No Count: Cell Transport, Photo and Cell Resp. Mini-Test Review

Movement of molecules from an area of high concentration to an area of low concentration is

• diffusion 

• passive transport

• osmosis

• all of the above

Answer explanation

The question asks about the transition of molecules from a high concentration zone to a low one. This process is defined as diffusion, passive transport, and osmosis. Therefore, all of the provided options are correct.

If a red blood cell is put in distilled water, what will most likely happen to the cell?

• Nothing will happen

• It will shrivel.

• It will burst and then shrivel up

• It will swell and burst

Answer explanation

When a red blood cell is placed in distilled water, it will swell and burst. This is because distilled water is hypotonic to the contents of the red blood cell. The water will move into the cell by osmosis to try and equalise the concentration of solutes. This influx of water causes the cell to swell, and eventually burst.

What does semi-permeable mean?

• Some molecules can move through the membrane

• Nothing can move through the membrane

• All molecules can pass through the membrane.

Answer explanation

The term 'semi-permeable' refers to a membrane that allows only certain types of molecules to pass through it. The correct answer, 'Some molecules can move through the membrane', accurately describes this feature. This means that the membrane does not allow all molecules nor does it restrict all molecules, which is why the other two options are incorrect.

What is equilibrium?

• When concentrations cannot be balanced between two substances 

• When concentrations are balanced between two substances 

• Making the energy in the top half of your body equal the the energy in the bottom half

• Concentrations do not exist 

Answer explanation

Equilibrium, in context of chemistry, refers to the state where concentrations of reactants and products are balanced. This state is reached when the rate of forward reaction equals the rate of backward reaction. Thus, 'When concentrations are balanced between two substances' is the correct answer to the question.

Which diagram best shows the end result of diffusion?

• F

• G

• H

• J

Answer explanation

The diagram labelled 'J' best represents the process of diffusion. Diffusion is the movement of particles from an area of high concentration to an area of low concentration until they are evenly distributed. The diagram 'J' likely illustrates this phenomenon correctly.

Which type of transport requires an input of energy?

• Passive Transport

• Osmosis

• Simple Diffusion

• Active Transport

Answer explanation

Active Transport is the correct answer because it is the process that requires an input of energy to move substances across the cell membrane, often against their concentration gradient. This is unlike Passive Transport, Osmosis, or Simple Diffusion, which don't require any energy as they move substances along the concentration gradient.

Movement of molecules through the cell membrane from high to low concentration

• passive transport

• active transport

Answer explanation

The movement of molecules through the cell membrane from high to low concentration is known as passive transport. This process doesn't require any energy as substances move along the concentration gradient. Therefore, the correct answer is 'passive transport'.

Active transport moves substances against a concentration gradient 

• true

• false 

Answer explanation

Active transport does indeed move substances against a concentration gradient. This means that it transports molecules from an area of lower concentration to an area of higher concentration, which is the opposite direction of natural diffusion. It requires energy to do this, hence the term 'active' transport.

Which form of active transport is being shown?

• Pinocytosis

• Endocytosis

• Exocytosis

• Osmosis

Answer explanation

The question asks about a form of active transport. Active transport mechanisms involve the movement of molecules against their concentration gradient, requiring energy. Exocytosis is a form of active transport where cells transport molecules out of the cell by expelling them in an energy-dependent process. Hence, the correct answer is 'Exocytosis'.

Which is NOT a form of active transport?

• Endocytosis

• Osmosis

• Exocytosis

• Sodium potassium pump

Answer explanation

Active transport is a process that moves molecules against their concentration gradient, requiring energy. Endocytosis, Exocytosis, and the Sodium-Potassium pump are all examples of active transport. However, Osmosis is a type of passive transport that doesn't require energy as it moves molecules from an area of high concentration to low concentration