Question

Two students were discussing inheritance in science class. Both students knew that genes and chromosomes had something to do with human inheritance. The students came up with four explanations of what genes do in the process of inheritance. Which is the best explanation of what genes do?

A. Genes directly cause physical changes on our cells’ nuclei. The nuclei then produce our traits.
B. Genes directly cause physical changes to our brain cells; then the brain cells produce our traits.
C. Genes make chromosomes and chromosomes make up our organs, therefore, organs give us the traits we inherit.
D. Genes are part of chromosomes and genes provide the instructions to cells on how to make our traits.

Answer 1

Genes provide the instructions to cells on how to make our traits and are part of the DNA housed in chromosomes. Through inheritance, they determine an organism's phenotype, with alleles causing variations in traits. Gregor Mendel's work was foundational in understanding genetic inheritance patterns.

Step-by-step explanation:

Understanding Genes in the Process of Inheritance

When discussing what genes do in the process of inheritance, the most accurate explanation is that genes are part of chromosomes and provide the instructions to cells on how to make our traits. Essentially, chromosomes are structures made of DNA, and segments of this DNA constitute genes. These genes contain the genetic codes that determine the biological and physical traits of an organism, referred to as the phenotype. Through the process of inheritance, genes are passed down from parents to offspring, with each parent contributing one set of genes to their children.

Genes are housed on the chromosomes within the nucleus of a cell, and they serve as the fundamental unit of heredity. Gregor Mendel's pioneering work laid the groundwork for our understanding of genetics through his experiments with pea plants, which revealed how traits are inherited. Mendel's laws of heredity demonstrated that traits are transmitted via discrete units, later identified as genes, rather than blending directly from one generation to the next.

The concept of alleles—variations of a gene—plays a crucial role in the diversity of traits observed among individuals. For a particular trait, there may be multiple alleles, each potentially causing a different manifestation of the trait. For instance, in Mendel's pea plants, the color of the flowers was determined by different alleles for purple (B) or white (b). Inheritance of these alleles in different combinations results in the expression of the observed traits.

The correct understanding of how genes contribute to inheritance is a cornerstone in biology and has vast implications for the field of medicine, including the diagnosis, treatment, and ethical considerations of genetic disorders. Comprehending the role of genes and chromosomes in heredity allows, for example, the explanation of why siblings might look similar yet have distinct differences unless they are identical twins, who share the exact same set of genes.