Explanations
1. A
Total magnification is calculated by multiplying the
power of the ocular and objective lenses. Since, in this case, the
ocular lens has a magnification power of 10x and none of the possible
objective lenses has a magnification power of 1x, it’s impossible
for the microscope to have a total magnification power of 10x.
2. B
Prokaryotes lack membrane-bound organelles but must
have ribosomes for protein synthesis. Prokaryotes do not have a
nucleus; DNA is stored in a coil in the cytoplasm.
3. D
The Golgi apparatus packages proteins for secretion
by the cell. As for the other answer choices: the nucleus controls
the cell’s activities, proteins are made in the cytoplasm and endoplasmic
reticulum by ribosomes, and lipids are synthesized by the smooth
endoplasmic reticulum.
4. D
All of the answers are forms of transport, but only
exocytosis is used to remove synthesized proteins from the cell.
These proteins cannot undergo diffusion because they are too large
to fit through the cell membrane. Osmosis refers only to the transport
of water. Pinocytosis is a form of transport that involves taking
liquids into the cell rather than secreting them. Passive transport
includes diffusion and osmosis.
5. A
The ribosomes attached to the ER membrane
give it its roughness. The smooth ER, not the rough ER, functions
in lipid synthesis. Cellulose is part of the cell wall in plants.
6. A
Lysosomes digest cellular debris. The other
choices refer to functions that are performed by organelles but
not by lysosomes. Chloroplasts produce energy through photosynthesis,
vacuoles store nutrients, the cell membrane regulates the movement
of substances in and out of the cell, and lipid synthesis takes
place in the smooth endoplasmic reticulum.
7. B
Clearly phospholipids must be a type of molecule in
the phospholipid bilayer. The bilayer also contains proteins, which
float in the bilayer like icebergs in a sea.
8. A
All of the processes listed are means of transport,
except for respiration. However, only diffusion is a process by
which molecules move from high to low concentration. Pinocytosis,
endocytosis, and exocytosis are means of active transport, while
diffusion is a type of passive transport.
9. D
The cell membrane consists of a floating sea of phospholipids.
If the membrane were rigid, organisms would fracture when they move.
10. B
Water is in lower concentration outside the
cell because there is more salt there. Since substances diffuse
from areas of high concentration to low concentration, water will
move out.