Membrane/ Cell signaling

In cell signaling, how is the flow of specific ions regulated? A. Opening and closing of ligand-gated ion channels B. Transduction C. Cytoskeleton rearrangement D. Endocytosis

A.

Which of the following component molecules of the plasma membrane is most important in the reception phase of cell signaling? A. Protein B. Phospholipids C. Cholesterol D. Carbohydrates

A.

Which of the following processes could result in the net movement of a substance into a cell if substance is my concentrated in the cell than the surroundings? A. Active transport B. Facilitated diffusion C. Diffusion D. Osmosis

A.

Active transport usually moves molecules A. In the same direction as diffusion moves them B. In a direction opposite to the one which diffusion moves them C. In a direction that tends to bring about equilibrium D. From a solution with a lower pH toward one with a higher pH. From inside the outside the cell.

B.

Large molecules are moved out of the cell by which of the following processes? A. Endocytosis B. Exocytosis C. Translocation D. Passive diffusion

B.

The mechanism of action of many common medication involves interfering with normal pathways that cells use to respond to hormones signals. Which of the following best describes a drug interaction that directly interferes with a signal transduction pathway? A. A medication causes the cell to absorb more of a particular mineral, eventually poisoning the cell. B. The medication enters the target cell and inhibits an enzyme that normally synthesizes a second messenger C. A medication enters the target cells nucleus and acts as a mutagen. D. A medication interrupt the transcription of ribosomal RNA genes.

B.

The solution in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride and water, but not to glucose. Side A is filled with a solution of 0.4 M Glucose and 0.5 M sodium chloride (NaCl), and Side B Is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same. Overall at the beginning of the experiment: A. Side A is hypertonic to side B B. Side A is hypotonic to side B C. Side A is isotonic to side B D. Side A is hypertonic to side B with respect to glucose

B.

What is a G protein? A. A specific type of membrane receptor protein B. A protein on the cytoplasmic side of a membrane that becomes activated by a receptor protein C. A membrane-bound enzyme that converts ATP to cAMP D. A guanine nucleotide that converts between GDP and GTP to activate and inactivate relay proteins

B.

What would be observed by live-cell florescence microscopy Immediately after HIV entry if the red for us and lipid dye-labeled HIV membrane fuses with the target sell plasma membrane? A. The red flowers and tie - labeled lipids will appear in the infected cells interior B. A spot of red florescence will diffuse in the infected cells interior C. A spot of red florescence will be visible on the infected cells plasma membrane marking the site of membrane infusion and HIV entry D. A spot of red Florescence well remain outside the cell after delivering the viral capsid.

C

Five dialysis bags, constructed from a semi permeable membrane that is impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 AM sucrose solution. At 10 minute intervals, The bags were mass in the percent change in mass of each bag was graphed Which line in the graph represents the bag that contain a solution isotonic to the 0.6 M solution at the beginning of the experiment A. Bag A B. Bag B C. Bag C D. Bag D E. Bag E

C.

If a hospital patient is mistakenly given an IV of pure water instead of saline solution that is isotonic to blood, the patient's red blood cells will A. Shrink and collapse B. Release water to the plasma along its concentration gradient C. Absorb water from the plasma and eventually burst D. Transport equal amounts of water across the cell membrane in both directions

C.

In biological membranes, the phospholipids are arranged in a_____, with the ______. A. Single layer; fatty acids facing the interior of the cell B. Bilayer; fatty acids facing outwards C. Bilayer; fatty acids pointing towards each other D. Single layer; phosphorus-containing region facing the interior of the cell E. Bilayer; phosphorus groups in the interior of the membrane.

C.

What kind of molecules pass through a cell membrane most easily? A. Large and hydrophilic B. Small and hydrophilic C. Small and hydrophobic D. Large and hydrophobic E. Ions (including polyatomic ions)

C.

An important consequence of the multiple steps to make up a signal transduction cascade is that the signal becomes______? A. Decreased B. Controlled C. Regulatory D. Amplified

D.

At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogens and other steroid hormones. How can one hormones such as estrogen mediate so many effects? A. Estrogen is produced in very large concentration and therefore diffuses widely B. Estrogen has specific receptors inside several cell types, but each cell responds in the same way too it's binding C. Estrogen is kept away from the surface of any cells not able to bind it at the surface D. Estrogen binds to specific receptors inside many kinds of cells, each of which have different responses to its binding

D.

If you examine side A after 3 days, you should find A. a decrease in the concentration of NaCl and glucose and an increase in the water level. B. a decrease in the concentration of NaCl, an increase in water level, and no change in the concentration of glucose. C. no net change in the system. D. a decrease in the concentration of NaCl and a decrease in the water level.

D.

Vitamin A is a relatively small, lipid-soluble molecule that can behave as a hormone. Most likely its receptor A. Is an ion channel receptor B. Is a protein kinase receptor C. Involves a G protein D. Is not connected to the cell membrane E. Is highly vulnerable to antagonists

D.

Which of the following can activate a protein by transferring a phosphate group to it? A. cAMP B. G protein C. Protein phosphatase D. Protein kinase

D.

Which of the following signal molecules pass to the plasma membrane and bind to the intracellular receptors that move into the nucleus and function as transcription factors to regulate gene expression? A. Epinephrine B. Neurotransmitters released into synapse between nerve cells C. Yeast meeting factors alpha and beta D. Testosterone: a steroid hormone

D.

Which of the following uses passive transport without protein channels to move materials across the cell membrane? A. The deep polarization of a muscle cell B. The uptake of glucose by the microvilli of cells lining the stomach C. The movement of insulin across the cell membrane D. The movement of carbon dioxide across the cell membrane

D.