Chapter 12 Notes - DNA Structure and Replication

Eukaryotes

________ have about 1000 times more DNA than prokaryotes- chromosomes are linear and tightly packed with proteins in the nucleus.

Replication

________- the process by which DNA is copied during the cell cycle.

Phages

________ are relatively simple- are a little more than a DNA molecule surrounded by a protein coat.

Bacteriophage

________- a type of virus that takes over a bacterium's genetic machinery and directs it to make more viruses.

Helicases

________- enzymes that start the process by unzipping the double helix to separate the strands of DNA.

Nucleotides

________- the small units (monomers) that make up DNA.

Protein

________ contains sulfer but little phosphorus, while DNA contains phosphorus but no sulfer.

Erwin Chargaff

________ found that the same four bases are in the DNA of all organisms but the proportion of the four bases differs somewhat from organism to organism.

Crick

The double helix: Watson and ________ made models of metal and wood to figure out the structure of DNA.

DNA double helix

The ________ is held together by hydrogen bonds between the bases in the middle.

Chemical analysis

________- the proportions of elements in the extract closely matched those found in DNA; proteins contain almost no phosphorus.

nitrogen containing

A(n) ________ base (single or double ring built around nitrogen and carbon atoms)

Double helix

________- two strands of DNA wind around each other like a twisted ladder.

DNA polymerases

________ and DNA ligase are also involved in repairing DNA damaged by harmful radiation or toxic chemicals in the environment.

DNA replication

________ is called semiconservative because one old strand is conserved, and one new strand is made.

Enzyme tests

________- when enzymes were added, the extract still transformed the R bacteria to the S form → transformation only failed to occur when an enzyme was added that specifically destroys DNA.

X ray evidence

________: Rosalind Franklin and Maurice Wilkins were studying DNA using x- ray crystallography.

Replication

________ begins when regulatory proteins bind to a certain point on the plasmid and proceeds in two directions until the whole plasmid is copied.

DNA

________ polymerases bond the nucleotides together and form new strands complementary to each template.

DNA replication

________ varies in prokaryotes and eukaryotes- prokaryotes have a single, circular piece of DNA (plasmid) in their cytoplasm.

DNA

________ polymerases- a group of enzymes that bond the new nucleotides together.

DNA

________ does nothing more than store information.