Core Principles of Biology

• Biology is the scientific study of life.

Core Principles of Biology

• Cell theory: all living organisms are composed of cells.
• Gene theory: heritable traits are passed down through genes.
• Evolution: all life forms have evolved over time from a common ancestor.
• Homeostasis: living organisms maintain a stable internal environment.
• Thermodynamics: life depends on the flow of energy.

Cell Structure and Function

• Cells are the basic structural and functional units of life.
• Prokaryotic cells (bacteria and archaea) lack a nucleus and other membrane-bound organelles.
• Eukaryotic cells (protists, fungi, plants, and animals) have a nucleus and other membrane-bound organelles.
• Key organelles include:
• Nucleus: contains DNA and controls cell activities.
• Mitochondria: produce energy through cellular respiration.
• Ribosomes: synthesize proteins.
• Endoplasmic reticulum (ER): involved in protein and lipid synthesis.
• Golgi apparatus: modifies, sorts, and packages proteins and lipids.
• Lysosomes: contain enzymes for breaking down cellular waste.

Genetics and Heredity

• Genes are units of heredity made of DNA.
• DNA (deoxyribonucleic acid) carries the genetic information.
• DNA structure: double helix composed of nucleotides.
• Nucleotides consist of a sugar, a phosphate group, and a nitrogenous base (adenine, guanine, cytosine, or thymine).
• DNA replication: process of copying DNA.
• Transcription: process of synthesizing RNA from DNA.
• Translation: process of synthesizing proteins from RNA.
• Mutations are changes in the DNA sequence.
• Chromosomes are structures containing DNA.
• Genes are located on chromosomes.
• Meiosis: cell division that produces gametes (sperm and egg cells) with half the number of chromosomes.
• Mitosis: cell division that produces two identical daughter cells.

Evolution

• Evolution is the change in the heritable characteristics of biological populations over successive generations.
• Natural selection: process by which organisms with advantageous traits are more likely to survive and reproduce.
• Key concepts in evolution:
• Genetic variation: differences in DNA among individuals.
• Adaptation: traits that enhance survival and reproduction.
• Speciation: process by which new species arise.
• Evidence for evolution:
• Fossil record: shows the history of life on Earth.
• Comparative anatomy: similarities and differences in the anatomy of different species.
• Molecular biology: similarities in DNA and protein sequences among different species.

Ecology

• Ecology is the study of the interactions between organisms and their environment.
• Key concepts in ecology:
• Populations: groups of individuals of the same species living in the same area.
• Communities: groups of different species living in the same area.
• Ecosystems: communities of organisms and their physical environment.
• Biosphere: all of the ecosystems on Earth.
• Trophic levels: position an organism occupies in a food chain.
• Food webs: interconnected food chains in an ecosystem.
• Energy flow: movement of energy through an ecosystem.
• Nutrient cycling: movement of nutrients through an ecosystem.

Plant Biology

• Plants are multicellular, eukaryotic organisms that belong to the kingdom Plantae.
• Photosynthesis: process by which plants convert light energy into chemical energy.
• Plant structure:
• Roots: anchor the plant and absorb water and nutrients.
• Stems: support the plant and transport water and nutrients.
• Leaves: site of photosynthesis.
• Flowers: reproductive structures.
• Plant reproduction:
• Sexual reproduction: involves the fusion of gametes (pollen and egg cells).
• Asexual reproduction: does not involve the fusion of gametes (e.g., vegetative propagation).

Animal Biology

• Animals are multicellular, eukaryotic organisms that belong to the kingdom Animalia.
• Key characteristics of animals:
• Heterotrophic: obtain energy by consuming other organisms.
• Motile: able to move.
• Sexual reproduction: reproduce sexually.
• Animal tissues:
• Epithelial tissue: covers the body surface and lines internal organs.
• Connective tissue: supports and connects other tissues.
• Muscle tissue: enables movement.
• Nervous tissue: transmits nerve impulses.
• Animal organ systems:
• Digestive system: breaks down food and absorbs nutrients.
• Respiratory system: exchanges gases (oxygen and carbon dioxide).
• Circulatory system: transports blood, oxygen, and nutrients.
• Excretory system: removes waste products.
• Nervous system: controls body functions.
• Endocrine system: produces hormones.
• Immune system: protects the body from disease.
• Reproductive system: enables reproduction.

Microbiology

• Microbiology is the study of microorganisms.
• Microorganisms include bacteria, archaea, fungi, protists, and viruses.
• Bacteria: prokaryotic cells that lack a nucleus and other membrane-bound organelles.
• Archaea: prokaryotic cells that are genetically and biochemically distinct from bacteria.
• Fungi: eukaryotic organisms that include yeasts, molds, and mushrooms.
• Protists: eukaryotic organisms that are not plants, animals, or fungi.
• Viruses: non-cellular entities that require a host cell to replicate.
• Microorganisms play important roles in:
• Nutrient cycling
• Decomposition
• Disease
• Biotechnology

Biotechnology

• Biotechnology utilizes biological systems, living organisms, or derivatives thereof, to make or modify products or processes for specific use.
• Key areas of biotechnology:
• Genetic engineering: modification of an organism's genes.
• Cloning: creating genetically identical copies of an organism
• Biopharmaceuticals: using living organisms to produce drugs.

Overview of the fundamental concepts in biology, including cell theory and genetics. Explains evolutionary processes shaping life and how organisms maintain stability through homeostasis. Also covers the crucial role of energy flow in living systems.