Question

exit ticket - dna structure practice
use the image at the right to complete the follow:
circle a nucleotide.
label the sugar and phosphate.
label the bases that are not already labeled
what bond holds the nitrogen bases together?
what 3 parts make up a nucleotide?
how many nucleotides are in the dna molecule above?
what does anti - parallel mean?
what is the complementary strand for the dna strand below?
ttcagactagggccaa

Explanation:

1. A nucleotide in the image consists of a sugar - phosphate backbone and a nitrogen - base. You can circle any one unit with these components.
2. The sugar in DNA is deoxyribose and the phosphate is part of the sugar - phosphate backbone.
3. In DNA, A pairs with T and G pairs with C. So label the unlabeled bases accordingly.
4. Hydrogen bonds hold the nitrogen bases together.
5. A nucleotide is made up of a phosphate group, a deoxyribose sugar, and a nitrogen - containing base.
6. Count each unit of sugar - phosphate - base to find the number of nucleotides in the given DNA molecule.
7. Anti - parallel means that the two strands of the DNA double - helix run in opposite directions (one 5' to 3' and the other 3' to 5').
8. To find the complementary strand, pair A with T, T with A, G with C and C with G for the given DNA strand TTCAGACTAGGGCA.

Answer:

1. (Circle a nucleotide in the image as described above)
2. Sugar: Deoxyribose; Phosphate: Part of sugar - phosphate backbone
3. (Label unlabeled bases according to base - pairing rules)
4. Hydrogen bonds
5. Phosphate group, deoxyribose sugar, nitrogen - containing base
6. (Count nucleotides in the image)
7. The two strands of the DNA double - helix run in opposite directions (one 5' to 3' and the other 3' to 5')
8. AAGTCTGATCCCGTT