NEET MDS Shorts
277849
General MicrobiologyHemolysis of Bacillus anthracis is typically absent or weak, depending on the strain.
389192
PhysiologyThe corpus luteum, which forms after ovulation, secretes estrogen and progesterone. These hormones are essential for preparing the endometrium for potential implantation and supporting early pregnancy.
817741
Oral SurgeryThe inferior alveolar nerve exits the mandibular foramen and runs in the
mandibular canal before it branches off to supply the teeth, including the
second premolar. To anesthetize the nerve at this point, the injection site is
commonly located between the first and second premolars, inferior to the root
apices, where the nerve is relatively superficial and accessible.
762512
ProsthodonticsThe purpose of the plane of orientation is to serve as a guide in establishing the occlusal plane.
403156
ProsthodonticsThe most common reason why hyperplastic tissue is removed or reduced during the construction of a complete denture is that it interferes with the stability of the denture.
368171
PhysiologyThe osmolarity of the tubular fluid leaving the ascending limb of the loop of Henle is 100mOsm/L, as it is impermeable to water and reabsorbs solutes.
149642
PeriodonticsA thin bluish line around the gingival margin is due to the absorption of lead.
887130
PathologyIndirect chemical carcinogens differ from direct acting agents in that they
require metabolic activation to exert their carcinogenic effects. This means
that indirect carcinogens must undergo a chemical transformation within the body
before they can damage DNA and induce cancer. Direct acting carcinogens, on the
other hand, can interact directly with DNA without the need for metabolic
conversion. Therefore, the correct answer is:
2. Induce carcinogenicity after chemical transformation
1. Induce carcinogenicity without chemical transformation: This statement is
incorrect for indirect chemical carcinogens. Indirect carcinogens are typically
non-reactive or less reactive in their original form and must undergo metabolic
activation to become DNA-reactive. This metabolic conversion is crucial for
their carcinogenic potential.
2. Induce carcinogenicity after chemical transformation: This is the correct
explanation. Indirect carcinogens require metabolic activation by the body's
enzyme systems, particularly phase I enzymes such as cytochrome P450, to convert
them into electrophilic or reactive intermediates that can interact with DNA.
This activation process can occur in various tissues, often the liver, where
these enzymes are present. The reactive metabolites then form DNA adducts, which
can lead to mutations and ultimately cancer if not repaired properly by the
cell's DNA repair mechanisms.
3. Don’t require metabolic conversion: This statement is incorrect. Indirect
carcinogens do require metabolic conversion to become active carcinogens. It is
the direct acting carcinogens that can interact with DNA without the need for
such activation because they are already electrophilic or reactive in their
original form.