Introduction to Life Science

Life science studies living organisms and life processes.

• It examines structure, function, growth, evolution, distribution, and taxonomy.
• Life science is also known as biology.

Sub-Disciplines

• Biochemistry studies chemical processes within living organisms.
• It focuses on the structure and function of biomolecules like proteins, carbohydrates, lipids, and nucleic acids.
• Molecular biology studies the molecular basis of biological activity.
• It explores interactions between DNA, RNA, and proteins.
• Cell biology (cytology) studies the structure, function, and behavior of cells.
• It examines cell organelles, cell division, and cell signaling.
• Genetics is the study of heredity and variation in organisms.
• It examines genes, DNA, and inheritance patterns.
• Microbiology studies microorganisms like bacteria, viruses, fungi, and protozoa.
• It also includes their role in health, disease, and the environment.
• Zoology studies animals, including their anatomy, physiology, behavior, and evolution.
• Botany studies plants, including their physiology, structure, genetics, ecology, distribution, classification, and economic importance.
• Ecology examines the interactions between organisms and their environment.
• Evolution concerns the processes transforming life on Earth, from its earliest forms to today's diversity.
• Physiology studies the normal functions of living organisms and their parts.
• Anatomy studies the structure of living organisms.

Key Concepts

• Cell theory states all living organisms are composed of cells.
• Cells are the basic unit of structure and function in living organisms.
• Gene theory states traits are inherited through genes located on chromosomes.
• Homeostasis is an organism's ability to maintain a stable internal environment despite external changes.
• Evolution is the process by which populations of organisms change over time.
• Ecosystems are communities of living organisms interacting with their physical environment.

Domains of Life

• Bacteria are single-celled prokaryotic organisms lacking a nucleus and other membrane-bound organelles.
• Archaea are single-celled prokaryotic organisms distinct from bacteria, often inhabiting extreme environments.
• Eukarya includes all eukaryotic organisms with cells containing a nucleus and other membrane-bound organelles.
• Kingdoms within Eukarya include protists, fungi, plants, and animals.

Scientific Method

• Observation involves noticing and describing events or processes carefully.
• Hypothesis is a testable explanation for a set of observations.
• Experiment is a procedure to make a discovery, test a hypothesis, or demonstrate a known fact.
• Data analysis is the process of inspecting, cleansing, transforming, and modeling data to discover useful information and inform conclusions.
• Conclusion is a judgment or decision reached by reasoning.
• Scientific theories are well-substantiated explanations incorporating facts, laws, inferences, and tested hypotheses.

Important Molecules

• Water is essential due to its properties as a solvent, its high heat capacity, and its role in biochemical reactions.
• Carbohydrates are the primary energy source and provide structural support.
• Lipids include fats, oils, and steroids, functioning in energy storage, insulation, and cell membrane structure.
• Proteins catalyze reactions, transport molecules, and provide structural support.
• Nucleic acids (DNA and RNA) store and transmit genetic information.

Energy and Metabolism

• Metabolism is the sum of all chemical reactions within an organism.
• Anabolism constructs molecules from smaller units.
• Catabolism breaks down molecules into smaller units to release energy.
• Photosynthesis converts light energy into chemical energy in the form of glucose.
• Cellular respiration breaks down glucose to release energy in the form of ATP.
• ATP (adenosine triphosphate) is the primary energy currency of the cell.

Genetics and Heredity

• DNA (deoxyribonucleic acid) carries genetic information in all living organisms.
• Genes are specific DNA sequences that encode proteins or RNA molecules.
• Chromosomes are structures within cells that contain DNA.
• Meiosis produces gametes (sex cells) with half the number of chromosomes as the parent cell.
• Mitosis results in two daughter cells with the same number and kind of chromosomes as the parent nucleus and is typical of ordinary tissue growth.
• Mutations are changes in the DNA sequence that can lead to genetic variation.
• Inheritance is the process by which traits are passed from parents to offspring.

Evolution and Diversity

• Natural selection is the process where organisms better adapted to their environment survive and reproduce more.
• Adaptation enhances an organism's survival and reproduction.
• Speciation is the process by which new species arise.
• Phylogeny is the evolutionary history of a species or group of species.
• Biodiversity is the variety of life in the world or in a particular habitat or ecosystem.

Ecology and Environment

• Population is a group of individuals of the same species living in the same area.
• Community is an assemblage of populations of different species living in the same area.
• Ecosystem is a community of organisms and their physical environment interacting as a unit.
• Biome is a large geographic area characterized by specific climate conditions, animal populations, and plant communities.
• Food chains/webs describe the flow of energy and nutrients through an ecosystem.
• Trophic levels refer to the position an organism occupies in a food chain.
• Symbiosis describes a close ecological relationship between two organisms of different species.
• Climate change refers to long-term shifts in temperatures and weather patterns, largely due to human activities increasing greenhouse gas emissions.

Life science is the scientific study of living organisms and life processes, also known as biology. It encompasses sub-disciplines such as biochemistry, molecular biology, and genetics. It delves into the structure, function, growth, and taxonomy of living organisms.