Question

An organism's traits are determined by the specific combination of inherited \(-------\) ' a. cells b. genes c. proteins d. chromatids

Short answer

Answer: Genes

Step-by-step solution

Understand the terms

Before answering the question, it is essential to understand the terminology involved. a. Cells: The basic building blocks of living organisms. b. Genes: Segments of DNA that carry the instructions for making proteins, which in turn determine traits. c. Proteins: Large molecules that perform various functions in organisms, including building and maintaining structures and carrying out biological processes. d. Chromatids: One of the two identical DNA strands that make up a chromosome, visible during cell division.

Analyze the options

Now that you know the meaning behind each term, it's time to determine which one is responsible for an organism's traits. a. Cells: While cells make up an organism's body, they don't directly determine its traits. b. Genes: Genes are responsible for the production of proteins, which in turn determine traits. c. Proteins: Proteins carry out tasks based on the genes that code for them, making them responsible for traits. d. Chromatids: Chromatids carry genes, but they aren't the direct determinants of traits.

Choose the correct answer

Based on the analysis of each option, it is clear that b. genes are the specific combination of inherited factors responsible for determining an organism's traits.

Key concepts

Understanding Genes

Genes are the fundamental units of heredity. These small segments of DNA contain the instructions needed to build and maintain the cells of an organism. Each gene carries the information required to produce proteins, which play a crucial role in developing and controlling the physical characteristics or traits of an organism.

Imagine genes as recipes in a cookbook. Each recipe contains a specific set of instructions for creating a dish, similar to how each gene provides the necessary guidelines for producing proteins. These proteins then orchestrate an array of functions in living organisms.

Some key points about genes include:

• Located on chromosomes, which reside in the cell nucleus.
• Composed of sequences of nucleotides in DNA.
• Specific sequences of genes lead to specific traits.

By understanding the role of genes, one can appreciate how they shape everything from the color of your eyes to the functioning of your internal organs.

The Role of DNA

DNA, or deoxyribonucleic acid, is a long, double-helix molecule that contains all the genetic information needed to develop, survive, and reproduce. DNA is often compared to a blueprint because it holds the detailed instructions necessary for constructing and operating living organisms.

Within each DNA molecule, there are specific sections known as genes. The sequence of nucleotides in DNA determines the structure and function of these genes. Here's a simple analogy: if DNA is a library, then genes are the books within that library, each outlining specific instructions.

Important features of DNA include:

• The double-helix structure, which consists of two intertwined strands.
• Four types of nitrogenous bases—adenine, thymine, cytosine, and guanine—pair with each other to form base pairs.
• DNA replication allows genetic information to be passed down to the next generation during cell division.

DNA ensures that our unique genetic information can be accurately copied and transmitted through generations.

Traits Explained

Traits are the observable characteristics or features of an organism. These can include anything from height and eye color to more complex attributes like behavior and disease susceptibility. The expression of traits in an organism is mostly controlled by genes, which dictate the production of specific proteins that influence these characteristics.

However, traits may also be influenced by environmental factors, leading to variations even among genetically identical organisms, such as identical twins. For instance, if one twin eats a different diet than the other, their physical traits could diverge over time due to nutritional differences.

Essential points about traits:

• Can be inherited from parents, as determined by genes.
• Are expressed through a combination of genetic and environmental factors.
• Some traits are dominant, while others are recessive, affecting how they manifest in offspring.

Understanding traits helps us see how the combination of genes and environment shapes the living world.

Principles of Inheritance

Inheritance refers to the process by which genes and the traits they control are passed from parents to offspring. This continuity of genetic information is what propagates traits across generations, shaping the biological diversity we see.

Gregor Mendel, the father of modern genetics, first uncovered the basic principles of inheritance through his work with pea plants. He demonstrated how traits are passed on through discrete units we now know as genes.

Key principles of inheritance include:

• Law of Segregation: During gamete formation, the two alleles for each gene separate so that each gamete receives only one allele.
• Law of Independent Assortment: Genes for different traits can segregate independently during the formation of gametes.
• Dominance: In a pair of alleles, one may mask the presence of the other.

By understanding these principles, we can predict the likelihood of an offspring inheriting particular traits, which is foundational to the study of genetics.