Important Questions for UP Class 12 Biology 2025

The process where existing cells divide to produce new cells, contributing to growth and repair.

Innate immunity is a non-specific defense mechanism present from birth, offering immediate protection. Acquired immunity develops over time through exposure to pathogens, providing a specific response to each one.

Untreated sewage contaminates water sources, spreading diseases like cholera and typhoid. It also pollutes the environment, harming aquatic life and causing eutrophication.

Producers are organisms (mostly plants) that make their own food through photosynthesis. Consumers are organisms that rely on others for food.

Biomagnification occurs when toxins accumulate in organisms as you move up a food chain, leading to higher concentrations in top predators. This can harm wildlife and even humans.

The life cycle of the malaria parasite involves multiple stages, with the parasite alternating between humans and mosquitos. It includes the sporozoite, merozoite, and gametocyte stages.

The lac operon regulates lactose metabolism in bacteria. It's a set of genes that can turn on or off depending on the presence of lactose, ensuring efficient use of resources.

Restriction endonucleases are enzymes that cut DNA at specific sequences. They are typically found in bacteria and not in eukaryotic cells.

Reproduction is the biological process by which organisms create new individuals of the same species, ensuring the continuation of life.

Genetic codes are sets of three-nucleotide sequences (codons) that correspond to specific amino acids, dictating the building blocks of proteins.

The law of dominance states that in a heterozygous organism, one allele (dominant) masks the expression of the other (recessive) allele.

Vegetative propagation is a method of asexual reproduction where new plants arise from vegetative parts like roots, stems, or leaves. Examples include potato tubers and onion bulbs.

Wastewater is harmful because it can contain pathogens, chemicals, and pollutants, contaminating water sources and harming public health.

It is wrong to blame women for the birth of a girl child as the father contributes 50% of the child's genetic material, and both parents are equally responsible.

DNA replication is the process of duplicating a DNA molecule to create two identical copies. It involves unwinding the double helix, separating the strands, and creating new complementary strands.

Photosynthesis is the process by which plants convert light energy into chemical energy (glucose), using carbon dioxide and water. It has two main stages: light-dependent reactions and the Calvin cycle.

The human heart is a four-chambered organ responsible for pumping blood throughout the body. Each chamber plays a specific role in receiving and pushing blood.

Mendel's laws of inheritance describe the patterns of inheritance of traits. These include the law of segregation (allele pairs separate during gamete formation) and the law of independent assortment (alleles for different traits separate independently).

Water transport in plants occurs through a system called xylem, which transports water and minerals from roots to leaves. This process involves transpiration, cohesion, and adhesion.

The human digestive system is a complex system of organs that breaks down food into smaller molecules for absorption and utilization. It includes the mouth, esophagus, stomach, small intestine, and large intestine.

Enzymes are biological catalysts that speed up chemical reactions without being consumed. They have specific structures and active sites that bind with specific molecules (substrates).

An ecosystem is a community of living organisms interacting with their physical environment. It includes abiotic factors like temperature and water and biotic factors like plants and animals.

The human reproductive system consists of organs responsible for reproduction. In males, it includes testes, sperm ducts, and the penis. In females, it includes ovaries, fallopian tubes, uterus, and vagina.

DNA and RNA are nucleic acids that carry genetic information. DNA is a double-stranded helix, while RNA is a single-stranded molecule. They differ in their structure and function within the cell.

Water pollution is the contamination of water bodies by harmful substances, including chemicals, sewage, and industrial waste. It can cause health problems, disrupt ecosystems, and affect drinking water sources.

The male reproductive system produces sperm and delivers it to the female reproductive system for fertilization. Sperm storage occurs in the epididymis.

Comparative anatomy provides evidence for evolution by comparing the structures of different organisms. Similarities suggest common ancestry and shared evolutionary history.

An ecological pyramid is a graphical representation of the energy flow or biomass distribution among trophic levels in an ecosystem. Examples include biomass pyramids showing the decreasing biomass at higher levels and energy pyramids illustrating energy loss at each level.