HW solutions - Honors and Regular

Hey all,

Here are your solutions. Enjoy!

Regular Class:
p. 315, 3-5, 7-9, 23

3. B
4. C
5. A
7. B
8. C
9. B

23. There are many different types of mutations - gene mutations involve a change in one or more nucleotides in a single gene. Chromosomal mutations are changes in the structure or number of whole chromosomes. Insertion mutations add one or more bases to a sequence. Deletions remove one or more bases from a sequence. Substitution mutations switch one base into another. Inversion mutations reverse the order of a sequence of two or more bases.

p. 269: #2, 4, 5
2. Punnett squares are used to predict and compare the possible outcomes (genotypes) that could result from a cross.

4. Genotype is the specific pair of alleles for a gene that an organism has (Bb or bb); phenotype is the physical trait or characteristic that the organism displays. (Brown hair or blond hair)

5. The cross will be tt x Tt, which results in genotypes Tt, Tt, tt, tt. This means 50% of the plants will be tall.

Honors:

p. 274 - 1, 3

1. During gamete formation, pairs of alleles for different traits segregate (separate) independently from each other. For example, the alleles for seed type (R or r) and seed color (Y or y) in pea plants are independent from each other. This means that in both genotypes RrYY and Rryy, the seed type will be round, while the seed color changes from yellow to green.

3. In incomplete dominance, two alleles combine to produce a single phenotype that is "in between" the dominant and recessive. The example used in class is the snapdragon flower, which is pink for the heterozygous case of Rr. In codominance, each allele is expressed separately in the same organism. For example, cats expressing codominant traits of brown (B) and orange (O) fur might result in fur that is BOTH orange and fur in the genotype BO.