Following statements are regarding to the molecular basis of the coincidence model in Arabidopsis.

A. In Arabidopsis under short days, there is little overlap between CO mRNA expression and daylight.

B. CO protein does not accumulate to sufficient levels in the phloem to promote the expression of the transmissible floral stimulus and the plant remains vegetative.

C. Under long days, the peak of CO mRNA abundance (at hours 12 through 16) overlaps with daylight (sensed by phyA and cryptochrome [cry]), allowing CO protein to accumulate.

D. CO activates FLC mRNA expression in the phloem, which causes flowering when the FT protein is translocated to the apical meristem.

Which of the following is incorrect?

#Question id: 2237

#Unit 2. Cellular Organization

Glucose enters erythrocytes via a GLUT-1 uniporter. As the levels of glucose in the bloodstream decrease between meals, what happens to the glucose in the cells?

#Question id: 2238

#Unit 2. Cellular Organization

Consider the transport of glucose into an erythrocyte by facilitated diffusion.  When the glucose concentrations are 5 mM on the outside and 0.1 mM on the inside, the free-energy change for glucose uptake into the cell is:  (These values may be of use to you:  R = 8.315 J/mol·K; T = 298 K; 9 (Faraday constant) = 96,480 J/V; N = 6.022×10²³ /mol.)

#Question id: 2239

#Unit 2. Cellular Organization

Consider the transport of K+ from the blood (where its concentration is about 4 mM) into an erythrocyte that contains 150 mM K+.  The transmembrane potential is about 60 mV, inside negative relative to outside.  The free-energy change for this transport process is:  (These values may be of use to you:  R = 8.315 J/mol.K; T = 298 K; 9 (Faraday constant) = 96,480 J/V; N = 6.022×10²³ /mol.)

#Question id: 2240

#Unit 2. Cellular Organization

 In which of the following cases is energy NOT needed for transmembrane transport?

a. Lysine moves into the cell against its concentration gradient via the Na+/lysine symporter.

b. Potassium ions (K+) move out of the cell down the K+ concentration gradient via potassium channels.

c. Glucose moves into the cell down its concentration gradient via a glucose uniporter.

d. Sodium ions (Na+) move out of the cell down the Na+ concentration gradient via sodium channels.

Which of the following are correct?

#Question id: 2241

#Unit 2. Cellular Organization

Which of the following statement(s) is (are) true of V-class proton pumps?

#Question id: 2242

#Unit 2. Cellular Organization

What two features of the structure of cholesterol make it somewhat amphipathic?