Passive Transport

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 a process in which molecules move from an area of high concentration to one of lower concentration until equilibrium is reached. In the given question, the correct answer is the explanation of this process. It is the phenomenon of spontaneous spreading of particles which can be anything - solid, liquid, or gas.

Where is there a low concentration of dye?

• at the bottom of cup

• in the color

• at the top of cup 

• no concenteraion gradient

Answer explanation

The question asks about the location of a low concentration of dye. The correct answer is 'at the bottom of the cup'. This is because the dye usually tends to rise up to the top due to its lighter weight, resulting in a lower concentration at the bottom.

The picture below is an example of _________________.

• osmosis

• isotonic

• diffusion

• active transport

Answer explanation

The question is asking for the process illustrated in the given image. The correct answer is 'diffusion'. Diffusion is the process where particles move from an area of high concentration to an area of low concentration until the concentrations are equal. Osmosis specifically involves water, isotonic is a state of equal concentrations and active transport involves energy to move particles against a concentration gradient.

Osmosis is the movement of _____ across a membrane.

• food

• energy

• oxygen

• water

Answer explanation

Osmosis is the process that involves the movement of a solvent (such as water) from an area of low solute concentration, through a membrane, to an area of high solute concentration. This is a vital process in biological systems as it helps in the transport of water and nutrients. Hence, the correct answer to the question is 'water'.

During osmosis

• water moves from high to low concentration

• large or oddly shaped molecules move across a cell membrane

• water moves when energy is used

• proteins are built

Answer explanation

Osmosis is a biological process where water moves from an area of high concentration to an area of low concentration. This movement occurs across a semi-permeable membrane, such as a cell membrane, until there is an equal concentration of water on both sides. Therefore, in the context of the given question, the correct answer is that 'water moves from high to low concentration' during osmosis.

Permeable means

• things can pass through

• the concentration levels are different

• it is permanent

• things are stuck

Answer explanation

The question is asking for the meaning of the term 'Permeable'. Out of the given options, 'things can pass through' accurately defines this term. A permeable substance is one that allows liquids or gases to pass through it. The other options do not correctly define the term.

The diffusion of water through a semi-permeable membrane is called?

• Osmosis

• Cell wall

• Diffusion

• Respiration

Answer explanation

The process of water molecules moving from a region of higher concentration to a region of lower concentration through a semi-permeable membrane is defined as osmosis. In the given question it is mentioned that water is diffusing through a semi-permeable membrane, hence the correct answer is 'Osmosis'.

Where is there a low concentration of perfume?

• in the bottle

• on the hand

• in the room

• in the top

Answer explanation

The question asks where there is a low concentration of perfume. The correct answer is 'in the room'. This is because perfume, once sprayed, disperses into the room where it is used. While it may still be on the hand or in the bottle, the concentration is lower in the room due to diffusion.

What is the definition of  Selective Permeability?

• The movement of materials across the cell membrane that requires NO ENERGY from the cell.
  

• The movement of materials through (or across) the cell membrane
  

• The ability of the cell membrane to allow some things to pass through while preventing other things from passing through.

• The movement of molecules from an area of high concentration to a area of low concentration 
  

Answer explanation

Selective Permeability is defined as the ability of the cell membrane to allow some substances to pass through while preventing others. This concept is vividly depicted in the correct option. It’s not about movement from high to low concentration or the energy requirement, but about the selectiveness of what the membrane allows to pass through.

When both inside and outside of a cell have the same amount of water it is said that the cell has reached a state of

• Osmosis

• Diffusion

• Equilibrium

Answer explanation

The state where the inside and outside of a cell have the same amount of water is called equilibrium. This is because equilibrium refers to a state of balance or stability, where no net change is occurring. Options 'Osmosis' and 'Diffusion' are processes involved in achieving equilibrium but are not the state itself.