Introduction to Biology and Cell Biology

Introduction to Biology

• Biology is the natural science studying life and living organisms, including structure, function, growth, origin, evolution, and distribution.
• It encompasses many disciplines, from molecular biology to ecology.
• Key concepts include cells (fundamental units of life), evolution (natural selection), and energy flow in ecosystems.
• Biology uses scientific methods: observation, hypothesis testing, and experimentation to understand biological phenomena.

Cell Biology

• Cells are the basic structural and functional units of all living organisms.
• The cell theory states all living things are composed of cells.
• Prokaryotic cells are simpler, lacking membrane-bound organelles, while eukaryotic cells are more complex and contain various organelles.
• Key organelles: nucleus, mitochondria, endoplasmic reticulum, and Golgi apparatus.
• Cell membranes regulate substance passage, maintaining homeostasis.
• Cellular processes like respiration, photosynthesis, and protein synthesis are crucial.

Genetics

• Genetics studies genes, heredity, and variation in living organisms.
• Genes are DNA segments, holding instructions for protein building.
• DNA carries genetic information determining organism traits.
• Genes are passed to offspring via sexual reproduction.
• DNA mutations create variations and potentially new traits.
• Genetic engineering manipulates genes for various purposes, including genetically modified organisms.

Evolution

• Evolution is the change in heritable characteristics of biological populations over generations.
• Natural selection drives evolution, favoring traits improving survival and reproduction.
• Evidence for evolution includes fossil records, comparative anatomy, biogeography, and molecular biology.
• Common ancestry connects all living organisms, descending from a shared ancestor.
• Speciation is the formation of new species from existing ones.
• Adaptation is how organisms become better suited to their environments.

Ecology

• Ecology studies relationships between organisms and their environment.
• Ecosystems have biotic (living) and abiotic (non-living) components.
• Energy flows through ecosystems, usually starting with producers like plants.
• Food webs show complex feeding relationships in communities.
• Population dynamics describe population changes over time.
• Biodiversity encompasses life's variety at all levels, from genes to ecosystems.

Classification of Life

• Organisms are classified into taxonomic groups based on shared characteristics.
• The classification hierarchy includes domains (Bacteria, Archaea, Eukarya), kingdoms, phyla, classes, orders, families, genera, and species.
• This system helps scientists understand evolutionary relationships.
• Modern classification relies on evolutionary relationships (phylogeny).

Microbiology

• Microbiology studies microscopic organisms (bacteria, viruses, fungi, and protists).
• Microorganisms have crucial roles: decomposition, nutrient cycling.
• Some microorganisms are pathogenic, causing disease.
• Understanding microbial communities is essential in medicine, agriculture, and environmental science.

Physiology

• Physiology studies the functions of living organisms and their parts.
• It covers a wide range of topics, from cellular processes to organ systems.
• Specific organ systems (nervous, digestive, circulatory) are also studied.
• Homeostasis maintains a stable internal environment in an organism.

Biotechnology

• Biotechnology uses biological systems, organisms, or their derivatives for product or process development.
• It applies biological knowledge to practical applications.
• Examples include genetic engineering, pharmaceutical production, and bioremediation.
• This field has potential for solving global challenges.