Biology Notes: Cell, Genetics, Ecology, Evolution, Plant, Microbiology, DNA, RNA, Genomics, Study notes of Biology

Download Biology Notes: Cell, Genetics, Ecology, Evolution, Plant, Microbiology, DNA, RNA, Genomics and more Study notes Biology in PDF only on Docsity! SIR JV NOTES SCIENCE BIOLOGY SCIENCE (BIOLOGY) Notes TERMINOLOGIES 1. **Cell Biology:** - **Introduction to cells:** Cells are the basic structural and functional units of living organisms. They carry out essential processes such as metabolism, growth, and reproduction. - **Example:** A human body is composed of trillions of cells, each specialized for specific functions such as nerve cells for transmitting signals and muscle cells for movement. - **Cell organelles:** Organelles are specialized structures within cells that perform specific functions. For example, the nucleus contains genetic material (DNA), mitochondria produce energy (ATP), and chloroplasts conduct photosynthesis in plant cells. - **Cell division:** Cells divide to reproduce and repair damaged tissues. Mitosis produces two identical daughter cells, while meiosis produces gametes (sperm and egg cells) with half the number of chromosomes. - **Example:** Mitosis occurs during growth and tissue repair, while meiosis occurs in sexual reproduction. 2. **Genetics:** - **Inheritance and heredity:** Genetics is the study of how traits are passed from parents to offspring. Traits are determined by genes, which are segments of DNA. - **Example:** In Mendelian genetics, traits like flower color in pea plants are determined by alleles inherited from each parent. For example, a plant with two dominant alleles (YY) will have yellow flowers, while a plant with two recessive alleles (yy) will have green flowers. - **Punnett squares:** Punnett squares are tools used to predict the possible outcomes of genetic crosses between organisms. SIR JV NOTES SCIENCE BIOLOGY - **Example:** In a cross between two heterozygous parents (Yy x Yy), a Punnett square can be used to show the possible genotypes and phenotypes of their offspring. 3. **Ecology:** - **Ecosystems:** An ecosystem is a community of organisms interacting with each other and their physical environment. - **Example:** A forest ecosystem includes trees, plants, animals, microorganisms, soil, water, and climate factors like temperature and rainfall. - **Food chains and webs:** Food chains show the flow of energy from one organism to another in an ecosystem. Food webs illustrate interconnected food chains. - **Example:** In a terrestrial food chain, grass is eaten by a grasshopper, which is eaten by a frog, which is then consumed by a snake. - **Environmental issues:** Environmental issues such as pollution, habitat destruction, climate change, and overexploitation of natural resources impact ecosystems and biodiversity. - **Example:** Deforestation reduces habitat for many species, leading to loss of biodiversity and disruption of ecosystem services like carbon sequestration and water regulation. 4. **Evolution:** - **Theory of evolution:** Evolution is the process by which species change over time through natural selection, genetic drift, mutation, and other mechanisms. - **Example:** The fossil record provides evidence of evolutionary changes over millions of years, such as the transition from land-dwelling mammals to whales. - **Natural selection:** Natural selection is the mechanism by which organisms with favorable traits survive and reproduce more successfully than those with less favorable traits. - **Example:** Peppered moths in England during the Industrial Revolution demonstrated natural selection as the dark-colored moths became more prevalent SIR JV NOTES SCIENCE BIOLOGY ecosystem stability, resilience, and ecosystem services. - **Example:** Biodiverse ecosystems are more resilient to environmental changes and provide services such as pollination, water purification, and climate regulation. - **Threats:** Biodiversity is threatened by habitat loss, pollution, invasive species, overexploitation, and climate change. - **Example:** Deforestation in the Amazon rainforest threatens biodiversity and contributes to habitat loss for countless plant and animal species. - **Conservation efforts:** Conservation aims to protect and preserve biodiversity through measures such as habitat conservation, captive breeding, and legislation. - **Example:** National parks and reserves are established to conserve biodiversity and provide habitats for endangered species. **DNA (Deoxyribonucleic Acid):** - **Structure:** DNA is a double-stranded molecule that resembles a twisted ladder, known as the double helix. Each "rung" of the ladder consists of two nucleotide bases paired together: adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C). The backbone of the DNA molecule is made up of sugar (deoxyribose) and phosphate molecules. - **Function:** DNA contains the genetic instructions necessary for the growth, development, functioning, and reproduction of all known living organisms and many viruses. It serves as the blueprint for the synthesis of proteins and the regulation of cellular activities. **RNA (Ribonucleic Acid):** - **Structure:** RNA is a single-stranded molecule that is typically shorter than DNA. It SIR JV NOTES SCIENCE BIOLOGY also consists of nucleotide bases, but instead of thymine (T), RNA contains uracil (U). The nucleotide bases in RNA are adenine (A), uracil (U), guanine (G), and cytosine (C). - **Function:** RNA plays various roles in the cell, including: 1. **Messenger RNA (mRNA):** mRNA carries the genetic information from DNA to the ribosomes, where it serves as a template for protein synthesis (translation). 2. **Transfer RNA (tRNA):** tRNA transports amino acids to the ribosomes during protein synthesis and helps in the assembly of polypeptide chains. 3. **Ribosomal RNA (rRNA):** rRNA is a component of ribosomes, the cellular machinery responsible for protein synthesis. It helps catalyze the formation of peptide bonds between amino acids. **Branches of Molecular Biology:** 1. **Genetics:** Genetics is the branch of biology that studies genes, heredity, and genetic variation. It encompasses topics such as Mendelian genetics, molecular genetics, population genetics, and genomics. 2. **Genomics:** Genomics is the study of the entire genetic material (genome) of an organism, including the structure, function, evolution, and mapping of genes and genomes. 3. **Epigenetics:** Epigenetics investigates changes in gene expression that do not involve alterations to the DNA sequence itself. It explores how environmental factors and lifestyle choices can influence gene activity and phenotype. 4. **Bioinformatics:** Bioinformatics combines biology, computer science, and information technology to analyze and interpret biological data, particularly large-scale datasets generated by genomic and proteomic studies. SIR JV NOTES SCIENCE BIOLOGY 5. **Molecular Evolution:** Molecular evolution examines the molecular mechanisms underlying evolutionary processes, including DNA mutation, natural selection, genetic drift, and speciation. These branches of molecular biology provide a deeper understanding of the structure, function, and regulation of DNA and RNA, as well as their roles in various biological processes.