You are interested in a new type of autosomal dominant mutation that gives purple eyes in Drosophila. You have a true-breeding purple-eyed line carrying a mutation that you call pr-1. You have isolated a second purple-eyed mutation that you call pr-2, which you have established in a true-breeding line that also carries a recessive marker st, which gives stubby legs. You cross a fly from the pr-1 line to a fly from the st, pr-2 line producing F1 females which you then cross to males from a true breeding st line (normal eyes). From this cross, 1000 progeny flies can be categorized into four different phenotypic classes:

                             

Normally, 3-factor crosses give eight different phenotypic classes, why does this particular cross give only four?

#Question id: 11739

#Unit 6. System Physiology – Plant

which of the following compound is resist to cleave by cytokinin oxidase and why?

#Question id: 11740

#Unit 6. System Physiology – Plant

Some given characteristics of the two types of sieve elements in seed plants such as Sieve tube elements and Sieve cells. Find out the  true characteristics of sieve tube elements from the given statements;

i) Found in angiosperms

ii) Sieve plate pores are open channels

iii) Albuminous cells sometimes function as companion cells

iv) P-protein is present in all eudicots and many monocots

v) There are no sieve plates; all sieve areas are similar

#Question id: 11741

#Unit 6. System Physiology – Plant

phloem transport indicating the importance of long distance transport in plants, the experiments demonstrated that removal of a ring of bark around the trunk of a tree, which removes the phloem. What will be its effect?

#Question id: 11742

#Unit 6. System Physiology – Plant

Mature sieve elements external view, showing sieve plates. The pores in the sieve plates between the sieve tube elements are open channels, what is the relevance of this open pores in the sieve plates?

#Question id: 11743

#Unit 6. System Physiology – Plant

The wall between the two mature sieve tube elements contain a sieve plates, these sieve plate pores are open —that is, unobstructed by

#Question id: 11744

#Unit 6. System Physiology – Plant

Large pores in cell walls are the prominent feature of sieve elements, the sieve area pores range in diameter from