1. The abbreviation for deoxyribonucleic acid is DNA.
2. A sequence of genes that determines a specific trait is called a chromosome.
3. The process by which the alleles of the father and mother are combined during sexual reproduction is called fertilization.
4. A gene that has a different form or trait, such as tall vs. short, is an allele.
5. The actual gene makeup of an organism is its genotype.
6. The observable physical characteristics of an organism passed down from one generation to the next is its phenotype.
7. Alleles are the two forms of a gene; one is inherited from each parent.
8. An organism with two identical alleles for a trait (e.g., TT or tt) is homozygous.
9. An organism with two different alleles for a trait (e.g., Tt) is heterozygous.
10. The likelihood that a particular event will occur is probability.
11. Mendel experimented with pea plants to learn about genetics.
12. When two organisms with different alleles for a trait cross, they produce offspring with a combination of traits.
13. The principles of inheritance discovered by Gregor Mendel are known as Mendelian genetics.
14. The basic unit of heredity is a gene.
15. A Punnett square is a tool used to show the possible gene combinations in offspring.
16. The genotype of an organism refers to its genetic makeup, while the phenotype refers to its observable characteristics.
17. In a cross between two heterozygous parents (Tt x Tt), the offspring have a 25% chance of being homozygous dominant (TT), 50% chance of being heterozygous (Tt), and 25% chance of being homozygous recessive (tt).
18. A dominant allele is represented by a capital letter (e.g., T), while a recessive allele is represented by a lowercase letter (e.g., t).
19. Organisms inherit one allele for each gene from each parent.
20. The study of how traits are passed from parents to offspring is called genetics.
21. For the following crosses, complete the Punnett squares:
a. Tt x Tt → Offspring: 25% TT, 50% Tt, 25% tt
b. TT x tt → Offspring: 100% Tt
c. Tt x tt → Offspring: 50% Tt, 50% tt
Parent Tip: Review the logic above to help your child master the concept of genetics challenge worksheet answers.
