Unit 2

• Comparative Ejaculate Volumes:
• Boar: Characterized by massive ejaculate volume of $150 - 300\text{ ml}$ (up to 500 ml).
• Stallion (Horse): High volume of $50 - 100\text{ ml}$.
• Dog: Volume typically ranges from $5 - 20\text{ ml}$ (including presperm, sperm-rich, and prostatic fractions).
• Bull: Concentrated, low volume of $4 - 8\text{ ml}$.
• Ram: Highly concentrated, very low volume of $0.8 - 1.2\text{ ml}$.
• Descending Sequence of Ejaculate Volume:

• nalysis:
• (Boar> horse> dog> bull): Correct sequence.

Correct option: (3) Boar> horse> dog> bull

• Mechanisms of Ovulation in Mammals:
• Reflex / Induced Ovulators: Ovulation does not occur spontaneously at the end of the follicular phase; mechanical coital stimulation of vaginal/cervical sensory mechanoreceptors is strictly required to trigger a neuroendocrine surge of GnRH and LH.
• Examples: Cat (Queen), Rabbit (Doe), Camel (Camelus), Ferret, Mink.
• Spontaneous Ovulators: Cyclic rising levels of follicular estradiol trigger the pre-ovulatory LH surge and ovulation independently of copulation:
• Examples: Dog (Bitch), Cow, Mare, Ewe, Sow, Human.
• nalysis:
• (Dog): Correct (spontaneous ovulator, not a reflex ovulator).

Correct option: (2) Dog

• Conformation of Trans vs Saturated and Cis Fatty Acids:
• Assertion (A): In trans-fatty acids, hydrogen atoms are on opposite sides of the double bond, creating an extended, straight-chain hydrocarbon conformation that closely resembles the linear geometry of a saturated fatty acid. (True).
• Reason (R): In cis-unsaturated fatty acids, the double bond introduces a rigid bend ($30^\circ$ kink) that disrupts dense crystalline packing, lowering melting point and making them liquid oils at room temperature, whereas saturated and trans fats pack tightly and remain solid. (True).
• nalysis:
• Both statements are scientifically true, but R explains the physical state of cis vs saturated rather than explaining why trans resembles saturated. Hence, Option 2 is correct.

• Mitochondrial NADH Shuttles: The inner mitochondrial membrane is impermeable to cytosolic NADH produced during glycolysis:
• Malate-Aspartate Shuttle: Operates predominantly in the liver, heart, and kidney. It transfers reducing equivalents to mitochondrial $\text{NAD}^+ \to \text{NADH}$, yielding $\approx 2.5\text{ ATP}$ per cytosolic NADH oxidized via Complex I of the electron transport chain.
• Glycerol-3-Phosphate Shuttle: Operates predominantly in skeletal muscle and brain. It transfers reducing equivalents to mitochondrial $\text{FAD} \to \text{FADH}_2$, yielding only $\approx 1.5\text{ ATP}$ per cytosolic NADH.
• Conclusion: The malate-aspartate shuttle operates in (A) Liver and (B) Heart only.

Correct option: (1) (A), (6) only,