1. April 12 Chromosomes and DNA
Get out your notebooks and sharpen your pencils! Be in your seat, ready to go when the bell rings.
April 12
Chromosomes and DNA

4. DNA=Genetic Material Gene=Small section of DNA that codes for a protein.(recipe for a protein) Chromosome=one large molecule of DNA coiled up tightly. Allele=an expression of a gene (one from mom and one from dad) (can be dominant or recessive) Trait=The combination of alleles

6. Almost every cell in your body has DNA in its nucleus.
Red blood cells have no nucleus and no DNA.
The DNA tells the cell what its job is…hair, skin, heart, bone

7. Phenomena
Mutations

8. Let’s start with a little test…
Create this in your notebook:
A- B- C-
D- E- F-
G- H- I-

9. Now SILENTLY write what you see on each slide

10. Now SILENTLY write what you see on each slideB-

11. Now SILENTLY write what you see on each slide

12. Now SILENTLY write what you see on each slide

13. Now SILENTLY write what you see on each slide

14. Now SILENTLY write what you see on each slideF-

15. Now SILENTLY write what you see on each slideG-

16. Now SILENTLY write what you see on each slide

17. Now SILENTLY write what you see on each slide

18. What were your answers?
A-12 B-8 C-29
D-5 E-3 F-15
G-74 H-6 I-45

19. This could be caused by a mutation on your X chromosome.
Sometimes we call this “colorblindness” but people who cannot distinguish between the colors red and green just have a gene that codes for a different protein than other people’s X chromosome codes for.

20. This “different protein” coding was probably the result of a mutation in the DNA many generations ago.
This “mutation” is passed from parent to offspring just like any other gene. Since the mutation is on the X chromosome, this phenotype (being colorblind) is much more likely to show up in males than in females. This is because males only have one X chromosome, not two X chromosomes like females. If that one X chromosome has the colorblind allele, there is no “backup protein” on the second chromosome.

21. So how do these “mutations” of a gene happen?
Make sure to pay attention and take some notes. There is a quiz after…

22. Let’s see how much of that video you remembered…
Quick Quiz
Number from 1-5

23. 1- True or False
Most mutations to an organism’s DNA are helpful, and are a step in adapting to the environment.

24. 2- What word goes in the blank?
_________

25. 3- True or False
Mutations in genes can be at the DNA level or even at the chromosome level.

26. 4- Fill in the missing word
Mutations are ______________, meaning that an organism can’t will a mutation to happen when it wants a new trait.

27. 5- True or False
Not all genes are “turned on” or activated at the same time.

28. A pedigree chart model

29. Make this chart in your notes:
Outcome of Mutation
Example
Beneficial
Neutral
Harmful

30. Mutations may be beneficial
Double Muscling is a mutation in the gene that controls reproducing muscle cells, so they don’t receive the “stop” message as often. Since strength is good for a bull to have, this is beneficial. Nylonase is an example of beneficial mutation in bacteria. The nylonase bacteria can eat short molecules of nylon, not just sugar, like regular bacteria. Nylonase can be used by humans in wastewater treatment plants.

31. Mutations may be beneficial
Ability to digest milk is a mutation that occurred thousands of years ago. We now produce lactase which is an enzyme that digests milk sugar, lactose. Anciently, almonds had a chemical that turned to cyanide inside human bodies. A mutation deleted this chemical, so now humans grow the “safe” form of almond trees.

32. Mutations may have no effect
Anciently, all humans had brown eyes. A mutation about 6,000 years ago produced a protein that makes blue eyes. This is neither beneficial or harmful. Some plants get a mutation in the gene that controls leaf color. These leaves are colored in the middle and white on the edges. This variegation is neutral. Most mutations are neutral because there is more than one gene sequence to make a protein.

33. Mutations may have no effect
Most mutations are neutral because there is more than one gene sequence to make a protein.

34. Mutations may be harmful
When a mutation makes extra structures, or structures where they shouldn’t be, this usually makes it harder for the organism to get food, survive, and/or reproduce.
These are harmful mutations, and they are usually eliminated from the gene pool.

35. Mutations may be harmful
Many human diseases are caused by mutations.
Rapid aging disease is caused by a single-point mutation in one gene.
Marfan Syndrome happens because of a mutation in DNA. People with this disorder have problems with their connective tissue.
Progeria