
Compare, Hypothesize, Invent
11. Scientists are very interested in understanding when cyanobacteria first emerged because, as the first organisms capable of oxygenic photosynthesis, it is thought that they triggered a sharp rise in atmospheric oxygen. For many years, certain lipid biomarkers have served as “molecular fossils” to date the first appearance of cyanobacteria. However, a 2010 study questioned whether these lipids, called 2-methylhopanoids, provide accurate information in light of a 2007 discovery that they also are produced by an anoxygenic phototrophic bacterium—a bacterium that does not produce oxygen as it uses light energy. The authors of the 2010 study identified genes in extant bacteria involved in synthesis of the lipid biomarkers and then constructed phylogenetic trees based on comparisons of these genes. They also identified the phyla to which the bacteria belonged (based on SSU rRNA analysis) and noted the habitats and
Read the original paper: Welander, P. V., et al. 2010. Identification of a methylase required for 2-methylhopanoid production and implications for the interpretation of sedimentary hopanes. Proc. Natl. Acad. Sci. USA. 107(19):8537.

Want to see the full answer?
Check out a sample textbook solution
Chapter 1 Solutions
Prescott's Microbiology
- Which of the follwowing cells from this lab do you expect to have a nucleus and why or why not? Ceratium, Bacillus megaterium and Cheek epithelial cells?arrow_forward14. If you determine there to be debris on your ocular lens, explain what is the best way to clean it off without damaging the lens?arrow_forward11. Write a simple formula for converting mm to μm when the number of mm's is known. Use the variable X to represent the number of mm's in your formula.arrow_forward
- 13. When a smear containing cells is dried, the cells shrink due to the loss of water. What technique could you use to visualize and measure living cells without heat-fixing them? Hint: you did this technique in part I.arrow_forward10. Write a simple formula for converting μm to mm when the number of μm's are known. Use the variable X to represent the number of um's in your formula.arrow_forward8. How many μm² is in one cm²; express the result in scientific notation. Show your calculations. 1 cm = 10 mm; 1 mm = 1000 μmarrow_forward
- Find the dental formula and enter it in the following format: I3/3 C1/1 P4/4 M2/3 = 42 (this is not the correct number, just the correct format) Please be aware: the upper jaw is intact (all teeth are present). The bottom jaw/mandible is not intact. The front teeth should include 6 total rectangular teeth (3 on each side) and 2 total large triangular teeth (1 on each side).arrow_forwardAnswer iarrow_forwardAnswerarrow_forward
- calculate the questions showing the solution including variables,unit and equations all the questiosn below using the data a) B1, b) B2, c) hybrid rate constant (1) d) hybrid rate constant (2) e) t1/2,dist f) t1/2,elim g) k10 h) k12 i) k21 j) initial concentration (C0) k) central compartment volume (V1) l) steady-state volume (Vss) m) clearance (CL) AUC (0→10 min) using trapezoidal rule n) AUC (20→30 min) using trapezoidal rule o) AUCtail (AUC360→∞) p) total AUC (using short cut method) q) volume from AUC (VAUC)arrow_forwardQUESTION 8 For the following pedigree, assume that the mode of inheritance is X-linked recessive, and that the trait has full penetrance and expressivity and occurs at a very low frequency in the hum population. Using XA for the dominant allele and Xa for the recessive allele, assign genotypes for the following individuals (if it is not possible to figure out the second allele of a genotype, that with an underscore): 2 m 1 2 1 2 4 5 6 7 8 9 IV 1 2 3 5 6 7 8 CO 9 10 12 13 V 1, 2 3 4 5 6 7 8 9 10 11 12 13 a. Il-1: b. 11-2: c. III-3: d. III-4: e. If individuals IV-11 and IV-12 have another child, what is the probability that they will have a boy with the disorder?arrow_forwardAnswerrarrow_forward
- Biology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxBiology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage LearningBiology: The Unity and Diversity of Life (MindTap...BiologyISBN:9781337408332Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa StarrPublisher:Cengage Learning
- Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage LearningConcepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax CollegeBiology Today and Tomorrow without Physiology (Mi...BiologyISBN:9781305117396Author:Cecie Starr, Christine Evers, Lisa StarrPublisher:Cengage Learning





