1. DNA Structure Simulation
Before we begin, let’s investigate the way DNA molecules are set up!

2. BioFacts /4
We are going to create a bubble map In the center of the bubble map, write “What is DNA?”

3. Today’s Order of Operations:
Agenda: 2/19
Grab the paper from the basket
Today’s Order of Operations:
Review Cell Division #2
DNA KWL Chart / Model
Test corrections / time for vocab project
Reminders: 1st section of vocab project due 3/1!

4. Agenda: 2/20 Order of Operations: Test corrections
Time for vocab project
Color sheet
Reminders: 1st section of vocab project due 3/1!

5. Time for vocab project / test corrections
Agenda: 2/21
Grab a paper from the basket!
Order of Operations:
DNA KWL Chart
DNA Structure Notes
DNA Model
Time for vocab project / test corrections
Reminders: 1st section of vocab project due 3/1! Biochem and Cells Test Corrections due ASAP!

6. DNA KWL Chart / Model (page 29)
On one side of the paper, create a KWL chart
K = Know, W = Want to know, L = learned
Fill in the first two columns
On the other side of the paper, you will glue your model and answer the questions

7. The Structure of DNA
What is DNA?

8. A bit about DNA… DNA is the genetic material found in cells
Stands for: “DeoxyriboNucleic Acid”
Is made up of repeating nucleotides
It’s the “Unit of Heredity”

9. Where is it found?
DNA is found in the cytoplasm of prokaryotes and the nucleus of eukaryotes
The nucleus of a human cell contains 30,000 or more genes in the form of DNA called a genome

10. Function of DNA DNA  RNA  Proteins
Purpose: DNA controls the production of proteins in the cell
This is essential to life!
DNA  RNA  Proteins
“THE CENTRAL DOGMA OF BIOLOGY” (write this in!)

11. Structure of DNA
DNA is packaged tightly into pieces called chromosomes that are visible during cell division
Each chromosome includes several thousand genes
Each gene contains the directions to make one or more proteins
Proteins are made of amino acids
These proteins play a key role in the way we look and grow…ever hear someone say “it’s in your genes?”

12. Each gene codes for a protein
Structure of DNA
One
Chromosome
Contains many genes
Each gene codes for a protein
Ex. Keratin protein

13. Specialization
In embryo, all genes on the DNA is “on”. This undifferentiated cell (stem cell) can develop into any type of cell.
Specialization occurs when certain genes are turned “off” and other genes remain “on” – making a particular type of cell
Ex. Muscle cells and Nerve cells in your body have the same DNA, but they have different genes activated.

14. But what does DNA look like?
Think of DNA as a spiral staircase!
DNA is comprised of two strands that twist around each other, called a double helix
Discovered by Watson and Crick in 1953
“Twisted ladder structure”

15. Structure of DNA DNA is a made of building blocks called nucleotides
A nucleotide is made of:
one phosphate
one 5-carbon sugar (called deoxyribose)
one nitrogen base
Adenine
Thymine
Guanine
Cytosine

16. Structure of DNA
Nucleotides put together make up the DNA strand!

17. Parts of DNA: Sides
The sides, or “backbone” of the DNA are composed of alternating phosphate-sugar groups

18. Parts of DNA: Bases
Each “rung of the ladder” is made up of complementary nitrogenous base pairs
The four bases are A (adenine), T (thymine), G (guanine), and C (cytosine)
A pairs with T (2 H Bonds)
G pairs with C (3 H Bonds)

19. Nitrogenous Base Pairs
They form weak hydrogen bonds that hold the DNA strand together and are the reason DNA can be replicated
A::T forms 2 H-bonds, and C:::G forms 3 H-Bonds

20. Agenda: 2/22 Grab a paper from the basket Order of Operations:
DNA Extraction Lab
Finish DNA model from yesterday
Fill in “LEARNED” section on KWL chart
Time for vocab project
Reminders: 1st section of vocab project due 3/1!

21. Agenda: 2/25 Grab a sheet from the basket Order of Operations:
DNA Replication Notes
Gummy Bear Lab
Time for vocab project
Reminders: 1st section of vocab project due 3/1 THAT IS THIS FRIDAY! Extra credit for turning it in early / it being colorful!

22. DNA REPLICATION
Making a new strand

23. DNA Replication
DNA replication is the process of producing 2 identical replicas from one original DNA molecule
Replicate means “to copy”
During replication, the DNA molecule separates into two strands, and builds two new complimentary strands using the base pairing rules (A::T, C:::G)
The molecule is unwound and “unzipped” with the help of helicase, an enzyme!

24. Steps in DNA Replication
Step 1: DNA unwinds, then “unzips,” exposing the N-bases (remember, the bases are ATCG)
Step 2: New DNA N-bases are added to each side of the molecule, making two separate strands
If the unzipped side read ATCG, then TAGC would be added to that side. Now it is an independent strand!

25. DNA Replication
Each new DNA strand (daughter chromosome) is made up of 1 strand from the original DNA (blue) and one new strand (red)
Called “semiconservative replication!” (add this)

26. Complementary Base Pairs
Given one strand, you can always find the other strand using base pairing rules!
Let’s practice!
If the DNA sequence of bases on one strand was G C T A C A T, what would the complementary side be during replication?
C G A T G T A

27. When finished with the lab…
Place large bags on the back counter
Finish model and KWL chart (page 30)
Work on vocab project!

28. BioFacts /9
7. What are the steps in DNA replication?
8. What is the outcome of DNA replication?
9. Given the following strand of DNA, what would the complementary side read?
C T G A A T C G A

29. DNA REPLICATION

30. BELLRINGER-10/20/15
DNA is packaged into pieces. What are these pieces called?
There are thousands of genes on a chromosome. A single gene contains the directions to make what?
The base adenine (A) always pairs with ____________, while the base guanine (G) always pairs with _________________.

31. Agenda Place cell phones in a pouch
Be in your seat and ready to start when the bell rings!
Today’s Order of Operations:
Photosynthesis & Respiration Test

32. The Cell Cycle
How does a cell grow and divide?

33. The Cell Cycle
The Cell Cycle describes the life of a cell from birth to death
There are three main parts of the cycle:
Interphase-Normal cell activities; broken up into 3 parts
Mitosis-The process of cell division (1 cell becomes 2!)
Cytokinesis-The division of the organelles and cytoplasm following mitosis

34. Cell Cycle Detailed
Interphase is indicated in grey-it is the longest phase of the cycle, broken into 3 parts
Mitosis is indicated in pink-we will discuss the stages of mitosis later!

35. The Cell Cycle: Interphase
G1 phase (Gap/Growth 1)-Period of cell growth
Cells can remain in the G1 phase indefinitely
Called G0
S phase (Synthesis)-Period when DNA replication occurs
Once a cell copies its DNA, it must divide
S phase allows daughter cells to have exact copy of parent DNA after division!
G2 phase (Gap/Growth 2)-Cell growth and preparation for Mitosis

36. The Cell Cycle: Mitosis
Mitosis is a form of asexual reproduction-means only 1 organism required
Occurs in response to the body’s need for growth and repair
4 stages of mitosis: Prophase, Metaphase, Anaphase, Telophase
We’ll talk more about this in a bit!

37. Cytokinesis
The cell cycle ends with cytokinesis the division of the cytoplasm
Accompanies mitosis
This means one cell has divided into two cells, and those two cells can continue with their own independent cell cycles!

38. The Cell Cycle

39. Regulation of the Cell Cycle
Cyclins-Proteins that regulate the rate of the cycle
Internal regulation-cell cycle can’t proceed until certain levels of these proteins are reached (ex. Poor nutrition cell stays in G1)
External regulation-cycle can speed up or slow down
Do you think a paper cut on your finger would cause the cell cycle to speed up or slow down?

40. Cell Cycle Checkpoints

41. Case Study: Cancer
Sometimes errors in the cell cycle can lead to cancer-
Errors can be genetic or due to an environmental toxin
Internal regulation error followed by external; cells cannot “feel” their neighbors, and thus begin uncontrolled division
Lack density dependence (tumor) and anchorage dependence (metastasized cancer cells)

42. Cancer Cell Growth
From 1: 15

43. BELLRINGER-3/23/15
Cytoplasm divides: 1 cell is now 2
Label the diagram on the right with the appropriate stage of the cell cycle.
Why would the cycle need to pause at checkpoints before moving to the next stage?
Explain how cancer is related to regulation of the cell cycle.
Cell Growth: Cell may stay indefinitely if it does not meet checkpoints
Cell divides
Growth and preparation for division
DNA is replicated.

44. Mitosis
Stages of Asexual Cell Division

45. The Cell Cycle
Recall that the cell cycle is made up of three main parts
Interphase (G1, S, and G2)
Mitosis
Cytokinesis
Mitosis refers to the division of the cell
Asexual reproduction for unicellular eukaryotes
Occurs in response to the bodies need for growth and repair

46. More About Mitosis Occurs in eukaryotes
1 cell divides to produce 2 daughter cells
These cells are identical to the original cell same number of chromosomes!

47. The Stages of Mitosis
What happens when the cell leaves interphase and is ready to begin division…?

48. Stage 1: Prophase What Happens? Nuclear membrane dissolves
Chromatin condenses into chromosomes
Chromatin: uncondensed DNA (looks like spaghetti)
Chromosome: condensed DNA (looks like X’s)
Centrioles move to opposite ends of the cell
Spindle forms and spindle fibers extend from one side to the other

49. Stage 2: Metaphase What Happens?
Centromeres (middle of chromosome) attach to spindle fibers
Chromosomes are pulled to the middle of the cell

50. Stage 3: Anaphase What Happens? Spindle fibers pull chromosomes apart
Each sister chromatid moves toward opposite end of the cell

51. Stage 4: Telophase What Happens? Nuclear membrane reforms
Spindle fibers disappear
Animal Cells:
Cell membrane pinches
Plant Cells:
New cell wall begins to form

52. Cytokinesis What happens? Division of the cytoplasm and organelles
1 cell is now 2 identical cells!

53. Stages of Mitosis INTERPHASE PROPHASE METAPHASE ANAPHASE TELOPHASE
CYTOKINESIS

54. Stages of Mitosis

55. Mitosis Oreo Lab!