PrincetonHigh SchoolBiology 1
Science DepartmentMrs. Skalecky
Review Sheet: Genetics
I. What is genetics? (Chapter 9.1)
A. What is heredity?
B. Who was Gregor Mendel? What organism did he use in his investigations? Why did he use this organism?
II. Mendel’s Laws (Chapters 9.1 and 9.2, Lab 29)
A. What is the Law of Dominance
1. What is a dominant trait? Symbol for key?
2. What is a recessive trait? Symbol for key?
3. What is a genotype?
4. What is a phenotype?
5. What is a Punnett Square?
6. What is a hybrid?
7. What are alleles?
8. What are homologous chromosomes?
9. What do the symbols P, F1, and F2, mean?
10. What does heterozygous mean? Homozygous?
11. Examples of dominant/recessive traits?
12. What is the phenotypic ratio of a cross between two hybrids?
13. What is the genotypic ratio of a cross between two hybrids?
14. What is a back cross or a test cross?
a. How is it used to determine the genotype of an organism?
B. What is the Law of Unit Characters? (Chapter 9.1)
1. What controls a genetic trait? Mendel’s vocabulary?
2. What is a gene?
3. When are genes passed to offspring?
C. What is the Law of Segregation? (Chapter 9.1)
1. When does segregation of alleles occur?
2. How many genes for each trait are found in a gamete?
D. What is the Law of Independent Assortment? (Chapter 9.2, Lab 31)
1. What is a dihybrid?
2. What is the phenotypic ratio of a cross between two dihybrids?
3. What are linked genes? (p238)
4. Does the Law of Independent Assortment apply to linked genes?
III. Blending Inheritance (Chapter 9.2)
A. What is incomplete dominance?
1. What are example(s) of traits exhibiting incomplete dominance?
2. What is the phenotypic ratio of offspring from a cross between two hybrids?
3. What are the symbols used in the key?
B. What is codominance?
1. What are example(s) of traits exhibiting codominance?
2. Distinguish between incomplete dominance and codominance.
C. What is a polygenic trait? Examples?(Chapter 12.2; Lab 30)
IV. Sex-Linkage
A. Chromosomal differences (Chapter 8.1; 12.1)
1. What is a karyotype?
2. What are autosomes? How many autosomes are found in human somatic cells?
3. What are sex chromosomes? How many sex chromosomes are found in human somatic cells?
4. What is the chromosomal make-up of a human male? Female?
5. What is the chromosomal make up of a human sperm cell? Egg cell?
6. Which parent determines the sex of the child?
7. What is the probability of a male child being conceived? Female?
B. What is a sex-linked trait? (Chapter 12.1)
1. What are some examples of sex-linked traits in humans?
2. What is an example of a sex-linked trait studied in fruit flies (Drosophila)?
3. What are the symbols used in the key?
4. What is a carrier? What is the phenotype of a carrier?
5. What is a sex-influenced trait? Example?
V. Multiple Alleles (Chapter 12.2)
1. What are multiple alleles?
2. What is an example of a human trait exhibiting multiple alleles?
3. What are the symbols used in the key?
4. How does type A blood differ from type B? AB? O?
VI. Pedigree (Chapter 12.2, Lab 32)
A. What is a pedigree?
1. What are the symbols used for males? Females?
2. Is the dominant gene always the most common gene in a population?
3. How can you determine if a gene is sex-linked by examining a pedigree?
VII. Mutations (Chapter 12.1 and 12.2)
A. What is a mutation?
1. How do mutations affect organisms?
2. In what types of cells must mutations occur to be passed on to the offspring?
B. Changes in chromosome number
1. What is nondisjunction?
2. When does it occur?
3. What conditions are caused by nondisjunction?
C. Changes in chromosome structure?
1. What is crossing over?
2. When does it occur?
3. How does it affect linked genes?
4. How does it affect heredity?
D. What is a point mutation?
E. What are the effects of the environment on heredity? Epigenetics?
1. What does the environment consist of?
2. What are mutagenic agents? Examples?
3. What are the effects of light on gene expression for chlorophyll in corn seedlings?
4. What are the effects of temperature on gene expression for
a. Coat color in Himalayan rabbits and Siamese cats?
b. Wing structure in fruit flies?
5. What are the effects of environment on human intelligence?
a. What kinds of individuals were used in these studies?
Rev. 4/13