1 DNA is a polymer. 2  Individual monomer units are called nucleotides. 3  The DNA polymer is composed of: 4  a backbone of molecules of the sugar deoxyribose (a 5 carbon sugar). 5  phosphate groups linking the deoxyribose sugar molecules together in a chain. The DNA polymer is composed of: 2  a backbone of molecules of the sugar deoxyribose (a 5 carbon sugar). 3  phosphate groups linking the deoxyribose sugar molecules together in a chain. 4  four principal bases (2 are pyrimidines and 2 are purines):
Rods and cones function as photoreceptors in the retina of the eye, turning visible light into neuronal signals, which are sent to the brain. This process is called transduction. Rods and cones perform at different wavelengths and sensitivities allowing detailed perception of light and color.
The main function of the proximal tubule is to reabsorb the water and solutes, as well as secrete the hydrogen ions to create a neutral blood composition. Loop of Henle The loop of Henle is the tubular portion of the nephron that lies between the proximal tubule and the distal tubule.The main function of the loop of Henle is to allow the reabsorption of the water and ions, such as sodium and chlorine, from the loop of Henle into the capillaries surrounding it.he main function of the proximal tubule is to reabsorb the water and solutes, as well as secrete the hydrogen ions to create a neutral blood composition. Loop of Henle The loop of Henle is the tubular portion of the nephron that lies between the proximal tubule and the distal tubule.