Chapter 4 - Genetics

Question 1

Gregor Mendel

Answer 1

Austrian monk and botanist whose experiments in breeding garden peas led to his eventual recognition as founder of the science of genetics (1822-1884)

Question 2

Reginald Punnett

Answer 2

created the Punnett square based on Gregor Mendel’s work

Question 3

Allele

Answer 3

an alternative form of a gene

Question 4

Dominant allele

Answer 4

one whose trait always shows up in the organism when the allele is present

Question 5

Recessive allele

Answer 5

an allele that is hidden whenever the dominant allele is present

Question 6

Homozygous

Answer 6

both alleles of a gene are the same

Question 7

Heterozygous

Answer 7

the alleles of a particular gene are different

Question 8

homozygous dominant

Answer 8

both alleles (factors) for a trait are the same and dominant (AA)

Question 9

homozygous recessive

Answer 9

both alleles (factors) for a trait are the same and recessive (aa)

Question 10

Genotype

Answer 10

an organism’s genetic makeup, or allele combinations

Question 11

phenotype

Answer 11

physical characteristics of an organism

Question 12

heredity

Answer 12

the study of how traits are passed from one generation to the next

Question 13

principles of heredity

Answer 13

1. Traits are controlled by alleles on chromosomes
2. An allele’s effect is dominant or recessive
3. When a pair of chromosomes separates during meiosis, the different alleles for a trait move into separate sex cells

Question 14

purebred

Answer 14

an organism that always produces offspring with the same form of a trait as the parent

Question 15

hybrid

Answer 15

an offspring with a mix of alleles for a specific character

Question 16

hybrid cross

Answer 16

a cross of two individuals heterozygous for the same trait; results in a 3:1 phenotypic ratio