LESSON 2

• Smallest unit of matter and cannot be broken down into anything simpler by chemical means

  atoms
• Building blocks of molecules

  atoms
• Smallest unit of most compounds formed by chemical bonding of atoms

  molecules
• Specialized structures that perform important cellular functions within cells

  organelles
• • Smallest unit of life
  • Collections of living matter enclosed by a barrier that separates them from their surroundings

  cell
• Groups of similar cells that perform a particular function

  tissue
• Groups of similar tissues that perform a particular function

  organ
• Groups of organs that work together to perform closely related functions

  organ system
• 12 biological system

  endocrine, nervous, circulatory, reproductive, respiratory, skeletal, immune, integumentary, muscular, digestive, urinary, lymphatic
• Living things composed of cells (multicellular organisms)

  organisms
• taxonomic rank

  kingdom, phylum, class, order, family, genus, species
• scientific name

  genus + species
• Total number of organisms of the same species living on the same area

  population
• Groups of different populations that live together

  community
• All organisms that live in a particular place including non-living things

  ecosystem
• Groups of ecosystems that have the same climate and similar dominant communities

  biomes
• Part of the earth in which life exists including life, water, air and atmosphere

  biosphere
• All cells came from pre-existing cells

  composed of cells
• Single cell

  unicellular
• • Many cells
  • Diversity and specialization of function (85 types of cells in the body)

  multicellular
• asexual and sexual

  reproduction
• • Single parent copies its DNA and then divides or buds to produce genetically 
  • Rapid fire reproduction of great numbers of identical organisms

  asexual reproduction
• • 2 different parent cells unite to produce the first cells of a new organism
  • Offspring are genetically unique leading to greater genetic diversity and speciation on earth

  sexual reproduction
• • Single-celled organism like bacteria, growth is mostly simple increase in size
  • Multicellular organisms undergo extensive development from single fertilized egg dividing many times to produce the multitude of cells in mature organisms

  all organisms grow and develop
• Change of shape and structure to perform different functions

  differentiation
• anabolism and catabolism

  metabolism
• synthesizing compounds - expends energy

  anabolism
• breaking compounds into simpler components

  catabolism
• Combination of chemical reactions that build and breakdown materials as organisms carry out their life processes

  metabolism
• Stimulus - signal

  respond to environment
• internal stimuli

  blood glucose level
• external stimuli

  light, sound, heat, smell, sight
• Autonomic processes by which organisms respond to stimuli such that conditions in the body are kept suitable to sustain life

  homeostasis
• DNA is a type of biomolecule known as nucleic acid that has 3-dimensional shape called a double helix


  DNA is the universal genetic code
• Common to all life, determining the inherited traits of all organisms


  all life is based on universal genetic code
• Ability of a group to change over time

  evolution
• Helps it to compete and survive to reproduce in its environment

  adaptation