# Science Notes

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• You can us the Principles Probability is the predict the results of a particular event.Probability is a number that describes how likely it is that an event will occur
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• What does probability have to do with genetics?﻿ In a Genetic cross, the allele that each parent will pass off on to it's offspring is based on Probability. Ex. Their are 4 possible combinations of alleles. The probability that an offspring will be RR is 1 in 4 ,or 25%. The probability that an offspring will be rr is also 1 in 4 ( 25%) but the probability that an offspring will be Rr is 2 in 4, or 50%.
• The spinner has a 50% probability that the spinner will land on the thumbs up
• ﻿How can you predict all the Combinations of alleles?
• The way that you can predict all the combinations of alleles is by using a Punnett Square.
• Step 2: Write the Male's parent alleles along the top and the female parent's alleles along the left side﻿
• ﻿Step 1:Make a square with 4 sections
• Copy all the Female parent's alleles into the box at their right and copy the male's alleles into the boxes beneath them .
• The completed square shows all the possible allele's combinations ﻿
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• ﻿A Punnett Square is a Chart that Shows all the possible combinations of aelles that can result from a genetic cross
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• Phenotype and genotype are 2 useful terms geneticists use.An organism's phenotype is its physical appearance, or visible traits.An organism's genotype is its genetic makeup, or allele combinations
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• In some cases alleles an inheritance pattern called codominance ﻿exists. In codominance the alleles are neither dominant or recessive,so both alleles are expressed in the offspring.
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