Top 60 Biology MCQs | Most Important Biology Questions & Answers

Added: 2026-05-06

[00:00:01]Which enzyme catalyzes the first step of glycolysis?

[00:00:09]Correct answer is hexokinise.

[00:00:13]A mutation in which a codon changes from coding an amino acid to a stop codon will most likely result in.

[00:00:25]Correct answer is truncated protein.

[00:00:30]Which of the following is the immediate product of translation?

[00:00:37]Correct answer is olipeptide chain.

[00:00:43]Which structure is directly responsible for synaptic transmission?

[00:00:51]Correct answer is synaptic vicles.

[00:00:56]Which of the following would most likely increase transpiration rate?

[00:01:04]Correct answer is strong wind.

[00:01:09]A population suddenly decreases in size due to a natural disaster. The resulting genetic change is called.

[00:01:20]Correct answer is bottleneck effect.

[00:01:25]Which of the following hormones has the shortest half-life in blood?

[00:01:33]Correct answer is adrenaline.

[00:01:38]Which structure in bacteria protects against desiccation and fagocytosis?

[00:01:47]Correct answer is capsule.

[00:01:51]Which of the following molecules can cross the cell membrane most easily?

[00:01:59]Correct answer is steroid hormones.

[00:02:04]Which of the following molecules is amphipathic?

[00:02:12]Correct answer is phospholipid.

[00:02:16]Which structure ensures proper alignment of chromosomes during metaphys?

[00:02:25]Correct answer is spindle fibers.

[00:02:30]Which of the following best explains why mitochondria have a higher mutation rate than nuclear DNA?

[00:02:40]Correct answer is lack of histones.

[00:02:45]Which structure in plants is responsible for secondary thickening of roots?

[00:02:54]Correct answer is lateral meristem.

[00:02:59]Which type of bond stabilize the secondary structure of proteins?

[00:03:07]Correct answer is hydrogen bond.

[00:03:12]Which of the following organisms shows radial symmetry?

[00:03:20]Correct answer is starfish.

[00:03:24]Which factor directly affects rate of transpiration?

[00:03:31]Correct answer is light intensity.

[00:03:36]Which of the following best explains why enzymes show specificity?

[00:03:45]Correct answer is their active site is complimentary to substrate.

[00:03:51]Which structure is primarily responsible for maintaining chromosome integrity?

[00:04:00]Correct answer is telomere.

[00:04:05]Which of the following best explains why viruses are obligate parasites?

[00:04:13]Correct answer is they cannot replicate outside host.

[00:04:20]Which of the following processes produces the highest amount of n?

[00:04:27]Correct answer is KBS cycle.

[00:04:32]Which factor would increase the rate of enzyme catalyzed reaction up to a limit?

[00:04:41]Correct answer is increasing substrate concentration.

[00:04:47]Which of the following explains mosaic evolution?

[00:04:54]Correct answer is different traits evolve at different rates.

[00:05:01]Which of the following processes is reversible in cells?

[00:05:08]Correct answer is many enzyme catalyzed reactions.

[00:05:14]Which of the following is a key feature of our selected species?

[00:05:22]Correct answer is short generation time.

[00:05:27]Which of the following best explains enzyme inhibition by heavy metals?

[00:05:36]Correct answer is they denature enzyme proteins.

[00:05:42]Which of the following is not a property of genetic code?

[00:05:49]Correct answer is overlapping.

[00:05:54]Which of the following best explains why diffusion is faster in gases than liquids?

[00:06:03]Correct answer is greater intermolecular spaces.

[00:06:09]Which of the following processes involves movement against concentration gradient?

[00:06:18]Correct answer is active transport.

[00:06:23]Which of the following hormones is lipid soluble?

[00:06:30]Correct answer is steroid hormones.

[00:06:35]Which of the following is the main function of rough endopplasmic reticulum?

[00:06:44]Correct answer is protein synthesis.

[00:06:49]Which of the following organisms is most evolutionarily advanced?

[00:06:57]Correct answer is arthropod.

[00:07:02]Which of the following best explains antagonistic hormones?

[00:07:09]Correct answer is hormones with opposite effects.

[00:07:15]Which of the following processes produces CO2 in respiration?

[00:07:23]Correct answer is Krebs cycle.

[00:07:28]Which of the following best explains adaptation?

[00:07:35]Correct answer is long-term genetic change improving survival.

[00:07:42]Which of the following is a key feature of enzymes?

[00:07:49]Correct answer is remain unchanged after reaction.

[00:07:55]Which of the following molecules is directly used in protein synthesis?

[00:08:04]Correct answer is mRNA.

[00:08:08]Which of the following best explains ecological niche?

[00:08:15]Correct answer is role and position of species in ecosystem.

[00:08:23]Which of the following best explains why enzymes lower activation energy?

[00:08:31]Correct answer is they stabilize the transition state.

[00:08:37]In ukarotes, which RNA undergoes extensive post-transcriptional modification?

[00:08:46]Correct answer is all of these.

[00:08:51]Which of the following best explains dosage compensation in mammals?

[00:08:59]Correct answer is inactivation of one X chromosome in females.

[00:09:07]Which process is responsible for maintaining genetic stability across generations?

[00:09:16]Correct answer is DNA repair mechanisms.

[00:09:21]Which of the following enzymes is alossterically regulated in glycolysis?

[00:09:30]Correct answer is phosphoprtokinus one.

[00:09:35]Which type of selection favors individuals at both extremes of phenotype distribution?

[00:09:45]Correct answer is disruptive.

[00:09:50]Which of the following best describes chemiosmosis?

[00:09:57]Correct answer is ATP synthesis using proton gradient.

[00:10:03]Which enzyme breaks hydrogen bonds between DNA strands during replication?

[00:10:12]Correct answer is helicase.

[00:10:17]Which part of the human brain is involved in language comprehension?

[00:10:25]Correct answer is vernick area.

[00:10:30]Which of the following is an example of parasitism?

[00:10:37]Correct answer is tapeworm in intestine.

[00:10:42]Which of the following processes increases ATP yield during aerobic respiration?

[00:10:52]Correct answer is electron transport chain.

[00:10:57]Which of the following best explains genetic code degeneracy?

[00:11:05]Correct answer is multiple codons code for same amino acid.

[00:11:12]Which type of speciation occurs without geographic isolation?

[00:11:20]Correct answer is sympatric.

[00:11:24]Which of the following is a function of ribosymes?

[00:11:31]Correct answer is catalysis by RNA.

[00:11:37]Which of the following best explains acclimatization?

[00:11:44]Correct answer is short-term physiological adjustment.

[00:11:50]Which of the following is not a feature of mitochondria?

[00:11:58]Correct answer is ATS ribosomes.

[00:12:03]Which stage of cell cycle involves DNA synthesis?

[00:12:11]Correct answer is S-phase.

[00:12:15]Which of the following best explains mutualism?

[00:12:22]Correct answer is both benefit.

[00:12:27]Which of the following is responsible for active transport?

[00:12:35]Correct answer is ATP?

[00:12:39]Which of the following processes occurs in ribosomes?

[00:12:47]Correct answer is translation.

[00:12:52]Which enzyme is responsible for removing super calls specifically during transcription?

[00:13:01]Correct answer is toposomease.

[00:13:06]Which of the following is the primary function of histone acetilation?

[00:13:14]Correct answer is increased transcription in camp plants. Stomata are open during.

[00:13:26]Correct answer is night only.