---
title: "Motor Proteins and Directed Movement Along Tracks"
description: "Myosins, kinesins and dyneins burn ATP to take steps along a filament, and each motor walks towards one particular end. Cargo is carried where it needs to go because the track has a direction and the "
canonical: https://lightmysky.com/learn/science/motor-proteins-and-directed-movement-along-tracks-mt_TUTmILr7y0
source: https://lightmysky.com/learn/science/motor-proteins-and-directed-movement-along-tracks-mt_TUTmILr7y0.md
retrieved: 2026-09-12
---

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# Motor Proteins and Directed Movement Along Tracks

Myosins, kinesins and dyneins burn ATP to take steps along a filament, and each motor walks towards one particular end. Cargo is carried where it needs to go because the track has a direction and the motor knows it.

Subject: Science · Area: Organisms & Life Processes · Ages 20 to 22
Page: https://lightmysky.com/learn/science/motor-proteins-and-directed-movement-along-tracks-mt_TUTmILr7y0

## Ready when they can

- Links one round of ATP binding and hydrolysis to one step of the motor.
- Predicts which way a cargo travels given the motor and the track polarity.
- Explains why a cell needs motors moving in both directions along the same track.

## Lesson: Tiny walkers on one way tracks

Motor proteins turn fuel into steps. Each motor burns one ATP molecule per stride through a fixed cycle: grip the track, pull, let go as fresh ATP arrives, and cock forward again. One fuel molecule buys exactly one step, which keeps each motor strictly one way.

Direction comes from the motor plus the track polarity. Kinesin strides toward the plus end of a microtubule while dynein heads toward the minus end, and myosin follows the polarity of actin. Cargo must travel both outward to the edge and back to the center on the same tracks, so the cell keeps opposite direction motors and hands cargo between them.

**Example.** Myosin on actin is the classic crew. In muscle, thousands of myosin heads row together: calcium uncovers the binding sites, each head grabs actin, pulls, releases with fresh ATP, and grabs again. Long range hauls run on microtubules with kinesin and dynein, while short local moves near the membrane run on actin with myosin.

**Tip.** To predict a delivery, first ask which track it rides, then ask which motor walks it, and read the direction off that pair.

**Recap.** One ATP buys one step, and the motor plus track polarity decides which way the cargo goes.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [The Sliding Filament Model of Muscle Contraction](https://lightmysky.com/learn/science/the-sliding-filament-model-of-muscle-contraction-mt_BsB4s4HfD8)
- [Microtubules, Dynamic Instability and the Spindle](https://lightmysky.com/learn/science/microtubules-dynamic-instability-and-the-spindle-mt_RWhMJxOmUu)

## Opens up

- [ATP Synthase as a Rotary Machine](https://lightmysky.com/learn/science/atp-synthase-as-a-rotary-machine-mt_PDe3f-FVfD)
- [Junctions, Adhesion and the Extracellular Matrix](https://lightmysky.com/learn/science/junctions-adhesion-and-the-extracellular-matrix-mt_Sjcd3kQUmw)