- Nucleotides
- DNA and RNA
- The DNA double helix
Nucleotides are the monomers that make up nucleic acids. In chapter 2 of your textbook, read the section on nucleic acids, focusing on Figures 2.16 and 2.17. Consult your notes for lecture 13, slides 1-3.
Biological macromolecules, such as nucleic acids, are polymers made of monomers, smaller units that repeat multiple times. In proteins, nucleic acids, and polysaccharides, monomers are linked together by dehydration reactions.
1. First, you should know what a nucleotide is made of. Answer question 1 below on a piece of paper. Then, mouse over the word "answer" to compare your answers with the correct ones (the order does not matter, as long as you have the three parts of the nucleotide in your answer).
A nucleotide is made of three parts. These three parts are:
a. __________
b. __________
c. __________
ANSWER
Pentose (Sugar)
Phosphate
2. In addition to knowing the parts of the nucleotide, you should be able to recognize them on a diagram. After you have learned the parts of the nucleotide, take a look at the diagram below and match the three letters on the image (A, B, C) to the three parts of a nucleotide. Mouse over HERE to see if you got the correct answers.
B. Nitrogenous base
C. Ribose (Pentose; Sugar)
3. It is very important to know how carbon atoms in the sugar portion of a nucleotide are numbered. Look at the figure of the nucleotide above. Draw the nucleotide on a piece of paper (this will help you remember what a nucleotide is) and label the carbon atoms of the pentose - there should be 5 of them. Now take a look at figure 2.16 in your textbook and see if you labeled your carbon atoms correctly. If you did - then great!, If not, then try it a few more times, until you get it right.
4. There are two kinds of nitrogenous bases found in nucleotides: purines and pyrimidines. Read about purines and pyrimidines in your textbook and in your notes. Then copy the table below on a piece of paper and try to fill it in without looking at your text or notes. Once you have filled it in, mouse over the word "ANSWER" below the table. If you did not get all the answers correctly, study your text and notes and try it again.
ANSWER
5. If you feel that you have mastered the concepts on this page, you can move to the next topic, which compares DNA to RNA.