NEET Biology 3 — Questions and Answers
Question 1: Which of the following is NOT a characteristic of cancer cells?
- Contact inhibition lost
- Uncontrolled cell division
- Increased apoptosis (Correct answer)
- Ability to metastasize
Correct answer: Increased apoptosis
Cancer cells typically evade apoptosis (programmed cell death) rather than showing increased apoptosis.
Question 2: Synapsis refers to:
- Separation of sister chromatids
- Pairing of homologous chromosomes (Correct answer)
- Attachment of spindle fibers to centromere
- Formation of the nuclear envelope
Correct answer: Pairing of homologous chromosomes
Synapsis is the pairing of homologous chromosomes during zygotene of Prophase I, facilitated by the synaptonemal complex.
Question 3: The R-group of which amino acid contains a sulfhydryl (-SH) group important for disulfide bonds?
- Methionine
- Cysteine (Correct answer)
- Serine
- Threonine
Correct answer: Cysteine
Cysteine contains a sulfhydryl (-SH) group that forms disulfide bonds (-S-S-) critical for protein tertiary structure.
Question 4: Emasculation in plant breeding refers to:
- Removal of petals before pollination
- Removal of anthers from bisexual flowers before pollen maturation (Correct answer)
- Artificial introduction of pollen to stigma
- Removal of sepals to expose reproductive parts
Correct answer: Removal of anthers from bisexual flowers before pollen maturation
Emasculation removes anthers from bisexual flowers before pollen matures to prevent self-pollination in controlled crosses.
Question 5: Which hormone is produced by the corpus luteum after ovulation?
- Estrogen only
- FSH
- Progesterone and estrogen (Correct answer)
- LH
Correct answer: Progesterone and estrogen
The corpus luteum secretes primarily progesterone along with some estrogen to prepare the uterus for implantation.
Question 6: Which of the following statements about ribosomes is CORRECT?
- Prokaryotic ribosomes are 80S
- Eukaryotic mitochondrial ribosomes are 80S
- Prokaryotic ribosomes consist of 50S and 30S subunits (Correct answer)
- Eukaryotic ribosomes consist of 60S and 40S subunits, forming 100S
Correct answer: Prokaryotic ribosomes consist of 50S and 30S subunits
Prokaryotic ribosomes (70S) consist of a large 50S subunit and a small 30S subunit.
Question 7: The respiratory quotient (RQ) for carbohydrates is:
- 0.7
- 0.8
- 1.0 (Correct answer)
- More than 1.0
Correct answer: 1.0
For carbohydrates, CO₂ produced equals O₂ consumed, giving RQ = CO₂/O₂ = 1.0.
NEET Biology 3
Which of the following is NOT a characteristic of cancer cells?