Which of the following was the likely origin of chloroplasts?
a. cyanobacteria
b. mitochondria
c. extremophiles
d. prokaryotes
a. cyanobacteria
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For an accurate diagnostic of a current infection, acute and convalescent sera should reflect a(n) _____ in the patient's antibody titer of _____ doubling dilutions
a. decrease; two b. increase; two c. decrease; four d. increase; four
Common spermicidal preparations have a toxic effect on Lactobacillus species and are associated with increased risk of urinary tract infection. Which of the following statements best explains this observation?
A. Production of spermicidal chemicals must be rigorously controlled to avoid contamination with organisms like E. coli. B. Lactobacillus can cause urinary tract infections when transferred from the reproductive system to the urinary system. C. Use of spermicide must be carefully monitored so that it doesn't inadvertently enter the urinary tract. D. Without the protective coating of Lactobacillus, organisms like E. coli can attach to bladder epithelial cells.
Which level of primary control in eukaryotic gene activity involves changes in the polypeptide chain before it becomes functional?
A. translational control B. transcriptional control C. posttranslational control D. feedback control E. posttranscriptional control
Which of the following cancers is often not detected in women until a late stage because of a lack of routine diagnostic testing?
A) prostate B) ovarian C) breast D) cervical