Ribosomal RNAs are manufactured in which specific area of a eukaryotic cell? ()
A. The nucleus
B. The cytoplasm
C. The nucleolus
D. The chromatin
查看答案
The current theory of the structure of the plasma membrane is best described by the _______model. ()
A. sandwich
B. fluid-mosaic
C. unit membrane
D. electrochemical
In a phospholipid bilayer, the ()
A. phosphate groups are hydrophobic.
B. proteins are located only between the two layers.
C. fatty acid tails are hydrophilic.
D. phosphate heads are oriented toward the exterior of the cell or toward the cytoplasm.
Molecules in the cell membrane that function as carriers are ()
A. proteins
B. glycerol
C. cholesterol
D. Phospholipids
Which of the following conditions is required for diffusion to occur? ()
ATP energy
B. A living cell
C. A concentration difference
D. A selectively-permeable membrane
微信支付 
支付宝支付