

Last Answer : Ans: A

The Symptoms of allergen-mediated asthma result from which of the following? (a) Increased release of mediators from mast cells (b) Increased adrenergic responsiveness of the airways (c) Increased vascular permeability of bronchial tissue (d) Decreased calcium influx into the mast cells (e) Decreased prostaglandin production

Description : The Symptoms of allergen-mediated asthma result from which of the following? (a) Increased release of mediators from mast cells (b) Increased adrenergic responsiveness of the airways (c) ... bronchial tissue (d) Decreased calcium influx into the mast cells (e) Decreased prostaglandin production

Last Answer : Ans: A

The release of neurotransmitter from synaptic vesicles: a. takes place by exocytosis b. is controlled by neuronal calcium influx c. is quantal d. all above

Description : The release of neurotransmitter from synaptic vesicles: a. takes place by exocytosis b. is controlled by neuronal calcium influx c. is quantal d. all above

Last Answer : all above

Acrosome reaction in sperm is triggered by (a) capacitation (b) release of lysin (c) influx of Na+ (d) release of fertilizin.

Description : Acrosome reaction in sperm is triggered by (a) capacitation (b) release of lysin (c) influx of Na+ (d) release of fertilizin.

Last Answer : (c) total

Poisons like cyanide inhibit Na+ efflux and K+ influx during cellular transport. This inhibitory effect is reversed by an injection of ATP. This demonstrates that (a) ATP is the carrier protein in the transport system (b) energy for Na+-K+ exchange pump comes from ATP (c) ATP is hydrolysed by ATPase to release energy (d) Na+-K+ exchange pump operates in the cell.

Description : Poisons like cyanide inhibit Na+ efflux and K+ influx during cellular transport. This inhibitory effect is reversed by an injection of ATP. This demonstrates that (a) ATP is the carrier protein in the ... is hydrolysed by ATPase to release energy (d) Na+-K+ exchange pump operates in the cell.

Last Answer : (b) energy for Na+-K+ exchange pump comes from ATP

The following ions help in enzymatic transfer of phosphate from ATP to pyruvic acid: (A) Sodium (B) Calcium (C) Magnesium (D) Potassium

Description : The following ions help in enzymatic transfer of phosphate from ATP to pyruvic acid: (A) Sodium (B) Calcium (C) Magnesium (D) Potassium

Last Answer : Answer : D

The two metal ions that cause hardness to water are: (1) Calcium, Magnesium (2) Sodium, Calcium (3) Sodium, Potassium (4) Sodium, Magnesium

Description : The two metal ions that cause hardness to water are: (1) Calcium, Magnesium (2) Sodium, Calcium (3) Sodium, Potassium (4) Sodium, Magnesium

Last Answer : (1) Calcium, Magnesium Explanation: Calcium and magnesium ion cause hardness of water.

What ions determine the resting potential of a nerve? a) sodium and calcium b) calcium and copper c) potassium and calcium d) sodium and potassium

Description : What ions determine the resting potential of a nerve? a) sodium and calcium b) calcium and copper c) potassium and calcium d) sodium and potassium

Last Answer : ANSWER: D -- SODIUM AND POTASSIUM

The resting potential of a neuron is dependent on what two ions? a) lead and calcium ions b) calcium and phosphate ions c) sodium and potassium ions d) potassium and phosphate ions

Description : The resting potential of a neuron is dependent on what two ions? a) lead and calcium ions b) calcium and phosphate ions c) sodium and potassium ions d) potassium and phosphate ions

Last Answer : ANSWER: C -- sodium and potassium ions

The two metal ions that cause hardness to water are: (1) Calcium, Magnesium (2) Sodium, Calcium (3) Sodium, Potassium (4) Sodium, Magnesium

Description : The two metal ions that cause hardness to water are: (1) Calcium, Magnesium (2) Sodium, Calcium (3) Sodium, Potassium (4) Sodium, Magnesium

Last Answer : Calcium, Magnesium

At the muscle end-plate, d-tubocurarine reduces the: A. Number of Na+ channels B. Duration for which the Na+ channels remain open C. Ion conductance of the open Na+ channel D. Frequency of Na+ channel opening

Description : At the muscle end-plate, d-tubocurarine reduces the: A. Number of Na+ channels B. Duration for which the Na+ channels remain open C. Ion conductance of the open Na+ channel D. Frequency of Na+ channel opening

Last Answer : D. Frequency of Na+ channel opening

Which of the following is the most suitable drug for a 6-year-old girl suffering from absence seizures with occasional generalized tonic-clonic seizures: A. Ethosuccimide B. Sodium valproate C. Carbamazepine D. Phenytoin

Description : Which of the following is the most suitable drug for a 6-year-old girl suffering from absence seizures with occasional generalized tonic-clonic seizures: A. Ethosuccimide B. Sodium valproate C. Carbamazepine D. Phenytoin

Last Answer : B. Sodium valproate

he antiepileptic drug which suppresses maximal electroshock as well as kindled seizures, raises pentylenetetrazol threshold and is effective in both generalized tonic-clonic as well as absence seizures is: A. Phenytoin B. Carbamazepine C. Sodium valproate D. Ethosuximide

Description : he antiepileptic drug which suppresses maximal electroshock as well as kindled seizures, raises pentylenetetrazol threshold and is effective in both generalized tonic-clonic as well as absence seizures is: A. Phenytoin B. Carbamazepine C. Sodium valproate D. Ethosuximide

Last Answer : C. Sodium valproate

The ion which activates salivary amylase activity is (A) Chloride (B) Bicarbonate (C) Sodium (D) Potassium

Description : The ion which activates salivary amylase activity is (A) Chloride (B) Bicarbonate (C) Sodium (D) Potassium

Last Answer : Answer : A

Name the ion responsible for unmasking of active sites for myosin for cross-bridge activity during muscle contraction. (a) Calcium (b) Magnesium (c) Sodium (d) Potassium

Description : Name the ion responsible for unmasking of active sites for myosin for cross-bridge activity during muscle contraction. (a) Calcium (b) Magnesium (c) Sodium (d) Potassium

Last Answer : (a) Calcium

The following are true about the sodium channels: a. they are made up of polypeptide chains b. have the highest densities at the nodes of Ranvier c. open in response to depolarization d. remain open as long as depolarization is maintained

Description : The following are true about the sodium channels: a. they are made up of polypeptide chains b. have the highest densities at the nodes of Ranvier c. open in response to depolarization d. remain open as long as depolarization is maintained

Last Answer : have the highest densities at the nodes of Ranvier

There are two properties of the cell necessary to maintain nonequilibrium cellular composition; the first is selectivity and the second is energy conversion. Which of the following statement(s) is/are true concerning energy converting transport? a. The site of energy conversion and transport in the plasma membrane involves the phospholipid component b. The Na+-K++-ATPase derives energy from hydrolysis of extracellular ATP c. In some systems, energy inherent in the transmembrane ion gradient can be used to drive transport of a second species d. Examples of species transported via secondary active transport include hydrogen ions, calcium, amino acids and glucose

Description : There are two properties of the cell necessary to maintain nonequilibrium cellular composition; the first is selectivity and the second is energy conversion. Which of the following statement(s ... transported via secondary active transport include hydrogen ions, calcium, amino acids and glucose

Last Answer : Answer: c, d The selectivity of the plasma membrane, although impressive, cannot account for the nonequilibrium composition of living cells. A cell can be maintained in a nonequilibrium state only by ... to drive the transport of a second species such as protons, calcium, amino acids, or glucose

Which of the following is true when HCL is passed through water. (i) It does not ionize in the solution as it is a covalent compound (ii) It ionizes in the solution (iii) It gives both hydrogen and hydroxyl ions in the solution (iv) It forms hydronium ion in the solution due to the combination of hydrogen ion with water molecule. (a) (i) only (b) (iii) only (c) (ii) and (iv) only (d) (iii) and (iv)

Description : Which of the following is true when HCL is passed through water. (i) It does not ionize in the solution as it is a covalent compound (ii) It ionizes in the solution (iii) It gives both hydrogen and hydroxyl ions in the solution ... ) (i) only (b) (iii) only (c) (ii) and (iv) only (d) (iii) and (iv)

Last Answer : (c) (ii) and (iv) only

pH is defined as the negative logarithm of the hydrogen ion concentration. Comparing a pH 5 and a pH 8 solution, which of the following is true? w) There are 1,000 times more hydrogen ions in the pH 8 solution. x) There are 1,000 times more hydrogen ions in the pH 5 solution. y) There are 3 times more hydrogen ions in the pH 8 solution. z) Cannot tell the difference between these two solutions by pH, since the numbers are so close.

Description : pH is defined as the negative logarithm of the hydrogen ion concentration. Comparing a pH 5 and a pH 8 solution, which of the following is true? w) There are 1,000 times more hydrogen ions in ... . z) Cannot tell the difference between these two solutions by pH, since the numbers are so close.

Last Answer : ANSWER: X -- THERE ARE 1,000 TIMES MORE HYDROGEN IONS IN THE PH 5 SOLUTION

The following is true of topiramate except: A. It is a broad spectrum antiepileptic drug B. It inhibits the enzyme carbonic anhydrase C. It is used as add-on therapy in refractory partial seizures D. It is not effective in generalized tonic-clonic seizures

Description : The following is true of topiramate except: A. It is a broad spectrum antiepileptic drug B. It inhibits the enzyme carbonic anhydrase C. It is used as add-on therapy in refractory partial seizures D. It is not effective in generalized tonic-clonic seizures

Last Answer : D. It is not effective in generalized tonic-clonic seizures

Cell regulation can be thought of as the effector side of cell communication. Most commonly cell regulation occurs by means of extracellular chemical messengers. Which of the following statement(s) is/are true concerning these messengers? a. Paracrine regulation involves a messenger which is produced and acts systemically b. The extracellular signal or stimulus is received by a receptor on or in the target cell c. Neurocrine regulation depends on a physical connection between the neuron and the target cell d. Most hormones, local mediators, and neurotransmitters readily cross the cell plasma membrane

Description : Cell regulation can be thought of as the effector side of cell communication. Most commonly cell regulation occurs by means of extracellular chemical messengers. Which of the following statement(s ... d. Most hormones, local mediators, and neurotransmitters readily cross the cell plasma membrane

Last Answer : Answer: b, c Depending on how the extracellular messenger arrives, cell regulation can be classified as paracrine, endocrine, or neurocrine. In paracrine regulation, a chemical messenger ... , local mediators, and neurotransmitters are water-soluble and cannot readily cross the plasma membrane

The following are true about the neurotransmitters: a. acetylcholine is inactivated mainly by presynaptic reuptake b. tyrosine is essential for the formation of dopamine c. noradrenaline is inactivated mainly by hydrolysis d. adrenaline is formed from methylation of the noradrenaline

Description : The following are true about the neurotransmitters: a. acetylcholine is inactivated mainly by presynaptic reuptake b. tyrosine is essential for the formation of dopamine c. noradrenaline is inactivated mainly by hydrolysis d. adrenaline is formed from methylation of the noradrenaline

Last Answer : adrenaline is formed from methylation of the noradrenaline

True statements about the following neurotransmitters include: a. dopamine is formed from tyrosine b. in the synapse, noradrenaline is inactivated by active reuptake into the presynpatic terminals c. noradrenaline is formed by hydroxylation of dopamine d. all above

Description : True statements about the following neurotransmitters include: a. dopamine is formed from tyrosine b. in the synapse, noradrenaline is inactivated by active reuptake into the presynpatic terminals c. noradrenaline is formed by hydroxylation of dopamine d. all above

Last Answer : all above

Q. Give some examples of ion channels.

Description : Q. Give some examples of ion channels.

Last Answer : A. Ion channels specific for calcium, potassium and chloride

Q. What are ion channels?

Description : Q. What are ion channels?

Last Answer : A. They are special devices for quick transport of electrolytes

e primary mechanism by which general anaesthetics produce their action is: A. Affecting receptor operated ion channels in cerebral neurones B. Blocking voltage sensitive Na+ channels in neuronal membrane C. Depressing metabolic activity of cerebral neurones D. Blocking production of high energy phosphates in the brain

Description : e primary mechanism by which general anaesthetics produce their action is: A. Affecting receptor operated ion channels in cerebral neurones B. Blocking voltage sensitive Na+ channels in neuronal ... activity of cerebral neurones D. Blocking production of high energy phosphates in the brain

Last Answer : A. Affecting receptor operated ion channels in cerebral neurones

Why do ion channels contribute to faster cellular responses than other signaling mechanisms, such as GPCR-mediated signaling?

Description : Why do ion channels contribute to faster cellular responses than other signaling mechanisms, such as GPCR-mediated signaling?

Last Answer : Ion channels generate electrical signals, which signals travel much more rapidly than chemical signals that depend on the process of molecular diffusion. An electrical signal can traverse the entire length of a nerve cell within milliseconds.

Briefly describe how ion channels function.

Description : Briefly describe how ion channels function.

Last Answer : Ion channels open and close in response to chemical or mechanical signals. When an ion channel opens, ions rapidly move into or out of the cell. Most ion channels close and enter a resting ... gradient and can lead to a rapid wave of ion channel activation throughout the entire plasma membrane.

What common cell types are regulated by ion channels and are commonly referred to as excitable cells?

Description : What common cell types are regulated by ion channels and are commonly referred to as excitable cells?

Last Answer : neurons, muscle cells, sensory receptor cells

What concentration of `Ag^(+)` ions will be in equilibrium with a saturated solution containing a precipitate of `Ag_(2)CrO_(4) and CrO_(4)`-ion conce

Description : What concentration of `Ag^(+)` ions will be in equilibrium with a saturated solution containing a precipitate of `Ag_(2)CrO_(4) and CrO_(4)`-ion conce

Last Answer : What concentration of `Ag^(+)` ions will be in equilibrium with a saturated solution containing a precipitate of ... D. `5.9xx10^(-6)` moles per litre

The ease of adsorption of the hydrated alkali metal ions on ion-exchange resins follows the order:

Description : The ease of adsorption of the hydrated alkali metal ions on ion-exchange resins follows the order:

Last Answer : The ease of adsorption of the hydrated alkali metal ions on ion-exchange resins follows the order: A. `K^(+)lt Na + ... (+)lt K^(+)lt Na^(+)lt Li^(+)`

To balance the bicarbonate ion loss in RBC the chloride ions move into RBC, it is known as :-

Description : To balance the bicarbonate ion loss in RBC the chloride ions move into RBC, it is known as :-

Last Answer : To balance the bicarbonate ion loss in RBC the chloride ions move into RBC, it is known as :- A. Chloride ... C. Bohr effect D. Both (1) and (2)

The number of moles of oxalate ions oxidised by one mole of `MnO_(4)^(-)` ion in acidic medium is :

Description : The number of moles of oxalate ions oxidised by one mole of `MnO_(4)^(-)` ion in acidic medium is :

Last Answer : The number of moles of oxalate ions oxidised by one mole of `MnO_(4)^(-)` ion in acidic medium is : A. `5//2` B. `2//5` C. `3//5` D. `5//3`

During the extraction of Ag and using a KCN solution and Zn, cyanide ions and Zn react with metal ion as respectively

Description : During the extraction of Ag and using a KCN solution and Zn, cyanide ions and Zn react with metal ion as respectively

Last Answer : During the extraction of Ag and using a KCN solution and Zn, cyanide ions and Zn react with metal ... acid C. A reducing agent D. A complexing agent