ScienceFreePrintable

Genetics Vocabulary and Inheritance

A free science worksheet ready for your classroom. Open in Kuraplan to grab the print-ready PDF, customize it for your students, or generate a fresh version in seconds.

Download now

Name:Date:

Genetics Vocabulary and Inheritance

Use the definitions and allele information in each question. Show your reasoning for inheritance predictions. In Punnett squares, each box represents one possible offspring genotype.

Key ideas

A gene is a section of DNA with instructions; alleles are versions of a gene. An organism’s genotype is its allele combination, while its phenotype is an observable trait. A dominant allele can affect phenotype when one or two copies are present; a recessive allele affects phenotype when two copies are present. Having two matching alleles for a gene is called one condition; having two different alleles is called another. A genome is an organism’s full set of genetic material. A mutation is a change in DNA. Inheritance passes genetic information from parents to offspring, and variation describes differences among individuals of a species.

1.Match each genetics term to its definition. Write the correct letter for each term.

Chromosome
Allele
Genotype
Phenotype
Mutation
Genome
Heredity
Variation

H. Differences among individuals of the same species
D. A feature that can be observed or measured
G. The passing of genetic information from parents to offspring
F. All of an organism’s genetic material
C. The set of alleles an organism has
A. A particular version of a gene
E. A change in the DNA sequence
B. A structure of DNA in a cell that carries genes

2.Complete the sentence with the correct genetics term. DNA is packaged into structures called .

3.Complete the sentence with the correct genetics term. An organism with two different alleles for a gene is .

4.Complete the sentence with the correct genetics term. A allele affects the phenotype only when no dominant allele is present.

5.Complete the sentence with the correct genetics term. Differences in features among members of one species are called .

6.Complete the sentence with the correct genetics term. An organism with two identical alleles for a gene is .

7.Classify each example as a genotype or a phenotype. a) A rabbit has white fur. b) The allele combination Rr. c) A person has attached earlobes. d) The allele combination mm. e) A plant has purple flowers.

8.In a fictional plant species, allele P gives purple flowers and is dominant to allele p, which gives white flowers. Two plants with genotype Pp are crossed (Pp × Pp). Complete the Punnett square, then state the possible genotypes, the genotype ratio, and the expected phenotype ratio.

9.Describe how a gene and an allele are related. Include what each term means.

10.In a species of beetle, B is dominant for striped shells and b is recessive for plain shells. Explain why a beetle with genotype Bb has a striped shell even though it carries the b allele.

11.In a cross involving one gene, 25% of the offspring are predicted to have genotype aa. Which parent genotypes could produce this result? Explain using the possible gametes.

12.A cross between two parents with genotype Aa gives an expected genotype ratio of 1:2:1. If 40 offspring are produced, how many of each genotype would this prediction suggest? Give the expected numbers, not a guarantee of the actual offspring.

13.Two parents with genotype Aa each produce gametes A and a. What is the probability that an offspring will have genotype aa?