Question

1. refer to the diagram in model 1.

a. what are the three parts of a nucleotide?
b. what kind of sugar is found in a nucleotide?
c. which nucleotide component contains nitrogen?
d. name the four nitrogen bases shown in model 1.

1. dna is often drawn in a \ladder model.\ locate this drawing in model 1.

a. circle a single nucleotide on each side of the ladder model of dna.
b. what part(s) of the nucleotides make up the rungs of the \ladder\?
c. what parts of the nucleotides make up the sides (backbone) of the \ladder\?
d. look at the bottom and top of the \ladder\ in model 1. are the rungs parallel (the ends of the strands match)
or antiparallel (the ends of the strands are opposites)?

Explanation:

1. a. A nucleotide consists of three parts: a phosphate group, a deoxyribose sugar, and a nitrogen - containing base.
2. b. Deoxyribose is the sugar found in a DNA nucleotide.
3. c. The nucleotide component that contains nitrogen is the nitrogen - containing base.
4. d. The four nitrogen bases shown in Model 1 are cytosine, guanine, thymine, and adenine.
5. a. The rungs of the "ladder" (which represent base - pairs) are made up of nucleotides. In DNA, base - pairs are formed by two nucleotides (one from each strand) through hydrogen bonding.
6. b. The sides (backbone) of the "ladder" are made up of alternating phosphate and deoxyribose sugar molecules.
7. c. The parts of the nucleotides that make up the sides (backbone) are the phosphate group and deoxyribose sugar.
8. d. In the ladder model of DNA, the rungs (base - pairs) are not parallel. The two strands of DNA are antiparallel, meaning that the 5' to 3' orientation of one strand is opposite to that of the other strand. This results in the base - pairs (rungs) having an orientation that is not parallel.

Answer:

1. a. Phosphate group, deoxyribose sugar, nitrogen - containing base.

b. Deoxyribose.
c. Nitrogen - containing base.
d. Cytosine, guanine, thymine, adenine.

1. a. Nucleotides.

b. Alternating phosphate and deoxyribose sugar molecules.
c. Phosphate group and deoxyribose sugar.
d. No.