Dentosphere : World of Dentistry

 # FALSE regarding biotransformation of drugs is: A. It usually converts a drug into its lipid soluble non ionized form B. It generally involves modifications of the chemical structure of the drug C. It principally occurs in the microsomal enzyme system of the liver D. The rate may vary significantly between species The correct answer is A.  It usually converts a drug into its lipid soluble non ionized form. Biotransformation involves the conversion of a lipid soluble non ionized form of a drug into its more water soluble metabolites. Biotransformation increases the absorption of the drug into the bloodstream, enhancing the bioavailability of the drug. Water soluble drugs are also easily excreted in the urine. CLICK HERE FOR MORE MCQs

 # Globulomaxillary cyst is found between: A. Central incisors B. Central incisor and lateral incisor C. Lateral incisor and canine D. Canine and premolar The correct answer is C. Lateral incisor and canine. The globulomaxillary cyst has traditionally been described as a fissural cyst found within the bone between the maxillary lateral incisor and canine teeth. Radiographically, it is a well-defined radiolucency which frequently causes the roots of the adjacent teeth to diverge. CLICK HERE FOR MORE MCQs

# The name of the second visceral arch is: A. Mandibular B. Hyoid C. Maxillary D. None of the above The correct answer is B. Hyoid. There is no specific name for each branchial arch except the first and second. The first one is called as the Mandibular and the second one is the hyoid arch. The nerve fibers from the mandibular division of the trigeminal nerve are derived from the mandibular arch. The seventh, ninth and tenth cranial nerves are derived from the second, third and fourth branchial arches respectively. CLICK HERE FOR MORE MCQs

 # The name of the first visceral arch is: A. Mandibular B. Hyoid C. Maxillary D. None of the above The correct answer is A. Mandibular. There is no specific name for each branchial arch except the first and second. The first one is called as the Mandibular and the second one is the hyoid arch. The nerve fibers from the mandibular division of the trigeminal nerve are derived from the mandibular arch. The seventh, ninth and tenth cranial nerves are derived from the second, third and fourth branchial arches respectively. CLICK HERE FOR MORE MCQs

 # Which type of RNA directs protein synthesis? A. Ribosomal RNA B. Transfer RNA C. Messenger RNA D. Sender RNA The correct answer is C. Messenger RNA Messenger RNA (mRNA) is the RNA that carries information from DNA to the ribosome, the sites of protein synthesis (translation) in the cell. The mRNA is a copy of DNA. The coding sequence of the mRNA determines the amino acid sequence in the protein that is produced. However, many RNAs do not code for protein (about 97% of the transcriptional output is non-protein-coding in eukaryotes.  Transfer RNA (tRNA) is a small RNA chain of about 80 nucleotides that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation. It has sites for amino acid attachment and an anticodon region for codon recognition that binds to a specific sequence on the messenger RNA chain through hydrogen bonding. Ribosomal RNA (rRNA) is the catalytic component of the ribosomes. The rRNA is the ...

 # Part of the brain responsible for posture and coordination of movements: A. Cerebellum B. Cerebrum C. Medulla oblongata D. Corpus callosum The correct answer is A. Cerebellum. The cerebellum lies dorsal to the pons and medulla and consists of two lateral hemispheres: the cerebellar hemispheres and a median worm-like part called vermis. It is connected to the midbrain, pons, and medulla by superior, middle, and inferior cerebellar peduncles, respectively. The surface of cerebellum has narrow transverse ridges called folia (leaf-like in sections) separated by deep fissures.  Functionally, the cerebellum is mainly concerned with the involuntary control of somatic motor activities, essential for the maintenance of equilibrium, muscle tone, and posture. CLICK HERE FOR MORE MCQs

 # Which type of neurotransmitter is found in basal ganglia? A. Epinephrine B. Histamine C. GABA D. Dopamine The correct answer is C. GABA. Basal ganglia is involved with movement control. It modulates information from the thalamus to the motor cortex in the execution of movement. GABA (Gamma Amino butyric acid) found in basal ganglia is an important neurotransmitter for many inhibitory synaptic connections.  CLICK HERE FOR MORE MCQs