Problem 11 - Biology Today and Tomorrow with Physiology

Question

Muscle cells differ from bone cells because they ________. a. have different genes b. use different genes c. are eukaryotic d. both a and b

Step-by-Step Solution

Answer

Muscle cells differ from bone cells because they use different genes (option b).

Step 1: Understanding the Difference

Muscle cells and bone cells differ not in the genes they contain, as all cells in the human body contain the same set of genes. The key difference lies in which genes they express. This means that muscle cells will express genes related to muscle function, while bone cells will express genes related to bone function.

Step 2: Examining the Options

The first option states that muscle cells have different genes, which is incorrect because all cells in an organism have the same DNA. The second option states that muscle cells use different genes, which is accurate since gene expression varies between different cell types to fulfill their specific functions. The third option states that muscle cells are eukaryotic, which is true but does not account for the difference we're asked about. The fourth option suggests that both having different genes and using different genes explain the difference, which is incorrect because the difference is not due to possession of different genes.

Step 3: Selecting the Correct Option

After revisiting the reasoning behind each option, it is clear that the correct option is that muscle cells use different genes compared to bone cells. This selective gene expression allows different cell types to perform their unique roles effectively.

Key Concepts

Cell Differentiation

Cell differentiation is an essential biological process where a single fertilized egg develops into various cell types. Each cell type has a unique structure and function. All cells start with the same basic genetic material but evolve to take on specific roles. This occurs mainly through the selective expression of specific genes.

• Cells become specialized by turning on (or off) particular genes.
• The environment surrounding the cell also influences its differentiation.
• During development, signals from neighboring cells or even from within the same cell guide this process.

In essence, cell differentiation enables the complex structures and functions found within a multicellular organism. This is key for forming tissues and organs with diverse capabilities, such as those in your skeletal and muscular systems.

Muscle Cells

Muscle cells, also known as myocytes, are specifically tailored to facilitate movement. They are elongated and packed with proteins like actin and myosin which slide past each other to contract, causing the muscle to shorten and generate force.

• These cells express genes necessary for producing muscle-specific proteins.
• Muscle cells consume more energy due to their active role in movement.
• They have ample mitochondria to meet high energy demands.

The ability of muscle cells to efficiently contract and relax is crucial for body movement, posture, facial expressions, and even vital functions like heartbeat and breathing.

Bone Cells

Bone cells, or osteocytes, contribute to the rigid structure and support of the body through the maintenance of the bone matrix. Unlike muscle cells that focus on movement, bone cells are integral to structure and mineral storage.

• They play a key role in producing components like collagen that form the bone matrix.
• Bone cells help regulate calcium levels within the body.
• They constantly remodel bone structure to accommodate growth and repair damage.

The function of bone cells ensures not just physical support and protection but also serves as a reservoir for important minerals essential for various bodily functions.