The Escherichia coli strain O157:H7 produces a life-threatening infection in humans if it gets into their digestive tracts. The O157:H7 toxin is suspected to have been transferred from a different bacterium called Shigella flexner. This is an example of ______ gene transfer.
horizontal
vertical
diagonal
jumping
The Correct Answer is A
A. Horizontal: Horizontal gene transfer refers to the movement of genetic material between organisms other than by descent; the toxin genes were transferred between different bacterial species, fitting this process.
B. Vertical: Vertical gene transfer occurs from parent to offspring during reproduction, not between unrelated bacteria.
C. Diagonal: Diagonal gene transfer is not a recognized biological process.
D. Jumping: “Jumping” may refer to transposons within a genome, but not to gene exchange between distinct organisms as described in this case.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
A. Apoenzymes: Apoenzymes are the protein portion of enzymes and do not indicate whether the enzyme is secreted or extracellular.
B. Exoenzymes: Exoenzymes are secreted by the cell into the surrounding medium to hydrolyze large extracellular substrates like casein, producing clear zones around colonies.
C. Ribozymes: Ribozymes are RNA molecules with catalytic activity that function mainly inside cells; they are not secreted protein enzymes that digest extracellular proteins like casein.
D. Regulated enzymes: The enzymes degrading casein may be regulated, but the defining feature shown (activity outside the colony) is secretion, so regulated describes control rather than location of action.
E. Endoenzymes: Endoenzymes act inside the cell; enzymes that produce extracellular clearing of casein are acting outside the cell and therefore are not endoenzymes.
Correct Answer is E
Explanation
A. In mitochondria:
Mitochondria are intracellular organelles in eukaryotes where many metabolic reactions occur, but exoenzymes are secreted enzymes that act outside the cell rather than inside organelles.
B. Within the cell membrane:
Some enzymes are membrane-associated and act at or through the membrane, yet exoenzymes are secreted beyond the cell surface to act on extracellular substrates.
C. In lysosomes:
Lysosomes contain hydrolytic enzymes that function inside the cell to digest materials; exoenzymes operate outside the cell rather than within intracellular digestive organelles.
D. In cytoplasm:
Cytoplasmic enzymes catalyze intracellular reactions; exoenzymes are exported and function extracellularly.
E. Outside of the cell:
Exoenzymes are secreted by the cell into the external environment (or into host tissues) where they break down large molecules into smaller units the cell can transport or where they contribute to pathogenicity.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.