ZO 250: Study Questions for Digestion and Muscles hint for use: the material here can be easily copied from this page into a word processor if you would like to format it differently or leave more room below each question.
1. What is a zymogen? What is their importance in digestion? Why not just secrete the active form of an enzyme?
2. How does the stomach manage to digest proteins without digesting itself? There are at least three specific adaptations in a vertebrate that you should be able to list and explain here. Along these lines: if acidic secretion (which acid?) increases due to stress, intake of compounds like caffeine, or infection with Helicobacter pylori an ulcer can develop. What is an ulcer and how does this relate to the protective mechanisms you listed above?
3. DAnG: Discuss in detail how each letter of this acronym relates to the structure and function of the small intestine with respect to increasing uptake of nutrients. Along these lines, explain why the stomach does not have an epithelium like that of the small intestine.
4. How does the digestion and absorption of lipids differ from that of amino acids, sugars, and nucleic acids? Discuss the role of accessory digestive organs and different components of the circulatory system in your answer.
5. Where in the mammalian digestive system does chemical digestion of the following types of biological molecules begin?: sugars and complex carbohydrates, proteins, fats, nucleic acids.
6. Why can't you get energy from the main structural component of wood and grass? How is it that termites and cows can?
7. Diagram the working of a skeletal muscle. Be sure to show the neuromuscular junction, sarcomere, Z lines, thick and thin filaments, and sarcoplasmic reticulum. You should be able to explain what happens at each of these points in the activation of a muscle. To test your knowledge, predict where muscle contraction would be blocked (i.e., how far would activation of the muscle fiber get) with each of the following metabolic inhibitors:
a. a-bungarotoxin: binds to and blocks acetylcholine receptors8. What is summation in a muscle? How does this term relate to the tension developed by a muscle fiber? To tetanus?b. a-conotoxin: blocks voltage-gated calcium channels
c. ouabain: blocks the sodium/potassium pump, preventing generation of a membrane resting potential in neurons and muscle cells
d. a toxin that blocked the calcium active transport pump of the sarcoplasmic reticulum
e. botulinum toxin: blocks the release of acetylcholine from motor neurons
f. a toxin that prevents the binding of Ca2+ to troponin
g. rotenone: inhibits the electron transport system and thereby greatly reduces production of ATP
9. Below is a drawing of the length tension curve for a muscle. Explain why tension rises rapidly as the muscle approaches its resting length then drops as it is stretched beyond this with specific reference to cross bridge formation.
(I'm working on inserting the image here - I haven't just forgotten it)
10. Following on this theme, how does a muscle ordinarily produce different tensions for different tasks? Answer on both the cellular and whole muscle levels.