chapter 1

• what are living organisms?

  • composed of one or more cells
  • reproduce using DNA
  • obtain energy from their environment to support metabolism
  • sense their environment and respond to it
  • maintain a constant internal environment
• what are cells?


  the foundation for all living things
• what is the name of the water-repellent layer that encloses a self-contained unit known as a cell?

  plasma membrane
• what is an example of a single-celled organism?

  bacterium
• what is composed of many different kinds of specialized cells working together?

  multicellular organisms
• what is DNA?

  a genetic material that contains all the instructions for building , maintaining, and growing a cell
• in plant and animal cells, DNA is stored within a membrane bound... what?


  nucleus
• what is a gene?

  a segment of DNA that codes for a specific genetic trait
• what happens in sexual repro?

  DNA from two different individuals is combined in the offspring during fertilization
• what happens during asexual repro?

  does not require fertilization, the results of offspring are genetically identical to the one parent
• what is metabolism?

  the capture of storage and use of energy by an organism
• what are producers?

  obtain energy from the nonliving part of their environment
• what are consumers?

  obtain energy from the LIVING part of their environment by consuming producers or other consumers
• what is a stimulus?

  anything that causes a response
• what is homeostasis?


  the tendency to resist change in order to maintain a stable, relatively constant internal environment
• what do negative feedback loops do?

  they oppose the stimulus or cue, that triggers them
• how many negative feedback loops do homeostatic circuits usually involve?

  2
• what are the 2 negative feedback loops in hemeostatic circuits?

  when the temp is above setpoint and when its below
• when does a positive feedback loop come into play?


  during childbirth
• what is a biological evolution?

  a change in the overall genetic characteristics in a group of organisms over generations
• what is artificial selection?


  evolutionary change that is caused by humans
• what is an adaptive trait?


  genetic characteristics that enables an individual to survive and reproduce better than its competitors in the population
• what is it called when all the species in our planet are grouped into three broad categories?

  domains
• which domain is divided into 4 main kingdoms?

  domain Eukarya
• what are atoms?

  the building blocks of matter
• what is a molecule?

  when 2 or more atoms are held together by chemical bonds
• what are biomolecules?


  molecules found in all living cells and generally contain carbon
• what is a cell?


  the smallest unit of life
• how is a tissue formed?

  when groups of cells perform a set of unique tasks
• what makes up an organ?


  different types of tissue
• what makes up an ecosystem?

  the physical environment and all the communities in it
• what are biomes?

  large regions of the world that have similar physical characteristics and similar types of organisms
• what is biosphere?

  all the worlds living organisms and the places where they live