Q41. What is the process by which an organism changes its form and structure during its life cycle?
a) Metabolism
b) Metamorphosis
c) Differentiation
d) Adaptation
Show Answer
Correct Answer: b) Metamorphosis
Explanation: Metamorphosis is the process by which an organism undergoes significant changes in its form, structure, and physiology as it progresses through different developmental stages during its life cycle. This phenomenon is commonly observed in insects, amphibians, and some other invertebrates and vertebrates.
Q42. Which process involves the uptake of oxygen and release of carbon dioxide by living organisms to produce energy?
a) Photosynthesis
b) Respiration
c) Fermentation
d) Transpiration
Show Answer
Correct Answer: b) Respiration
Explanation: Respiration is the biochemical process by which living organisms, including plants, animals, fungi, and bacteria, take in oxygen from the environment and release carbon dioxide as they convert organic molecules into energy through oxidative metabolic pathways, such as aerobic or anaerobic respiration.
Q43. What is the process by which genetic material is exchanged between two homologous chromosomes during meiosis?
a) Crossing over
b) Replication
c) Transcription
d) Translation
Show Answer
Correct Answer: a) Crossing over
Explanation: Crossing over, or genetic recombination, is the process by which segments of genetic material are exchanged between two homologous chromosomes during meiosis, the cell division process that produces gametes (sperm and egg cells). This genetic exchange results in genetic diversity among offspring.
Q44. Which process involves the conversion of atmospheric nitrogen into nitrogen-containing compounds by lightning or industrial processes?
a) Nitrogen fixation
b) Nitrification
c) Denitrification
d) Ammonification
Show Answer
Correct Answer: a) Nitrogen fixation
Explanation: Nitrogen fixation is the process by which atmospheric nitrogen gas (N2) is converted into nitrogen-containing compounds, such as ammonia (NH3), nitrites (NO2-), and nitrates (NO3-), by natural or industrial processes, such as lightning, microbial activity, or the Haber-Bosch process.
Q45. What is the process by which an organism adapts to its environment over time through genetic changes?
a) Evolution
b) Mutation
c) Selection
d) Variation
Show Answer
Correct Answer: a) Evolution
Explanation: Evolution is the process by which populations of organisms change over successive generations through the accumulation of heritable genetic variations, driven by mechanisms such as natural selection, genetic drift, mutation, and gene flow. It is the fundamental principle underlying biodiversity and the origin of species.
Q46. Which process involves the conversion of glucose into pyruvate to produce energy in the absence of oxygen?
a) Glycolysis
b) Krebs cycle
c) Electron transport chain
d) Oxidative phosphorylation
Show Answer
Correct Answer: a) Glycolysis
Explanation: Glycolysis is the metabolic pathway that converts glucose into pyruvate in the cytoplasm of cells, producing a small amount of ATP (adenosine triphosphate) and NADH (nicotinamide adenine dinucleotide) as energy carriers. It is the initial stage of both aerobic and anaerobic respiration.
Q47. What is the process by which an organism maintains stable internal conditions despite changes in its external environment?
a) Homeostasis
b) Adaptation
c) Regulation
d) Tolerance
Show Answer
Correct Answer: a) Homeostasis
Explanation: Homeostasis is the physiological process by which organisms maintain stable internal conditions, such as body temperature, pH, osmotic pressure, and glucose concentration, despite fluctuations in their external environment. It involves regulatory mechanisms that monitor and adjust internal variables to achieve optimal conditions for cellular function and survival.
Q48. Which process involves the rearrangement of atoms in chemical substances to form new substances with different chemical compositions?
a) Chemical reaction
b) Physical reaction
c) Ionization
d) Redox reaction
Show Answer
Correct Answer: a) Chemical reaction
Explanation: A chemical reaction is a process in which chemical substances (reactants) undergo a rearrangement of their atoms to form new substances (products) with different chemical compositions and properties. Chemical reactions involve the breaking and formation of chemical bonds and are governed by the conservation of mass and energy.
Q49. What is the process by which excess water is removed from the body by the kidneys and excreted in urine?
a) Filtration
b) Reabsorption
c) Secretion
d) Osmoregulation
Show Answer
Correct Answer: a) Filtration
Explanation: Filtration is the initial step in urine formation by the kidneys, in which blood is filtered through the glomerulus to remove waste products, excess ions, and water, forming a fluid called filtrate. This filtrate is subsequently modified through processes such as reabsorption and secretion to produce urine.
Q50. Which process involves the production of ATP (adenosine triphosphate) by the phosphorylation of ADP (adenosine diphosphate) using energy derived from the flow of protons across a membrane?
a) Glycolysis
b) Krebs cycle
c) Electron transport chain
d) Oxidative phosphorylation
Show Answer
Correct Answer: d) Oxidative phosphorylation
Explanation: Oxidative phosphorylation is the final stage of cellular respiration in which ATP is synthesized from ADP and inorganic phosphate (Pi) using energy derived from the flow of electrons along the electron transport chain and the generation of a proton gradient across the inner mitochondrial membrane.