NEET-PG 2013 Practice Questions

Q: Cone of light focuses on which quadrant of tympanic membrane?

Anteroinferior. ***Anteroinferior*** - The **cone of light** (or light reflex) is a characteristic triangular reflection of the otoscope's light, normally visible in the **anteroinferior quadrant** of a healthy tympanic membrane. - Its presence indicates a **healthy, intact eardrum** with normal tension and transparency; its absence or distortion can suggest pathology. *Posteroinferior* - While part of the tympanic membrane, the **posteroinferior quadrant** does not normally exhibit the focused cone of light. - This area is more often associated with the **round window niche** on its medial aspect in relation to the middle ear. *Anterosuperior* - The **anterosuperior quadrant** is located above the handle of the malleus and does not show the cone of light reflection. - This area contains the **anterior malleolar fold** and part of the **pars flaccida** (attic region). *Posterosuperior* - The **posterosuperior quadrant** is also not the usual site for the cone of light. - This area is relevant for the proximity to the **facial nerve** and structures like the **long process of the incus**.

Q: Most commonly used tuning fork in ear examination?

512 Hz. ***512 Hz*** - The **512 Hz tuning fork** is the most commonly recommended and used for auditory tests like **Rinne** and **Weber** because its vibratory decay is slow enough to allow adequate testing, and it falls within the **speech frequency range**. - Its frequency is optimal for assessing both **bone conduction** and **air conduction** without introducing confusing overtones or being too low to be felt as a vibration rather than heard as a tone. *128 Hz* - A **128 Hz tuning fork** produces a strong vibratory sensation and is primarily used for **neurological examinations** to test **vibration sense**, not typically for ear examinations. - Its low frequency can be easily perceived as a **tactile vibration** through bone, making it less ideal for purely auditory assessment. *256 Hz* - While it falls within the audible range, a **256 Hz tuning fork** is less commonly used than 512 Hz for standard hearing tests. - Its vibratory tone may have a faster decay and might not provide as clear a distinction for **bone conduction** as the 512 Hz fork. *1024 Hz* - A **1024 Hz tuning fork** is a higher frequency tone, which may decay too quickly for accurate **Rinne and Weber tests**, especially when assessing subtle differences in hearing. - While audible, its higher pitch can be less representative of the critical **speech frequencies** typically evaluated in basic hearing screenings.

Q: What are the potential causes of myringosclerosis?

Chronic inflammation from recurrent infections. ***Chronic inflammation from recurrent infections*** - **Myringosclerosis** is often a consequence of **chronic inflammation** and repair processes in the tympanic membrane (eardrum), commonly triggered by **recurrent otitis media** (middle ear infections). - The inflammatory exudates and subsequent healing lead to the deposition of **calcium and phosphate crystals** within the fibrous layer of the tympanic membrane, causing it to become stiff and opaque. *Genetic predisposition* - While genetics can play a role in some ear conditions, **myringosclerosis** is primarily an **acquired condition** rather than one solely determined by genetic factors. - No specific strong genetic link has been identified as a primary cause compared to environmental triggers. *Otosclerosis* - **Otosclerosis** is a condition affecting the **ossicles** (typically the stapes) in the middle ear, leading to conductive hearing loss due to abnormal bone growth, not directly affecting the tympanic membrane. - Myringosclerosis involves the eardrum itself, characterized by **calcification of the tympanic membrane**, which is distinct from the pathology of otosclerosis. *None of the options* - This option is incorrect because **chronic inflammation from recurrent infections** is a well-established cause of myringosclerosis. - The presence of a correct answer negates this choice.

Q: Site for injection of cell culture rabies vaccine-

Deltoid. Deltoid - The **deltoid muscle** is the recommended site for intramuscular injection of cell culture rabies vaccine due to its size and accessibility [1]. - Intramuscular administration in this area ensures optimal vaccine absorption and immunogenicity [1]. Gluteus - The **gluteus muscle** is not the preferred site for rabies vaccine due to the risk of injecting into fat, which can lead to reduced immune response [1]. - Additionally, there is a higher risk of **sciatic nerve injury** with gluteal injections. Subcutaneous - **Subcutaneous administration** is not the standard route for cell culture rabies vaccines as it can lead to slower absorption and potentially a less robust immune response. - This route is typically reserved for specific vaccine types or in situations where intramuscular injection is contraindicated. Anterior abdominal wall - The **anterior abdominal wall** is an unsuitable site for intramuscular injection of rabies vaccine. - This area is primarily used for **subcutaneous injections** (e.g., insulin) and lacks sufficient muscle mass for effective intramuscular vaccine delivery.

Q: Which of the following is true about Hepatitis A virus?

Common cause of hepatitis in children. ***Common cause of hepatitis in children*** - **Hepatitis A virus (HAV)** infection is often acquired in childhood, particularly in areas with poor sanitation, and many infections are **asymptomatic** or mild in children [1]. - Due to their developing immune systems and often exposure in daycare or school settings, children are a highly susceptible population for HAV transmission [1]. *Causes cirrhosis* - **HAV infection** is an **acute self-limiting illness** and typically does not lead to chronic liver disease or cirrhosis [1]. - **Cirrhosis** is primarily associated with chronic viral hepatitis (e.g., HBV, HCV), alcohol-related liver disease, or certain autoimmune conditions. *Helps HDV replication* - **Hepatitis D virus (HDV)** is a **defective virus** that requires the presence of **Hepatitis B virus (HBV)** surface antigen (HBsAg) for its replication and assembly [1]. - **HAV** has no role in the replication or pathogenesis of **HDV** [1]. *Causes chronic hepatitis* - **HAV infection** results in an **acute inflammatory response** in the liver that resolves spontaneously in most cases [1]. - Unlike **HBV** and **HCV**, **HAV** does not establish a persistent infection and, therefore, does not cause chronic hepatitis [1].

Q: Which is not a DNA virus?

Rhabdovirus. ***Rhabdovirus*** - Rhabdoviruses, such as the rabies virus, are characterized by their **single-stranded RNA genome** and distinctive bullet-shaped morphology. - They replicate in the cytoplasm of infected cells, using their **RNA-dependent RNA polymerase** to transcribe their genome. *Papovavirus* - Papovaviruses (now split into Papillomaviridae and Polyomaviridae) are **DNA viruses** known for causing warts and some cancers. - They possess a small, **double-stranded, circular DNA genome**. *Poxvirus* - Poxviruses are large, complex **DNA viruses** that replicate entirely within the cytoplasm of the host cell. - They have a **double-stranded DNA genome** and are notable for causing diseases like smallpox and molluscum contagiosum. *Parvovirus* - Parvoviruses are among the smallest viruses, characterized by their **single-stranded DNA genome**. - They require actively dividing host cells to replicate their **linear DNA**.

Q: Which of the following statements about viruses is false?

Viruses are capable of independent motility.. ***Viruses are capable of independent motility.*** - Viruses are **acellular infectious agents** and lack the cellular machinery required for independent movement or motility. - They rely on host cell processes or environmental factors for their dissemination and entry into cells. *Viruses lack ribosomes.* - Viruses are **obligate intracellular parasites**; they lack ribosomes and other cellular organelles necessary for protein synthesis. - They hijack the host cell's ribosomes and metabolic machinery to replicate their genetic material and produce viral proteins. *Viruses lack mitochondria.* - Viruses lack mitochondria, as they are **not capable of generating their own ATP** through cellular respiration. - They depend on the host cell's energy-generating systems to provide the ATP required for their replication cycle. *Viruses contain nucleic acid.* - All viruses contain a **nucleic acid genome**, which can be either DNA or RNA. - This genetic material carries the instructions for viral replication and is enclosed within a protein coat called a **capsid**.

Q: Which gene of the hepatitis B virus has the longest coding sequence?

P gene. ***P gene*** - The **P gene** (polymerase gene) encodes the viral **reverse transcriptase**, which is crucial for replicating the HBV genome. - This enzyme is very large and complex, requiring the **longest coding sequence** to accommodate all its functional domains. *X gene* - The **X gene** encodes the **HBx protein**, which is a transcriptional transactivator and plays a role in hepatocarcinogenesis. - It has a relatively **short coding sequence** compared to the P gene. *S gene* - The **S gene** encodes the **surface antigens (HBsAg)**, which are involved in viral entry and immune evasion. - It has a **shorter coding sequence** than the P gene, as it primarily codes for structural proteins. *C gene* - The **C gene** encodes the **core protein (HBcAg)**, which forms the viral nucleocapsid, and the **HBeAg**. - Its coding sequence is also **shorter** than that of the P gene, reflecting its role in structural and regulatory functions.

Q: What is the cause of rabies in wild animals?

Wild-type rabies virus. ***Wild-type rabies virus*** - Rabies in wild animals is caused by infection with the **wild-type rabies virus (Lyssavirus)**, which is maintained in specific wildlife reservoirs. - Rabies virus is a **neurotropic RNA virus** belonging to the family *Rhabdoviridae*. - This virus is transmitted through the saliva of an infected animal, typically via a **bite**. *Laboratory passage in rabbits* - **Laboratory passage in animals**, particularly rabbits, was a historical *method for attenuating the rabies virus* to develop vaccines (e.g., Pasteur's vaccine), not a cause of infection in wild animals. - Attenuated viruses are **less virulent** and do not represent the primary cause of naturally occurring rabies in wildlife. *Fatal encephalitis within 6 days* - This statement describes a **rapid progression of the disease**, which can occur, but it is a *consequence of infection*, not the cause itself. - The incubation period for rabies can vary significantly in animals, from days to months, depending on the **site of the bite** and **viral load**. *Negri bodies are not observed* - **Negri bodies** are *pathognomonic microscopic inclusions* found in the brain cells of animals infected with rabies. - Their *absence* would generally suggest that the animal does not have rabies, making this an incorrect statement about the disease's characteristics.

Q: Color of granules in mycetoma caused by Actinomadura pelletierrii -

Red. ***Red*** - *Actinomadura pelletierrii* is a common cause of **actinomycetoma** and is characterized by producing **red granules** in the lesions. - The color of these granules is a key diagnostic feature, helping differentiate it from other causes of mycetoma. *Black* - **Black granules** are typically associated with **eumycetoma** caused by **dematiaceous fungi** such as *Madurella mycetomatis*. - This color indicates the presence of **melanin**, a pigment produced by these fungal species. *Yellow* - **Yellow granules** are commonly seen in actinomycetoma caused by organisms such as *Nocardia brasiliensis* or sometimes *Actinomadura madurae*. - This color helps differentiate these specific actinomycetes from other types that produce different granule colors. *Brown* - While varying shades of color can occur, **brown granules** are not the characteristic color produced by *Actinomadura pelletierrii*. - Some *Streptomyces* species or certain eumycetoma agents can occasionally produce brownish granules, but red is specific for *A. pelletierrii*.

Question 1

Cone of light focuses on which quadrant of tympanic membrane?

Accepted Answer

Anteroinferior

Answer

Posteroinferior

Answer

Anterosuperior

Answer

Posterosuperior

Question 2

Most commonly used tuning fork in ear examination?

Accepted Answer

512 Hz

Answer

128 Hz

Answer

256 Hz

Answer

1024 Hz

Question 3

What are the potential causes of myringosclerosis?

Accepted Answer

Chronic inflammation from recurrent infections

Answer

Genetic predisposition

Answer

Otosclerosis

Answer

None of the options

Question 4

Site for injection of cell culture rabies vaccine-

Accepted Answer

Deltoid

Answer

Gluteus

Answer

Subcutaneous

Answer

Anterior abdominal wall

Question 5

Which of the following is true about Hepatitis A virus?

Accepted Answer

Common cause of hepatitis in children

Answer

Causes chronic hepatitis

Answer

Helps HDV replication

Answer

Causes cirrhosis

Question 6

Which is not a DNA virus?

Accepted Answer

Rhabdovirus

Answer

Poxvirus

Answer

Papovavirus

Answer

Parvovirus

Question 7

Which of the following statements about viruses is false?

Accepted Answer

Viruses are capable of independent motility.

Answer

Viruses contain nucleic acid.

Answer

Viruses lack mitochondria.

Answer

Viruses lack ribosomes.

Question 8

Which gene of the hepatitis B virus has the longest coding sequence?

Accepted Answer

P gene

Answer

X gene

Answer

S gene

Answer

C gene

Question 9

What is the cause of rabies in wild animals?

Accepted Answer

Wild-type rabies virus

Answer

Laboratory passage in rabbits

Answer

Fatal encephalitis within 6 days

Answer

Negri bodies are not observed

Question 10

Color of granules in mycetoma caused by Actinomadura pelletierrii -

Accepted Answer

Red

Answer

Black

Answer

Yellow

Answer

Brown

NEET-PG 2013

ENT

Internal Medicine

Microbiology