Having some issues

[Guest Emma Jacob]

I am new to this to bare with me...

I having issues with this question:

1. In pea plants, a plant that breeds true for yellow pods was crossed with a plant that breeds true for green pods. 200 seeds were harvested, and they were planted the following year. All of those progeny had green pods.

 

a. Name the characteristic (gene), name the alleles (forms), and designate abbreviations.

b. Draw Punnett square for the cross above

c. Draw a Punnett square for the cross of the F1 progeny to one another

d. Draw a Punnett square for a cross where one of the F1 is crossed back to the yellow pod true-breeder. What is this cross called? Why is it called that?

 

Its driving me insane My professor gave one lecture and is testing us on Fri..

Help...

[Schrödinger's hat]

For the right terms you'll have to go to your textbook or someone versed in biology, but I can explain the concepts.

 

You have a gene, call it Color, it has the yellow (y) form and the green (G)

When we breed a YY with a gg (plant that breeds true yellow w/ true green) we get the following possibilities

| G G

y yG yG

y yG yG

Because each parent had two of the same gene, there was only one possibility.

We can also know that the green pods are dominant because the all the hybrids had green and not yellow pods.

For the F1 cross with another F1, we have four possibilities, I'll fill in the first two for you:

| y G

y yy yG

G

 

Same principle for d

 

Each row in the square represents a possibility from one parent

each column represents a possibility from the second parent

 

For the names you'll have to do a bit of research, pretty sure the pea colors thing should be in most textbooks (or try wiki).

Edited August 24, 2011 by Schrödinger's hat

[Guest Emma Jacob]

For the right terms you'll have to go to your textbook or someone versed in biology, but I can explain the concepts.

 

You have a gene, call it Color, it has the yellow (y) form and the green (G)

When we breed a YY with a gg (plant that breeds true yellow w/ true green) we get the following possibilities

| G G

y yG yG

y yG yG

Because each parent had two of the same gene, there was only one possibility.

We can also know that the green pods are dominant because the all the hybrids had green and not yellow pods.

For the F1 cross with another F1, we have four possibilities, I'll fill in the first two for you:

| y G

y yy yG

G

 

Same principle for d

 

Each row in the square represents a possibility from one parent

each column represents a possibility from the second parent

 

For the names you'll have to do a bit of research, pretty sure the pea colors thing should be in most textbooks (or try wiki).

 

hmmm Thanks a lot.... really appreciated