Question

The energy in ATP is used to fuel the movement of kinesin motor proteins along microtubules. Sort each of the following events into the proper category, indicating whether they occur on the leading or trailing head of kinesin.

Answer 1

Kinesin motor proteins use ATP hydrolysis to move along microtubules, carrying cellular cargo. The leading head binds to microtubules ready for the next step, while the trailing head detaches after hydrolysis, swinging forward to become the new leading head.

Step-by-step explanation:

Function of Kinesin Motor Proteins

Kinesin motor proteins are essential for intracellular transport, utilizing the energy from ATP hydrolysis to move along microtubules and carry various cellular cargoes, such as organelles and vesicles. This dynamic process involves a coordinated set of conformational changes within the kinesin molecule, particularly at its two heads. The 'leading head' is generally bound to a microtubule and ready to take the next step forward upon ATP binding, while the 'trailing head' detaches and swings forward after ATP hydrolysis has released its energy. The cycle of ATP binding, hydrolysis, and phosphate release drives the movement of the kinesin along the microtubule track.

Each head of the kinesin dyad functions differently during the walking process. When ATP binds to the leading head, it induces a conformational change that strengthens its attachment to the microtubule, preparing it for the next step. Conversely, ATP hydrolysis and the release of ADP and phosphate in the trailing head cause it to release from the microtubule, swing forward, and become the new leading head upon attachment at a new site on the microtubule.

In summary, active transport facilitated by kinesin is a fundamental biological process that is crucial for the proper functioning of cells. The motor protein action of kinesin is an intricate dance, with each head playing a specific role, all powered by the chemical energy of ATP.

Answer 2

This is the correct sorting of events into the proper category:

Leading Head

• ATP binding
• Neck linker zippers to catalytic core of head group

Trailing Head

• ATP hydrolysis
• P, release
• ADP release

What are these events?

Leading Head

ATP binding: The leading head of kinesin binds to ATP, which provides the energy for the movement of the head.

Neck linker zippers to catalytic core of head group: The neck linker of the leading head zips up to the catalytic core of the head group, which allows the head to undergo a power stroke.

Trailing Head

ADP release: The trailing head of kinesin releases ADP, which is the byproduct of ATP hydrolysis.

P, release: The trailing head of kinesin releases inorganic phosphate (Pi), which is also a byproduct of ATP hydrolysis.

ATP hydrolysis: ATP hydrolysis occurs on both the leading and trailing heads of kinesin.

Complete question:

The energy in ATP is used to fuel the movement of kinesin motor proteins along microtubules. Sort each of the following events into the proper category, indicating whether they occur on the leading or trailing head of kinesin. Items (5 items) (Drag and drop into the appropriate area below) ATP binding ATP hydrolysis P, release ADP release Neck linker zippers to catalytic core of head group Categories Leading Head Trailing Head Drag and drop here Drag and drop here