Biology
Jones
Name:
Period:
Date:
DNA and the Cell’s Life Cycle
Fill in the blanks:
Every cell has a life cycle with different stages just like there are different
stages in your life. The cells life cycle is controlled by a molecule called (1)______.
The cell spends most of its time in (2)____________________ of its life cycle.
During G1, the first stage, the cell (3)_________________. The next stage is called
the S phase; this is where the DNA goes through (4)__________________________.
When the DNA is copied, the two identical sides called (5)______________________,
are created. These sides are held in the center by a (6)__________________. The
cell has to replicate not just its DNA before it divides, it also has to duplicate its
(7)___________________ in the (8)________ phase of the life cycle. During all
three stages of Interphase, DNA is in its relaxed state called (9)________________.
Following Interphase, the cell will prepare the DNA for cell division. DNA must
condense to form (10)_________________. DNA now can be divided during a process
called (11) _____________ or ____________, depending on what types of cells will be
created. Following this stage of the cell’s life cycle it will finally divided into two cells
during a process called (12)_____________________. The DNA will relax again as
the two new cells enter Interphase and start to grow during the (13)_______ phase.
14. How many chromosomes do human autosome/somatic (body) cells have? _______
15. What are gametes? __________________.
Give two examples: ____________ & ___________
16. How many chromosomes do human gametes have? ________
17. What is macromolecule that DNA belong to? ____________________________
18. What is the monomer of DNA? __________________________
What are the three parts to this monomer?



19. Specifically, where is the genetic code?
20. What is a gene?
21. What is Chargaff’s rule?
22. Draw a small section of DNA. Include in your drawing:
- At least 5 stair steps
- Demonstrate Chargaff’s Rule
- A twist
- Bases are attached to sugars
- Alternating sugar phosphate backbone
23. Fill in the diagram below to represent the correct order of the stages in the life cycle of a
cell. Then describe what happens in each stage in the table to the right.
Stage of
Cell Cycle
G1
S
G2
M
S
24. Why are the first three boxes shaded?
Description