Active and Passive Transport

Where is there a low concentration of dye?

• at the bottom of cup

• in the color

• at the top of cup 

• no concentration gradient

Answer explanation

The dye concentration is highest at the top of the cup due to diffusion. Therefore, the lowest concentration is at the bottom of the cup, where the dye has not yet settled or mixed.

The picture below is an example of _________________.

• osmosis

• isotonic

• diffusion

• active transport

Answer explanation

The picture illustrates diffusion, which is the movement of particles from an area of higher concentration to an area of lower concentration. This process occurs naturally and does not require energy, distinguishing it from active transport.

Osmosis is the movement of _____ across a membrane.

• food

• energy

• oxygen

• water

Answer explanation

Osmosis specifically refers to the movement of water molecules across a semipermeable membrane. This process is crucial for maintaining cell turgor and overall homeostasis, making 'water' the correct answer.

Permeable means

• things can pass through

• the concentration levels are different

• it is permanent

• things are stuck

Answer explanation

Permeable refers to materials that allow substances to pass through them. Therefore, the correct choice is 'things can pass through', as it accurately describes the nature of permeable materials.

Passive transport requires no

• concentration gradients

• osmosis

• motion

• energy

Answer explanation

Passive transport requires no energy because it relies on the natural movement of molecules down their concentration gradient, allowing substances to cross membranes without the input of energy.

What is diffusion?

• when molecules move 

• when molecules move from a high concentration to a low.

• no movement 

• molecules move everywhere

Answer explanation

Diffusion is the process where molecules move from an area of high concentration to an area of low concentration. This movement continues until equilibrium is reached, making the correct choice "when molecules move from a high concentration to a low."

Which type of transport requires an input of energy?

• Passive Transport

• Osmosis

• Simple Diffusion

• Active Transport

Answer explanation

Active transport requires an input of energy to move substances against their concentration gradient, unlike passive transport methods such as osmosis and simple diffusion, which do not require energy.

Which form of active transport is being shown?

• Facilitated Diffusion

• Exocytosis

• Endocytosis

• Protein Pumps

Answer explanation

Endocytosis is a form of active transport where cells engulf substances, bringing them into the cell. This distinguishes it from facilitated diffusion, exocytosis, and protein pumps, which involve different mechanisms.

Which is NOT a form of active transport?

• Endocytosis

• Osmosis

• Exocytosis

• Pinocytosis

Answer explanation

Osmosis is the passive movement of water across a membrane, not requiring energy, while endocytosis, exocytosis, and pinocytosis are forms of active transport that require energy to move substances across cell membranes.

Which form of active transport is being shown?

• Pinocytosis

• Endocytosis

• Exocytosis

• Osmosis

Answer explanation

Exocytosis is the process where cells expel materials. It involves vesicles fusing with the plasma membrane to release their contents outside the cell, distinguishing it from endocytosis, which brings substances in.