Four Exam Study Guide
1. Discuss the richest source of stored chemical energy in the body.
a. An animals diet.
2. What qualifies certain nutrients to be considered essential in the diets of some
animals?
a. Essential nutrients are required by cells and must be obtained from dietary
sources.
3. List the vitamins according to whether theyre fat soluble or water-soluble.
a. Fat-soluble: A, D, E, K
b. Water-soluble: B, C
4. Describe the process of absorption, hydrolysis, digestion, ingestion, and
elimination in human nutrition.
a. Absorption
a.i. Uptake of nutrients by body cells
a.ii. Occurs mostly in the small intestine
a.iii. Passes into blood vessels through diffusion into the simple
columnar epithelial tissue of the small intestine
b. Hydrolysis
b.i. Enzymatic hydrolysis splits bonds into molecules with the addition
of water
c. Digestion
c.i. Breaking down food into absorbable molecules
c.ii. Mechanical digestion increases surface area
c.iii. Chemical digestion splits food into small molecules that can pass
through membranes and later go on to build larger molecules
c.iv. Mouth (mastication) esophagus stomach (HCl) chime
sent to the small intestine large intestine defecation
d. Ingestion
d.i. The act of eating or drinking
e. Elimination
e.i. The passage of undigested materials out of the alimentary canal
5. What is the value of the large surface area in the gut?
a. A larger surface area facilitates a higher rate of absorption.
b. Carnivores have an expandable stomach to allow them to consume large
amounts of food in order to plan for long periods of time with no food.
6. Describe the compartments of the alimentary canals in earthworms, grasshoppers,
and birds.
a. Earthworm
a.i. Mouth pharynx esophagus crop (stores and moistens
food) gizzard (churns food) intestine anus
b. Grasshopper
b.i. Mouth pharynx esophagus crop (stores and moistens)
gizzard (churns food) pyloric valve Stomach intestine
anus
c. Bird
c.i. Beak esophagus crop gizzard small intestine cloaca
(anus for birds)
7. What is peristalsis in the digestive system?
a. Peristalsis is a series of rhythmic contractions of muscles in the alimentary
canal
8. After ingestion by humans, what is the first category of macromolecules to be
chemically digested by enzymes in the mouth?
a. The mouth first digests carbohydrates through enzymes, including
amylase
9. Discuss the locations in the human alimentary canal where each of the categories
of macromolecules is digested.
a. Carbohydrates digested are in the mouth by amylase and also in the
stomach by HCl
b. Proteins are digested in the stomach by pepsin and enzymes secreted by
the pancreas and also in the duodenum (first part of the small intestine)
c. Lipids are digested in the small intestine by bile salts
10. Where are bile salts produced and what is their function?
a. Bile salts are produced in the liver, stored in the gall bladder, and exist to
emulsify lipids
11. What is the significant contribution of intestinal bacteria to human nutrition?
a. Through digestion of ingested materials, some bacteria produce vitamins
(ex: vitamin K, biotins) that are absorbed through the walls of the intestine
b. They also prevent growth of harmful bacteria and produce some hormones
that direct the host to store fat
12. How are stomach cells moderately well adapted to the acidity and proteindigesting activities in the stomach?
a. The cells are thicker, perform more forceful contractions, and are covered
by a layer of mucus that protects the cells from stomach juice.
b. The cells secrete pepsin and HCl,
b.i. Pepsin is a protease, which means it digests protein into smaller
peptides
c. Some cells secret pepsinogen, which turns into pepsin when mixed with
HCl
d. The pH is 2, which kills bacteria and denatures protein
e. Parietal cells allow protein digestion
13. How are cattle able to survive on a diet consisting almost entirely of plant
material?
a. Cattles are able to regurgitate and chew their food, which allows for
further digestion
b. They have cellulose digesting, symbiotic microorganisms in chambers of
their stomachs
14. What happens to excess organic molecules when their digestion and absorption
results in more energy-rich molecules than are immediately required by an
animal?
15. How is hypoglycemia, or low levels of glucose in the blood of a healthy human,
corrected?
16. In which order does a fasting animal whose energy needs exceed those provided
in its diet draw on its stored resources (i.e. muscle glycogen, fat liver glycogen)
17. Hoe do jackrabbits living in hot, arid lands control their body temperatures when
the temperature of the outside air exceeds their internal body temperature?
18. Why do penguins, seals, and tuna have body forms that permit rapid swimming?
19. Why did the specialized structures of complex animals evolve?
20. Each living cell of all animals, whether large or small, is in contact with an
aqueous medium (internal pond or interstitial fluid). Discuss.