Biology

• Properties of Life

  • Order or Organization
  • Reproduction
  • Growth and Development
  • Response to Stimulus from the Environment or Irritability
  • Energy Processing or Metabolism
  • Regulation or Homeostasis
  • Evolutionary Adaptation
• Order or Organization


  Life is characterized by highly ordered structures
• Cells


  The structural and functional unit of life
• Atoms


  Make up molecules, which in turn make up cell organelles and other components
• Tissues


  Similar cells make up tissues
• Organs


  Tissues collaborate to create organs (body structures with distinct functions)
• Organ systems


  Organs work together, forming organ systems
• Reproduction


  Organisms reproduce their kind
• DNA replication


  Single-celled organisms reproduce by replicating their DNA
• Germ cells


  Multicellular organisms produce through specialized reproductive germ cells that form new individuals
• Genes


  Genes containing DNA are passed along to the offspring, ensuring the offspring belongs to the same species and will have similar characteristics
• Growth and Development


  Inherited information in the form of DNA controls how organisms grow and develop as they mature
• Genes


  Genes provide instructions that direct cellular growth and development, ensuring the young will grow up to exhibit the same characteristics as their parents
• Response to Stimulus

  All living beings respond to their environment
• Plant responses


  • Plants grow toward a light source, climb fences and walls, and respond to touch
• Bacterial responses


  • Tiny bacteria can move toward or away from chemicals (chemotaxis) or light (phototaxis)
• Positive response


  Movement toward a stimulus
• Negative response


  Movement away from a stimulus
• Energy Processing or Metabolism


  Organisms take in energy to drive all their activities
• Photosynthesis


  Some organisms capture energy directly from the sun and convert it into chemical energy
• Heterotrophs


  Others use chemical energy in molecules they take in as food
• Regulation or Homeostasis


  Organisms have different mechanisms in order to maintain a beneficial internal environment
• Organs


  Organs perform specific functions, such as carrying oxygen, removing wastes, delivering nutrients, and cooling the body
• Homeostasis


  The ability of an organism to maintain constant internal conditions despite environmental changes
• Evolutionary Adaptation


  Adaptations of organisms to their environment evolve as traits that help individuals survive are passed over time
• Adaptations


  Advantageous traits that become more common in a population over time
• Evolution


  The process that changes organisms over time and explains the diverse species seen in biology
• Ecological niches


  Adaptations help organisms survive in their ecological niches
• Structural, behavioral, and physiological adaptations


  Adaptations may be structural, behavioral, or physiological
• Living beings are composed of matter manifesting in the form of atoms, molecules, and compounds.
• Carbon is the basis for the chemistry of life and is capable of forming vast numbers of compounds.
• The most abundant element in cells is hydrogen (H), followed by carbon (C), oxygen (O), nitrogen (N), phosphorus (P), and sulfur (S).
• Organic compounds in organisms are generally larger and more complex than inorganic compounds.
• Biomolecules contain functional groups - groups of atoms within molecules categorized by their specific chemical composition and the chemical reactions they perform.
• Monomers are the smaller molecules that act as building blocks for macromolecules called polymers.
• Dehydration reactions link monomers to form polymers, while hydrolysis breaks down polymers into monomers.
• The four main groups of carbon-containing macromolecules in cells and cell structures are carbohydrates, lipids, proteins, and nucleic acids.
• Monosaccharides

  Simple sugar molecules, the monomers of carbohydrates
• Isomers


  Biomolecules with the same chemical formula but different structures
• Pentoses


  Five-carbon sugars