1. What is a gene?

2. Is a gene a triplet of consecutive DNA nucleotides?

3. How is the concept of a chromosome related to the concept of the gene?

4. What is meant by a "gene locus"?

5. What are alleles?

6. Do the alleles of a gene necessarily originate in such a way that one comes from the father and the other comes from the mother? Are there exceptions?

7. What is a phenotype?

8. What is a genotype? What is the difference between a genotype and a phenotype?

9. Does the environment have an influence on the phenotype?

10. Are environmental phenotypical changes passed on to offspring?

11. In what situations can the environment alter the genotype of an individual? What is the condition for this type of change to be passed on to offspring?

12. What are some examples of phenotypical characteristics that present two or more varieties and of phenotypical features that do not vary? In relation to the genes corresponding to those characteristics, which vary among individuals, what can be expected regarding their alleles?

13. Considering a pair of homologous chromosomes containing a gene with two different alleles, how many different genotypes can that individual present?

14. For an individual with a genotype formed of two different alleles that condition different varieties of the same phenotypical trait, what does the phenotypical feature actually manifested depend on?

15. What is the difference between a dominant allele and a recessive allele?

16. Whenever a pair of alleles contains different alleles, is there dominance between them?

17. What is the difference between homozygosity and heterozygosity?

18. Why can a recessive allele remain hidden in the phenotype of an individual and only be revealed when manifested via homozygosity in its offspring?