Explanations
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.

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