1. DNA in the Cell Cycle 8.2 & 11.1

2. Pretest!

3. Bell Ringer – turn in
What are the three things that limit how large/small cells get?
_________
__________________________
Is a smaller cell more or less efficient than a larger cell? Why?
Diffusion
DNA
Surface area-to-volume ratio
A smaller cell is more efficient b/c it allows diffusion of molecules to happen faster, and it increases the surface area-to-volume ratio allowing for nutrients and waste to effectively flow in and out of the cell.

4. Brain Teaser
Nothing specific, but more than a few. This many clustered together will do.
Bunch. It’s a vague term that means more than a few. And clustered items like bananas, grapes or celery come in bunches.
A bunch

5. The Cell Cycle G1 S G2 Mitotic phase Mitosis Cytokinesis Prophase
Metaphase
Anaphase
Telophase
Cytokinesis

6. Interphase G1 S G2

7. G1 Objectives Students will be able to
Sequence the events of the cell cycle by developing a cell cycle wheel.
Discuss what is happening within each phase of the cell cycle
Construct a model of dna and demonstrate replication before mitosis begins.

8. G1 Phase
Will someone volunteer to read what they have for G1 in their cell cycle wheel?
“where cells grow and perform its function for the organism”
This is where it grows and carries out its function
Liver cells break down fat to make energy
Kidney cells filter the blood for toxins
Brain cells (neurons) carry signals to the brain to carry out daily functions

9. S Objectives Students will be able to
Sequence the events of the cell cycle by developing a cell cycle wheel.
Discuss what is happening within each phase of the cell cycle
Construct a model of dna and demonstrate replication before mitosis begins.

10. S Phase
Will someone volunteer to read what they have for S in their cell cycle wheel?
“cell is copying and synthesizing DNA”
Makes a copy of DNA, copies of cell organelles

11. Discovering the structure of DNA
Structure was discovered in 1953 by James
Watson and Francis Crick
Rosalind Franklin

12. DNA Nucleotide O O=P-O N CH2 O C1 C4 C3 C2
DNA = Deoxyribose nucleic acid O
O=P-O
Phosphate
Group
Made out of sugars (deoxyribose), phosphates
and nitrogen bases N
Nitrogenous base
(A, G, C, or T)
CH2 O C1 C4 C3 C2 5
Sugar
(deoxyribose)

13. The structure of DNA is like a zipper
Like the teeth of a zipper holds the zipper together, the nitrogenous bases of the nucleotides hold the 2 strands of DNA together with weak hydrogen bonds (H-bonds).

14. Nitrogenous bases (4) A≠C T≠G T≠C A≠G Adenine (A) Guanine (G)
Thymine (T)
Cytosine (C)
Pair together
A = T & G = C
A≠C
T≠G
T≠C
A≠G

15. Two complementary strands are joined by weak hydrogen bonds
DNA replication
Two complementary strands are joined by weak hydrogen bonds
To make a DNA molecule.

16. Enzymes break Hydrogen bonds1 2
Enzymes break Hydrogen bonds
Two strands separate
W.B.K.HETTIARACHCHI

17. Nucleotides with Complementary bases are assembled alongside each strands
Sugar phosphate backbone is made by joining the adjacent nucleotides ( DNA polymarase enzyme( ) )
W.B.K.HETTIARACHCHI

18. Two identical DNA molecules are formed
W.B.K.HETTIARACHCHI

19. Double helix unwinds Enzymes, called DNA helicase, breaks the H bonds
DNA replication
Double helix unwinds
Enzymes, called DNA helicase, breaks the H bonds
2 strands separate and form replication fork
Other enzymes and proteins hold them apart

20. DNA replication
Enzymes, called DNA polymerase, move along the separated strands and add nucleotides to the exposed bases by the base pairing rule
As DNA polymerase moves along the strands, 2 new double helixes are formed
Enzymes continue adding nucleotides until it reaches a signal for it to detach

21. Nucleotides as Language
nucleotides – A, G, C and T are a special language
Language of DNA

22. What would the complementary strand be?
T C G A T A C G C T T A

23. ATGCTA AUGCUA TACGAT CGTGGC
A strand of DNA that contains the bases TACGAT replicates. Which base sequence is in the new strand produced during replication?
ATGCTA
AUGCUA
TACGAT
CGTGGC

24. What preserves the genetic code from one generation to the next?
DNA replication
RNA translation
protein synthesis
enzyme activation

25. Let’s build our own DNA model and simulate DNA replication
Monday we’ll talk about G2 and mitosis! The final phases of the cell cycle!

26. Worksheet to turn in tomorrow!
Homework
Worksheet to turn in tomorrow!