How Organelles Work Together to Make and Secrete the Protein Insulin
Human Biology Unit 1 Assignment
The human body is made up of 100 trillion cells. All cells have the same basic structure (see figure 1) however some cells are specialised to suit a specific purpose. An example of this is the pancreatic beta cells found in the islets of Langerhans. These cells are specialised to synthesise the protein insulin that is involved in the metabolism of glucose in the cells. (Layden, 2010)
Figure 1 - Picture to show basic structure of a cell.
(Farrabee, M J. 2007)
But how is insulin made? The production of insulin starts in the nucleus which is the cellular organelle where the DNA (deoxyribonucleic acid) is found. They form a series of multiple linear molecules which are then folded in the nucleolus in to chromosomes as a gene. Genes are sections of DNA which contain instructions on how to make proteins and in this case insulin. The DNA molecule however is too large to get through the nuclear pores of the membrane so by the process of transcription a section of the instruction is copied in to RNA (ribonucleic acid). The RNA then takes the section of the instruction and leaves the nucleus and joins with a ribosome where it can be used to synthesise the protein. (Hickman and Thain 2004) Ribosomes are either free in the cytoplasm or are attached to the ER. Each ribosome has one conformational groove to fit the growing polypeptide chain and another for the messenger RNA. It has a gap between both of its sub units to permit the entry of transfer RNA. The tRNA is then bonded to an amino acid from the amino acid pool. The amino acid pool is composed by amino acids that the body has broken down and put in to the bloodstream via facilitated diffusion.
Figure 2- Passive Transport, Diffusion & Osmosis
(Coli, E. 2007)
Diffusion is the process that is used in oxygen entering a cell, and carbon dioxide leaving. These molecules will move from where they are at a high concentration to where they are at a lower concentration they diffuse down a
The human body is made up of 100 trillion cells. All cells have the same basic structure (see figure 1) however some cells are specialised to suit a specific purpose. An example of this is the pancreatic beta cells found in the islets of Langerhans. These cells are specialised to synthesise the protein insulin that is involved in the metabolism of glucose in the cells. (Layden, 2010)
Figure 1 - Picture to show basic structure of a cell.
(Farrabee, M J. 2007)
But how is insulin made? The production of insulin starts in the nucleus which is the cellular organelle where the DNA (deoxyribonucleic acid) is found. They form a series of multiple linear molecules which are then folded in the nucleolus in to chromosomes as a gene. Genes are sections of DNA which contain instructions on how to make proteins and in this case insulin. The DNA molecule however is too large to get through the nuclear pores of the membrane so by the process of transcription a section of the instruction is copied in to RNA (ribonucleic acid). The RNA then takes the section of the instruction and leaves the nucleus and joins with a ribosome where it can be used to synthesise the protein. (Hickman and Thain 2004) Ribosomes are either free in the cytoplasm or are attached to the ER. Each ribosome has one conformational groove to fit the growing polypeptide chain and another for the messenger RNA. It has a gap between both of its sub units to permit the entry of transfer RNA. The tRNA is then bonded to an amino acid from the amino acid pool. The amino acid pool is composed by amino acids that the body has broken down and put in to the bloodstream via facilitated diffusion.
Figure 2- Passive Transport, Diffusion & Osmosis
(Coli, E. 2007)
Diffusion is the process that is used in oxygen entering a cell, and carbon dioxide leaving. These molecules will move from where they are at a high concentration to where they are at a lower concentration they diffuse down a
Bibliography: Bailey, R. (2013) Diffusion and Passive Transport. Available at: http://biology.about.com/od/cellularprocesses/ss/diffusion_2.htm (Accessed 5th March 2013). Figure 4 - Bailey, R. (2012) About.Com Website. Available at: http://biology.about.com/od/cellanatomy/ss/mitochondria.htm (Accessed 5th March 2013). Barret, K. Brooks, H. Boitano, S. Barman S. Ganong 23rd Edition. (2009) Review Of Medical Physiology. Available at:http://www.scribd.com/doc/57882272/Review-of- Medical-Physiology-Ganong-23rd-Ed (Accessed 5th March 2013). Figure 5 - Biology Mad, (2004). The Cell Membrane. Available at: http://www.biologymad.com/cells/cellmembrane.htm (Accessed 5th March 2013. Biology Online. (2008). Vesicles. Availible at: http://www.biology-online.org/dictionary/Vesicle (Accessed 5th March 2013) BSCB, (2013) Figure 2 - Coli, E. (2007) Passive Transport. Availible at: http://eschecoli.blogspot.co.uk/2007/08/facilitated-diffusion.html (Accessed 5th March 2013) Coordination Group Publications Ltd. (2009) AS & A2 BIOLOGY. Page 19. Figure 1 - Farabee, M J Hickman, M. And Thain, M. (2004). The penguin dictionary of biology, London: Penguin books. Page 622. Layden, B. (2010) G-Protein-Coupled Receptors, Pancreatic Islets, and Diabetes. Available at: http://www.nature.com/scitable/topicpage/g-protein-coupled-receptors-pancreatic-islets-and-14257267 (Accessed: 5th March 2013). Mandal, A, (no date) Figure 3 Noske, Andrew.(2010). Location and function of beta cells within the islets of Langerhans. Available at: http://www.andrewnoske.com/student/uq_phdthesis.php (Accessed 5th March 2013). Figure 2 - Pearson Education Inc. (2010) Eukaryotic Cell Components. Available at:http://www.uic.edu/classes/bios/bios100/lectures/cells.htm (Accessed 5th March 2013). S-cool, (2013). Movement And Diffusion. Available at: http://www.s-cool.co.uk/a-level/biology/cells-and-organelles/revise-it/movement (Accessed 5th March 2013).