4. Movement across Membranes

What is the term given to the cell membrane, that enables only small particles to pass through?

• Selectively porous

• Selectively leaky

• Selectively permeable

• Selectively partial

What substances need to pass into every living cell, to enable them to obtain energy through the process of respiration?

• Water and glucose

• Water and oxygen

• Carbon dioxide and oxygen

• Glucose and oxygen

What is diffusion?

• The movement of substances down a concentration gradient

• The movement of substances up a concentration gradient

• The movement of substances from a low to a high concentration

• The movement of substances from a high to a low concentration, using energy

How does oxygen pass into animal and plant cells?

• Active transport

• Diffusion

• Osmosis

Is diffusion an active or a passive process?

• Active

• Passive

What does it mean to go down a concentration gradient?

• Move from an area of high concentration to low concentration

• Move from an area of low concentration to high concentration

Why is visking tubing used to model the cell membrane?

• It has large holes in its membrane

• It has tiny holes called pores which only allow large particles through

• It has large pores which allow small particles through

• It has tiny pores which only allow small particles through

What is osmosis?

• The diffusion of water down its concentration gradient

• The diffusion of water against its concentration gradient, through a selectively permeable membrane

• The diffusion of water from a region of high solute concentration to a region of low solute concentration, through a selectively permeable membrane

• The diffusion of water down its concentration gradient, through a selectively permeable membrane

What happens to the water concentration in a solution if you add a solute, such as salt or sugar?

• Increases

• Decreases

• Stays the same

What is active transport?

• The movement of substances down a concentration gradient, using ATP from respiration

• The passive movement of substances against a concentration gradient

• The movement of substances against a concentration gradient, using ATP from respiration

• The movement of substances down a concentration gradient