Genes that control coat color in mammals represent some of the best early examples of genes with multiple alleles exhibiting different phenotypes. A classic example is the C gene in hamsters. Three of the known alleles of this gene are C, c^a and c^k. Each supplies a different amount of black pigment to the coat hair. The phenotypes of three different homozygous strains are as follows.

Based on the concepts of recessivity, determine whether ck and ca were dominant or recessive alleles by crossing the true-breeding albino hamsters  with the true-breeding sepia hamsters. From the resulting F1 progeny phenotype, what would be the ratio of F2 phenotype

#Question id: 10487

#Unit 6. System Physiology – Plant

During the patch clamp experiments measure outward electric current in picoamps, pA at the plasma membrane of a guard cell protoplast stimulated by two points A and B showing in the graph.

What is A and B

#Question id: 10488

#Unit 6. System Physiology – Plant

Blue light activates a proton pump at the guard cell plasma membrane. The relationship between proton pumping at the guard cell plasma membrane and stomatal opening is evident from the observations that;

 a.) Orthovandate inhibits the fusicoccin-stimulated opening

 b.) fusicoccin stimulates both proton extrusion from guard cell protoplasts and stomatal opening

 c.) CCCP inhibits the fusicoccin-stimulated opening

 d.) CCCP, a proton ionophore that makes the plasma membrane highly permeable to protons resulting stomatal opening

 Which one of the following observation from the above statements should  be correct?

#Question id: 10489

#Unit 6. System Physiology – Plant

Malate anions, by contrast, are synthesized in the guard cell cytosol, in a metabolic pathway that uses carbon skeletons generated by

#Question id: 10490

#Unit 6. System Physiology – Plant

Which of the following is a correct Match of the stomatal opening and closing mechanism;

               COLUMN A                                                                    COLUMN B

P- Opening of Stomata                        i) Chloride anions are taken up into the guard cells from the apoplast

Q- Closing of stomata                         ii) The malate content of guard cells decreases

iii) starch content in guard cells increases during end of the

iv) Acidification of the lumen stimulates zeaxanthin formation which activates the H+ ATPase causing

v) Accumulation of solute in vacuole such as sucrose and malate leads to

#Question id: 10491

#Unit 6. System Physiology – Plant

Acidification of the lumen stimulates zeaxanthin formation, and alkalinization favors violaxanthin formation. Lumen pH depends on photosynthetic photon flux density, most effective at

#Question id: 10492

#Unit 6. System Physiology – Plant

Three major distinct metabolic pathways that can supply osmotically active solutes to guard cells have been clearly characterized,