1. Wednesday 4/9/14 AIM: Why is Gregor Mendel the father of genetics?
DO NOW: How many chromosomes do you have and where do they come from?
What would happen if you had an extra chromosome and why?
HOMEWORK: Text read pages Reading check pages 267 and 268, q 1 and 2 pages 270

2. What is genetics?

3. Genetics The study of inherited traits
Chromosomes are the units of inheritance
Chromosomes carry genes
Genes are the specific direction or code for your physical trait
Genes: code for proteins
Proteins cause chemical reactions
Chemical reactions lead to physical traits

4. Where do your inherited traits come from?
Your dads sperm and your moms egg

6. Homologous chromosome
Similar in size shape and genetic content
Homologous chromosomes pair up at fertilization
n+n=2n

8. Remember Zygote gets one complete set of chromosomes from the egg
And one complete set of chromosomes from the sperm
Bringing together homologous chromosomes

9. Haploid + haploid = diploid

10. Human Chromosomes Total we have 23 pairs 2(23)=46
22 of those pairs are called autosomes
The 23 pair is the sex chromosomes

11. Sex Chromosomes
XX female
XY male

12. Y chromsome Carries the SRY gene SRY: sex determining region
If the SRY gene is turned on, then gonads develop into testis and fetus becomes male
If not then gonads become ovaries

13. AIM: How does the structure of DNA relate to its function?
DO NOW: How many chromosomes do each of your cells have?
How many genes does each of your cells have?
How many nuclei does each of your cells have?
Homework: text read pages 293,296,297 and Answer Reading questions 293,296,297

14. Somatic or body cells have 46 chromosomes
Examples of somatic cells
Cardiac cells lung cells brain cells
Skin cells muscle cells gall bladder cells
Tracheal cells esophagal cells liver cells
Gametes or sex cells have 23 chromosomes
Male-sperm
Female-ova or egg
There are thousands of genes in each cell
There is one nucleus in each cell that houses the chromosomes which carry genes on them
Each cell expresses specific genes to make them specialized

15. So how do we know anything about genetics and homologous chromosomes?

16. Gregor Mendel Father of genetics Looked at the pea plant
Specifically 7 visible traits
Followed their inheritance over many generations
HE KNEW NOTHING ABOUT GENES!!!!!

18. Mendel was lucky
Each of the 7 traits Mendel observed was only present in 1 of 2 possible forms
Ex: Plant color was either purple or white
Pea shape was either round or wrinkled
Mendel used this when performing his experiments.

19. Thursday 4/10/14
AIM: How did Gregor Mendel develop his basic laws of heredity?
DO NOW: What is genetics? How do we know anything about genetics?
HOMEWORK: Textbook read pages do the reading check on page 277

20. Genetics The study of inherited traits
Chromosomes are the units of inheritance
Chromosomes carry genes
Genes are the specific direction or code for your physical trait
Genes: code for proteins
Proteins cause chemical reactions
Chemical reactions lead to physical traits

21. AIM: How did Mendel develop his basic laws of heredity?
DO NOW: What is the difference between self fertilization and cross fertilization?
HOMEWORK: textbook read pages Explain the difference between true breeding and hybrid.
2- Define P generation, first filial generation and second filial generation.’
3- Explain why Mendel studied pea plants

22. Gregor Mendel’s experiments: Fertilization
Self-fertilization: egg in the flower is fertilized by the sperm of the same flower
Cross-fertilization: sperm from a foreign plant fertilizes an egg

23. Gregor Mendel
Used both the processes of self fertilization and cross fertilization to experiment on pea plants
This helped him develop his basic laws of heredity

24. Definitions
True breed or pure breed: plants with a trait such as purple flowers that is always inherited by all offspring
Can only produce one type of gamete
HYBRID:
The offspring of a cross fertilization
2 parents similar to sexual reproduction
Can produce different types of gametes

25. Definitions continued
Monohybrid cross: tracks one trait at a time
Ex: flower color
Dihybrid cross:

26. Mendel’s work Self fertilized true breed parents for many generations
All offspring gave the same results
Cross fertilized true breeds to get an F1 generation
Self fertilized the F1 and observed the F2 generation

28. Mendel’s Experiment Parent Generation (P1):
Purple true breed X White true breed
First Filial (F1)
100% Purple flowers Self fertilize
Second Filial (F2)
75% Purple: 25% White
3:1 ratio

29. Why were all the F1 generation flowers purple?
Purple Trait is obviously dominant over the white trait
The white trait was hidden but not gone

30. Why were some of the F2 generation part purple and part white?
The F1 parent was carrying the white trait but it was masked or hidden.
White is recessive to purple

31. Just from looking at these results, what can Mendel conclude?

32. Mendel’s Conclusions from a monohybrid cross
1- Copies of inherited traits must be separated when gametes are formed
2- When present in 2 forms one form is dominant over the other
3- the recessive trait will show itself when present in two copies

33. Tuesday 4/22/14

34. From these experiments, Mendel concluded:
Traits are determined by physical unit that come in pairs (he did not know these would later be called alleles)
Gametes separate and carry only 1 allele(copy) for each gene
The particular allele that ends up in a gamete is caused by chance
One allele is dominant and one recessive
True-breeding organisms have the 2 copies of the same allele (homozygous)

35. AIM: How can we predict the possible genotypes and phenotypes of offspring?
DO NOW: 2- if I cross fertilized a true breed green seed pea plant by a true breed yellow seed pea plant, what phenotypes do I expect to get?
HOMEWORK: Textbook read pages answer questions 1,2,3 on page 275

36. Create a list 7 traits observed by Gregor Mendel 1- Flower color
2- Plant size
3- Flower position
4-Seed color
5- shape of pod
6- Pod color
7- Seed shape
Each of these traits has a dominant and a recessive phenotype

38. Seed color Dominant phenotype: green Recessive phenotype: yellow
Genotype Phenotype GG Gg gg

39. Mendel had no idea about the following
We know we get 2 copies of genes
1 from sperm
1 from egg
Allele: is a copy of a gene
Homologous chromosomes carry alleles

41. Monohybrid Cross
Tracked one (mono) trait at a time

42. Mendel’s work
Cross fertilized two true breed parents that displayed opposite traits.(P or Parental generation)
All First filial or F1 offspring were purple

43. What happened to the white color?

44. Self-fertilized F1
Second filial or F2 generation yielded about ¼ white and ¾ purple
So the white flower color was not lost just masked

45. Self-fertilized F2
Saw that all white flowered F2 yielded all white F3 but the purple still yielded 3:1 ratio of purple to white
Therefore the white allele was not lost but rather hidden or masked by the purple allele

46. From these experiments, Mendel concluded:
Traits are determined by physical unit that come in pairs (he did not know these would later be called alleles)
Gametes separate and carry only 1 allele for each gene
The particular allele that ends up in a gamete is caused by chance
One allele is dominant and one recessive
True-breeding organisms have the 2 copies of the same allele

47. Thursday 4/24/14
AIM: why did Mendel decide to perform a dihybrid cross?
DO NOW: Let A represent the allele coding for terminal flowers and a axial flowers. Complete the following table:
HOMEWORK: text read pages answer questions 3 and 4 page 275
Genotype
Phenotype AA
Homozygous dominant
terminal Aa
Heterogygous aa
Homozygous recessive
axial

48. Mendel’s Law of dominance
When two different alleles are present, the dominant alleles gives the resulting phenotype and masks the trait of the recessive allele
However the recessive allele is still present
Homozygous Dominant and heterozygous organisms display the same phenotype
Recessive alleles are only displayed when present in 2 copies
Homozygous recessive

49. Mendel’s Law of segregation
Pairs of alleles on homologous chromosomes separate from each other during gamete formation
Gametes receive only one allele from a homologous pair.
Fertilization produces offspring with a copy of one allele from mom and one from dad

53. Mendel’s Hypothesis were consistent with his results
2 plants that look alike may actually carry different combinations of alleles
Genotype: the combination of alleles carried by an organism
Homozygous Dominant: AA
Heterozygous: Aa
Homozygous recessive: aa
Phenotype: The physically observable feature
So a homozygous dominant individual and a heterozygous individual will display the same phenotype but have different genotypes
The only way for the recessive phenotype is observed is if the individual is homozygous recessive

54. Mendel was not satisfied
He wanted to see if alleles could be inherited together
He asked himself are all round seeds yellow?
Are all green seeds wrinkled?
He looked at two traits at the same time
Dihybrid cross
Ex: seed shape and seed color
His results were inconclusive which means all round seeds were not yellow all wrinkled seeds were not green

55. In order to investigate, Mendel performed a dihybrid cross
Dihybrid cross: crossed plants that differed in more than one trait
Specifically Mendel looked at seed shape and seed color

56. Cross Fertilization Homozygous Dominant Homozygous recessive
ALL heterozygous
Dominant shape
Recessive color
Dominant color
Recessive shape
Both Dominant traits
Both recessive traits

57. R-round
r-wrinkled
Y-Yellow
y-green

59. Friday 4/25/14

60. Mendel’s dihybrid cross
P: true breed RRYY(Round Yellow) x rryy(wrinkled green)
All F1: RrYy (Round Yellow)
Allowed F1 to self-fertilize which yielded the following phenotypic ratio
F2: 9:3:3:1 ratio of
Round Yellow: Round green: wr Yellow: wr,green

61. F1: Self Fertilization

62. F1: self fertilization

64. Display of all possible genotypes

70. Law of independent assortment
Multiple traits are inherited independently of each other because alleles of genes are distributed independently during gamete formation
Genes found on different chromosomes assort independently of each other during gamete formation
Genes are inherited independently

71. What was the major question Mendel was trying to answer when he performed his dihybrid cross?
Mendel asked himself if two characteristics were inherited together.
Specifically is seed color inherited with seed shape?

72. Testcross
Cross fertilize a dominant phenotype plant with a homozygote recessive plant
WHY?
Purpose is to analyze the ratio of the offspring
This will tell us the parents genotype
(homozygous dominant or heterozygous)

73. What do we call this type of cross ad why would we perform it?

74. Test cross
Determines the genotype of a dominant displayed phenotype

75. Testcross
The only way to display the recessive phenotype is to have a homozygous recessive genotype
After performing a testcross, If the f1 offspring display ALL dominant phenotypes then I know the Parent genotype is homozygous Dominant.
If the offspring display 50% dominant phenotype and 50% recessive than the Parental genotype is heterozygous