Compare and contrast the digestive process in animals with two-way flow through their digestive
system and those that have a digestive system with one-way flow. What will be an ideal response?
In both processes, food molecules are broken down by digestive enzymes secreted into a defined
space. In a one-way flow digestive process, food enters a gastrovascular cavity through a mouth-like
opening. Digestive enzymes are secreted into this cavity, and the products of digestion are absorbed
into the cells that line the cavity. The undigested particles are ejected through the mouth-like opening
which now functions as an anus. In a two-way flow digestive process, the digestive system is a tubelike
structure with a mouth at one end and an anus at the other. Food enters through the mouth, is
pushed via peristalsis through the digestive tube where digestion occurs. The undigested particles are
eliminated through the anus. This “tube-within-a-tube” system allows for specialization of parts of the
digestive tube, and the animal can eat and eliminate continuously.
You might also like to view...
Bacteria ____
a. are haploid b. are diploid c. are polyploid d. have double-stranded RNA genomes e. have single-stranded DNA genomes
Which of the following is incorrect about transfer RNA?
A. It has an anticodon that is complementary to a codon. B. It has a bottom hairpin loop with an anticodon. C. The initiator tRNA that binds to the P site has the anticodon UAC. D. The initiator tRNA in bacteria carries tryptophan. E. It contains a binding site for an amino acid.
Courtship is often dependent on what?
A. social releasers B. a stimulus/response chain C. an alarm call D. taxis E. size and colors
At what two checkpoints does the cell check for the integrity of the DNA?
A. G1 and mitotic B. G1 and cytokinesis C. G2 and mitotic D. cytokinesis and G2 E. G1 and G2