Description : Which of the following statement(s) is/are true concerning the cell plasma membrane? a. The plasma membrane is composed of amphipathic molecules b. The hydrophobic core of the lipid bilayer of the ... contribute to the cell coat d. The membrane proteins of nerve cells are highly voltage-dependent
Last Answer : Answer: a, b, d The plasma membrane defines the boundary of the cell and serves to contain and concentrate enzymes and other macromolecule constituents. The plasma membrane is ... and bear carbohydrate moieties primarily as oligosaccharide chains that contribute to the cell coat or glycocalyx
Description : What characteristic of the plasma membrane allows selective molecules to pass through it?
Last Answer : It is semi-permeable.
Description : The basic structure of cell membranes (a) Is a lipid bilayer that serves as a barrier to water soluble molecules (b) Differs ultra structurally for internal and external membranes ... dispersed within a protein bilayer (d) Is visualised as bilaminar structure with transmission electron microscopy
Last Answer : Ans:(a)
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
Description : Assertion :- Zeolite is shape selective catalyst. Reason :- Size of the pores of the catalyst are such that they can trap only selective molecules.
Last Answer : Assertion :- Zeolite is shape selective catalyst. Reason :- Size of the pores of the catalyst are such ... . D. If both Assertion & Reason are False.
Description : 04. The main mechanism of most drugs absorption in GI tract is: a) Active transport (carrier-mediated diffusion) b) Filtration (aqueous diffusion) c) Endocytosis and exocytosis d) Passive diffusion (lipid diffusion)
Last Answer : PHARMACOKINETICS
Description : Which of the following is not true of the blood-brain barrier: A. It is constituted by tight junctions between the endothelial cells of brain capillaries and the glial tissue B. It allows passage ... of highly ionized drugs into the brain D. It regulates passage of substances from brain into blood
Last Answer : D. It regulates passage of substances from brain into blood
Description : 06. A hydrophilic medicinal agent has the following property: a) Low ability to penetrate through the cell membrane lipids b) Penetrate through membranes by means of endocytosis c) Easy permeation through the blood-brain barrier d) High reabsorption in renal tubules
Last Answer : a) Low ability to penetrate through the cell membrane lipids
Description : The specific yield of soil depends upon (A) Compaction of stratum (B) Distribution of pores (C) Shape and size of particles (D) All the above
Last Answer : (D) All the above
Description : The reason why materials appear colored is (a) The selective absorption of spectral colors (b) The interaction between the light and the electrons of the dye molecules (c) The composition of the white light from various spectral colors (d) All of these
Last Answer : All of these
Description : How are lipid molecules arranged in the membrane? -Biology
Last Answer : answer:
Description : The blood-brain-barrier: a. contains the foot processes of astrocytes b. contains endothelial cells with tight junction c. allows transport in one direction only ie from the vascular system into the brain d. does not allow diffusion of water
Last Answer : does not allow diffusion of water
Description : The success of oral rehydration therapy of diarrhoea depends upon the following process in the intestinal mucosa: A. Sodium pump mediated Na+ absorption B. Glucose coupled Na+ absorption C. Bicarbonate coupled Na+ absorption D. Passive Na+ diffusion secondary to nutrient absorption
Last Answer : B. Glucose coupled Na+ absorption
Description : Cell membranes a. consist almost entirely of protein molecules b. are impermeable to fat-soluble substances c. in some tissues permit the transport of glucose at a greater rate in the presence of ... to electrolytes but not to proteins e. have a stable composition throughout the life of the cell
Last Answer : in some tissues permit the transport of glucose at a greater rate in the presence of insulin
Description : In a plasma membrane, which of the following provides a general barrier to the movement of molecules? a) lipids b) proteins c) carbohydrates d) all of these
Last Answer : ANSWER: A -- LIPIDS
Description : The capacity of an antihistaminic to produce sedation depends on the following except (a) Relative affinity for central versus peripheral H1 receptors (b) Ability to penetrate blood-brain barrier (c) Individual susceptibility (d) Ratio of H1 : H2 blockade produced by the drug
Last Answer : Ans: D
Description : The capacity of an antihistaminic to produce sedation depends on the following except: A. Relative affinity for central versus peripheral H1 receptors B. Ability to penetrate blood-brain barrier C. Individual susceptibility D. Ratio of H1:H2 blockade produced by the drug
Last Answer : D. Ratio of H1:H2 blockade produced by the drug
Description : The process by which cell can take in fluid and molecules too large to be carried across the plasma membrane by active transport is called a. phagocytosis b. Pinocytosis c. absorption d. diffusion
Last Answer : Pinocytosis
Description : Opioid analgesics are either contraindicated or must be used with extreme caution in several clinical situations. For morphine, such situations do not include (a) Aqueous diffusion (b) Aqueous hydrolysis (c) Lipid diffusion (d) Pinocytosis or endocytosis (e) Special carrier transport
Last Answer : Ans: E
Description : 3 Diffusion of drugs across cell membrane: A. Is dependent upon metabolic activity of the cell B. Is competitively inhibited by chemically related drugs C. Is affected by extent of ionization of drug molecules D. Exhibits saturation kinetics
Last Answer : C. Is affected by extent of ionization of drug molecules
Description : What is the bacterial structure that acts as a selective barrier allowing nutrients to enter the cell and wastes to leave the cell.?
Last Answer : plaama membrane
Description : Which are the cholesterol esters that enter cells through the receptor-mediated endocytosis of lipoproteins hydrolyzed? (A) Endoplasmin reticulum (B) Lysosomes (C) Plasma membrane receptor (D) Mitochondria
Last Answer : B
Description : Glucose enters the cells by (A) insulin independent transport (B) insulin dependent transport (C) enzyme mediated transport (D) Both (A) and (B)
Last Answer : D
Description : A key process in metabolism is the transport of hydrogen ions (H+) across a membrane to create a concentration gradient. Explain which arrangement of hydrogen ions (unequal concentration or equal concentration) allows work to be done.
Last Answer : It is clear that an unequal concentration, not an equal one, would be the only possibility that work will be done; the unequal concentration of hydrogen ions would allow them to flow across the membrane and increase not only entropy but also work.
Description : Which of the following is/are true concerning wound fibroblasts? A. Fibroblasts synthesize and secrete collagen molecules. B. Wound fibroblasts are derived from blood-borne precursor cells. C. ... clot can act as a physical barrier to fibroblast penetration, which delays normal wound healing.
Last Answer : Answer: ACD DISCUSSION: Fibroblasts appear in the wound on about the third day of healing and begin to synthesize and secrete collagen molecules. Wound fibroblasts arrive from cells surrounding ... enzymes, and large amounts of fibrin and blood clot prevent fibroblasts from entering the wound
Description : The most important mechanism by which tetracycline antibiotics exert antiimicrobial action is (a) They chelate Ca2+ ions and alter permeability of bacterial cell membrane (b) They bind to 30S ribosomes ... peptide chain in the bacteria (d) They interfere with DNA mediated RNA synthesis in bacteria
Last Answer : Ans: B
Description : Aminoglycoside antibiotics exert the following action(s) on sensitive bacteria: A. Induce synthesis of defective proteins B. Make bacterial cell membrane more leaky C. Augment their own carrier mediated entry into the bacteria D. All of the above
Last Answer : D. All of the above
Description : The most important mechanism by which tetracycline antibiotics exert antimicrobial action is: A. They chelate Ca2+ ions and alter permeability of bacterial cell membrane B. They bind to 30S ribosomes ... peptide chain in the bacteria D. They interfere with DNA mediated RNA synthesis in bacteria
Last Answer : B. They bind to 30S ribosomes and inhibit bacterial protein synthesis
Description : Which of the following features is predicted by the Nicolson–Singer fluid mosaic model of biological membranes? (A) Membrane lipids do not diffuse laterally (B) Membrane lipid is primarily in a monolayer form (C) Membrane lipids freely flip-flop (D) Membrane proteins may diffuse laterally
Last Answer : Answer : D
Description : Which of the following statement is correct about membrane cholesterol? (A) The hydroxyl group is located near the centre of the lipid layer (B) Most of the cholesterol is in the form ... forms a rigid, planar structure (D) The hydrocarbon chain of cholesterol projects into the extracellular fluid
Last Answer : C
Description : All the following processes occur rapidly in the membrane lipid bilayer except (A) Flexing of fatty acyl chains (B) Lateral diffusion of phospholipids (C) Transbilayer diffusion of phopholipids (D) Rotation of phospholipids around their long axes
Description : Which of the following phospholipids is localized to a greater extent in the outer leaflet of the membrane lipid bilayer? (A) Choline phosphoglycerides (B) Ethanolamine phosphoglycerides (C) Inositol phosphoglycerides (D) Serine phosphoglycerides
Last Answer : A
Description : Chemical reaction rate of a component depends upon the (A) Composition of the component only (B) Temperature of the system (C) Pressure of the system (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : In a continuous flow stirred tank reactor, the composition of the exit stream (A) Is same as that in the reactor (B) Is different than that in the reactor (C) Depends upon the flow rate of inlet stream (D) None of these
Last Answer : (A) Is same as that in the reactor
Description : In a homogeneous solution, the activity co-efficient of a component depends upon the (A) Pressure (B) Composition (C) Temperature (D) All (A), (B) and (C)
Description : In a homogeneous solution, the fugacity of a component depends upon the (A) Pressure (B) Composition (C) Temperature (D) All (A), (B) and (C)
Description : Diffusion co-efficient of a metal in a solid solution depends upon its (A) Composition (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) & (B)
Description : Maximum hardenability of steel depends upon its (A) Chemical composition (B) Carbon content (C) Grain size (D) Alloying elements content
Last Answer : Option D
Description : Assertion : Insulin is not given orally. Reason : Insulin hormone is lipid-soluble and directily enters inside the cell membrane.
Last Answer : Assertion : Insulin is not given orally. Reason : Insulin hormone is lipid-soluble and directily enters ... D. If both Assertion and Reason are false.
Description : Which of the following statements are true of oxidants? A. In addition to their pathophysiologic roles in inflammation, injury, and infection, oxidants also have physiologic roles. B. Oxidants may ... involved the catalytic production of superoxide anion (O 2 ) by the enzyme xanthine oxidase.
Last Answer : Answer: ABCD DISCUSSION: Oxidants are reactive oxygen metabolites that have both physiologic and pathophysiologic roles. As potent oxidizing agents, oxidants are involved in cytochrome P ... leukocyte infiltration and activation, causing further tissue damage by the release of cytotoxic proteases
Description : According to widely accepted fluid mosaic model cell membranes are semi-fluid, where lipids and integral proteins can diffuse randomly. In recent years, this model has been modified in several ... domains of the membrane. (d) Many proteins remain completely embedded within the lipid bilayer.
Last Answer : (b) Proteins can also undergo flip-flop movements in the lipid bilayer.
Description : Keeping in view the fluid mosaic model' for the structure of cell membrane, which one of the following statement is correct with respect to the movements of lipids and proteins from one lipid ... ) Both lipids and proteins can flip-flop (d) While lipids can rarely flip-flop, proteins cannot.
Last Answer : (d) While lipids can rarely flip-flop, proteins cannot.
Description : The mode of action of thiocarbonates is a). Lipid inhibitor b). Cell membrane dispruption c). Pigment inhibitor d). Shoot inhibitor
Last Answer : d). Shoot inhibitor
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 : The life of a wooden sleeper depends upon A. Quality of its timber B. Resistance to weathering C. ability to resist decay D. All the above
Last Answer : D [All the above] Explanation: Indian Railways is divided into 18 zones. Recently added South Coast Railway zones in Indian Railway (2019).
Description : The ability of a driver to stop the vehicle moving with the designed speed, depends upon: (A) Perception time (B) Brake reaction time (C) Efficiency of the brakes (D) All the above
Last Answer : Answer: Option D