NEET · Biology doubts
340 doubts found
I keep getting “Innate vs acquired immunity” questions wrong in Human Health & Disease. What's the trap?
thinking all immunity is present from birth.
I keep getting “Gametogenesis” questions wrong in Human Reproduction & Reproductive Health. What's the trap?
thinking oogenesis produces four functional eggs like spermatogenesis makes four sperm.
I keep getting “Recombinant DNA technology” questions wrong in Biotechnology & its Applications. What's the trap?
thinking any gene can be expressed without a proper vector and host.
I keep getting “Energy flow” questions wrong in Ecosystem & Ecology. What's the trap?
thinking energy is recycled like nutrients.
Mushrooms don't move and grow in soil like plants — so why are fungi a separate kingdom?
Classification rests on cell structure and nutrition, not appearance.
Why do desert plants like cacti have sharp spines instead of broad leaves?
Broad leaves lose a lot of water through transpiration, which a desert plant can't afford.
Why does removing a complete ring of bark around a tree trunk ('girdling') eventually kill it?
The phloem lies in the bark.
Why do plants droop and wilt on a hot afternoon but recover by the next morning?
On a hot day, leaves transpire faster than the roots can absorb water.
Why does keeping a ripe banana or apple with unripe fruit help the unripe ones ripen faster?
Ripening fruit releases ethylene, a gaseous plant hormone that triggers ripening — softening, sweetening and colour change.
Why do the biceps and triceps have to work as a pair to bend and straighten your arm?
A muscle can only actively shorten and pull — it cannot push.
What is 'double fertilisation', and why is it special to flowering plants?
A pollen grain delivers two male gametes into the embryo sac.
What makes bread rise and dough fluffy, and how is the same microbe used to brew alcohol?
Both use yeast, a fungus that ferments sugars.
Two pink four-o'clock flowers are crossed and give red, pink and white in a 1:2:1 ratio, not 3:1. Why?
Flower colour here shows incomplete dominance, so the heterozygote (Rr) is pink -- a visible blend, not red.
Why is the genetic code called degenerate, and how does that protect an organism?
There are 64 codons but only 20 amino acids, so most amino acids are specified by more than one codon (leucine has six).
A recessive disease allele has a frequency of 0.1 in a population. Using Hardy-Weinberg, what fraction are carriers?
Let q = 0.1 for the recessive allele, so p = 1 - q = 0.9.
Why is the human heart called myogenic, and what proves it?
A myogenic heartbeat originates in the heart muscle itself, not in nerves.
What does “Nerve impulse” actually mean in Neural Control and Coordination, and why does it matter for NEET?
at rest the membrane is polarised with more sodium outside; a stimulus lets sodium rush in (depolarisation), generating the impulse.
A pyramid of numbers for one big tree with many insects and birds is inverted, yet its energy pyramid is upright. Why?
A pyramid of numbers counts individuals, so one large tree supporting thousands of insects gives an inverted shape.
How does Bt cotton kill bollworms without being poisonous to humans?
Bt cotton carries a cry gene from Bacillus thuringiensis that makes a protoxin -- an inactive crystal protein.
Why does a vaccinated person respond faster and more strongly when they later meet the real pathogen?
A vaccine exposes the immune system to a harmless form of the antigen, producing not only antibodies but also long-lived memory B and T cells.
What does “Prokaryotic cell” actually mean in Cell: The Unit of Life, and why does it matter for NEET?
a cell without a membrane-bound nucleus or organelles — like bacteria.
What does “Enzyme specificity” actually mean in Biomolecules, and why does it matter for NEET?
each enzyme acts on a specific substrate, like a lock fitting only its key.
What does “Mitosis” actually mean in Cell Cycle & Cell Division, and why does it matter for NEET?
division that produces two genetically identical diploid daughter cells for growth and repair.
What does “Calvin cycle (dark reaction)” actually mean in Photosynthesis in Higher Plants, and why does it matter for NEET?
occurs in the stroma, fixing CO₂ into sugar using the ATP and NADPH from the light reactions.