16

22) Cell walls 
          A) Have many small holes 
 

B) Only occur in plant cells  

C) Dissolve when a plant dies 

D) Are made primarily from phospholipids 

E) All of the above 

 
23) The movement of molecules across a membrane from an area of higher  
       concentration (of the molecule)to an area of lower concentration is best  
       described as 
 A) 

Osmosis 

B) Passive transport 

C) Active transport 

D) Electron transport 

 E) 

Receptor-mediated 

endocytosis 

 
24) From your knowledge of the function of lysosomes, the pH of lysosomes is  
       likely to be 
 A) 

Always 

changing 

 D) 

9 

 B) 

5 

   E) 

12 

 C) 

Neutral 

25) In a phospholipid bilayer, the 
          A) Phosphate groups are hydrophobic 
 

B) Fatty acids tails are ionized 

C) Fatty acid tails are hydrophilic 

D) Proteins are located only between the two phospholipid bilayers 

E) Phosphate heads are oriented toward the exterior of the cell or toward  

               the cytoplasm 

26) If enzymes were used during a reaction, which of the following could be added  
       to a system to make the reaction occur faster? 
 A) 

Water 

B) A decrease in temperature 

C) An small increase in heat energy 

D) End products 

E) All of the above 

 
27) Which of the following does NOT describe a chemical reaction? 
          A) The products are placed to the left of the arrow 
 

B) The reactants are placed to the left of the arrow 

C) The arrow represents the direction in which the reaction proceeds 

D) Atoms must be balanced on both sides of the equation 

E) All of the above are true