#Question id: 11804
#Unit 6. System Physiology – Plant
P-proteins have been characterized at the molecular level. P-proteins from the genus Cucurbita consist of two major proteins;
#Question id: 11805
#Unit 6. System Physiology – Plant
P-proteins from the genus Cucurbita consist of two major proteins: PP1, the phloem filament protein, and PP2, the phloem lectin. Both PP1 and PP2 are thought to be synthesized in_______A___________and transported via the_______B_________to the_______C______, where they associate to form P-protein filaments and P-protein bodies.
#Question id: 11806
#Unit 6. System Physiology – Plant
sap is translocated from areas of supply, called
sources, to areas of metabolism or storage, called sinks. Which of the
following statements about source and sink are TRUE?
a.) Sinks include any nonphotosynthetic organs of the
plant and organs that do not produce enough photosynthetic products to support
their own growth or storage needs
b.) Sources include exporting organs that are capable
of producing photosynthate in excess of their own needs
c.) During the growing season of the first year,
storage root is a sink, when it accumulates sugars received from the source
leaves. During the second growing season the same root becomes a source
d.) Roots, tubers, developing fruits, and immature
leaves, which must import carbohydrate for normal development, are all examples
of sources tissues
Find the correct combination of the source and sink pattern of translocation.
#Question id: 11807
#Unit 6. System Physiology – Plant
Given below are few statements regarding the cytokinin
signalling pathway;
a) Cytokinin inhibits the activation of a Cdc25- like
phosphatase, whose role is to remove an inhibitory phosphate group from the
Cdc2 kinase
b) Cytokinin oxidase irreversibly inactivates cytokinins,
and it could be important in regulating or limiting cytokinin effects
c) Cytokinin signal transduction pathway is completed on
multiple places such as ER, Cytosol and Nucleus
d) Elevation of endogenous cytokinin levels in transgenic
Arabidopsis results in overexpression of the KNOTTED homeobox transcription
factor homologs KNAT1 and STM—genes
Which of the following combinations from the given above statements is correct?
#Question id: 11808
#Unit 6. System Physiology – Plant
In addition to the free bases, which are the only active
forms, active cytokinin levels are decreased through;
a) Addition of sugar molecule to the 3, 7, or 9 nitrogen of
the purine ring, called glycosylation-mediated inactivation
b) cis-trans isomerisation of zeatin
c) Irreversible cleavage by cytokinin oxidases.
Which of the following is incorrect?
#Question id: 11809
#Unit 6. System Physiology – Plant
Shortly after the discovery of kinetin, it was observed that
the differentiation of cultured callus tissue derived from tobacco pith
segments into either roots or shoots depends on the ratio of auxin to cytokinin
in the culture medium. Whereas
a) high auxin:cytokinin ratios stimulated the formation of
roots
b) high auxin:cytokinin ratios stimulated the formation of
shoots
c) low auxin:cytokinin ratios led to the formation of shoots
d) low auxin:cytokinin ratios stimulated the formation of
roots
which of the following combination is correct about the ratio of auxin to cytokinin