Humber Admissions Practice Test

What happens during active transport?

1. Materials move from low concentration to high concentration

2. Materials move passively down the concentration gradient

3. No energy is required

4. It only occurs in plant cells

The correct answer is: Materials move from low concentration to high concentration

Active transport is a critical process in cellular biology that involves the movement of materials across a cell membrane against their concentration gradient. This means that substances are transported from an area of lower concentration to an area of higher concentration. This process is essential for maintaining cellular functions, such as nutrient uptake and waste removal, and is facilitated by specific proteins in the cell membrane, known as transport proteins or pumps. Unlike passive transport, which allows materials to flow down their concentration gradient without the input of energy, active transport requires energy typically derived from ATP (adenosine triphosphate). This is necessary to move molecules against the natural direction of diffusion. Additionally, active transport is not limited to plant cells; it occurs in various types of cells, including animal cells. This versatility underscores the importance of active transport in maintaining the necessary concentrations of ions and molecules for optimal cellular functioning.