Ch. 16 Bio Terms

Front 1

genetic transformation

Back 1

DNA is required to do this

Front 2

Griffith

Back 2

studied genetic transformation; studied pneumococcus in mice; some “transforming principle” from the heat-killed S strain changed the R strain to make it deadly

Front 3

Avery and colleagues

Back 3

identified DNA as the “transforming principle” of Griffith's experiment

Front 4

Hershey-Chase

Back 4

concluded that phage injected DNA into bacteria to infect them

Front 5

bacteriophages or phages

Back 5

viruses that infect bacteria; viruses execute a “genetic takeover” of cells

Front 6

purines

Back 6

the bases adenine and guanine

Front 7

pyrimidines

Back 7

bases cytosine and thymine

Front 8

phosphodiester linkage

Back 8

link nucleotides together 3' to 5'

Front 9

Chargaff and colleagues

Back 9

found any one organism they tested had amounts of A ≈ T and C ≈ G

Front 10

Rosalind Franklin and Maurice Wilkins

Back 10

x-ray diffraction studies indicated a helical molecule
(double helix)

Front 11

complementary

Back 11

the sequence of one strant of DNA had to have an appropriate, complementary sequence on the other for the molecule to hold together

Front 12

James Watson and Francis Crick

Back 12

the accepted model for the structure of the DNA double helix was published by them

Front 13

semiconservative replication

Back 13

the model suggested that each strand could serve as a template for making a complementary strand; one strand old, one strand new

Front 14

replication bubble

Back 14

synthesis generally proceeds in both directions from an origin creating this

Front 15

replication forks

Back 15

both strands are replicated at the same time on both sides of the replication bubble, producing these Y-shaped things on both sides; they move as synthesis proceeds

Front 16

DNA helicase

Back 16

does the unwinding and opening of DNA

Front 17

single-strand DNA binding proteins

Back 17

keep the 2 strands open after the DNA helicase unwinds them

Front 18

topoisomerases

Back 18

break and rejoin strands, resolving knots and strains that occur

Front 19

DNA polymerases

Back 19

direct synthesis of new strands; synthesis can only proceed in the 5’ à 3’ direction

Front 20

primase

Back 20

starts the strand by making an RNA primer

Front 21

the leading strand

Back 21

has its 3’ end at the fork; thus, its synthesis can proceed continuously, in the direction that the fork moves

Front 22

lagging strand

Back 22

has its 5’ end at the fork; it must be synthesized in the “opposite direction” from the leading strand

Front 23

Okazaki fragments

Back 23

the lagging strand makes these when it synthesizes away from the replication fork

Front 24

DNA ligase

Back 24

joins the Okazaki fragments

Front 25

telomeres

Back 25

the ends of chromosomes

Front 26

telomerase enzymes

Back 26

can generate longer telomeres

Front 27

nucleosomes

Back 27

the main packaging mechanism for eukaryotic DNA

Front 28

histones

Back 28

the proteins of DNA; positively charged, and thus able to associate with the negatively charged phosphates of the DNA backbone

Front 29

“linker DNA” regions

Back 29

parts of the continuous DNA molecule that are not wound on histones; nucleosomes are linked together by these

Front 30

H1 - histone

Back 30

associates with the linker DNA regions; binding leads to packing of nucleosomes into a chromatin fiber that is 30nm wide

Front 31

scaffolding proteins

Back 31

fibers produced by H1 form loops that are often held together by these non-histone things

Front 32

Beadle and Tatum

Back 32

developed the “one gene, one enzyme” hypothesis; found mutant genes in the fungus Neurospora that each affected a single step in a metabolic pathway

Front 33

Pauling

Back 33

“one gene, one polypeptide” hypothesis

Front 34

RNA (ribonucleic acid)

Back 34

serves mainly as an intermediary between the information in DNA and the realization of that information in proteins; single-stranded

Front 35

ribose

Back 35

sugar

Front 36

uracil(U)

Back 36

functions in place of T in an RNA strand

Front 37

mRNA

Back 37

messenger RNA: copies the actual instructions from the gene

Front 38

tRNA

Back 38

transfer RNA: links with amino acids and bring them to the appropriate sites for incorporation in proteins

Front 39

rRNA

Back 39

ribosomal RNA: main structural and catalytic components of ribosomes, where proteins are actually produced

Front 40

Central Dogma of Gene Expression

Back 40

DNA to RNA to protein

Front 41

transcription

Back 41

making RNA using directions from a DNA template; transcribe = copy in the same language

Front 42

translation

Back 42

making a polypeptide chain using directions in mRNA; translate = copy into a different language; here the translation is from base sequence to amino acid sequence

Front 43

RNA polymerases

Back 43

RNA polymerase I is used in making rRNA; RNA polymerase II is used in making mRNA and some small RNA molecules; RNA polymerase III is used in making tRNA and some small RNA molecules

Front 44

template strand

Back 44

the DNA strand that is read during transcription

Front 45

upstream

Back 45

toward the 5’ end of the RNA strand, or toward the 3’ end of the template strand

Front 46

downstream

Back 46

toward the 3’ end of the RNA strand, or toward the 5’ end of the template strand