Active transport interactive worksheet - Free Printable

Here is the complete solution to the worksheet on Active Transport, with explanations for each answer.

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## A. Select the correct option

1. Active transport is the movement of molecules from an area of lower concentration to an area of higher concentration.

✔ Explanation:
Unlike passive transport (which moves substances *down* the concentration gradient — from high to low concentration), active transport moves substances *against* the gradient — from low to high concentration. This requires energy because it’s going against the natural flow.

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2. Active transport moves materials against the concentration gradient.

✔ Explanation:
This is the defining feature of active transport. It uses cellular energy (usually ATP) to pump molecules or ions across a membrane in the direction they wouldn’t naturally move.

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3. Active transport requires energy.

✔ Explanation:
Because active transport works against the concentration gradient, it cannot happen spontaneously. The cell must expend energy — typically in the form of ATP — to power protein pumps or other mechanisms that move the substances.

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## B. Match the type of transport shown in the image

We have three images and four options. Let’s match each image correctly:

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Image 1:

> Shows a vacuole forming from the plasma membrane, engulfing material from outside into the cytoplasm.

🔹 Correct match: c. Endocytosis

✔ Explanation:
Endocytosis is the process by which cells take in materials by engulfing them with their plasma membrane, forming vesicles. The image clearly shows the membrane folding inward to form a vesicle (labeled “Vacuole”) containing material from outside — classic endocytosis.

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Image 2:

> Shows a carrier protein embedded in the membrane using ATP to move small blue molecules from low concentration (outside) to high concentration (inside).

🔹 Correct match: b. Carrier-assisted transport

✔ Explanation:
This is also known as active transport via carrier proteins. The presence of ATP indicates energy use, and the carrier protein is specifically transporting molecules against their gradient. While “facilitated diffusion” also uses carrier proteins, it does NOT require ATP. So this is carrier-assisted active transport.

*(Note: Option “d. Facilitated Diffusion” is incorrect here because it doesn’t require energy.)*

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Image 3:

> Shows vesicles inside the cell fusing with the plasma membrane and releasing their contents outside.

🔹 Correct match: a. Exocytosis

✔ Explanation:
Exocytosis is the opposite of endocytosis — it’s the process where vesicles fuse with the plasma membrane to release materials *out* of the cell. The image shows vesicles moving toward and fusing with the membrane to expel their contents — classic exocytosis.

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## ✔ Final Answers:

A.

1. lower → higher
2. against
3. requires

B.

- Image 1 → c. Endocytosis
- Image 2 → b. Carrier-assisted transport
- Image 3 → a. Exocytosis

*(Option d. Facilitated Diffusion is not used — it would show passive movement through a channel/carrier without ATP.)*

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Let me know if you’d like diagrams or further clarification!