Question

64 multiple choice 2 points
which of the following is not a basic layer of the digestive system?
mucosa
all of the above are basic layers of the digestive system
submucosa
serosa
muscularis externa

65 multiple choice 2 points
what limits the rate of catalysis?
an enzyme
all of the above
decreasing substrate concentration
lowering the activation energy
none of the above

Explanation:

Identify basic layers of the digestive system

The four basic layers of the alimentary canal from inside out are the mucosa, submucosa, muscularis externa, and serosa (or adventitia). Since mucosa, submucosa, serosa, and muscularis externa are all basic layers, the correct option is "All of the above are basic layers of the digestive system".

Determine what limits the rate of catalysis

The rate of an enzymatic reaction is directly dependent on the concentration of the substrate. Decreasing the substrate concentration reduces the frequency of effective collisions between substrate molecules and active sites, thereby limiting and decreasing the rate of catalysis. Lowering the activation energy increases the rate, and the presence of an enzyme increases the rate. Thus, "Decreasing substrate concentration" is the correct limiting factor.

Answer:

Question 64

• mucosa
• All of the above are basic layers of the digestive system (Correct answer)
• submucosa
• serosa
• muscularis externa

Question 65

• An enzyme
• all of the above
• Decreasing substrate concentration (Correct answer)
• Lowering the activation energy
• none of the above