Answer to Question 1
Thiamin plays an important role in the synthesis of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and triglycerides. To aid in energy synthesis, thiamin acts as a coenzyme, meaning that an enzyme will not function unless thiamin is present. Without thiamin acting as a coenzyme, the enzymes that make DNA and RNA cannot work, and protein synthesis is halted. As a result, cell division is impeded because the genetic material (DNA and RNA) cannot be replicated.
Answer to Question 2
Vitamin A has many important functions beyond vision. Vitamin A plays an important role in cell differentiation, the process by which a nonspecialized, immature cell type becomes a specialized, mature cell type. Vitamin A is also critical for growth and reproduction, and it has a variety of immunological functions. These include the maintenance of protective barriers (such as skin and those that line organs) and the production of immune cells (such as those that produce antibodies). Preformed vitamin A is also essential for healthy bones.
Schematic of typical animal cell depicting the various organelles and structures.
cell
cell membrane
The receptive fields of an on-center cell and an off-center cell.
Dolly the sheep was the first mammal cloned by nuclear transfer from a somatic cell
animal cell