NUCLEOTIDES AND NUCLEIC ACIDS

Nucleotides and nucleic acids are not actually what we think of as food, but they are very important in the assembly of proteins and in metabolism. We will learn much more about them in future lectures. Each nucleotide has a five-carbon sugar (ribose or deoxyribose), a nitrogen-containing base (single or double-ringed), and a phosphate group.

Some nucleotides are involved in metabolism. Adenosine phosphates are chemical messengers (cAMP), or energy carriers ( ATP or adenosine triphosphate). Nucleotide coenzymes transport hydrogen atoms and electrons (examples are NAD+ . and FAD).

RNA and DNA are examples of nucleic acids. RNA (ribonucleic acid) is a single stranded molecule which functions in the assembly of proteins. DNA (deoxyribonucleic acid) is a double stranded molecule. Genetic messages are encoded in its base sequences. In nucleic acids, five different kinds of nucleotides are bonded together in large macromolecules. It's common to say there are four bases as opposed to five. This is because DNA and RNA each use four bases, but differ in one of the four they use.

This animation (Audio - Important) describes the subunits of DNA.

This animation (Audio - Important) describes the structure of DNA.

This web site, put together by a publisher for a different textbook than ours has an excellent tutorial (Audio - Important) on macromolecules. When one module is finished, click on the OPTIONS tab in the lower left corner to select another module. After you've done all four modules, click on and read the Conclusion. Then click on and take the Quiz.

REVIEW: Nucleotides contain what kind of sugars?

REVIEW: _____ are to nucleic acids as monomers are to polymers

REVIEW: _____ are to proteins as _____ are to nucleic acids.

REVIEW: A denatured protein or DNA molecule has lost its _____
a. hydrogen bonds
b. shape
c. function
d. all of the above

PREVIOUS

NEXT

LECTURE 3 INDEX

MAIN INDEX