Answer the following question given this paragraph: 30.5 Applications of Atomic Excitations and De-Excitations 30. Figure 30.39 shows the energy-level diagram for neon. (a) Verify that the energy of the photon emitted when neon goes from its metastable state to the one immediately below is equal to 1.96 eV. (b) Show that the wavelength of this radiation is 633 nm. (c) What wavelength is emitted when the neon makes a direct transition to its ground state? 31. A helium-neon laser is pumped by electric discharge. What wavelength electromagnetic radiation would be needed to pump it? See Figure 30.39 for energy-level information. Ruby lasers have chromium atoms doped in an aluminum oxide crystal. The energy level diagram for chromium in a ruby is shown in Figure 30.64. What wavelength is emitted by a ruby laser?. Q: A desmosome is a cell structure that anchors the ends of what fibers together? Choices: - skeletal muscle - controllable muscle - smooth muscle - cardiac muscle A:
cardiac muscle
Answer the following question given this paragraph: Comets carry materials in from the outer solar system. Comets may have brought water into the early Earth. Other substances could also have come from comets. Q: What is rusting an example of? Choices: - radiation change - Decomposition - contamination change - chemical change A:
chemical change
Q: Answer the following question given this paragraph: Neurogenesis At one time, scientists believed that people were born with all the neurons they would ever have. Research performed during the last few decades indicates that neurogenesis, the birth of new neurons, continues into adulthood. Neurogenesis was first discovered in songbirds that produce new neurons while learning songs. For mammals, new neurons also play an important role in learning: about 1,000 new neurons develop in the hippocampus (a brain structure involved in learning and memory) each day. While most of the new neurons will die, researchers found that an increase in the number of surviving new neurons in the hippocampus correlated with how well rats learned a new task. Interestingly, both exercise and some antidepressant medications also promote neurogenesis in the hippocampus. Stress has the opposite effect. While neurogenesis is quite limited compared to regeneration in other tissues, research in this area may lead to new treatments for disorders such as Alzheimer's, stroke, and epilepsy. How do scientists identify new neurons? A researcher can inject a compound called bromodeoxyuridine (BrdU) into the brain of an animal. While all cells will be exposed to BrdU, BrdU will only be incorporated into the DNA of newly generated cells that are in S phase. A technique called immunohistochemistry can be used to attach a fluorescent label to the incorporated BrdU, and a researcher can use fluorescent microscopy to visualize the presence of BrdU, and thus new neurons, in brain tissue (Figure 16.20). Q: What was first discovered in songbirds that produce new neurons while learning songs? Choices: - proteins - Brain Cord - homeostasis - neurogenesis A:
A: neurogenesis
Question: Answer the following question given this paragraph: All living cells are surrounded by a cell membrane. Plant cells (Figure 17.3 "An Idealized Plant Cell") and animal cells (Figure 17.4 "An Idealized Animal Cell") contain a cell nucleus that is also surrounded by a membrane and holds the genetic information for the cell. (For more information about genetics and DNA, see Chapter 19 "Nucleic Acids". ) Everything between the cell membrane and the nuclear membraneincluding Saylor URL: http://www. saylor. org/books. Q: What part of the cell is surrounded by a membrane and holds the genetic information for the cell? Choices: - cell wall - upper - lower - nucleus A:
Answer: nucleus
*Question*
Answer the following question given this paragraph: Q: The logistics of carrying out cellular metabolism sets limits on what physical property of the cell? Choices: - surface - composition - layer - size A:
**Answer**
size
Answer the following question given this paragraph: Deposition also occurs when a stream or river empties into a large body of still water. In this case, a delta forms. A delta is shaped like a triangle. It spreads out into the body of water. An example is shown in Figure above . Q: What triangular feature is formed when a river empties into a large body of still water? Choices: - flow - confluence - region - delta A:
delta