NEET-PG 2012

1213 Questions — Page 45 of 122

Biochemistry

2 questions

Q441

What vitamin is significantly absent in breast milk?

Q442

Mechanism of cyanide poisoning is by inhibiting: NEET 2013

NEET-PG 2012 - Biochemistry NEET-PG Practice Questions and MCQs

Question 441: What vitamin is significantly absent in breast milk?

A. Vitamin D
B. Vitamin K (Correct Answer)
C. Vitamin C
D. Vitamin A

Explanation: ***Vitamin K*** - Breast milk contains **critically low amounts** of **vitamin K** (approximately 2-5 μg/L), making it the **most significantly absent** vitamin in breast milk. - Newborns are at high risk for **Vitamin K deficiency bleeding (VKDB)**, which can be life-threatening. - This deficiency is so critical that **prophylactic vitamin K injection** is routinely administered to **all newborns** at birth to prevent hemorrhagic disease. - Vitamin K is essential for the synthesis of **clotting factors II, VII, IX, and X** in the liver. *Vitamin D* - While breast milk does contain **some vitamin D**, the levels are often **insufficient** to meet the infant's daily requirements (contains ~25-78 IU/L; infant needs 400 IU/day). - However, it is **present in measurable amounts**, unlike vitamin K which is nearly absent. - Infants are recommended to receive **vitamin D supplementation** starting soon after birth, especially if the mother has low vitamin D levels or limited **sun exposure**. *Vitamin C* - **Breast milk** contains adequate amounts of **vitamin C** (40-50 mg/L), which is sufficient for the infant's needs. - Maternal diet typically provides enough vitamin C to ensure its presence in breast milk. *Vitamin A* - Breast milk is a **good source** of **vitamin A**, particularly in the form of **beta-carotene** and retinol. - Vitamin A levels in breast milk are adequate for infant **vision development** and **immune function**.

Question 442: Mechanism of cyanide poisoning is by inhibiting: NEET 2013

A. DNA synthesis
B. Cytochrome oxidase (Correct Answer)
C. Protein breakdown
D. Protein synthesis

Explanation: ***Cytochrome oxidase*** - **Cyanide** is a potent poison because it binds to the **ferric iron (Fe3+)** in the active site of **cytochrome c oxidase**. - This binding completely inhibits the enzyme, halting **cellular respiration** and **ATP production**, leading to rapid cell death. *DNA synthesis* - **Cyanide** does not directly inhibit **DNA polymerase** or other enzymes involved in DNA replication. - While overall cellular processes are disrupted, its primary toxic effect is not on DNA synthesis. *Protein breakdown* - **Cyanide** does not directly interfere with proteasomes or lysosomal enzymes responsible for **protein degradation**. - Its mechanism of action is upstream, affecting energy production necessary for all cellular processes, including protein turnover. *Protein synthesis* - **Cyanide** does not directly inhibit **ribosomes** or the enzymatic machinery for **protein synthesis**. - The lack of **ATP** caused by cyanide poisoning would eventually shut down protein synthesis, but this is a secondary effect, not the primary mechanism of action.

Community Medicine

2 questions

Q441

Measles vaccination is given at -

Q442

The Mid Day Meal Programme comes under which ministry?

NEET-PG 2012 - Community Medicine NEET-PG Practice Questions and MCQs

Question 441: Measles vaccination is given at -

A. 9 months (Correct Answer)
B. At birth
C. 4 weeks
D. 8 weeks

Explanation: ***9 months*** - The first dose of the **measles vaccine (MMR)** is typically administered at **9 months** of age in many national immunization programs. - This timing is chosen because maternal antibodies, which can interfere with vaccine effectiveness, generally wane by this age. *At birth* - Vaccines given at birth, such as **Hepatitis B** and **BCG**, target diseases with early exposure risks or have efficacy despite maternal antibodies. - Giving measles vaccine at birth would be ineffective due to the presence of **maternal antibodies** that neutralize the vaccine virus. *4 weeks* - This age is generally too early for measles vaccination as significant levels of **maternal antibodies** are often still present, which would reduce the vaccine's efficacy. - Other vaccines, like the rotavirus vaccine, might be given around this age, but not measles. *8 weeks* - While maternal antibodies might be decreasing, 8 weeks of age is still generally considered too early for optimal measles vaccine response. - Many primary vaccine series (e.g., DTaP, IPV, Hib) begin at 6-8 weeks, but measles is usually delayed further for better efficacy and seroconversion rates.

Question 442: The Mid Day Meal Programme comes under which ministry?

A. None of the options
B. Ministry of Social Welfare
C. Ministry of Human Resource Development (Correct Answer)
D. Ministry of Education

Explanation: ***Ministry of Human Resource Development*** - In **2012**, when this NEET-PG exam was conducted, the **Mid Day Meal Programme** was administered by the **Ministry of Human Resource Development (MHRD)**. - The programme aimed to enhance school enrollment, retention, and improve the nutritional status of children in classes I-VIII. - This was the correct answer at the time of the examination. *Ministry of Education* - The Ministry of Human Resource Development was **renamed to Ministry of Education in 2020**, eight years after this exam. - While this is the current administering ministry (now called PM POSHAN Scheme), it was not the correct answer for the 2012 exam. *Ministry of Social Welfare* - This ministry focuses on social justice, empowerment of vulnerable sections, and broader welfare schemes. - The Mid Day Meal Programme's primary goal is linked to education and child development through schooling, not under this ministry. *None of the options* - This is incorrect as the programme clearly fell under the Ministry of Human Resource Development at the time of the 2012 examination.

Microbiology

1 questions

Q441

Which virus is known for its brick-shaped morphology?

Ophthalmology

5 questions

Q441

Corneal endothelial cell count is measured by?

Q442

Irregular pupil is seen in which of the following conditions?

Q443

What is the most common cause of intermittent proptosis in adults?

Q444

Most common orbital tumor has its origin from?

Q445

What is the treatment of choice for amblyopia?

NEET-PG 2012 - Ophthalmology NEET-PG Practice Questions and MCQs

Question 441: Corneal endothelial cell count is measured by?

A. Specular microscope (Correct Answer)
B. Ophthalmoscope
C. Synoptophore
D. Amsler's grid

Explanation: ***Specular microscope*** - A **specular microscope** is specifically designed to provide a high-magnification, non-contact view of the **corneal endothelium**, allowing for direct visualization and counting of endothelial cells. - It measures cell density, morphology, and polymegethism, which are crucial for assessing corneal health, especially before and after intraocular surgeries. *Ophthalmoscope* - An **ophthalmoscope** is used to examine the **fundus** or the back of the eye, including the retina, optic disc, macula, and blood vessels. - It does not have the magnification capabilities required to visualize or count individual corneal endothelial cells. *Synoptophore* - A **synoptophore** is an instrument used to diagnose and treat **strabismus** (eye misalignment) and to assess **binocular vision**. - Its function involves showing different images to each eye to test fusion, suppression, and stereopsis, unrelated to corneal cell count. *Amsler's grid* - **Amsler's grid** is a diagnostic tool used to detect **macular degeneration** and other retinal diseases that affect central vision. - It consists of a grid of straight lines and helps identify distortion or missing areas in the patient's central visual field.

Question 442: Irregular pupil is seen in which of the following conditions?

A. Glaucoma
B. Trauma (Correct Answer)
C. Retinal detachment
D. Oculomotor palsy

Explanation: ***Trauma*** - **Direct injury to the iris** can cause tears or distortion, leading to an **irregularly shaped pupil** - Results in conditions like **traumatic mydriasis** (dilated pupil) or **iridodialysis** (iris detachment from its root at the ciliary body) - **Sphincter pupillae tears** cause characteristic irregularity with notching or peaked appearance *Glaucoma* - Primarily characterized by **optic nerve damage** due to increased intraocular pressure - In acute angle closure glaucoma, pupil may be **mid-dilated and fixed**, but remains **round**, not irregular - Pupil shape irregularity is not a feature of chronic glaucoma *Retinal detachment* - Involves **separation of the neurosensory retina** from the underlying retinal pigment epithelium - This is a **posterior segment pathology** that does not affect anterior segment structures - **Pupil shape remains regular** despite severe vision loss *Oculomotor palsy* - Affects the **third cranial nerve (CN III)**, leading to ptosis, strabismus, and loss of parasympathetic innervation - Pupil is typically **dilated and fixed** due to unopposed sympathetic action - Pupil remains **round but unresponsive to light**, not irregular in shape

Question 443: What is the most common cause of intermittent proptosis in adults?

A. Orbital varix (Correct Answer)
B. Thyroid ophthalmopathy
C. Neuroblastoma
D. Retinoblastoma

Explanation: ***Orbital varix*** - An **orbital varix** is essentially a varicose vein within the orbit, which can cause intermittent proptosis. - Proptosis in an orbital varix is often exacerbated by activities that increase venous pressure, such as **Valsalva maneuvers**, crying, or bending over. *Thyroid ophthalmopathy* - This condition is characterized by **persistent proptosis**, lid retraction, and ophthalmoplegia, rather than intermittent symptoms. - While it can cause proptosis, it typically presents as **constant and progressive** rather than intermittent proptosis that varies with head position or straining. *Neuroblastoma* - This is a **malignant tumor** that primarily affects infants and young children, not typically adults. - Orbital metastasis from neuroblastoma would cause **progressive, constant proptosis** rather than intermittent proptosis. *Retinoblastoma* - **Retinoblastoma** is a malignant tumor of the retina that primarily affects young children, typically under the age of 5. - While it can cause proptosis in advanced stages, it presents as **constant and progressive proptosis** due to tumor growth, not intermittent proptosis.

Question 444: Most common orbital tumor has its origin from?

A. Blood vessels (Correct Answer)
B. Nerves
C. Muscle
D. Lymph node

Explanation: ***Blood vessels*** - The most common orbital tumor in childhood is a **capillary hemangioma**, which originates from blood vessels. - In adults, the most common primary orbital tumor is an orbital varix, also a **vascular lesion**. *Nerves* - Tumors of neural origin, such as **optic nerve gliomas** or **meningiomas**, are less common than vascular tumors. - While significant, they do not represent the *most* common overall origin for orbital tumors. *Muscle* - Tumors originating from muscle, such as **rhabdomyosarcoma** in children (a malignant tumor), are relatively rare. - **Pseudotumor** (idiopathic orbital inflammation), though common, is an inflammatory condition, not a true neoplasm of muscle origin. *Lymph node* - Tumors of lymphoid origin, such as **lymphomas**, are malignant and can occur in the orbit. - However, they are not the most common primary orbital tumor compared to those of vascular origin.

Question 445: What is the treatment of choice for amblyopia?

A. Corrective spectacles
B. Surgical intervention
C. Occlusion therapy (Correct Answer)
D. Convergent exercises for vision therapy

Explanation: ***Occlusion therapy*** - **Occlusion therapy** involves patching the stronger eye to force the weaker, amblyopic eye to work harder, thereby strengthening its neural connections. - This treatment is most effective when initiated during the **critical period of visual development** in childhood. *Corrective spectacles* - While essential for addressing **refractive errors** that may contribute to amblyopia, spectacles alone are often insufficient to resolve the amblyopia. - Spectacles primarily optimize the image quality on the retina, but don't directly address the **cortical suppression** of the amblyopic eye. *Surgical intervention* - **Surgical intervention** is typically reserved for correcting structural issues like **strabismus** (misalignment of the eyes) that contribute to amblyopia. - Surgery for strabismus aims to align the eyes, which can then be followed by occlusion therapy or other treatments to address the functional amblyopia. *Convergent exercises for vision therapy* - **Vision therapy exercises**, including convergent exercises, may be used as an adjunct to occlusion therapy or in cases of **convergence insufficiency**. - However, they are not the primary or solitary treatment of choice for amblyopia, which requires direct stimulation of the amblyopic eye.