Download Honors Biology - Genetics Study Guide

Honors Biology - Genetics Study Guide
Name:_______________________
1. Explain the difference between the following & provide an example of each:
a. genotype & phenotype
b. homozygous & heterozygous
c. recessive & dominant
d. true breed & hybrid
e. autosome & sex chromosome
f. incomplete dominance & codominance
g. allele vs. gene
h. law of segregation vs. law of independent assortment
i. polygenic inheritance vs. multiple alleles (be sure to not only tell how these are different but examples
in the human body where you would find each type of inheritance)
j. homologous chromosome (just define)
k. carrier (just define)
2. What type of cross always results in all heterozygous offspring?
3. What type of cross results in a 3:1 phenotypic ratio?
4. If you cross a red flower with a white flower, what will be the genotype and phenotype ratios if the gene
exhibits incomplete dominance?
5. If you were to cross two roan (red and white) cattle, what would be the chances of the offspring having a
red phenotype (assuming the gene exhibits codominance)?
6. What would the phenotypic ratio of the offspring be if you were to cross DdEe x DdEe?
7. In the dihybrid cross AaBb x AaBb, how many different phenotypes are possible in the offspring?
8. In the dihybrid cross AaBb x AABB, what are the possible genotypes for the offspring?
9. In a monohybrid cross, how many phenotypes are possible if the parents are both true breeds? What if
they are both heterozygous?
10. What fraction of the offspring would have the genotype aabbcc if we were to cross AaBbCc x AaBbCc?
11. If a female that is colorblind (a sex linked trait) and is crossed with a normal male, what genotypes and
phenotypes would be possible in the offspring?
12. If a female is a carrier for colorblindness and the male is colorblind, what percentage of their offspring
would be colorblind?
13. If a female's father was colorblind, and only one of her two sons is colorblind, what is her genotype?
14. Why are sex linked traits expressed more in males? Why can't males be carriers of a sex linked trait?
15. If a trait for free earlobes is autosomal recessive, and a female has free earlobes, what is her genotype?
What is her phenotype?
16. Can a male be a carrier of an autosomal recessive disorder? Why?
17. Is it possible for a male or female to be a carrier of an autosomal dominant disorder? Why?
18. What are the possible genotypes for the following blood types?
Blood
Genotype
Type
A
B
AB
O
19. Could a child with type O blood have a father with type AB blood? Why?
20. If a woman with type A blood had a child with a man that had type B blood, what are all the possible
blood types that the child could have?
21. What types of blood can the following individuals accept in a blood transfusion?
Blood
Types they may
Types:
receive:
A
B
AB
O
22. Why can't people with type O blood receive blood from anyone but other with type O?
23. What are the symbols for each of the following on a pedigree chart:
Normal Female
Carrier Female
Female with disorder
Normal Male
Male with disorder
24. A cross was done between 2 flowers exhibiting incomplete dominance and all of the offspring were
pink.
a. What are the genotypes of the parents?
b. What are the phenotypes of the parents?
c. Draw a Punnett square showing this crossing.
Use the pedigree below to answer questions 25-28
25. Label the generation and individual numbers for the pedigree.
26. Write the genotype for each individual under their symbol. If there is not enough information to
determine the phenotype of an individual then put a ? for the 2nd allele.
27. Individual 1 in generation III mates with a female who is a carrier for colorblindness.
a. Draw this female into the pedigree.
b. Create a Punnett square predicting the offspring of these 2 individuals.
c. What percentage of their offspring would be expected to be colorblind?
28. Individual 3 in generation III mates with a normal male.
a. Draw this male into the pedigree.
b. Create a Punnett square predicting the offspring of these 2 individuals.
c. What percentage of their offspring would be expected to be colorblind?
29. What happens in metaphase of meiosis that explains the laws of segregation and independent
assortment?