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· Web view DNA REPLICATION DNA replication occurs during the _____ of the eukaryotic cell cycle. Steps to DNA replication:

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Name ______________________________ Period ______

CELL REPRODUCTION

Chromosomes and DNA Replication

CHROMOSOMES

1. What is the composition of chromosomes? ______________________________________________________________________________

2. Each chromosome is a _______________________ DNA molecule.

3. Define chromatin: ______________________________________________________________________________

4. What does DNA wrap around during the S phase? __________________________

5. Nucleosomes are ____________________________________ formed by multiple wrapped histone proteins.

6. Long strings of nucleosomes form thick coils that pack together to make up ________________.

7. During what phase of mitosis are chromosomes visible under a microscope? ________________

8. What shape does DNA take in prokaryotic organisms? __________________________________

Chromatids and the Centromere

9. After replication each chromosome consists of _____________ identical copies called ______________________________ attached to one another at a region called the___________________________.

Chromosome Numbers

10. Do all species have the same number of chromosomes in their cells? ________________

11. How many chromosomes are found in human cells? ____________

12. Chromosomes of the same size and shape with the same genes are called __________________________________________.

DISCOVER OF DNA STRUCTURE

13. What is the genetic material of all life on Earth? ______________

Griffith Searches for the Genetic Material

14. What was he searching for? __________________________________________________________________

15. Briefly explain the experiment that led to Griffith’s conclusion and discoveries.

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

16. Based on his observations, Griffith deduced that something in the killed S-strain was transferred to the previously harmless R-strain, making the R-strain deadly.

What did he call that something? ___________________________

Avery’s Team Makes a Major Contribution

17. Whose experiments did his team replicate? ________________________________________________

18. Why did they replicate these experiments?

_____________________________________________________________________________________

_____________________________________________________________________________________

19. What conclusions did Avery come up with?

_____________________________________________________________________________________

_____________________________________________________________________________________

Hershey and Chase Seal the Deal

20. Briefly explain Hershey & Chase experiment.

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

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21. What was their conclusion?

_____________________________________________________________________________________

Chargaff Writes the Rules

22. What did Chargaff study? _____________________________________________________________________________________

23. What discovery did Chargaff make?

_____________________________________________________________________________________

_____________________________________________________________________________________

24. What name is giving to his discovery? __________________________________________________________

The Double Helix

25. What did Watson & Crick discover? _______________________________________________________

26. In what year was this discovery made? ______________

27. What is the shape of a DNA molecule? __________________________________________

28. What type of bonds hold the nucleotides together? __________________________________________

29. What are the three parts of a nucleotide? __________________________________________________

30. Name the four nitrogenous bases found in DNA. ____________________________________________________________________________________

31. Which nitrogenous bases always pair together? ____________________________________________________________________________________

DNA REPLICATION

32. DNA replication occurs during the _________________ of the eukaryotic cell cycle.

33. Steps to DNA replication:

(1) ___________________________________________________________________________

(2) ______________________________________________________________________________________________________________________________________________________

(3) ______________________________________________________________________________________________________________________________________________________

(4) ___________________________________________________________________________

34. What is the name of the enzyme that opens the DNA molecule? _________________________

35. What is the name of the enzyme that “reads” the DNA molecule? _______________________

DNA Replication is Semi-Conservative · DNA replication of one helix of DNA results in two identical helices · original DNA helix is called the "parental" DNA · two resulting helices can be called "daughter" helices · DNA replication is semi-conservative, meaning that one parent strand is always passed on to the daughter helix of DNA

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