## MarieSoLoved 2 years ago i dont understand this?

1. MarieSoLoved

13. Complete the monohybrid cross below the example using the directions for completing the Punnett Square in the reading and the example below. Then, list the genotypic ratio and describe the offspring. Be sure to remember that the capital letter is dominant. Example: A green pea plant (GG) is being crossed with a green pea plant (Gg) yellow is the recessive color. G G GG GG Gg Gg G genotype = 2 GG : 2 Gg : 0 gg g phenotype = 4 green pea plants : 0 yellow pea plants A green pea plant (Gg) is crossed with a yellow pea plant (gg). Complete the Punnett Square using THESE genotypes. Genotype: ___ GG : ____ Gg : ____ gg Phenotype: ____ green plants : ____ yellow plants

2. MarieSoLoved

they have bin boxes were the gs r .

3. MarieSoLoved

this is very comfussing

4. tafkas77

Oh, I can definitely help you with this. Let me just finish up with another student real quick, okay?

5. MarieSoLoved

ok thx :)

6. tafkas77

Okay, I am here. :) Please give me just a moment to type this stuff up. :)

7. tafkas77

So your box looks like this, right? Just a little neater... :) |dw:1363383193534:dw|

8. MarieSoLoved

yes

9. tafkas77

Okay. This is called a Punnett square. This will help you find out what genes an organism will have and what it will look like, based on the genes the parent gives it. Punnett squares usually test for one gene (a monohybrid cross), (in this case color) but they can test for more than one at the same time. Does this make sense? If so, I can move on.

10. MarieSoLoved

yes

11. tafkas77

Okay, great. :) To figure out a Punnett square, you have to realize that everything is based on probability (yes, math). To get a punnett square filled out, we have to multiply the alleles together to figure out gene probability. But don't worry - it's not too hard once you get the knack of it. :) Here's the first one: |dw:1363383633186:dw| Do you get this?

12. tafkas77

In that first box, I multiplied G * G to get GG

13. MarieSoLoved

|dw:1363383742031:dw|

14. tafkas77

Perfect! :D You got it! Now do you feel comfortable moving on to the next part?

15. MarieSoLoved

yes :)

16. tafkas77

great! Now we do the probability part. Looking at the cross, we can see that ALL of then contain the dominant allele, "G" That means that there is a 100? chance that the flowers will have the dominant color, and a zero percent chance that they will have the recessive (g) color. We can write the ratio like this: 2:2, since there IS a 50% chance that they could *have* the (g) in their genes, even though they won't use it. Does that make sense? |dw:1363384226703:dw|

17. MarieSoLoved

oh yes

18. MarieSoLoved

phenotype = 4 green pea plants : 0 yellow pea plants

19. tafkas77

Beautiful! :D

20. MarieSoLoved

:)

21. tafkas77

So, do you think you could do part 2 on your own, or would you still like me to help you?

22. MarieSoLoved

imma try on my own frist then c how i do .

23. tafkas77

Okay, great. :) Let me know if you get stuck or would like me to double-check anything. :)

24. MarieSoLoved

|dw:1363384842981:dw|

25. tafkas77

Wait a minute... A green pea plant (Gg) is crossed with a yellow pea plant (gg). Complete the Punnett Square using THESE genotypes. your square should look like this: |dw:1363385208090:dw|

26. MarieSoLoved

oh its crossed lol oh ok

27. MarieSoLoved

Gg.....gG gG.....gG

28. tafkas77

You're going to want to make sure the multiplication is right. Also, you may give your science teacher a heart attack if you put the dominant allele last! The dominant (capital letter) allele ALWAYS goes first. :) |dw:1363385814570:dw| Do you think you could get those now?

29. tafkas77

Also, if it helps, this is how you do the genes. So, let's the mommy flower is gg, and the daddy flower is Gg. Mommy goes on the side, and Daddy goes on top: |dw:1363386017181:dw| lol it sounds kind of sill to put it that way, but do you get it?

30. tafkas77

*silly

31. MarieSoLoved

so..it Gg..gg at the bottom

32. tafkas77

Perfect. :) And now... Genotype: ___ GG : ____ Gg : ____ gg Phenotype: ____ green plants : ____ yellow plants

33. MarieSoLoved

gg=0 Gg=2 gg=2 phenotyp:=2 yelow plant =2

34. MarieSoLoved

GG=0

35. MarieSoLoved

GG=0 Gg=2 gg=2

36. tafkas77

For the genotype....Not quite... Oh, never mind, I see you changed it. :) Great job! :D

37. MarieSoLoved

i did it right?

38. tafkas77

Yes! :D

39. MarieSoLoved

YAY thx so much:)

40. tafkas77

Oh, you're welcome! You did an awesome job. :) *gives extra medal*