Tutor profile: Hugh M.

How does the structure of DNA differ from the stucture of RNA?

Both DNA and RNA are composed of a ribose sugar with a base attached. There are two main structural differences between DNA and RNA. At the level of the ribose sugar, DNA is missing an OH group on carbon #2 of the ribose ring. That is the basis of the term Deoxyribose. RNA has an OH group on carbon #2. In addition, the types of bases attached to the ribose differ between DNA and RNA. DNA has Adenine, Thymine, Guanine, and Cytosine. RNA has Uracil in place of Thymine.

What is the role of electrons when creating molecules.

Atoms contain protons and neutrons in their nucleus and electrons orbit around the nucleus. When two atoms are allowed to react to form a molecule, it is the electrons that form the basis of the bonds that hold the atoms together. Electrons can either be shared between two atoms, which is called a covalent bond or one atom can attract the electrons toward its nucleus, which is called an ionic bond.

How does a cell use glucose to supply the energy needed for its functions?

The cell will utilize two enzyme pathways; one in the cytosol called Glycolysis and the other in the mitochondria called the Kreb Cycle. During these pathways, high energy electrons are removed from glucose and attached to a carrier molecule such as NAD+. During this process, the glucose is broke down into carbon dioxide. The high energy electrons are transported into the mitochondria and their energy is used to pump protons across the inner mitochondrial membrane. This creates a high concentration of protons in the inner membrane space. This high concentration of protons pass through a membrane protein called the ATP Synthase, and their movement through this protein is used to make ATP. ATP is the general energy "battery" for the cell.