1. The body of a slime mold that flows over a rotten log appears to lack any partitioning into distinct cells; however it does become cellular when it changes form to produce spores. The surfaces of parasitic flatworms and some insect tissues are "syncytial" layers of living material that has many nuclei but lack partitioning by cell membranes. These tissues actively consume food and produce wastes. Considering that the cell theory states "all living things are composed of cells," then
A. these tissues are not living because they violate the cell theory.
B. this proves some vital force is involved beyond normal cell structures in order to give life to living organisms.
C. these tissues are obviously a bridge between nonliving and primitive living cells.
D. the general concept of life-is-cellular still holds since sometime in their life these organisms still utilize cells, but this shows cell membranes can be abandoned.
E. All of the above are true.
2. Each time water in a cell freezes slowly, long sharp crystals spear through the membrane structures of the cell. The most reasonable explanation for the bad taste of meat that has "freezer burn" from repeated freezing is the destruction of
A. the nuclear membrane, causing mixing of nucleoplasm and cytoplasm.
B. ribosomes, causing them to break into subunits.
C. lysosomes, and the resultant self-digestion.
D. rough endoplasmic reticulum causing the release of ribosomes.
E. the Golgi apparatus and vesicles.
3. If we move cells to a low-gravity environment, such as in space exploration, we could most likely expect a change in the
A. nucleus and the genetic process.
B. chloroplast and energy capture.
D. vacuoles and lysosomes.
E. mitochondrion and energy release.
4. An agent would make a good antibiotic if it affected a structure or process only found in bacterial cells and not in our (eukaryotic) cells. Which of the following actions would theoretically make a good candidate antibiotic?
A. prevents repair of the peptidoglycan cell wall
B. damages the nuclear membrane
C. damages DNA
D. prevents mitochondrial ribosomes from producing proteins
E. stops cell respiration
5. The endosymbiotic hypothesis argues that prokaryotes became some of the organelles of early eukaryotic cells. This would be supported by what evidence?
A. The vacuoles can "come and go" across the plasma membrane.
B. The mitochondria and chloroplasts have their own DNA.
C. Mitochondria and chloroplasts are nearly identical to some free living prokaryotes.
D. Both B and C are evidence for endosymbiosis.
6. Many lotions and hand creams soon disappear from the surface of the skin when they have not been wiped off. This is mostly due to
A. Water soluble molecules evaporate.
B. Nearly all molecules are absorbed by plasma membranes.
C. Noncharged, lipid-soluble molecules can cross the plasma membrane with ease.
D. Any molecule in higher concentration outside a cell will diffuse across.
E. Because they are healthy molecules, cells actively transport the lotion molecules across.
7. In the Malpighian tubules of an insect, salt molecules are actively transferred from body fluids to the inside of the tubule. What effect does this have on other factors?
A. Water is also "pulled" by osmosis into the Malpighian tubule.
B. Waste molecules move into the Malpighian tubule.
C. "Good" but permeable molecules needed by the insect move into the Malpighian tubule.
D. All of the above would occur.
E. None of the above since diffusion is dependent on the species.
8. A potato slice, when placed in water for several hours, will become very stiff because
A. water has passed into the potato cells to produce turgor.
B. water has passed out of the potato cells causing plasmolysis.
C. cellulose synthesis has been stimulated.
D. salt has entered the cells of the potato.
T F 9. A hypertonic solution will have a greater concentration of solute and water per unit volume than is found inside the cell.