Question

read each question and fill in the proper answer.

1. label every sugar (s), phosphate (p), and nitrogen base (a, t, c, g) in the diagram

below.

1. examine the objects inside the box labeled #2. what is this called?
2. what is the special shape of dna called?
3. which type of chemical bonds will join the two dna bases?
4. where is dna found in eukaryotic cells?
5. which nucleotide part(s) make up the outside of the dna ladder? (circle all that apply)

sugar phosphate base

1. which nucleotide part(s) make up the rungs of the dna ladder? (circle all that apply)

sugar phosphate base

Explanation:

1. Labeling:

• In DNA, the sugar is deoxyribose (pentagon - shaped), phosphate is circular, and nitrogen bases (A - adenine, T - thymine, C - cytosine, G - guanine) are rectangular.
• For the un - labeled nitrogen bases:
• Opposite A (adenine) is T (thymine) (by base - pairing rules A - T).
• Opposite C (cytosine) is G (guanine) (by base - pairing rules C - G).
• The first un - labeled base (opposite G) is C.

1. Box #2:

• A nucleotide is composed of a sugar (deoxyribose), a phosphate group, and a nitrogen base. The objects in box #2 (sugar, phosphate, and base) make up a nucleotide.

1. Shape of DNA:

• DNA has a double - helix structure. It resembles a twisted ladder, where the sides (sugar - phosphate backbones) are the rails and the base pairs are the rungs.

1. Bonds between DNA bases:

• Hydrogen bonds join the two DNA bases. Adenine (A) forms two hydrogen bonds with thymine (T), and cytosine (C) forms three hydrogen bonds with guanine (G).

1. Location of DNA in eukaryotic cells:

• In eukaryotic cells, DNA is mainly found in the nucleus. Some DNA is also present in mitochondria (in the form of mitochondrial DNA) and chloroplasts (in plant cells).

1. Outside of DNA ladder:

• The sugar and phosphate make up the outside of the DNA ladder (the sugar - phosphate backbone).

1. Rungs of DNA ladder:

• The nitrogen bases make up the rungs of the DNA ladder as they pair up (A - T and C - G) in the middle of the two sugar - phosphate backbones.

Answer:

1. First un - labeled base: C; Second un - labeled base: T.
2. Nucleotide
3. Double - helix
4. Hydrogen bonds
5. Nucleus (also mitochondria and chloroplasts in some cases)
6. Sugar, Phosphate
7. Base