NEET MDS Shorts
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NEETMDSMitochondrial inheritance is characterized by a mother transmitting the disease to all her children because offspring inherit mitochondria exclusively from the mother's egg cell.
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Biochemistry
Epinephrine, also known as adrenaline, is a hormone and neurotransmitter that
is synthesized in the body from the amino acid tyrosine. Tyrosine is a
non-essential amino acid, which means that it can be synthesized in the body
from phenylalanine, another essential amino acid. The synthesis of epinephrine
occurs in two main steps:
1. Hydroxylation of tyrosine: Tyrosine is converted into dihydroxyphenylalanine
(DOPA) by the enzyme tyrosine hydroxylase. This is the rate-limiting step in the
synthesis of epinephrine.
2. Decarboxylation and further hydroxylation: DOPA is then decarboxylated to
form dopamine, which is further hydroxylated to produce norepinephrine.
Norepinephrine is the immediate precursor of epinephrine.
3. Formation of epinephrine: Norepinephrine is methylated by the enzyme
phenylethanolamine N-methyltransferase (PNMT) and converted into epinephrine.
The other amino acids listed are not directly involved in the synthesis of
epinephrine:
1. Valine and Leucine are branched-chain amino acids that are primarily involved
in the metabolism of muscles and energy production.
2. Cysteine is a sulfur-containing amino acid that is important for the
synthesis of proteins with disulfide bridges and is a precursor for other
molecules like glutathione and taurine, but not directly involved in the
synthesis of epinephrine.
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Oral medicineFull thickness grafting is effective in minimizing wound contraction because it provides a more stable and vascularized tissue bed for healing
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General PathologySudden painful enlargement of the thyroid with hyperthyroidism that lasts for 6-8 weeks is the typical clinical course of subacute granulomatous thyroiditis.
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State PSC PYQThe DMFT (Decayed, Missing, and Filled Teeth) index is used to measure both the prevalence and severity of dental caries in an individual. It quantifies the number of teeth that are decayed, missing due to caries, or filled, providing a comprehensive assessment of past and present caries experience.
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EndodonticsThe primary cause of weakening in an endodontically treated tooth is the loss of sound tooth structure during the access cavity preparation and subsequent canal instrumentation. The extent of this preparation, particularly the removal of marginal ridges and cusps, significantly compromises the tooth's structural integrity.
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Pathology
Nuclear cytoplasmic asynchrony refers to a condition where the nucleus and
cytoplasm of a cell do not develop at the same rate. This can occur in various
forms of anemia and other pathological conditions. Here's a detailed explanation
of the concept and its relevance to the options provided: correct answer is:
1. Megaloblastic Anemia: Megaloblastic anemia is a type of anemia characterized
by the presence of large, immature, nucleated red blood cells (megaloblasts) in
the bone marrow and peripheral blood. This condition is primarily caused by a
deficiency in vitamin B12 or folic acid, which are essential for DNA synthesis
during cell division. The nucleus of the cells divides more slowly than the
cytoplasm, leading to an asynchronous development and the formation of large,
abnormal cells. In megaloblastic anemia, the nucleus is often large and
hyperchromatic (darkly stained), while the cytoplasm is relatively less
developed and pale. Therefore, this option is the most appropriate answer.
2. Fe Deficiency Anemia: Iron deficiency anemia is the most common type of
anemia worldwide, resulting from a lack of iron in the body. Iron is a critical
component of hemoglobin, which is responsible for carrying oxygen in red blood
cells. In this condition, the body produces smaller than normal red blood cells
(microcytic) that lack hemoglobin, leading to decreased oxygen transport. The
nucleus and cytoplasm of the erythrocytes are typically smaller than normal, and
there is no significant asynchrony in their development. Hence, this option is
not a characteristic feature of nuclear cytoplasmic asynchrony.
3. Erythroblastosis Fetalis: This is a condition that occurs when an Rh-negative
mother has an Rh-positive fetus. The mother's immune system produces antibodies
against the fetal red blood cells, leading to their destruction. This causes
anemia in the newborn. However, erythroblastosis fetalis is not typically
associated with nuclear cytoplasmic asynchrony. The anemia is a result of
hemolysis (destruction of red blood cells) rather than an intrinsic defect in
the development of the cells themselves. Thus, this option is not the correct
answer for this characteristic feature.
1. Megaloblastic anemia
This is because megaloblastic anemia is the condition where nuclear cytoplasmic
asynchrony is a hallmark feature due to the disproportionate growth of the
nucleus and cytoplasm in red blood cell precursors, resulting from vitamin B12
or folic acid deficiencies affecting DNA synthesis.
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Oral PathologyHydroquinone is the initiator in developing solutions for photographic films.
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General Microbiologythe live oral vaccine for typhoid fever is Typhoralx, which is a Gal E mutant of S. typhi. The mechanism of action involves the attenuated bacteria colonizing the intestinal mucosa and inducing an immune response that protects against subsequent infection with the pathogenic strain.
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Oral PathologyJunctional nevi are moles where the nevus cells (melanocytes) are located at the junction of the epidermis (outer layer of skin) and the dermis (inner layer of skin). Because they are in the basal layer of the epidermis, where melanomas originate, they have a higher potential for malignant transformation into melanoma compared to intradermal nevi, where cells are deeper in the dermis. Lichen planus and papillomas are generally benign conditions