Biological Molecules in Biology

Biological Molecules

• Biology is the study of life, encompassing a vast spectrum of organisms, from microscopic bacteria to complex mammals, and their interactions with the environment
• Life is characterized by a complex hierarchy of organization, progressing from atoms to molecules, to cells, tissues, organs, organ systems, and ultimately complete organisms.
• Four major classes of biological macromolecules are essential for life: carbohydrates, lipids, proteins, and nucleic acids.
• Carbohydrates provide energy and structural support. They are composed of carbon, hydrogen, and oxygen atoms. Common examples include sugars (glucose, fructose) and starches.
• Lipids, including fats, oils, and phospholipids, are crucial for energy storage, insulation, and cell membrane structure. They are hydrophobic molecules, primarily composed of carbon and hydrogen atoms.
• Proteins are complex macromolecules composed of amino acids, performing a wide array of functions like catalysis, transport, and structure. They determine the characteristics and capabilities of living organisms.
• Nucleic acids, such as DNA and RNA, store and transmit genetic information. DNA carries the code for all the proteins needed for the organism, while RNA plays a key role in protein synthesis.

Cell Structure and Function

• Cells are the basic units of life, exhibiting a remarkable diversity of structure and function in different organisms.
• Prokaryotic cells, exemplified by bacteria, lack a membrane-bound nucleus and other organelles.
• Eukaryotic cells, found in plants, animals, fungi, and protists, possess a nucleus and a variety of membrane-bound organelles, such as mitochondria and chloroplasts.
• The cell membrane is a selectively permeable barrier regulating the passage of materials into and out of the cell.
• The cytoplasm encompasses the contents of a cell outside the nucleus.
• The nucleus contains the cell's genetic material, DNA.
• Mitochondria are the powerhouses of the cell, producing energy.
• Chloroplasts, found in plant cells, carry out photosynthesis, converting light energy into chemical energy.

Cellular Processes

• Cellular respiration is a metabolic process that breaks down glucose to produce ATP, the primary energy currency of the cell.
• Photosynthesis is the process by which plants and other photosynthetic organisms convert light energy into chemical energy in the form of sugars.
• Cell division is essential for growth, repair, and reproduction. Mitosis is a type of cell division that produces two genetically identical daughter cells. Meiosis is a specialized type of cell division that produces gametes (sperm and eggs).
• DNA replication is crucial for cell division, ensuring that each daughter cell receives a complete copy of the genetic material.
• Protein synthesis involves the transcription of DNA into RNA and the translation of RNA into proteins.

Genetics

• Genes are segments of DNA that carry hereditary information.
• DNA replication is a process that duplicates DNA molecules.
• Mutations are changes in DNA sequences that can lead to variations in traits.
• Gene expression regulation controls the production of proteins from genes, allowing cells to respond to their environment.
• Mendelian genetics describes the basic principles of inheritance, including dominant and recessive traits.
• Non-Mendelian inheritance patterns, such as incomplete dominance and codominance, demonstrate more complex patterns of inheritance.

Ecology

• Ecology is the study of organisms and their relationships with each other and their environments.
• Ecosystems are communities of organisms and their physical environment.
• Biomes are large-scale ecosystems characterized by specific climates and dominant plant life.
• Food webs depict the flow of energy and nutrients among organisms in an ecosystem.
• Competition and predation are crucial interactions among organisms in an ecosystem.
• Symbiotic relationships, such as mutualism and parasitism, significantly influence ecosystem dynamics.

Evolution

• Evolution is the change in the heritable characteristics of biological populations over successive generations.
• Natural selection is a key mechanism of evolution, favoring traits that enhance survival and reproduction in a given environment.
• Genetic drift is a random change in allele frequencies within a population, particularly pronounced in small populations.
• Speciation is the formation of new and distinct species in the course of evolution.
• The fossil record provides evidence of evolutionary change over time.
• Comparative anatomy and molecular biology offer further support for evolutionary relationships among organisms.