In-Class Quizzes Flashcards
why is it so difficult to study hormones?
Horomones are difficult to study because they are very small and can be found in low concentrations. Horomones move a lot and cells may not have receptors sensitive to that hormone. It takes a small amount to trigger a response, so it is difficult to find the hormone, which is why many times horomones are found on accident.
how are plant hormones different from animal hormones?
Plant hormones are different than animal hormones is a variety of ways such as they can elicit different responses in different tissues, fewer quantities, most tissues can synthesize hormones, with the exception of dead tissues, can be used where they are or transported, plant hormones are neutral or negatively charged, elicit a specific response, and can join together to make even more specific responses, and hormones in plants can make a negative response when in a high concentration.
how can shoots most easily be depleted of Auxin?
Shoots can be depleted of auxin by cutting off the tip of the coleoptile or covering it, this is because auxin is accumulated and synthesized there.
what are the specific functions of auxin in plants?
Auxin is responsible for growth in stem, inhibit growth in roots, leaf development, all cell elongation, all tropisms (phototropism and gravitropism), regulating phyllotaxy (new leaves), floral bud development, development of lateral and adventitious roots, delays onset of leaf abscission, promotes fruit development, promotes growth of new leaves, apical dominance, axial polarity, and vascular differentiation.
what do gibberellins control generally? what specific developmental processes do they control? how are they linked to auxin responses?
General: cell elongation and cell division
Specific: transition from growth to reproductive phase, sex determination, seed set, germination, initiation of flower development, internode elongation (only in dwarf plants, rosette species, and grasses), fruit growth, promote root growth
Linked to auxin: GAs are independent of auxin, they are not interacting with auxin in a direct way, which is why there are mutants that do not have to have gibberellins
What is the difference between meristem identity genes, floral organ identity genes, and cadastral genes?
meristem identity genes: controls the transcription factors that tells a meristem to become a floral meristem instead of vegetative meristem
floral organ identity genes: activate a particular structure to be apart of the flower; organs within an organ - different whorls produce different organs
cadastral genes: set the boundaries to where the other genes are expressed; set where the whorls will be to produce the different organs
