Anonymous
1 hour ago
Describe the biosynthesis of peptide hormones.
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ChatGPT
1 hour ago
Peptide hormones are synthesized in the body through a complex process that involves several steps.
1. Transcription: The first step in the biosynthesis of peptide hormones is the transcription of the gene that codes for the hormone. This process takes place in the cell's nucleus and involves the synthesis of messenger RNA (mRNA) from the DNA template.
2. Translation: Once the mRNA is synthesized, it leaves the nucleus and enters the cytoplasm where it binds to ribosomes. The ribosomes then read the mRNA sequence and use it as a template to synthesize a chain of amino acids, which will eventually form the peptide hormone.
3. Post-translational modifications: After the amino acid chain is synthesized, it undergoes several post-translational modifications to form the mature peptide hormone. These modifications can include cleavage of certain amino acids, addition of sugar molecules (glycosylation), and formation of disulfide bonds.
4. Packaging and secretion: Once the peptide hormone is fully synthesized and modified, it is packaged into secretory vesicles within the cell. These vesicles then move towards the cell membrane and release the hormone into the bloodstream through a process called exocytosis.
Overall, the biosynthesis of peptide hormones is a highly regulated and intricate process that involves multiple steps to ensure the proper production and secretion of these important signaling molecules in the body.
1. Transcription: The first step in the biosynthesis of peptide hormones is the transcription of the gene that codes for the hormone. This process takes place in the cell's nucleus and involves the synthesis of messenger RNA (mRNA) from the DNA template.
2. Translation: Once the mRNA is synthesized, it leaves the nucleus and enters the cytoplasm where it binds to ribosomes. The ribosomes then read the mRNA sequence and use it as a template to synthesize a chain of amino acids, which will eventually form the peptide hormone.
3. Post-translational modifications: After the amino acid chain is synthesized, it undergoes several post-translational modifications to form the mature peptide hormone. These modifications can include cleavage of certain amino acids, addition of sugar molecules (glycosylation), and formation of disulfide bonds.
4. Packaging and secretion: Once the peptide hormone is fully synthesized and modified, it is packaged into secretory vesicles within the cell. These vesicles then move towards the cell membrane and release the hormone into the bloodstream through a process called exocytosis.
Overall, the biosynthesis of peptide hormones is a highly regulated and intricate process that involves multiple steps to ensure the proper production and secretion of these important signaling molecules in the body.
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Google Gemini AI
1 hour ago
Biosynthesis of Peptide Hormones
Peptide hormones are synthesized in specialized cells called endocrine cells. Here is a general overview of their biosynthesis:
1. Gene Transcription and Translation:
- The genetic information for the hormone is transcribed from DNA into mRNA.
- The mRNA is then translated by ribosomes into a preprohormone.
2. Preprohormone Processing:
- The preprohormone undergoes a series of post-translational modifications within the rough endoplasmic reticulum (RER):
- Signal peptide (presequence) removal, resulting in the prohormone.
- Glycosylation: Addition of sugars to the protein.
- Proteolytic cleavage of specific peptide bonds, releasing the hormone and other hormone precursors.
3. Prohormone Processing:
- The prohormone is further processed within the Golgi apparatus:
- Removal of additional peptide sequences, resulting in the mature hormone.
- Formation of disulfide bonds that stabilize the hormone structure.
4. Hormone Storage and Release:
- Mature hormones are stored in secretory granules within the Golgi complex.
- When stimulated by specific signals (e.g., hormones, neurotransmitters), the secretory granules fuse with the plasma membrane and release the hormones into the bloodstream via exocytosis.
Regulation of Biosynthesis:
- The biosynthesis of peptide hormones is tightly regulated at multiple levels:
- Gene expression: Hormones, neurotransmitters, and other factors can influence gene transcription and mRNA levels.
- Processing and secretion: Calcium ions and protein kinases can modulate hormone processing and release.
- Feedback mechanisms: Released hormones often exert negative feedback to suppress their own synthesis.
Examples:
- Insulin (pancreas)
- Glucagon (pancreas)
- Growth hormone (pituitary gland)
- Adrenocorticotropic hormone (pituitary gland)
- Thyroid-stimulating hormone (pituitary gland)
Peptide hormones are synthesized in specialized cells called endocrine cells. Here is a general overview of their biosynthesis:
1. Gene Transcription and Translation:
- The genetic information for the hormone is transcribed from DNA into mRNA.
- The mRNA is then translated by ribosomes into a preprohormone.
2. Preprohormone Processing:
- The preprohormone undergoes a series of post-translational modifications within the rough endoplasmic reticulum (RER):
- Signal peptide (presequence) removal, resulting in the prohormone.
- Glycosylation: Addition of sugars to the protein.
- Proteolytic cleavage of specific peptide bonds, releasing the hormone and other hormone precursors.
3. Prohormone Processing:
- The prohormone is further processed within the Golgi apparatus:
- Removal of additional peptide sequences, resulting in the mature hormone.
- Formation of disulfide bonds that stabilize the hormone structure.
4. Hormone Storage and Release:
- Mature hormones are stored in secretory granules within the Golgi complex.
- When stimulated by specific signals (e.g., hormones, neurotransmitters), the secretory granules fuse with the plasma membrane and release the hormones into the bloodstream via exocytosis.
Regulation of Biosynthesis:
- The biosynthesis of peptide hormones is tightly regulated at multiple levels:
- Gene expression: Hormones, neurotransmitters, and other factors can influence gene transcription and mRNA levels.
- Processing and secretion: Calcium ions and protein kinases can modulate hormone processing and release.
- Feedback mechanisms: Released hormones often exert negative feedback to suppress their own synthesis.
Examples:
- Insulin (pancreas)
- Glucagon (pancreas)
- Growth hormone (pituitary gland)
- Adrenocorticotropic hormone (pituitary gland)
- Thyroid-stimulating hormone (pituitary gland)
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