DNA Structure and replication worksheet answers PDF

Preview

Summary

This Assignment will explain about structure of DNA and Process of Replication. This assignment emphasize the Structures and components involved in DNA Structure....

Description

Name

Date

Period

DNA & Replication Worksheet 1. Write out the complete name for DNA:

2. A nucleotide is made of three parts: a phosphate group, a five carbon nitrogen containing

base

phosphate sugar and a

Label these three parts on the diagram to the right:

3. In a single strand of DNA, the phosphate group binds to the 4. The 5' end of a single DNA strand contains a free contains a free

N base

deoxyribonucleic acid

sugar of the next group.

phosphate, while the 3' end

sugar

OH.

5. DNA was not thought to be the genetic blueprint originally; instead many scientists hypothesized that

protein contained the genetic code and blueprint of life. (They were later proven wrong.) 6. Purines have

two rings, and pyrimidines have one ring.

7. Chargaff's rule states that the DNA of any species contains equal amounts of also equal amounts of guanine &

adenine & thymine and

cytosine.

8. Wilkinsand Franklin studied the structure of DNA using

x-ray crystallography and determined that

the shape of the molecule was a helix. 9. James Watson and Francis Crick amended Franklin and Wilkin's conclusions and determined that the shape of the molecule was instead a double

helix.

10. Name the scientist(s) responsible for each of the following discoveries.

Griffith Chargraff Hershey & Chase Franklin (& Wilkins) Watson & Crick

Bacterial transformation The base-pair rule DNA was the hereditary material of viruses The shape of DNA was a helix The shape of DNA was a double helix

11. In DNA, thymine is complementary to

adenine ; cytosine is complementary to guanine.

12. In a strand of DNA, the percentage of thymine is 30%. What is the percentage of cytosine in the same DNA strand?

20%

13. The figure below shows DNA replicating. In the space provided, describe what is occurring.

DNA unwinds Helicase splits apart helix

The DNA of the daughter strands winds together with its parent strand

Daughter strands are formed using complementary base pairing DNA polymerase adds DNA nucleotides

14. Number the steps of DNA replication in the correct order (1, 2, 3)

2 1 3

Daughter strands are formed using complementary base pairing. DNA unwinds The DNA of the daughter strands winds with together with its parent strand.

15. Why is DNA replication called "semi-conservative"?

½ is old, ½ is new

16. What enzyme unwinds or unzips the parent strand?

helicase

17. What enzyme binds fragments of DNA on the lagging strand?

sugar phosphate

ligase 3’

18. DNA polymerase builds the DNA daughter strand in the

5’ to

3’ direction.

5’ T

19. On the diagram: Label the 3' and 5' ends. Circle a nucleotide. Label the sugar and phosphate. Label the bases that are not already labeled

A C

20. The two sides of the DNA helix are held together by

hydrogen bonds- between nitrogen bases (covalent bonds – between the sugars and phosphates in the backbone) 21. In your own words, explain why the discovery that DNA was the molecule of heredity was an important discovery.

3’

G A

T

C

G 5’...