Question

practice: dna structure and replication

1. label each part of the model to the right. include specific nitrogen base pairs

in your labeling.

1. what molecule is it?
2. what is its purpose?
3. where can it be found in a prokaryotic cell?
4. where can it be found in a eukaryotic cell?
5. it gets copied during a process called replication. when does this happen?

1. what is the result of dna replication?

1. why is dna replication necessary?

1. why is dna replication said to be semi - conservative? draw a picture to support your answer.

1. what would the chromosome to the right look like after dna replication?
2. what would the chromosome to the right be called after dna replication?

1. replicate the following four dna strands using what you know about complementary base pairs.

a. aatacgtccagatttt
c. cccgcggaatataca
b. ttaaccgagttcaga
d. agggctacttcagac

Explanation:

1. The model shows DNA's double helix: phosphate groups (circles), deoxyribose sugars (pentagons), and nitrogen base pairs (rectangles; A-T, G-C).
2. The molecule is DNA (deoxyribonucleic acid).
3. Its purpose is to store genetic information.
4. In prokaryotes, DNA is in the cytoplasm (nucleoid region).
5. In eukaryotes, DNA is in the nucleus (and mitochondria/chloroplasts).
6. DNA replication occurs before cell division (e.g., S phase of interphase).
7. Result: Two identical DNA molecules.
8. Necessary to pass genetic info to daughter cells.
9. Semi-conservative: Each new DNA has one original and one new strand.
10. After replication, the chromosome has two sister chromatids (X-shaped).
11. Called a replicated chromosome (with sister chromatids).
12. Complementary strands follow A-T, G-C pairing.

Answer:

1. Phosphate group, deoxyribose sugar, nitrogen base pairs (A-T, G-C)
2. DNA (deoxyribonucleic acid)
3. Stores genetic information
4. Cytoplasm (nucleoid region)
5. Nucleus (and mitochondria/chloroplasts)
6. Before cell division (S phase of interphase)
7. Two identical DNA molecules
8. To transmit genetic information to daughter cells
9. Each new DNA molecule has one original strand and one new strand
10. X-shaped with two sister chromatids
11. Replicated chromosome (with sister chromatids)
12. a. TTATGCAGGTCAAAAA

b. AATTGGCTCAAGTCT
c. GGGCGCCTTATATGT
d. TCCCGATGAAGTCTG