Biology 12 Genetics Quiz Name _____________________
1. This is about Mendel. Explain two ways that he used good science in his genetics experiments with pea plants. 4 points
2. Please show your work for these questions.
a. Suppose that you toss a coin 4 times. Each time a head comes up. What is the chance that the next toss is also a head? 1 point
b. What is the chance of tossing 3 heads in a row? 1 point
c. Suppose that you toss two coins at the same time. What is the chance of getting two tails? 1 point
3. Two black guinea pigs are crossed together numerous times – approximately 75% of the offspring are black and 25% are white.
a. Which trait is dominant? 1 point.
b. Which of Mendel’s laws is illustrated by the result? 1 point.
c. Use a Punnett square to show the cross – also give the expected genotype ratio. 2 points.
4. Suppose that you wanted to determine the genotype of the black guinea pig offspring from the question above. Describe or show the easiest way to do so – what is this type of cross, called? 2 points
5. These questions are about two trait crosses
a. A heterozygous tall pea plant with white flowers (Ttpp) is crossed with a short pea that is heterozygous for purple flower colour. (ttPp) Show the expected phenotype ratio for this cross. 4 points.
b. Show the results of a cross between two heterozygous tall, purple flowered plants. 4 points.
c. Which one of Mendel’s laws is being illustrated here? 1 point
6. Suppose that two individuals that are heterozygous for three traits (AaBbDd). Show your calculations.
a. Determine the probability of having an offspring that is homozygous recessive.
b. What proportion of the offspring are expected to show the dominant phenotype?
7. How many different gametes could one of the parents in question #6 produce?
List the gametes that could be formed.