The order of events in a signaling pathway can be determined by the analysis of mutants. Cells that express a mutant defective Raf protein cannot be stimulated to proliferate uncontrollably by constitutively active RasD (dominant active). This indicates:

TLS Online TPP Program

#Question id: 2251

#Unit 2. Cellular Organization

Differences between cotransport and active ion transport include

TLS Online TPP Program

#Question id: 2252

#Unit 2. Cellular Organization

The generation and maintenance of a membrane electric potential requires which of the following:

a. active pumping of ions       

b. ion-specific membrane channel proteins

c. ATP                                    

d. a generally permeable membrane

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#Question id: 2253

#Unit 2. Cellular Organization

Match the following lipid linked proteins (column I) with their function (Column II).

Column I	Column II
A. prenylated proteins	i. These proteins are located in a number of subcellular compartments, including the cytosol, the endoplasmic reticulum, the inner face of the plasma membrane, and the nucleus.
B. fatty acylated proteins	ii. The core structure of these proteins consists of phosphatidylinositol glycosidically linked to a linear tetrasaccharide composed of three mannose residues and one glucosaminyl residue.
C. glycosylphosphatidylinositol-linked proteins	iii. The proteins that have covalently attached lipids that are built from isoprene units

TLS Online TPP Program

#Question id: 2253

#Unit 1. Molecules and their Interaction Relevant to Biology

Match the following lipid linked proteins (column I) with their function (Column II).

Column I	Column II
A. prenylated proteins	i. These proteins are located in a number of subcellular compartments, including the cytosol, the endoplasmic reticulum, the inner face of the plasma membrane, and the nucleus.
B. fatty acylated proteins	ii. The core structure of these proteins consists of phosphatidylinositol glycosidically linked to a linear tetrasaccharide composed of three mannose residues and one glucosaminyl residue.
C. glycosylphosphatidylinositol-linked proteins	iii. The proteins that have covalently attached lipids that are built from isoprene units

TLS Online TPP Program

#Question id: 2254

#Unit 2. Cellular Organization

If the intracellular [Ca2+] is 10⁻⁷ mol/L and the extracellular [Ca2+] is 2 × 10⁻³ mol/L, at what potential difference across the cell membrane will Ca2+ be at electrochemical equilibrium?

TLS Online TPP Program

#Question id: 2255

#Unit 2. Cellular Organization

Following statements are regarding to the Na+/K+ ATPase maintains the intracellular Na+ and K+ concentrations in animal cells. Which of the following statement is incorrect?