Lesson 2: Understanding Inheritance

What controls traits?

• Genes

• Environment

• Diet

• Exercise

Inside each cell is a nucleus that contains threadlike structures called _______.

• chromosomes

• mitochondria

• ribosomes

• lysosomes

Mendel's factors are parts of chromosomes, and each cell in offspring contains chromosomes from both _______.

• parents

• friends

• siblings

• neighbors

A(n) _______ is a section on a chromosome that has genetic information for one trait.

• gene

• chromosome

• allele

• nucleotide

The different forms of a gene are called _______.

• alleles

• chromosomes

• proteins

• nucleotides

Geneticists refer to how a trait appears, or is expressed, as the trait’s _______.

• phenotype

• genotype

• allele

• chromosome

The two alleles that control the phenotype of a trait are called the trait’s _______.

• genotype

• phenotype

• chromosome

• allele

In genetics, uppercase letters represent dominant alleles, and lowercase letters represent recessive alleles. True or False?

• True

• False

When two alleles of a gene are the same, its genotype is _______.

• homozygous

• heterozygous

• dominant

• recessive

If two alleles of a gene are different, its genotype is _______.

• heterozygous

• homozygous

• dominant

• recessive