Page 16 - Q & A STPM 2022 Biology

Biology STPM Chapter 3 Membrane Structure and Transport
Answer : B
Facilitated diffusion shows saturation at a higher solute concentration when
all the binding sites on the transport proteins are used up. In simple diffusion,
a maximum rate of diffusion is usually not achieved.
Penerbitan Pelangi Sdn Bhd. All Rights Reserved.
Question 4
The diagram below shows the water potentials of three neighbouring plant
cells.
Semester
1
X Y
0 kPa -1500 kPa

Z
-4500 kPa

In which direction will water move?
A From cell X to cells Y and Z.
B From cell Y to cells X and Z.
C From cell Z to cell X.
D From cell Z to cell Y.

Answer : A
Water moves from a region of high water potential to a region of lower (more
negative) water potential, down a water potential gradient.

Question 5
A cell takes in dissolved materials by forming tiny vesicles around fluid droplets
trapped by folds of the plasma membrane. This process is
A active transport.
B receptor-mediated endocytosis.
C pinocytosis.
D facilitated diffusion.

Answer : C
In pinocytosis, the material taken up by the cell is liquid. Tiny droplets are
trapped by the folds of the membrane. It is then pinched off into the cytosol
as tiny vesicles.

56

Chapter 3.indd 56 11/2/21 9:21 AM