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Why is a second messenger not necessary in a steroid hormone?
Steroid hormones act in the transcriptional level in the nucleus of a cell, due to their ability to travel through cell membranes (hydrophillic). Second messengers are necessary for hormones that cannot penetrate cell membranes (peptides).
True or false steroid hormones perform accoding to the second messenger mechanism?
steroid hormones are hydrophobic and bind to transport proteins which bind to receptors within the nucleus. hydrophillic hormones bind to plasma membrane receptors and act through second messenger systems
What hormones can cross the cell membrane?
steroid hormonesSteroidalHormones are steroids and go across the membrane through specific receptors - this is why a hormone will act on certain tissue only e.g. estrogen only on mammary glands, uterus etc.
What signal that act within the animal body are produced by glands?
hormones
How are prostaglandins different from hormones?
Hormones and prostaglandins are similar because they deliver messages throughout the body.Prostaglandins act the same way hormones do, but only act in the specific area intended. They are synthesized from fatty acids.
Do hormones of the same chemical class have the same functions?
Hormones within a chemical class have the same function, but act on different substrates.
What hormones regulate protein synthesis?
Steroid hormones pass through the cell membrane and bind to a specific steroid hormone receptor protein. The combined steroid and receptor protein then bind to a specific sequence of bases in the DNA molecule. This sequence of bases is part of the promotor of a gene. Binding of the steroid - receptor complex either activates (switches on) or represses (switches off) the gene which is controlled by that promotor. If the gene is switched on then it will produce mRNA (transcription) which will lead to the sysnthesis of protein (translation). If the gene is switched off then mRNA will not be produced and no protein will be synthesised. In summary, steroid hormones can act to operate 'switches' for genes, switching protein synthesis on or off. See: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/SteroidREs.html http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Promoter.html http://biology.about.com/od/cellularprocesses/a/aa073004a.htm http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/moaction/intracell.html
Act as storage sacks within cell?
vacuole
What is the role of Golgi in the cell?
Golgi act as "informants" within the cell. They tell the cell to move, stretch, etc.
What nervous system cell act as phagocytes within the central nervous system?
Both Macrophages and leukocytes act as phagocytes within the CNS
What is the difference between circulating and local hormones?
Local hormones become active without first entering the bloodstream. They act locally on the same cell that secreted them or on neighboring cells.Circulating hormones enter the bloodstream to be transported to their target cells.
Anabolic steroid users have been known to act Passively. True or False if its false then how do anabolic steroid users have been known to act?
To say all steroid users act in any one particular way would be incorrect. Sometimes when steroids are abused aggressive behaviour can be noted, but this occurs in less than 5% of all steroid users. Generally there is no noticeable change in the behaviour of steroid users.
