steel

  a spider’s web

  cotton fibers

  nylon fibers

it is in period 2 of the Periodic Table

  it is a non-metal

  it has a valence of 4

  it is highly electronegative

protein with small amounts of sugar

  petroleum derivative

  short-chain carbohydrate

  long-chain hydrocarbon

is very dense for a sugar

  loses water to its environment

  attracts water from the air

  expands rapidly on heating

Carboxyl group

  Carbonyl group

  Amine group

  Hydrogen atom

A peak indicating an amino group

  A peak indicating a carboxylic acid –OH stretch

  A peak indicating a carbon-carbon double bond

  A peak indicating sp2-hybridized carbon-hydrogen bonds

Cells within the biofilm are encased within a layer of polysaccharide [pol-ee-SAK-uh-ryd]

  Biofilms almost always consist of only a single bacterial species

  Biofilms are restricted to freshwater environments

  Biofilms typically are small because resources are unable to circulate through them

DNA polymerase [POL-uh-muh-rays]

  RNA polymerase

  Helicase

  Primase

DNA polymerase is added between each period of heating and cooling

  The DNA polymerase used is from a species of bacteria that live in hot springs, so the DNA polymerase can function at high temperatures

  RNA polymerase is more heat resistant and is used instead, and then the DNA is reverse transcribed from the RNA

  DNA polymerases in most species are proteins that do not denature easily, so this process can function at high temperatures

One strand on each of the two DNA segments is radioactively labeled, while the other strand on each of the two segments is unlabeled

  Both strands of one DNA segment are radioactively labeled, while both strands of the other segment are unlabeled

  Both strands on each segment of DNA contain a mixture of radioactively labeled and unlabeled base pairs

  Both segments of DNA have all their nitrogenous bases in both strands labeled