Science: Genetics and Heredity Worksheet

Question 1

Define heredity in your own words.

Accepted Answer

Heredity is the passing of traits from parents to their offspring through genetic information.

Question 2

What is a gene, and what does it do in a living organism?

Accepted Answer

A gene is a section of DNA that contains instructions for a trait or for making a product in the body. Genes help determine how an organism grows, functions, and looks.

Question 3

Explain the difference between a trait and an inherited trait.

Accepted Answer

A trait is any characteristic of an organism, such as eye color or height. An inherited trait is a characteristic passed from parents to offspring through genes.

Question 4

What role does DNA play in heredity?

Accepted Answer

DNA stores the genetic instructions that are passed from parents to offspring. These instructions help determine inherited traits.

Question 5

Describe what chromosomes are and where they are found in a cell.

Accepted Answer

Chromosomes are organized structures made of DNA and proteins. They are found in the nucleus of a cell.

Question 6

A plant has tall stems because it inherited that trait from its parent plants. Is stem height an example of heredity, environment, or both? Explain.

Accepted Answer

Stem height can be an example of both heredity and environment. Genes influence how tall the plant can grow, but water, sunlight, and soil conditions also affect its actual height.

Question 7

What is the difference between dominant and recessive alleles?

Accepted Answer

A dominant allele can show its effect when only one copy is present. A recessive allele usually shows its effect only when two copies are present.

Question 8

If B represents a dominant allele for brown eyes and b represents a recessive allele for blue eyes, what eye color phenotype would a person with genotype Bb most likely have?

Accepted Answer

A person with genotype Bb would most likely have brown eyes because the dominant allele B masks the recessive allele b.

Question 9

Explain the difference between genotype and phenotype.

Accepted Answer

Genotype is the genetic makeup of an organism, such as Bb or bb. Phenotype is the observable trait that results, such as brown eyes or blue eyes.

Question 10

Two parents each have the genotype Tt for a trait where T is dominant. List the possible genotypes of their offspring.

Accepted Answer

The possible genotypes are TT, Tt, and tt. These combinations come from the different allele pairs the offspring can inherit from the parents.

Question 11

In the cross Tt x Tt, what fraction of offspring would be expected to show the recessive phenotype?

Accepted Answer

One out of four offspring, or 1/4, would be expected to show the recessive phenotype. The recessive phenotype appears only in offspring with the genotype tt.

Question 12

Why are siblings from the same parents not usually genetically identical?

Accepted Answer

Siblings are not usually genetically identical because each parent passes on a different combination of alleles to each child. This creates variation among offspring.

Question 13

Give one example of a trait influenced by both genes and the environment, and explain how both affect it.

Accepted Answer

Human height is influenced by both genes and the environment. Genes affect a person's growth potential, while nutrition and health affect how fully that potential is reached.

Question 14

A scientist says that mutations can sometimes be passed to offspring. Explain what a mutation is.

Accepted Answer

A mutation is a change in the DNA sequence. If a mutation occurs in reproductive cells, it can be passed from parents to offspring.

Question 15

Summarize how genes, DNA, chromosomes, and traits are connected.

Accepted Answer

DNA is the molecule that stores genetic information. Genes are sections of DNA, chromosomes are structures that contain many genes, and traits are characteristics influenced by those genes.

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Science: Genetics and Heredity

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