Steroid and thyroid hormones, Biology

Assignment Help:

Steroid and Thyroid Hormones

Cytoplasmic receptors for steroids are proteins with two subunits that bind to the steroid molecules. When both receptor sites are occupied by the steroid then the receptor-steroid complex migrates to the nucleus where one subunit ensures that the complex binds to the specific site on the chromatin. Then the receptor subunits separate and the other subunit interact directly with the adjacent region of DNA molecule resulting in the transcription of the DNA segment into mRNA.

Thyroid hormone acts in a similar manner except that the receptor is located in the nucleus. The major hormone secreted by thyroid is thyroxine (T4). It travels in blood attached to carrier proteins. Thyroid also secretes a small amount of triiodothyronine (T3). Carrier proteins have higher affinity for T4 and very little T4 is free in the plasma. Only the free T4 and T3 enter the cells. The rest of the bound T4 acts as a reservoir for slow release. The free T4 that enters the cell s also converted to T3 enzymatically. Therefore, T3 is the chemically more potent and active form of thyroid hormone.

552_Steroid and Thyroid Hormones.png

Figure:Steroid and Thyroid Hormones


Related Discussions:- Steroid and thyroid hormones

Mention chemical agents available for sterilization, Q. Mention chemical ag...

Q. Mention chemical agents available for sterilization? Various chemical agents available for sterilization are: Alcohols: ethyl alcohol, isopropyl alcohol, trichlorobuta

What is bone modeling, Bone Modeling It is a surface-specific activity ...

Bone Modeling It is a surface-specific activity (apposition or resorption) that produces a net change in the size and/or shape of a bone after initial bone formation in the emb

Explain biological mechanisms, Biological mechanisms Annual rhythm....

Biological mechanisms Annual rhythm. Innate behaviour pattern stimulated by environmental cues (shortened day length is the cue for preparation - candidates should exp

Determine the initiation of muscle contraction, Describe the Capillarity Th...

Describe the Capillarity Theory in respect of ascent of water in plants. Name the tissue included. Determine the initiation of muscle contraction. What is the role of Sarcoplas

Lipoidal models, LIPOIDA L MODELS According to Overton (1902) plasm...

LIPOIDA L MODELS According to Overton (1902) plasma membrane consists of single layer of lipid, because cell permeability is related to lipids. According to Gorter and

Prevalence of coronaru heart diseases, Q. Prevalence of coronaru heart dise...

Q. Prevalence of coronaru heart diseases? Incidence of obesity, diabetes and CHD is increasing in India in almost all age groups. At present, obesity, which is a major risk fa

What is enzyme assay, What is Enzyme assay Enzyme assay may also be use...

What is Enzyme assay Enzyme assay may also be used to determine whether stored plant products are suitable for use as food commodities, for e.g.  α-amylase should be present

Define factors that affecting the bmr, Define Factors that Affecting the BM...

Define Factors that Affecting the BMR? Basal metabolic rate, we know, is the largest component of the daily energy demand representing 45 to 70 percent of daily total energy ex

Immobilisation of cells, Immobilisation of cells Immobilisation of cel...

Immobilisation of cells Immobilisation of cells enables Re-use of biomass by rotation of cells Separation of cells from the medium and Leaching of metab

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd