Two forms of hemophilia are determined by genes on the X chromosome in humans. Assume that a phenotypically normal woman whose father had hemophilia is married to a normal man. What is the probability that their first son will have hemophilia?
A) 1/2
B) 100%
C) zero
D) 1/4
E) 1/3
Answer: A
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Aminoacyl-tRNA synthetases catalyze covalent addition of ________ to tRNAs.
Fill in the blank(s) with the appropriate word(s).
Many bacteria are pathogenic because they carry large segments of DNA called ________ ________, which were acquired by horizontal gene transfer, and which carry genes responsible for virulence.
What will be an ideal response?
New polypeptide chains for proteins are assembled on
1.Golgi bodies. 2.lysosomes. 3.ribosomes. 4.peroxisomes. 5.centrosomes.
MRSA is the acronym for methicillin-resistant Staphylococcus aureus. Many of the strains of the common bacterium are also resistant to other antibiotics in use today. The resistance is linked to a collection of genes carried on plasmids that are passed from one bacterium to another by conjugation. Suppose a newly discovered, chemically different antibiotic is used in place of methicillin. Which of the following would be the most likely effect on Staphylococcus aureus antibiotic resistance?
(A) The gene for methicillin resistance, no longer needed, would disappear entirely from Staphylococcus aureus populations within a few generations. (B) Transmission of the methicillin-resistance plasmid by conjugation would increase among the Staphylococcus aureus population as the genes would confer resistance to the new antibiotic. (C) Transmission of the methicillin-resistance plasmid would gradually decrease but the plasmid would not entirely disappear from the Staphylococcus aureus population. (D) Transmission of the methicillin-resistance plasmid by conjugation would increase among the Staphylococcus aureus population due to destruction of bacteria without the plasmid through use of the new antibiotic.