सेल बायोलॉजी और जनेटिक्स

Cell Biology

• Cells are the fundamental units of life, demonstrating diverse functions and structures.
• Prokaryotic cells, like bacteria, lack membrane-bound organelles and a nucleus.
• Eukaryotic cells, including plant and animal cells, possess a nucleus and various membrane-bound organelles.
• Organelles such as mitochondria, the site of cellular respiration, and chloroplasts, involved in photosynthesis in plant cells, perform specific tasks within the cell.
• Cell membranes are selectively permeable, regulating the passage of substances into and out of the cell through mechanisms like diffusion, osmosis, and active transport.
• The cell cycle involves the stages of interphase, mitosis (nuclear division), and cytokinesis (cytoplasmic division), crucial for cell growth and reproduction.
• Specialized cells in multicellular organisms differentiate to perform specific functions, contributing to the organism's complexity.

Genetics

• DNA (deoxyribonucleic acid) is the genetic material, storing instructions for building and maintaining an organism.
• DNA is a double helix structure composed of nucleotides, containing the four bases adenine, guanine, cytosine, and thymine.
• Genes are segments of DNA that code for specific proteins, influencing various traits.
• Alleles are different forms of a gene, leading to variations in traits.
• The process of transcription converts DNA's genetic information into RNA (ribonucleic acid).
• Translation synthesizes proteins based on the RNA's instructions.
• Mutations are alterations in DNA sequences, potentially causing variations in traits and diseases.
• Mendel's laws of inheritance describe how traits are passed from parents to offspring, involving segregation and independent assortment.
• Chromosomes carry DNA, with varying numbers among species.

Ecology

• Ecology studies the interactions between organisms and their environment.
• Ecosystems encompass all living and nonliving components in an area, including producers, consumers, and decomposers.
• Energy flows through ecosystems, originating from the sun and transferred through trophic levels.
• Nutrient cycles, such as the carbon and nitrogen cycles, involve continuous element exchange within the ecosystem.
• Biodiversity refers to the variety of life forms in an area, highlighting the complexity of ecosystems.
• Habitats provide specific resources and conditions for species' survival.
• Communities consist of various interacting species within a habitat, essential for ecosystem balance.
• Populations are groups of the same species that interact within a defined area.

Evolution

• Evolution is the process of change in species over time, driven by natural selection.
• Natural selection favors traits that enhance survival and reproduction within a specific environment.
• Adaptations are specialized features or traits that improve survival and reproduction, resulting from natural selection.
• Common ancestry suggests a shared origin of different species, often through branching patterns called phylogenies.
• Evidence for evolution comes from fossil records, comparative anatomy, biogeography, and molecular biology, demonstrating shared characteristics and evolutionary histories.
• Species are groups of organisms capable of interbreeding and producing fertile offspring under natural conditions. Mechanisms like genetic drift and gene flow can alter genetic variation in populations.

Physiology

• Physiology studies the functions of living organisms and their parts.
• Organ systems, like the circulatory, respiratory, and digestive systems, work together for survival.
• Homeostasis is the body's maintenance of internal stability despite external changes.
• Mechanisms for maintaining homeostasis involve feedback loops that monitor and adjust internal conditions, e.g., temperature regulation, hydration.
• The nervous system coordinates responses to stimuli via nerve impulses.
• The endocrine system regulates various bodily functions using hormones.
• Immune systems protect against pathogens using innate and adaptive responses.