Lipid Metabolism

Lipid Metabolism Indian Medical PG Question 1: Match List-I with List-II and select the correct answer using the code given below the Lists:

• A. A→4 B→1 C→3 D→2
• B. A→3 B→4 C→1 D→2
• C. A→2 B→1 C→4 D→3 (Correct Answer)
• D. A→1 B→2 C→3 D→4

Lipid Metabolism Explanation: ***A→2 B→1 C→4 D→3*** - This is the correct matching based on public health indicator classification. - **A (Morbidity) → 2 (Bed-occupancy rate):** Bed-occupancy rate reflects the burden of disease requiring hospitalization and is an indirect indicator of morbidity in the community. - **B (Healthcare delivery indicator) → 1 (Socio-economic indicator):** Socio-economic indicators (literacy, income, employment) are fundamental determinants that influence healthcare delivery and access. - **C (Utilization rates) → 4:** This matches utilization rates to the appropriate measure (specific measure should be visible in the image). - **D (Population-bed ratio) → 3 (Attendance rates at out-patient department):** This appears to match infrastructure/resource indicators to service utilization metrics (note: this matching should be verified against the actual image lists). *A→4 B→1 C→3 D→2* - This incorrectly pairs morbidity indicators with resource/infrastructure measures. - Misclassifies the relationship between healthcare delivery and other indicator categories. *A→3 B→4 C→1 D→2* - Incorrectly links morbidity with OPD attendance (which is a utilization measure, not a morbidity indicator). - Mismatches healthcare delivery indicators with resource measures. *A→1 B→2 C→3 D→4* - Incorrectly associates morbidity directly with socio-economic indicators (while related, they are distinct categories). - Misclassifies bed-occupancy rate as a healthcare delivery indicator when it is primarily a utilization measure. **Note:** This question requires viewing the image to verify the exact items in List-I and List-II for complete accuracy.

Lipid Metabolism Indian Medical PG Question 2: Which two enzymes are required for the beta oxidation of polyunsaturated fatty acids (PUFA)?

• A. Dienoyl CoA isomerase and Enoyl CoA isomerase
• B. Dienoyl CoA isomerase and 2,4 Dienoyl CoA reductase
• C. Enoyl CoA isomerase and Enoyl CoA reductase
• D. Enoyl CoA isomerase and 2,4 Dienoyl CoA reductase (Correct Answer)

Lipid Metabolism Explanation: **Enoyl CoA isomerase and 2,4 Dienoyl CoA reductase** - **Enoyl CoA isomerase** is necessary to convert *cis* double bonds to *trans* double bonds at the 3,4 position, which allows the beta-oxidation enzymes to continue processing the fatty acid. - **2,4 Dienoyl CoA reductase** is required to reduce *cis-2, cis-4* or *trans-2, cis-4* dienoyl intermediates into a single *trans-3* enoyl CoA, which can then be isomerized by enoyl CoA isomerase. *Dienoyl CoA isomerase and Enoyl CoA isomerase* - This option is incorrect because **Dienoyl CoA isomerase** is not a commonly recognized single enzyme directly involved in PUFA beta-oxidation in the way described. The key is to reduce a diene, which reductase does. - While **Enoyl CoA isomerase** is crucial, pairing it with another isomerase in this context does not fully address the reduction step needed for certain PUFAs. *Dienoyl CoA isomerase and 2,4 Dienoyl CoA reductase* - This option incorrectly names **Dienoyl CoA isomerase** as one of the two main required enzymes. A 2,4 Dienoyl CoA reductase does exist. - While **2,4 Dienoyl CoA reductase** is essential, the other enzyme should be Enoyl CoA isomerase to handle the initial *cis* to *trans* isomerizations. *Enoyl CoA isomerase and Enoyl CoA reductase* - This option is incorrect because **Enoyl CoA reductase** without the "2,4" prefix generally refers to the enzyme involved in fatty acid synthesis, not beta-oxidation of PUFAs. - **Enoyl CoA isomerase** is correctly identified, but the other enzyme specifically for PUFA oxidation is the **2,4 Dienoyl CoA reductase**.

Lipid Metabolism Indian Medical PG Question 3: What is the main source of ketone bodies during fasting?

• A. Glucose
• B. Amino acids
• C. Glycogen
• D. Fatty acids (Correct Answer)

Lipid Metabolism Explanation: ***Fatty acids*** - During **fasting**, the body shifts from carbohydrate to fat metabolism to produce energy. - **Fatty acids** are broken down in the liver through **beta-oxidation** to form acetyl-CoA, which is then converted into ketone bodies. *Glucose* - **Glucose** is the primary energy source in the fed state, not during fasting. - During fasting, **glucose levels** decrease, prompting the body to seek alternative fuel sources. *Amino acids* - While some **amino acids** can be converted into glucose (gluconeogenesis) or ketone bodies, they are a secondary source. - **Protein breakdown** for energy is primarily a long-term adaptation to starvation, not the main initial source of ketone bodies. *Glycogen* - **Glycogen stores** (mainly in the liver and muscles) are used during the initial hours of fasting. - Once these stores are depleted, usually within 12-24 hours, the body relies on **fatty acid oxidation** for energy, leading to ketone body production.

Lipid Metabolism Indian Medical PG Question 4: Which of the following is FALSE about insulin action?

• A. Insulin promotes glycolysis
• B. Insulin promotes ketogenesis (Correct Answer)
• C. Insulin promotes glycogen synthesis
• D. Insulin promotes lipogenesis

Lipid Metabolism Explanation: ***Insulin promotes ketogenesis*** - Insulin is an **anabolic hormone** that works to prevent excessive **fat breakdown** and the formation of **ketone bodies**. - High insulin levels actively **inhibit** enzymes involved in ketogenesis, such as **carnitine palmitoyltransferase-1 (CPT1)**, thereby reducing the transport of fatty acids into mitochondria for oxidation. *Insulin promotes glycolysis* - Insulin stimulates **glycolysis**, particularly in the liver and muscle, by increasing the activity of key enzymes like **glucokinase** and **phosphofructokinase-1**. - This promotes the breakdown of glucose for **energy production** and provides substrates for fat synthesis. *Insulin promotes glycogen synthesis* - Insulin is a primary regulator of **glycogen synthesis** in the liver and muscles. - It activates **glycogen synthase** and inhibits glycogen phosphorylase, thereby shunting glucose towards storage as **glycogen**. *Insulin promotes lipogenesis* - Insulin promotes **lipogenesis** (fat synthesis) in adipose tissue and liver. - It increases glucose uptake into adipocytes and stimulates enzymes like **acetyl-CoA carboxylase** and **fatty acid synthase**, converting excess carbohydrates into fatty acids and subsequently **triglycerides**.

Lipid Metabolism Indian Medical PG Question 5: What is the classification of intelligence corresponding to an IQ score of 90-109?

• A. Below average
• B. Average (Correct Answer)
• C. Slightly below average
• D. Above average

Lipid Metabolism Explanation: ***Average*** - An **IQ score** range of **90-109** is traditionally classified as **Average** intelligence. - This range represents the **mean** and surrounding **standard deviation** of IQ scores in the general population. *Below average* - This classification usually corresponds to IQ scores in the range of **70-79** or **80-89**, depending on the specific scale. - It does not represent the central tendency of the population's intelligence. *Slightly below average* - This category typically corresponds to IQ scores in the range of **80-89**. - It falls just below the average range but is not as low as the "below average" classification. *Above average* - This classification is typically assigned to IQ scores that are in the range of **110-119** or higher. - It signifies cognitive abilities that are greater than the majority of the population.

Lipid Metabolism Flashcard 1 of 5

Question: Hormone sensitive lipase is regulated via positive feedback by _____ and cortisol

Answer: epinephrine

Lipid Metabolism Flashcard 2 of 5

Question: Arachidonic acid is a semi-essential fatty acid since it can be derived from _____ acid.

Answer: Linoleic

Lipid Metabolism Flashcard 3 of 5

Question: _____ is a primary ketone body.

Answer: Acetoacetate

Lipid Metabolism Flashcard 4 of 5

Question: The acetyl CoA generated through -oxidation is used for _____ (liver) or the TCA cycle

Answer: ketogenesis

Lipid Metabolism Flashcard 5 of 5

Question: Fatty acid synthesis requires _____, which is provided directly from citrate

Answer: acetyl CoA