Question 1

What is active transport in the context of Edexcel GCSE Combined Science?

Accepted Answer

Active transport is a biological process where cells move molecules across a cell membrane from a region of lower concentration to a region of higher concentration. This process requires energy, usually in the form of ATP, because it is moving substances against their concentration gradient. It is a key concept in biology, particularly in understanding how cells maintain homeostasis and acquire necessary nutrients.

Question 2

How does active transport differ from passive transport in biology?

Accepted Answer

Active transport differs from passive transport in that it requires energy to move substances against their concentration gradient, from low to high concentration. In contrast, passive transport does not require energy and involves the movement of substances down their concentration gradient, from high to low concentration, through processes like diffusion and osmosis.

Question 3

Why is active transport important for cells?

Accepted Answer

Active transport is crucial for cells because it allows them to absorb essential nutrients and ions that are in lower concentrations outside the cell compared to inside. It also helps in removing waste products and maintaining optimal concentrations of ions and molecules necessary for cellular functions, which is vital for processes like nerve impulse transmission and muscle contraction.

Question 4

Can you provide an example of active transport in human biology?

Accepted Answer

A common example of active transport in human biology is the sodium-potassium pump. This pump moves sodium ions out of cells and potassium ions into cells, both against their concentration gradients. This process is essential for maintaining the electrochemical gradient across the cell membrane, which is necessary for nerve impulse transmission and muscle contraction.

Question 5

What role does ATP play in active transport?

Accepted Answer

ATP, or adenosine triphosphate, provides the energy required for active transport processes. During active transport, ATP is hydrolyzed to ADP and an inorganic phosphate, releasing energy. This energy is used to change the shape of transport proteins in the cell membrane, allowing them to move substances against their concentration gradient.

Active Transport

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