How Does Dna Determine the Traits of an Organism Worksheet Answer Key

How Does DNA Determine the Traits of an Organism Worksheet Answer Key: Understanding the Basics


DNA, or deoxyribonucleic acid, is the genetic material that carries the information needed to build and maintain an organism. It serves as the blueprint for all living organisms, determining their inherited traits, such as eye color, hair texture, height, and susceptibility to diseases. Understanding how DNA determines these traits is crucial in comprehending the fundamental principles of genetics. In this article, we will explore the answer key to a worksheet that delves into the intricate relationship between DNA and traits. Additionally, we will provide a FAQs section to address common queries related to this topic.

Answer Key:

1. What is DNA?

DNA is a double-stranded molecule composed of nucleotides. Each nucleotide consists of a sugar molecule (deoxyribose), a phosphate group, and one of four nitrogenous bases: adenine (A), thymine (T), guanine (G), or cytosine (C). The specific sequence of these bases along the DNA molecule carries genetic information.

2. How does DNA determine traits?

DNA contains genes, which are segments of DNA that code for specific proteins. Proteins are responsible for carrying out various functions in an organism, and the sequence of amino acids in a protein is determined by the sequence of bases in the corresponding gene. Thus, variations in the DNA sequence result in different proteins being produced, leading to variations in traits.

3. How are traits inherited?

Traits can be inherited through two main mechanisms: dominant and recessive alleles. Each gene has two alleles, one inherited from each parent. Dominant alleles mask the effects of recessive alleles. If an individual inherits two copies of the dominant allele, they will display the dominant trait. However, if they inherit one copy of the dominant allele and one copy of the recessive allele, the recessive trait will be observed.

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4. What is a genotype?

A genotype refers to the specific combination of alleles an individual possesses for a particular gene. It represents the genetic composition of an organism. For example, the genotype for eye color could be represented as BB (homozygous dominant, brown eyes), Bb (heterozygous, brown eyes), or bb (homozygous recessive, blue eyes).

5. What is a phenotype?

A phenotype is the observable characteristic or trait resulting from the interaction between an organism’s genotype and its environment. It encompasses physical attributes, physiological functions, and behaviors. Examples of phenotypes include eye color, hair texture, and height.

6. Can traits be influenced by environmental factors?

Yes, traits can be influenced by environmental factors. While DNA provides the blueprint for traits, the expression of certain genes can be influenced by external factors such as diet, temperature, and exposure to toxins. This phenomenon is known as gene-environment interaction.


1. Can DNA determine behavioral traits?

While DNA plays a significant role in determining traits, including certain behavioral traits, it is important to note that behavior is also influenced by environmental factors and complex interactions between genes. The contribution of genetics to behavior is a topic of ongoing research.

2. Are all traits determined by a single gene?

No, many traits are influenced by multiple genes. These traits are called polygenic traits. For instance, height, skin color, and intelligence are influenced by the interaction of several genes.

3. Can DNA mutations affect traits?

Yes, mutations in DNA can alter the sequence of bases, thereby changing the information carried by genes. Depending on the location and nature of the mutation, it can result in variations in traits and, in some cases, the development of genetic disorders.

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4. Can traits be modified or changed over an individual’s lifetime?

While DNA is relatively stable, traits can be modified or changed over an individual’s lifetime due to factors such as aging, environmental influences, and lifestyle choices. However, these changes do not alter the underlying DNA sequence.


Understanding how DNA determines the traits of an organism is key to comprehending the fundamental principles of genetics. By exploring the answer key to the worksheet, we have gained insights into the role of DNA in determining traits and the mechanisms of inheritance. Additionally, the FAQs section has provided clarification on common queries related to this topic. With further research and advancements in genetics, we continue to unravel the intricate relationship between DNA and traits, paving the way for a deeper understanding of our genetic makeup.

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