Practice free Zoology NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
What happens to the number of primary follicles in a human female from birth to puberty?
The NCERT explicitly states, 'A large number of these follicles degenerate during the phase from birth to puberty. Therefore, at puberty only 60,000-80,000 primary follicles are left in each ovary.'
Which of the following components of seminal plasma are essential for the maturation and motility of sperms?
The NCERT states, 'Sperms released from the seminiferous tubules, are transported by the accessory ducts. Secretions of epididymis, vas deferens, seminal vesicle and prostate are essential for maturation and motility of sperms.'
Human gametes are ______ and the zygote is ______.
From the exercise fill-in-the-blanks, it's clarified that 'Male and female gametes are haploid' and 'Zygote is diploid'.
Gametogenesis refers to the formation of:
The general introduction to human reproduction states: 'The reproductive events in humans include formation of gametes (gametogenesis), i.e., sperms in males and ovum in females'.
What is the chromosome number of a human primary spermatocyte?
The NCERT states, 'Each spermatogonium is diploid and contains 46 chromosomes. Some of the spermatogonia called primary spermatocytes periodically undergo meiosis.' A diploid cell is represented as $2n$, with 46 chromosomes in humans.
Hormones that typically interact with membrane-bound receptors utilize which of the following mechanisms for their action?
According to NCERT, 'Hormones which interact with membrane-bound receptors normally do not enter the target cell, but generate second messengers (e.g., cyclic AMP, $IP_3$, $Ca^{++}$ etc) which in turn regulate cellular metabolism (Figure 19.5a).' Options 1, 2, and 4 describe mechanisms employed by hormones interacting with intracellular receptors.
Which of the following hormone types primarily regulates gene expression or chromosome function by interacting with intracellular receptors?
The NCERT states: 'Hormones which interact with intracellular receptors (e.g., steroid hormones, iodothyronines, etc.) mostly regulate gene expression or chromosome function by the interaction of hormone-receptor complex with the genome.' Peptide hormones, protein hormones, and amino-acid derivatives typically interact with membrane-bound receptors and use second messengers.
Hormone receptors are located in the target tissues only and exhibit specificity. What does this specificity imply?
The NCERT text explicitly states: 'Each receptor is specific to one hormone only and hence receptors are specific.' This means a particular hormone will only bind to its specific receptor.
Which of the following is NOT an example of a secondary messenger involved in hormone action?
According to NCERT, 'second messengers (e.g., cyclic AMP, $IP_3$, $Ca^{++}$ etc) which in turn regulate cellular metabolism'. Testosterone is a steroid hormone, which acts as a primary messenger by binding to intracellular receptors, not a secondary messenger.
A hormone-receptor complex formation primarily leads to what in the target tissue?
The NCERT states: 'Hormone-Receptor complex formation leads to certain biochemical changes in the target tissue. Target tissue metabolism and hence physiological functions are regulated by hormones.'
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The bank mixes NEET previous year questions (PYQs) with practice questions, each tagged with its exam appearances where applicable.