ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Biology => Topic started by: belinda on August 19, 2008, 09:28:56 am
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Heredity and Environment..
we did an experiment on the relative effects of heredity and environment on barley seeds.
- i saw that the effect of the environment on phenotypes can lead to characteristics that may assist or be detrimental to the survival of organism. eg Albinism which is of no survival advantage to plants
-i understand, that Green is the dominant trait to albino in tobacco leaves. the parents used were both heterozygous for green/ albino Q) how do we know they were heterozygous?
a ratio of 3:1 resulted in the light environment..however in the dark the genotype couldnt express itself, due to a lack of light/chlorophyl production. therefore the seedlings in the dark remained albino..
when placed in the light ( after being in the dark) the phenotype will change quickly to green in those seedlings possessing the gene for gree. this should restore the 3:1 ratio?
any1 done this experiment????? am i on the right track?????
please help..i dont want to stress tooo much
my teacher is giving us questions on this..any1 have any idea of the sorts of q??????
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(let G = green and g = albino)
The parents will HAVE to be heterozygous, as if you set up a cross only Gg x Gg would give a 3:1 ratio green to albino.
G g
G GG (green) Gg (green)
g Gg (green) gg (albino)
But if they are in the dark, the gene that produces chlorophyll will not be expressed it seems, making all the offspring appear albino, despite may having green genotype.