A cell is placed into a 1 millimolar solution of substance X and over time you witness the concentration of X inside the cell increase to 5 millimolar. What is the best explanation for this observation?
A. X is moving into the cell by simple diffusion.
B. X is moving into the cell by diffusion through a protein channel.
C. X is moving into the cell by facilitated diffusion.
D. X is moving into the cell by primary active transport.
E. Water is leaving the cell by osmosis.
D
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The superior orbital fissure is formed in the sphenoid bone, whereas the inferior orbital fissure is formed between the sphenoid and ________.
A) maxilla B) zygomatic C) ethmoid D) lacrimal
Answer the following statements true (T) or false (F)
1. Vitreous humor is the thick fluid in the posterior chamber of the eye. 2. The potentially blinding condition called glaucoma can occur if the fluid pressure of the eye drops too low. 3. The optic disc is able to respond only to bright light. 4. The nerve impulse of the eye begins when light enters through the iris of the eye and ends in the occipital lobe of the brain. This is called the visual pathway. 5. The external ear has two parts, the auricle and the pinna.
Molecules bind to receptor sites and are enclosed in vesicles in the process of
A) receptor-mediated endocytosis. B) pinocytosis. C) exocytosis. D) phagocytosis.
The structure that stores sperm before ejaculation is the ________.
Fill in the blank(s) with the appropriate word(s).