5.4 Inheritance

5.4 inheritence
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BiologieMiddelbare schoolvwoLeerjaar 2

This lesson contains 13 slides, with interactive quizzes and text slides.

time-iconLesson duration is: 45 min

Items in this lesson

5.4 inheritence

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alleles: varieties of one gene
on each chromosome you
have an allele of a gene.
For example eye colour:
blue allele or brown allele

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Is it a gene or an allele?
skin colour
curly hair
flower colour
blue eyes
blood type
type A blood
hair type
short wings in a fruit fly

Slide 4 - Drag question

Oliver says: 'all humans have the same genes, but not the same alleles'. Charley says: 'all humans have the same alleles, but not the same genes'.
Who is right?
They both are
They are both wrong

Slide 5 - Quiz

dominant and recessive
genotype is written down in letters.
for example
brown eye color A
blue eye color  a
genotype Aa    fenotype = brown eyes

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dominant, recessive alleles
dominant A    'wins'
recessive a 'looses'
possible genotypes
AA  => homozygous dominant  => brown eyes (fenotype)
Aa => heterozygous => brown eyes (fenotype)
aa => homozygous recessive => blue eyes (fenotype)

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mendelian inheritence
we can calculate probable percentages of offspring with different genotypes/fenotypes
we use a Punnet square

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Some fruit flies have curly wings instead of normal wings (see the pictures below). Answer the questions using the letter R for normal wings and r for curly wings:

normal wings                 curly wings
a. Which is the dominant allele? Give the letter and the characteristic.
b. Which is the recessive allele? Give the letter and the characteristic.
c. What is the genotype of a fruit fly that is homozygous for curly wings? 
d. Which two genotypes will result in the ‘normal wings’ phenotype?
e. Can a fruit fly with curly wings have a heterozygous genotype? Explain your thinking.

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Check out the steps on page 136.  

Let's practice! A guinea pig is homozygous for blue fur. This guinea pig mates with a guinea pig with yellow fur. Use a punnet square to determine the probability of one of their offspring having blue fur.

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