Q. What are ion channels?

1 Answer

Answer :

A. They are special devices for quick transport of electrolytes

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Description : Q. Give some examples of ion channels.

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

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

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

Description : 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

Last Answer : there is a net influx of sodium ions

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.

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

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

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.

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.

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

Description : If Nf , Nd and H are total number flow channels, total number of potential drops and total hydraulic head differences respectively, the discharge q through the complete flow is given by (where K is a constant) (A) q = (Nf/Nd) (B) q = KH (Nd/(Nf ) (C) q = KH (Nf/Nd) (D) q = KH Nf/Nd)

Last Answer : Answer: Option C

Description : Consider the follwing complexes ion `P,Q` and `R` `P =[FeF_(6)]^(3-), Q=[V(H_(2)O)_(6)]^(2+)` and `R=[Fe(H_(2)O)_(6)]^(2+)` The correct order of the c

Last Answer : Consider the follwing complexes ion `P,Q` and `R` `P =[FeF_(6)]^(3-), Q=[V(H_(2)O)_(6)]^(2+)` and `R=[Fe( ... lt P` C. `R lt P lt Q` D. `Q lt P lt R`

Description : The following points about microfilaments are true except (A) They form cytoskeleton with microtubules (B) They provide support and shape (C) They form intracellular conducting channels (D) They are involved in muscle cell contraction

Last Answer : C

Description : Which enzyme irreversibly channels glucose to energy production, rather than retaining glucose for blood sugar regulation?

Last Answer : Pyruvate dehydrogenase is an irreversible reaction.

Description : In a solution having a pH of 7.4, the hydrogen ion concentration is (A) 7.4 nmol/L (B) 40 nmol/L (C) 56 nmol/L (D) 80 nmol/L

Last Answer : Answer : B

Description : Chloride shift is (A) H ions leaving the RBC in exchange of Cl- (B) Cl– leaving the RBC in exchange of bicarbonate (C) Bicarbonate ion returns to plasma and exchanged with chloride which shifts into the cell (D) Carbonic acid to the plasma

Last Answer : Answer : C

Description : The oxygen d issoc iat ion curve for hemoglobin is shifted to the right by (A) Decreased O2 tension (B) Decreased CO2 tension (C) Increased CO2 tension (D) Increased pH

Last Answer : Answer : C

Description : An inorganic ion required for the activity of an enzyme is known as (A) Activator (B) Cofactor (C) Coenzyme (D) None of these

Last Answer : Answer : B

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

Last Answer : Answer : A

Description : The following technique makes use of the difference in net charges of proteins at a given pH: (A) Thin layer chromatography (B) Ion exchange chromatography (C) High performance liquid chromatography (D) Paper chromatography

Last Answer : Answer : B

Description : In the following reaction, Alanine acts as a 3 3 3 3 + + → H H | | H N – – COO —— H N – – COOH C C | | CH CH (A) Acid (B) Base (C) Zwitter ion (D) None of these

Last Answer : Answer : C

Description : A Zwitter ion is one which has in aqueous solution: (A) One positive charge and one negative charge (B) Two positive charges and one negative charge (C) Two negative charges and one positive charge (D) No electrical charges at all

Last Answer : Answer : A

Description : A Zwitterion is (A) Positive ion (B) Negative ion (C) Both (A) and (C) (D) None of these

Last Answer : Answer : C

Description : The technique for purification of proteins that can be made specific for a given protein is (A) Gel filtration chromotography (B) Ion exchange chromatography (C) Electrophoresis (D) Affinity chromatography

Last Answer : Answer : D

Description : G lucose on reduct ion w ith sod ium amalgam forms (A) Dulcitol (B) Sorbitol (C) Mannitol (D) Mannitol and sorbitol

Last Answer : B

Description : PH is the negative logarithm of the hydrogen Ion Concentration express4ed in moles/liter of aqueous solution. PH of buffer solution is calculated by. Henderson's equation Name the best ... Chemical kinetics deals with study of. Rates and mechanisms of chemical and Biochemical reactions

Last Answer : What does Thermodynamics helps in predicting ?

Description : The bond formed between the transition metal ion and ligand is ?

Last Answer : Co-ordination covalent bond Transitional metal Ions can form complex compounds by. By accepting the lone pair of electrons from ligand

Description : Why FE3+ ion is more stable than Fe2+ ion is ?

Last Answer : Because of stable, half filled 3 d5 electronic configurations in fe3+

Description : What is the basic principle of ion-exchange chromatography?

Last Answer : Here, the separation is based on electrostatic attraction between charged molecules to oppositely charged groups on the ion exchange resins.