In this problem we will explore some of the many ways that mutations in two different genes can interact to produce different Mendelian ratios. Consider a hypothetical insect species that has red eyes. Imagine mutations in two different unlinked genes that can, in certain combinations, block the formation of red eye pigment yielding mutants with white eyes. In principle, there are two different possible arrangements for two biochemical steps responsible for the formation of red eye pigment. The two genes might act in series such that a mutation in either gene would block the formation of red pigment. Alternatively, the two genes could act in parallel such that mutations in both genes would be required to block the formation of red pigment.

Further complexity arises from the possibility that mutations in either gene that lead to a block in enzymatic activity could be either dominant or recessive. If the crosses is made between a wild type insect with red eyes and a true breeding white eyed strain with mutations in both genes. Such considerations yield the Pathways in series with recessive mutations in both genes, the F1 progeny shows will have red eye, what is the expected phenotypic ratio of red to white eyed insects in the F2.

#Question id: 10538

#Unit 6. System Physiology – Plant

Injury to the leaf caused by herbivory activates which types of ion channels?

#Question id: 10539

#Unit 6. System Physiology – Plant

All plants releases green-leaf volatiles in response to mechanical damage, this volatile is a mixture of

#Question id: 10540

#Unit 6. System Physiology – Plant

The following statements are made regarding volatile compounds of plant;

a) secondary metabolites also fuction in defence mechanism but this is not the volatile compound

b) These volatiles can act as cues for natural enemies of the insect herbivore such as parasitic wasps

c) All plants releases green-leaf volatiles in response to mechanical damage that is a mixture of aldehydes, alcohols, and esters

d) These volatiles attracts natural enemies of the attacking insect herbivores—predators or parasites

Which one of the following options represents a combination of correct statements?

#Question id: 10541

#Unit 6. System Physiology – Plant

Green-leaf volatiles act as potent signals,  which of the following option is incorrect about this volatile compound

#Question id: 10542

#Unit 6. System Physiology – Plant

Following are certain strategies used by pathogen to attack over the host plant that describe plant-pathogen interactions:

                      I                                                                                             II

A. Necrotrophic pathogens                              i) most of the plant tissue remains alive and only minimal cell damage can be observed, as the pathogens feed on substrates provided by their host

B. Biotrophic pathogens                                 ii) In which the host cells are kept alive as described for biotrophic  Pathogens and followed by a necrotrophic stage, in which the pathogens can cause extensive tissue damage

C. Hemibiotrophic pathogens                         iii) attack their host by secreting cell wall–degrading enzymes or toxins, which eventually kill the affected plant cells, leading to extensive tissue maceration. This dead tissue is then colonized by the pathogens and serves as a food source

Which of the following above combination is correct?

#Question id: 10543

#Unit 6. System Physiology – Plant

Effectors are molecules that change the plant’s structure, metabolism, or hormonal regulation to the advantage of the pathogen, which of the following is effector molecules?