1. Genetics Review

2. An x-ray photo was a key to DNA's discovery (Deoxyribonucleic Acid)
With the help of the x-ray photo above (taken by Franklin), Watson & Crick developed the model for DNA’s structure.

3. A double helix is shaped like a twisted ladder.

4. The bases pair up to make the code that controls traits
A sequence of nitrogen bases (A’s,T’s, C’s & G’s) make up the genetic code for a trait.

5. Miscoded DNA is a Mutation “Good Mutations” are called Adaptations!
Mutation can cause birth defects in newborns that frequently results in death
Mutation of DNA causes cancer and other diseases.
“Good Mutations” are called Adaptations!

6. Exposure to CHEMICALS or RADIATION
What Causes Mutation?
Exposure to CHEMICALS or RADIATION

7. A trait is controlled by long series
of base pairs that make up a single GENE.
A CHROMOSOME is a bunch of genes twisted tightly together.
Both Genes and Chromosomes are made of Deoxyribonucleic Acid (DNA).

8. Hair color and tongue-rolling can both be inherited traits.
Traits are characteristics that can be inherited from your parents or acquired later.
Hair color and tongue-rolling can both be inherited traits.
BUT… some traits like hair color could be acquired after birth and not passed on to offspring.

9. (In sexual reproduction)
2 Genes for EVERY Trait
(In sexual reproduction)
You get a gene from Mom and one from Dad for each of your traits, EVERY TRAIT.

10. Gregor Mendel The “Father of Genetics” Worked with Pea Plants
Developed the Law of Dominance.

11. Law of Dominance (True for all sexually reproducing species)
2 genes, one from mom and one from dad control each trait.
In hybrids the dominant gene is expressed so the offspring gets the dominant trait and the recessive trait is hidden.
The dominant trait usually shows in more individuals

12. Using Punnett Squares to Predict Heredity
Freckles are a dominant trait in humans. Cross a pure dominant with a
pure recessive in a Punnett square.
F F f F f F f F f F f
All offspring boxes have hybrid genotypes so ALL of their kids will have the dominant trait (Freckles).

13. Using Punnett Squares to Predict Heredity
F f
Freckles are a dominant trait in humans. Cross a hybrid with a hybrid in a Punnett square. F f F F F f F f f f
FF or Ff ff ONLY!
3 of 4 offspring boxes have a dominant gene in them so 75% of the kids will have freckles. The other 25% has none.

14. Purebred TT BB RR rr tt bb Genotype with 2 of the same genes.
Homozygous means the same. TT BB RR rr tt bb
All of these are purebred (homozygous) because the two paired genes match.

15. Hybrid Tt Bb Rr Genotype with 2 different genes.
Heterozygous means not the same. Tt Bb Rr
All of these are hybrid (heterozygous) because the two paired genes don’t match.

16. Incomplete Dominance (or Codominance)
Neither gene is stronger.
The traits mix.
2 capital letters are used
Happens with cattle, flowers & our skin color.

17. Incomplete Dominance or Codominance Punnett Square
W W R R W R W
Fill in offspring boxes!
Do a Punnett square for a pure red cow mated or crossed with a pure white bull whose color is controlled incomplete dominance. R W R W
All offspring will be HYBRID ROANS

18. Genotype TT BB RR rr tt bb Tt Bb Rr Describes genes
Uses caps & lower case letters TT BB RR rr tt bb Tt Bb Rr

19. Phenotype Describes what the trait looks Red-eyed Brown-eyed Tall Tall
(Wild) (Sepia)
Tall
Tall
Short
TT tt Tt
Hybrid Genotype
Purebred Genotypes
For For
RR or Rr rr (only)
Genotypes Genotype

20. Labridore Retriever Coat Color
Pedigree Charts
They are like family trees
They track one trait through a family.
How many generations of dogs are in this chart?
How many pups did the first generation have?
How many of those were black labs?
How many great-grandpups did they have?
Labridore Retriever Coat Color
Male
Female
Dark Coat
Light Coat

21. Asexual Reproduction
Only one parent is needed.
One set of DNA is used

22. Offspring from Asexual Reproduction
All DNA is exactly the same as the parent.
(except mutations)
Every offspring is exactly like the parent.

23. Budding A form of asexual reproduction
The parent grows a body part that falls off to become a clone.

24. Runners & Chutes
Plant parts that asexually produce offspring

25. Regeneration
A part broken or cut off grows back can be asexual reproduction

26. Mitosis Cell division, one cell divides into 2. DNA copied,
Chromosomes line up in the middle.
split to each side.
cell then divides.

27. Growth in Multi-cellular Organisms
Can only happen if asexual reproduction occurs.
Bigger organisms have more cells

28. Sexual Reproduction 2 parents,
2 sets of genes combine during fertilization

29. Offspring of Sexual Reproduction
They have different traits (variation)
A combination of traits from both parents.

30. Determining Gender Eggs can only have x chromosomes
½ of sperms have y’s and the other ½ have x chromosomes
Female
X sperm with x egg
Male
y sperm with x egg

31. Gametes Sex cells (sperm or egg)
Gametes are made by the process of Meiosis

32. Number of Chromosomes Gametes have ½ as many chromosomes
Humans have 46 chromosomes in body cells and only 23 in their gametes

33. Variation
Differences between members of the same species

34. Cloning
Clones made by putting DNA from an individual put into an egg cell that had its DNA taken out.
Clones have only 1 set of DNA
May be able to replace damaged or diseased organs and/or cure diseases

35. Twins (Multiple Births)
Identical twins come from the same egg and sperm so their DNA is the same.
Fraternal twins come from 2 eggs and two sperm cell so they have different DNA and traits

36. Genetic Engineering
Changing DNA to get new traits.

37. Selective Breeding
Choosing parents with traits we want in the offspring.

38. Adaptation in Asexually Reproducing Organisms
All of them are the same. There is no variation to adapt.

39. Adaptation in Sexually Reproducing Organisms
Some variation from sexual reproduction allows them to survive the changes in the environment

40. Competition
The struggle to get limited resources needed for survival

41. Natural Selection Survival of the fittest.
Best adapted organisms pass on their genes.

42. Evolution
Change in a species over many generations

43. Causes of Evolution
Good variations allow for survival and change the species over time.
Natural selection eliminates weaker organisms.

44. Extinction
Organisms that don’t adapt to changes in their environment go extinct.
dinosaurs, mammoths, dodos, passenger pigeons, Tasmanian tigers