Homework 1 – Genetic Crosses (Differentiated)
If Marge and Homer both have blue eyes, what colour eyes would you expect Bart to have?
If Marge has blue eyes and Homer’s eyes are brown, what colour eyes could Bart have?
How Can we Work it Out?
Each possible child (offspring) gets one letter from each parent. What four combinations could Marge and Homer make?
b = blue eyesB = brown eyes
Parents’ genes bb BB
Remember, when we have genes for two different eye colours, the capital letter wins.
F = frecklesf = no freckles
Parents’ genes Ff ff
Homework 1 – Genetic Problems
Answer each of the following questions as completely as possible. Show punnett squares and all ratios requested.
- Explain the difference between the concepts of genotype and phenotype.
- Explain why there can NOT be a heterozygous recessive organism.
- List at least five reasons Mendel was successful with using the pea plant forgenetics work. Research required.
- Use the information below to assist you in answering questions 4 and 5 which follow.
** In guinea pigs, black fur is dominant over white fur.
- What phenotype (coat colour) would each of these guinea pig genotypes result in:
a. Bb b. BB c. bb
- Use a Punnett Square to solve this cross in guinea pigs --- BB x Bb showing the F1 phenotypic and genotypic ratios.
- Huntington disease is a dominant lethal condition which usually results in the death of its victims in middle age. Show the genotypic and phenotypic ratios of a cross between a normal individual and a heterozygous individual for Huntington disease.
Huntingtons=Hh Huntintons=HH Normal=hh
- Since heterozygous and homozygous individuals with Huntington's both die due to the condition, explain why the Huntington allele is not eliminated from the human population.
Homework 2 - Mitosis
Make a comic flip book to show the stages of mitosis (including descriptions). Be creative and have the cells brightly coloured.
Homework 3 - Therapeutic value of stem cells
Read the article in the Scotland on Sunday.
© The Scotsman Publications Ltd.
Scientists study stem cells for many reasons, for example to better understand the cell cycle and to develop and test new ways to treat patients.
- Give one more reason why Dr Tilo Kunath is doing this research.
In 2006, scientists discovered a new technique. They can now take a cell from a body, for example a skin cell, and turn it into a cell that behaves like stem cells from an embryo.
- What are these special types of cells called?
- Why is Dr Tilo Kunath keen to use this technique to study Parkinson’s?
- Scientists are very excited about this new technique. Why do you think that is?