Hormones II Flashcards
what is metamorphosis
body-wide transformation that occurs in most phyla of animals
what do signals from the environment do to tadpoles
- secretion of thyroid hormone
- increase concentration of thyroid hormone (later stages)
what does thyroid hormone act as in tadpoles that are going to undergo metamorphosis
transcription factor
how is the thyroid hormone a transcription factor
it binds to specific genes and activates gene expression in the target cell
in order for the thyroid hormone to initiate metamorphosis, what must happen
there must be an adequate amount of thyroid hormone and there must be receptors for the thyroid hormone
what happens to the cells in the legs when they start growing
undergo mitosis and cell differentiation
- acquire a new structure and function
what are the 4 stages of frog mitosis
tadpole, early, late, froglet
what happens to the eyes in tadpole metamorphosis
they are lateral in tadpole, then frontal in a froglet
how do the eyes move during metamorphosis
the thyroid hormone acts as a transcription factor and the genes are activated, which migrate the eyes from the sides of the head to the front
what are the stages of muscle growth in frog legs
myoD is expressed during mitosis, myogenin is expressed during differentiation which activates genes for muscles, the thyroid hormone acts as a transcription factor, mitosis occurs, differentiation and then maturation
what does the thyroid hormone bind to in order to be effective
- the thyroid hormone receptor
- the hormone-receptor complex goes into the nucleus to activate gene expression
what does the gut undergo in metamorphosis
herbivore to carnivore
what type of cell signal is the thyroid hormone
endocrine
what is the complex called that becomes the transcription factor in metamorphosis
hormone-receptor complex
what does the transcription factors depend on to undergo metamorphosis
concentration, stage of development, and location in the body
