1. Warm Up Read each “sentence”: THE FAT CAT SAT THE FAT RAT SAT
How are the similar? How are they different?
Do the sentences have the same meaning?

2. So… Back to our Warm Up Read each “sentence”: THE FAT CAT SAT
THE FAT RAT SAT
HEF ATR ATS AT
How are the similar? How are they different?
Do the sentences have the same meaning? Would the same proteins be produced?
What causes changes in the genetic code?

3. How are chromosomes, genes, and DNA related?
Genes & DNA
How are chromosomes, genes, and DNA related?

4. What does DNA look like? Genes – determine inherited traits
Chromosomes – where genes are located; made of protein & DNA
Nucleus – where chromosomes are located
DNA (deoxyribonucleic acid) – genetic material that determines inherited characteristics.
BrainPop Video - DNA

5. Nucleotides Nucleotides – subunits of DNA Sugar + Phosphate + Base
Nucleotides are identical except for the base.
4 bases:
Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)

6. DNA’s Double Structure
“Double helix” = twisted ladder
Sides:
Alternating sugar and phosphate molecules
Steps or Rungs:
Pair of bases
Adenine always pairs with Thymine (A – T)
Guanine always pairs with Cytosine (G – C)

7. The Genetic Code
The sequence of nitrogen bases tells the cell what proteins to make.
These proteins help to determine the size, shape, and other traits of the cell (& the organism).

8. Making Copies of DNA Video: Amoeba Sisters – DNA Replication
The pairing of bases allows DNA to replicate, or make copies of, DNA.
Each base only bonds with one other base:
A – T or T – A
C – G or G – C
These are complementary to each other.

9. DNA Replication Occurs during Interphase. DNA makes a copy of itself
Steps:
DNA separates (or unzips) down the middle (between the pairs of nitrogen bases).
Complementary nucleotides (sides + base) in the nucleus pair up with nitrogen bases on each strand of the DNA ladder.
Two DNA molecules form – exact duplicates of the original molecule (one half is old DNA, the other half is new DNA).

10. DNA Replication

11. Replication Steps 1 & 2:
Original DNA strand

12. What are the complementary nitrogen bases for a strand of DNA with the following sequence on ½ of the strand?
A T C G G A C A A T
? ? ? ? ? ? ? ? ? ?

13. Video Introduction
Amoeba Sisters - Mutations

14. Changes in Genes
Mutations – changes in the number, type, or order of bases on a piece of DNA.
Substitution – wrong base is used (this is the most common mutation)
Insertion – when an extra base is added
Deletion – when a base is left out

15. Do Mutations Matter? Mutations can be:
Harmful – reduce chance for survival
Ex: white (albino) deer living in the wild
Helpful – helps chance for survival
Ex: Antibiotic resistance in bacteria
Neither – neutral
Ex: white buffalo living in captivity

16. Type of Cell Reproductive/Sex Cells: Somatic/Body Cells:
Mutation usually occurs during meiosis.
Does not affect the parent, but the mutation is passed on to the offspring.
Somatic/Body Cells:
Mutation is not passed on to offspring.
However, any cells produced from the mutated cell (during mitosis) will also have the mutation.
Cancer= uncontrolled growth.

17. How Do Mutations Happen?
Random errors when DNA is copied
Substitution, Insertion, or Deletion of nitrogen bases
Ex: Sickle Cell Disease

18. Sickle Cell Disease: Caused by a “substitution” of a nitrogen base.
This changes the protein that is made.
Produces RBC’s that are “sickle” or crescent-shaped.
Sickle cells are stiff and sticky, and can block blood circulation. This can cause pain and organ damage.

19. Punnett Square Practice
A woman with sickle cell disease is expecting her first child. Her husband is a carrier of the disorder.
What is the probability that they child will also have the disorder? What is the probability that the child will be a carrier?

20. How Do Mutation Happen?
2. Mutagens – any physical or chemical agent in the environment that can cause a mutation
Ex:
radiation from X-rays or UV radiation (in sunlight)
Asbestos
chemicals in cigarette smoke
All of the above examples can cause different types of cancer.

21. “A World Without Color”
Student Handout
Article