Problem 6 - Campbell Biology Concepts & Connections

Question

Your bone cells, muscle cells, and skin cells look different because a. each cell contains different kinds of genes. b. they are present in different organs. c. different genes are active in each kind of cell. d. they contain different numbers of genes. es wh

Step-by-Step Solution

Answer

c: different genes are active in each kind of cell.

Step 1: Understand Cellular Differentiation

Cellular differentiation is the process by which a cell becomes specialized to perform a specific function. This occurs even though all the cells in an organism contain the same DNA.

Step 2: Analyze Gene Activity

Different cells look different and perform various functions because different genes are active in each type of cell. Gene expression determines cell function and identity.

Step 3: Eliminate Incorrect Options

Option a is incorrect because all cells contain the same set of genes. Option b is irrelevant to why the cells look different. Option d is incorrect because the number of genes is the same in each cell.

Step 4: Choose the Correct Answer

Given that cellular differentiation is determined by gene expression, the correct answer is option c: different genes are active in each kind of cell.

Key Concepts

Gene Expression

Gene expression is a process where specific segments of DNA are used to produce proteins, which carry out various functions within the cell. This is fundamental for cellular differentiation, wherein a single-cell type can become a specialized cell, such as a muscle cell or a skin cell.
Gene expression essentially decides which proteins are made in a cell. These proteins then determine the cell's function.

• Transcription: The DNA segment is copied into mRNA.
• Translation: The mRNA is used as a blueprint to create proteins.

Since different proteins are needed for different cell types, only certain genes are activated, leading to varied cell functions and appearances despite having the same DNA.

Specialized Cells

Specialized cells are those that have developed to perform a particular function in the body. This specialization occurs through cellular differentiation, guided by gene expression.
Unique characteristics of specialized cells include:

• Specific shapes: For example, nerve cells have long extensions to transmit signals.
• Unique functions: Muscle cells can contract, while red blood cells carry oxygen.

Such differences are critical since each specialized cell type supports the overall functioning of organs and systems within an organism.

Cell Function

Cell function refers to the specific activities carried out by different cell types to help maintain the body’s health. These functions are dictated by the proteins produced through gene expression.
Different functions include:

• Energy production in mitochondria of muscle cells.
• Protection by skin cells forming a barrier against pathogens.
• Signal transmission by nerve cells to control body activities.

The concentration of specific proteins within a cell type underlies the capacity to execute its designated tasks efficiently. This underscores how gene expression and specialization direct each cell toward fulfilling its unique role.