Genetics Test Retake Packet

Name ______Date ______Period _____

Genetics Test Retake Packet

Biology Textbook: Chapters 11 and 14

Accelerated Biology Textbook: Chapter 9

1. What type of inheritance is shown when you cross a red cow (RR) and a white bull (WW), which gives a roan offspring (RW)? ______

2. What type of offspring does selective breeding produce? ______

______

3. The principles of probability can be used to predict ______

______

4. P generation: Cross a true-breeding tall plant with a true-breeding short plant.

b. Are all of the offspring in the F1 generation homozygous or heterozygous? ______

c. Do they have the same genotype as either of the parents? ______

d. Do they have the same phenotype as either of the parents? ______

e. Cross two of the offspring from the F1 generation.

f. What is the probability that a plant in the F2 generation will be tall? ______%

5. Organisms with two identical alleles for a particular trait are said to be ______.

6. Organisms with two different alleles for a particular trait are said to be ______.

7. In hamsters, black fur is dominant and white fur is recessive.

a. Identify the alleles:

B = b =

b. Cross a heterozygous hamster with a hamster that is homozygous dominant.

c. What is the genotypic ratio? ______

d. What is the phenotypic ratio? ______

8. Can a punnett square show the actual results of a genetic cross? ______Why or why not? ______

______

9. How many different allele combinations would be found in the gametes produced by a plant with the following genotype, GGYy. (Hint: use FOIL) ______

10. a. Cross the following heterozygous parents: Nn x Nn

b. How is it possible that these parents could get an offspring with the genotype, nn? (Check all that apply)

______Principle of Dominance: some alleles are dominant and some are recessive

______Principle of Segregation: two alleles (Nn) are segregated from each other so each gamete carries only a single copy of each gene (N or n).

______Principle of Independent Assortment: genes for different traits (seed color & seed shape for example) can segregate independently during gamete formation.

11. What is the ultimate source of genetic variability? (page 320) ______

12. Write the two genotypes for the blood type A phenotype ______or ______

13. Write the two genotypes for the blood type B phenotype ______or ______

14. What is the genotype for blood type AB? ______

15. What is the genotype for blood type O? ______

16. What could be possible blood types of the offspring if a man had blood type A and a woman had blood type O? (Remember: type a has 2 possible genotypes à make two punnett squares)

Possible offspring blood types: ______

17. How is sickle cell caused? ______

______

18. Why are people heterozygous for sickle cell usually healthy?

19. What is the probability that a human offspring will be female? ______%

20. What is the probability that a human offspring will be male? ______%

21. Many sex-linked genes are located on which chromosome? ______

Why? ______

22. Why is colorblindness more common in males than in females? ______

______

23. Which of the sex chromosomes sometimes forms a Barr Body? ______

24. Does a Barr Body form in males or females? ______

25. What sex would a calico cat be if it had three colors: white, orange, and black? ______

26. For a trait associated with the autosomal chromosomes, not the sex chromosomes, how many recessive alleles for a trait must an organism inherit in order to show that trait? ______

27. In a two trait cross, in which both parents are heterozygous for each trait, what would the phenotypic ration always be? ____:____:_____:_____.