In a population, the allele frequency of 'a' is 0.4 and 'A' is 0.6. If the population is in Hardy-Weinberg equilibrium, what is the expected frequency of heterozygotes?
Answer: C
Frequency of heterozygotes = 2pq = 2(0.6)(0.4) = 0.48 in Hardy-Weinberg equilibrium.
Q.142Medium
A frameshift mutation occurs in the middle of a gene. What is the most likely consequence?
Answer: C
Frameshift mutations shift the reading frame for all downstream codons, typically resulting in nonfunctional proteins or premature termination.
Q.143Medium
A silent mutation in the third codon position of a gene coding for protein synthesis most likely occurs due to:
Answer: A
The wobble hypothesis explains how changes in the third codon position often don't change the amino acid due to the degeneracy of the genetic code, resulting in silent mutations.
Q.144Medium
In a testcross of a dihybrid (AaBb) with a homozygous recessive (aabb), if the offspring ratio deviates from 1:1:1:1, it indicates:
Answer: B
A 1:1:1:1 ratio indicates independent assortment. Deviation suggests the genes are linked on the same chromosome, with recombination occurring at a frequency less than 50%.
Q.145Medium
Peppered moths in industrial England showed rapid evolution from predominantly light-colored to dark-colored populations. This is an example of:
Answer: A
Industrial pollution darkened tree bark, favoring dark moths through directional selection. This is a classic example of evolution in response to environmental change.
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Q.146Medium
A mutation converts an amino acid codon (GUU for valine) to a stop codon (UAA). This type of mutation would most severely affect the protein by:
Answer: B
A nonsense mutation (codon to stop codon) causes premature termination of translation, resulting in a truncated, usually nonfunctional protein. This is more severe than missense mutations.
Q.147Medium
In a cross between two heterozygous individuals (Aa × Aa), if the homozygous dominant genotype (AA) is lethal and dies in utero, the surviving offspring ratio would be:
Answer: B
Aa × Aa normally produces 1 AA : 2 Aa : 1 aa. If AA is lethal, only Aa and aa survive in a 2:1 ratio.
Q.148Medium
What is the role of GnRH in reproductive health?
Answer: B
GnRH (Gonadotropin-Releasing Hormone) from the hypothalamus stimulates the anterior pituitary to release FSH and LH, initiating the reproductive cycle.
Q.149Medium
In females, the LH surge causes:
Answer: B
The LH (Luteinizing Hormone) surge triggers ovulation, the release of a mature ovum from the ovary, typically occurring around day 14 of the menstrual cycle.
Q.150Medium
Which contraceptive method has the highest efficacy rate in India as per 2024 guidelines?
Answer: B
Copper T IUD has the highest efficacy rate at 99.2%, making it one of the most reliable contraceptive methods available in India.
Q.151Medium
What is the primary cause of infertility in males in India?
Answer: B
Oligospermia (low sperm count) and asthenozoospermia (poor motility) are the major causes of male infertility, often due to lifestyle factors, infections, or genetic issues.
Q.152Medium
A 25-year-old woman has irregular menstrual cycles with heavy bleeding. What could be a likely cause?
Answer: A
PCOS is characterized by irregular cycles, heavy bleeding, and hormonal imbalances. It's a common cause of menstrual irregularities in reproductive-age women.
Q.153Medium
Which of the following is a natural method of family planning?
Answer: B
The Billings ovulation method is a natural family planning technique based on observing changes in cervical mucus to identify fertile days.
Q.154Medium
What is the significance of hCG (human Chorionic Gonadotropin) in pregnancy?
Answer: A
hCG, produced by the trophoblast after implantation, maintains the corpus luteum, ensuring continued progesterone production essential for pregnancy maintenance.
Q.155Medium
During which phase of the menstrual cycle are FSH levels highest?
Answer: C
FSH levels peak during the follicular phase, stimulating follicle development and estrogen production. Levels decline after ovulation.
Q.156Medium
Which of the following contraceptive methods has the highest failure rate among barrier methods?
Answer: C
Diaphragm has a failure rate of 12% with typical use, higher than male condoms (18%) and female condoms (21%) when considering perfect vs typical use. However, among barrier methods, diaphragm shows higher typical-use failure rates.
Q.157Medium
A woman exhibits symptoms of amenorrhea, hirsutism, and obesity. What could be the most likely endocrine disorder affecting her reproductive health?
Answer: C
PCOS presents with the triad of amenorrhea/oligomenorrhea, hirsutism (due to androgen excess), and obesity. It's the most common endocrine disorder affecting reproductive-age women in India.
Q.158Medium
Which of the following statements about lactation is correct?
Answer: D
Prolactin maintains and sustains milk secretion, while oxytocin causes milk ejection reflex. Frequent suckling increases prolactin levels and maintains lactation.
Q.159Medium
At what level of hCG concentration in serum is an ectopic pregnancy typically detected via ultrasound?
Answer: B
Ectopic pregnancy is typically visible on transvaginal ultrasound when serum hCG levels reach 1000-2000 mIU/mL (discriminatory zone), though this varies.
Q.160Medium
Which oral contraceptive formulation has the lowest risk of thromboembolic events?
Answer: D
Progestin-only pills (minipills) have minimal thromboembolic risk as they lack estrogen. Combined oral contraceptives carry increasing risk: second-generation < third-generation < drospirenone-containing pills.
