AP Bio

• emergent properties

  new properties that emerge with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases
• negative feedback

  a mechanism of response in which a stimulus initiates reactions that reduce the stimulus
• positive feedback


  a physiological control mechanism in which a change in a variable triggers mechanisms that amplify the change
• inductive reasoning

  reasoning based on observed patterns
• polymer


  large compound formed from combinations of many monomers
• hydrolysis


  a chemical process in which a compound is broken down and changed into other compounds by taking up the elements of water
• enzyme


  protein that acts as a biological catalyst
• phospholipids


  a molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail
• cellular respiration


  process that releases energy by breaking down glucose and other food molecules in the presence of oxygen
• phosphorylation


  the transfer of a phosphate group, usually from ATP, to a molecule. Nearly all cellular work depends on ATP energizing other molecules by phosphorylation
• chemiosmosis


  a process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.
• fermentation


  the process by which cells break down molecules to release energy without using oxygen
• gametes


  reproductive cells, have only half the number of chromosomes as body cells
• meiosis


  a process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, which results in the production of sex cells
• somatic cell


  cell that makes up all of the body tissues and organs, except gametes
• crossing over


  the interchange of sections between pairing homologous chromosomes during the prophase of meiosis
• transcription


  process in which part of the nucleotide sequence of DNA is copied into a complementary sequence in mRNA
• codons

  a three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code.
• RNA splicing


  process by which the introns are removed from RNA transcripts and the remaining exons are joined together
• mutations


  random errors in gene replication that lead to a change in the sequence of nucleotides; the source of all genetic diversity
• repetitive DNA

  nucleotide sequences, usually noncoding, that are present in many copies in a eukaryotic genome.
• transposons


  small mobile DNA segments
• homeobox


  one of various similar homeotic genes that are involved in bodily segmentation during embryonic development
• genome project

  Research and technology development effort aimed at mapping and sequencing some or all of the genome of human beings and other organisms
• adaptations

  the behaviors and physical characteristics that allow organisms to live successfully in their environments
• natural selection


  process by which individuals that are better suited to their environment survive and reproduce most successfully
• vestigial structures


  remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species
• convergent evolution

  process by which unrelated organisms independently evolve similarities when adapting to similar environments
• protists

  single-celled or simple multicellular eukaryotic organisms that generally do not fit in any other kingdom
• diatoms

  unicellular algae that have a unique glass-like wall made of hydrated silica embedded in an organic matrix
• ciliates

  a group of protozoans that move by waving tiny, hair-like organelles called cilia
• amoeba

  A type of protist characterized by great flexibility and the presence of pseudopodia
• gastrula


  an embryonic stage in animal development encompassing the formation of three layers: ectoderm, mesoderm, and endoderm
• cephalization

  the concentration of nerve tissue and sensory organs at the anterior end of an organism
• symmetry

  the way an animal's body parts match up around a point or central line
• coelom

  fluid-filled body cavity lined with mesoderm
• sustainable agriculture


  farming method that preserves long-term productivity of land and minimizes pollution
• nitrogen fixation


  process of converting nitrogen gas into nitrogen compounds that plants can absorb and use (ammonia)
• crop rotation

  the system of growing a different crop in a field each year to preserve the fertility of the land
• epiphyte


  plant that is not rooted in soil but instead grows directly on the body of another plant