Genetics Part 1

Question 1

alleles

Answer 1

variations of a gene

Question 2

dominant allele

Answer 2

expressed even when paired with a recessive allele

Question 3

recessive allele

Answer 3

only visible when paired with another recessive allele

Question 4

Genetics History

Answer 4

Gregor Mendel used peas bc…

1. ) they had a short generation time
2. ) had polymorphic traits
3. ) mating was easy to control
4. ) large # of seeds
5. ) inexpensive & easy to grow

Question 5

true breeding

Answer 5

produce pure lines/ strains for each trait

Question 6

Generations

Answer 6

P: true breeding
F1: hybrids
F3: both types; 3:1 ratio

Question 7

Mendel’s Law of Segregation

Answer 7

2 gene pairs segregate into different gametes during formation of eggs and sperm

Question 8

What is the purpose of a test cross?

Answer 8

to determine the genotype of an individual with a dominant phenotype. You cross the individual with the unknown genotype with a homo recessive phenotype and based on the ratios you can determine the genotype

Question 9

Dihybrid crosses

Answer 9

2 separate traits in a single cross. F1 generation shows dominant phenotypes for each trait, F1 self fertilizes, F2 shows all 4 possible phenotypes in 9:3:3:1 ratio

Question 10

Principle of Independent Assortment

Answer 10

2 copies of each gene segregate into gametes independently of the 2 copies of another gene

Question 11

Product rule and Sum rule

Answer 11

2 probabilities multiplied, probability of one event added to probability of second event