Introduction to BiologyBiology is the study of life. While biologists have made great strides in discovering things on Earth, there are still many new things to learn. The first fundamental questions are: What is Life? What does it mean to have life? These inquiries are essential to the discoveries that biologists find every day. With such a vast scope of information, biologists must organize these discoveries that will stand the test of time. In this unit, we introduce the major topics that biologists study and the theories they use and apply to their workBasic ChemistryNature is not based on one field of study. It incorporates biology, physics, chemistry, and other academic disciplines. Life is multidisciplinary and is driven by chemical processes. Since so many biology topics overlap with basic principles of chemistry, you need a basic understanding and appreciation of chemistry to fully understand biology. For example, in Unit 1, we discussed that the atom is the first part of the biological hierarchy. In this unit, we provide an understanding of this foundational level of organization.Biological MoleculesBiological molecules are the essential molecules needed for life. These molecules can be organic or inorganic. Organic chemistry is the study of carbon, which is an element that forms strong covalent bonds essential for the foundational structures of all living things. Water, salts, acids, and bases are mostly essential inorganic molecules that facilitate many biological processes. All organisms contain organic biological molecules – carbohydrates, proteins, lipids, and nucleic acid – that are essential to life. This unit will help you understand the structures and functions of these organic molecules and how our body needs them to function properlyCells and Cell MembranesCells are the smallest units of life. In this unit, we explore the characteristics, components, and functions of cells. Learning about the structures of cells allows us to see the similarities and differences among organisms. Bacteria, plant, animal, and fungus cells are similar in many ways and contain many of the same small structures known as organelles. However, some characteristics help distinguish whether a cell belongs to an animal, plant, fungus, or bacteria. For example, all plant cells contain cell walls, while animal cells lack this particular extracellular structure. The water within a cell that presses against the cell wall gives a plant its rigidity and your celery its crunch!classificationClassification is a fundamental concept in biology. It's the process of grouping organisms based on their shared characteristics. This helps scientists understand the relationships between different organisms and how life has evolved over time.There are different hierarchical levels of classification, from the broadest (kingdom) to the most specific (species). Metabolism, Enzymes, and Cellular RespirationMetabolism refers to the sum total of every chemical reaction in every organism. Cells use enzymes and metabolic pathways to conduct these chemical reactions. It is essential to understand the reactions that comprise metabolism to learn how organisms acquire and use energy to survive. Since this process is quite complicated, we will explore it from several different angles in this unit.PhotosynthesisHave you ever wondered how a plant grows from a tiny acorn into a giant oak tree? Where does all that biomass come from? How does it get the energy to grow? Photosynthesis is the fascinating process plants use to convert light energy to chemical energy. Because plants are at the bottom of the food pyramid in almost all ecological systems, understanding how they grow and develop will give you a greater understanding of your environment.Cellular Reproduction: MitosisOrganisms require their cells to divide for the purposes of reproduction, growth, development, or repair. Cellular division is divided into two phases: mitosis and cytokinesis. Mitosis involves the division of the nuclear chromosomes, while cytokinesis is the division of the cytoplasmic components into new daughter cells. Serious consequences, such as cancer, can occur if this cell cycle is disrupted in some way.Cellular Reproduction: MeiosisMeiosis is a specialized type of cellular reproduction that only occurs in the ovaries and testes and results in an egg or sperm, respectively. Sexual reproduction is responsible for the amazing amount of diversity within a species. When sperm fertilizes an egg, the resulting offspring contain genes from the father and the mother. In essence, you contain genes from ALL of your ancestors, at least in a small part.