Lesson #5: Active Transport

Question 1

Active
Transport

Answer 1

The movement of molecules against
the concentration gradient (from an
area of low concentration to an area
of high concentration)

This requires ENERGY

The energy comes from ATP (Adenosine
Triphosphate) produced by the
mitochondria

ATP is broken down into ADP and a
phosphate ion, releasing 7000 calories of
energy.

Question 2

The Steps

Answer 2

The solute binds to the transport protein

ATP binds to the transport protein, providing
energy to move the solute against the
concentration gradient

Transport protein changes shape and deposits the
solute on the other side of the cell membrane.

Question 3

Endocytosis

Answer 3

A specialized form of active transport used to transport
molecules that are too large to pass through transport proteins
into the cell.

Molecules bind to glycoproteins (receptors) on the
outer surface of the cell which triggers the membrane
to fold inwards.

The membrane pinches off forming a vesicle.

The vesicle travels to the appropriate organelle.

Question 4

Types of
Endocytosis

Answer 4

Phagocytosis

endocytosis of larger solid molecules and
materials

Pinocytosis

endocytosis of liquid materials such as dissolved
nutrients

Question 5

Exocytosis

Answer 5

A specialized form of active transport used to transport molecules
that are too large to pass through transport proteins out of the cell.

Molecules bind to glycoproteins (receptors) on the inner
surface of the cell which triggers the membrane to fold
outwards.

The membrane pinches off forming a vesicle.

The vesicle travels to the appropriate target.