1. Today you need pencil and science notebook
Learning target – I will be able to define words related to DNA and genetics.
Question –
What is mitosis?
Cell division that ensures each daughter cell gets exact copies of parent cell DNA.

2. Using a Punnett Square

3. What is a PUNNETT SQUARE?
A tool to predict the probability of certain traits in offspring that shows the different ways alleles can combine
A way to show phenotype & genotype
A chart that shows all the possible combinations of alleles that can result when genes are crossed

4. Trait – physical characteristics of an organism
Examples?
Blue eyes, brown hair, tall plants
Offspring – the next generation of the parents

5. More PUNNETT SQUARE Vocabulary?
Punnett Square – a tool to predict the probability of a trait
Alleles –various form of a gene, ex….
Genotype – genetic code, represented by letters. Ex. BB, Bb, bb
Phenotype – visible genetic trait. Ex. tall
Gene – unit of heredity with a specific location on the DNA
Heredity – passing of gene from parent to offspring

6. Letters stand for dominant and recessive alleles
An uppercase letter stands for a dominant allele. ex. B
Lowercase letters stand for recessive alleles. Ex. b

7. What is a PUNNETT SQUARE Vocabulary?
Recessive – only expressed in phenotype when two identical copies of alleles are present.
Ex. bb or cc
Dominate – always expressed in phenotype, even when alleles do not match.
Ex. BB, Bb, or CC, Cc

8. Question –
What does recessive mean?
Trait is masked by a dominant allele
What does dominant mean?
Trait always shows up in the organism

9. Hybrid – a mixture of genes. Ex. Bb
Purebred – pure genes. Ex. BB, bb
Homozygous – purebred, pure genes, both alleles match. Ex. BB, bb
Heterozygous – hybrid, mixture of genes, alleles do not match. Ex. Bb

10. Learning target – I will be able to use a Punnett square to predict the results of a simple genetic cross.
Questions –
What is a genotype?
genetic code, represented by letters
What is a phenotype?
The visible genetic (physical) trait

11. Using a PUNNETT SQUARE
To set up a Punnett square, draw a large square, and then divide it into 4 equal sections (also squares). It should look something like this:

12. Rr x rr Using a PUNNETT SQUARE
Now you need to know the genotypes of two parents.
Red flowers are dominant to white flowers.
For example, a red flower (genotype Rr) and a white flower (genotype rr).
Rr x rr

13. Using a PUNNETT SQUARE
Place one of the genotypes on top, and one on the left. You should get a something similar to this:

14. Using a PUNNETT SQUARE Rr rr Rr rr
Take each letter in each column and combine it with each letter from each row in the corresponding square. Rr rr Rr rr

15. Using a PUNNETT SQUARE You should now have a picture close to this:
The 2 letter combinations are the genotypes of the offspring.

16. genotypes For this cross, they are: Rr, Rr, rr, and rr genotypes.
What are the possible phenotypes?
Red and white

17. Percentages and ratios
For this cross, they are:
Rr, Rr, rr, and rr genotypes
So it is possible for us to determine the probability (chance) that a flower will have a red phenotype (2/4 or 50%) or a white phenotype (2/4 or 50%)

18. Let’s do another Punnett Square
Draw another large square, and then divide it into 4 equal sections (also squares).

19. Let’s do another Punnett Square
Parent’s genotpyes: Tt x Tt
Tall is dominant to short
Genotypes of offspring:
TT =
Tt =
tt = T t TT Tt T Tt tt
Phenotype of offspring:
Tall =
Short = t

20. Let’s do another Punnett Square
Parent’s genotpyes: Tt x Tt
Tall is dominant to short
Genotypes of offspring:
TT = 25%
Tt = 50 %
tt = 25% T t TT Tt T Tt tt
Phenotype of offspring:
Tall = 75%
Short = 25% t

21. PP x pp Using a PUNNETT SQUARE
Now you need to know the genotypes of two parents. Purple is dominant to white.
For example, a purple flower (genotype PP) and a white flower (genotype pp).
PP x pp

22. Using a PUNNETT SQUARE P P p p
Place one of the parents on top, and one on the left. You should get a something similar to this: P P p p

23. Using a PUNNETT SQUARE P P p Pp Pp p Pp Pp
Take each letter in each column and combine it with each letter from each row in the corresponding square. P P p Pp Pp p Pp Pp

24. Using a PUNNETT SQUARE
The two-letter combinations are the possible genotypes of offspring
They are: Pp, Pp, Pp, Pp genotypes
From this it is possible to determine the probability (chance) that a flower will have a purple phenotype (4/4 or 100%) or a white phenotype (0/4 or 0%)

25. Homozygous/Heterozygous
Ho / He
Cross a homozygous dominant tall plant with a homozygous recessive short plant.
Dominant trait = tall
Recessive trait = short
T = tall
What letters would you use to represent this cross?
t = short

26. What is the genotype of a homozygous dominant tall plant? TT
What is the genotype of a homozygous recessive short plant? tt
TT x tt
Genotype
% TT
% Tt
% tt
t t
100 Tt Tt
T T
Phenotype
% tall
% short
100 Tt Tt

27. 2. Cross a heterozygous brown haired rabbit with a homozygous recessive white haired rabbit.
What letters would you use to represent this cross?
Dominant trait = brown hair
Recessive trait = white hair
B = brown
b = white

28. What is the genotype of a heterozygous brown haired rabbit? Bb
What is the genotype of a homozygous recessive white haired rabbit? bb
Bb x bb
Genotype
% BB
% Bb
% bb
b b 50 Bb Bb B b 50
Phenotype
% brown
% white 50 bb bb 50

29. 3.. Cross a homozygous dominant long haired guinea pig with a heterozygous long haired guinea pig.
What letters would you use to represent this cross?
Dominant trait = long hair
Recessive trait = short hair
L = long
l = short

30. What is the genotype of a homozygous dominant long haired guinea pig? LL
What is the genotype of a heterozygous long haired guinea pig? Ll
LL x Ll
Genotype
% LL
% Ll
% ll 50
L l 50 LL Ll L
Phenotype
% long
% short
100 LL Ll

31. Learning target – I will be able to use a Punnett square to predict the results of a simple genetic cross. Rate yourself again, 1, 2, 3, or 4. Hold up your whiteboard.

32. 4. Cross a heterozygous wrinkly elephant with another heterozygous wrinkly elephant.
What letters would you use to represent this cross?
Dominant trait = wrinkly skin
Recessive trait = smooth skin
W = wrinkly
w = smooth

33. What is the genotype of a heterozygous wrinkly-skinned elephant? Ww
Ww x Ww
Genotype
% WW
% Ww
% ww 25
W w 50 W w WW Ww 25
Phenotype
% wrinkly
% smooth 75 Ww ww 25

34. Today you need packet, pencil and notebook
Learning target – I will be able to identify some of my own traits.
Questions-
What is a Punnett square?
a tool to predict the probability of a trait showing up in offspring

35. Using a PUNNETT SQUARE Rr rr Rr rr Parent genotypes -Rr x rr
Take each letter in each column and combine it with each letter from each row in the corresponding square.
RR = 0%
Rr = 50%
rr = 50%
Dominant = 50%
Recessive = 50% Rr rr Rr rr

36. Volunteer for some examples from the packet
Brain pop first
Read pages 101 – 103 silently,
Discuss – what are acquired traits and what are inherited traits?
WS – complete the chart.

37. A plant that is homozygous dominant for round seeds is crossed with a heterozygous plant. What is the probability that the offspring will have wrinkled seeds?
R = round
r = wrinkled
RR x Rr
Genotype
% RR
% Rr
% rr 50
R r 50 R RR Rr
Phenotype
% round
% wrinkled
100 RR Rr

38. Today you need pencil, notebook.
Learning target – I will be able to design a model of an offspring using genotypes of the parents.
Question – What are alleles?
Different forms of the same gene, ex. Tall and short plants
Agenda –
Turn in homework
Get quiz back
Start lab on page 108.
Clean up

39. Parent genotypes: Rr x rr. Round seeds (dominant) and wrinkled seeds.
What is the probability that the offspring seeds will be round?
50%
What is the ratio of round seeds to wrinkled seeds?
2 to 2, 2:2

40. Parent genotypes: Rr x rr. Round seeds (dominant) and wrinkled seeds.
What is the probability that the offspring seeds will be round?
50%
What is the ratio of round seeds to wrinkled seeds?
2 to 2, 2:2