In a myofibril, each I band is bisected by

Options

A. Z-line
B. K-line
C. M-line
D. H-line

Answer

To answer the question "In a myofibril, each I band is bisected by," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Myofibrils**: Myofibrils are the basic rod-like units of a muscle cell. They are composed of repeating units called sarcomeres, which are the functional units of muscle contraction.

2. **Identify the Bands in a Myofibril**: In a myofibril, there are different bands:
- **I Band**: This is the light band that contains only thin filaments (actin).
- **A Band**: This is the dark band that contains thick filaments (myosin) and overlaps with thin filaments.
- **Z Line**: This is the boundary between adjacent sarcomeres.

3. **Locate the I Band**: The I band is the region on either side of the Z line. It appears lighter under a microscope compared to the A band.

4. **Determine What Bisects the I Band**: The Z line runs through the center of each I band, effectively bisecting it. This means that each I band is divided into two equal halves by the Z line.

5. **Conclude the Answer**: Therefore, the answer to the question is that in a myofibril, each I band is bisected by the **Z line**.

### Final Answer:
In a myofibril, each I band is bisected by the **Z line**.

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