Biology Chapter 18, 2

Front 1

gene

Back 1

a DNA sequence whose final product is either a polypeptide or an RNA molecule.

Front 2

gene expression

Back 2

DNA-directed synthesis of proteins (or RNAs)

Front 3

RNA

Back 3

the link between a gene and teh protein for which it codes

Front 4

transcription

Back 4

transfer of information from DNA to messenger RNA or another type of RNA using the "laguage" of nucleic acids.

Front 5

Translation

Back 5

transfers information from mRNA to a polypeptide, changing from the language of nucleotides to that of amino acids.

Front 6

ribosomes

Back 6

sites of translation( synthesis of a polypeptide).

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messenger RNA

Back 7

a type of RNA, synthesized using a DNA template, that attaches to ribosomes n the cytoplasm and specifies hte primary structure of a protein.

Front 8

RNA processing

Back 8

the modification of pre-mRNA or of the primary transcript of any gene within the nucleus, occurs only in eukaryotes.

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triplet code

Back 9

the translation of nucleotides into amino acids uses this to specify each amino acid.

Front 10

template strand

Back 10

base triplets along this strand are transcribed into mRNA codons.

Front 11

codon

Back 11

a three-nucleotide sequence of DNA or mRNA that specifies a praticular amino acid or termination signal; the basic unit of the genetic code

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redundant code

Back 12

more than one codon can specify a single amino acid, but no codon specifies two different amino acids.

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reading frame

Back 13

starting at a start codon and reading each triplet sequentially

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promoter

Back 14

the DNA sequence where RNA polymerase attaches and initiates transcription. The binding site for RNA polymerase and determines where transcription starts and which DNA strnad is used as the template.

Front 15

RNA polymerase

Back 15

an enzyme that links ribonucleotides into a grwoing RNA chain during transcription.

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terminator

Back 16

in bacteria, the sequence that signals the end of transcription.

Front 17

transcription unit

Back 17

the sequence of DNA that is transcribed into one RNA molecule

Front 18

RNA polymerase II

Back 18

synthesizes mRNA

Front 19

TATA box

Back 19

a recognition sequence common in eukaryotes, upstream from the start point, crucial for forming the transcirption initiation complex.

Front 20

transcription factors

Back 20

in eukaryotes, must first recognize and bind to the promoter before RNA polymerase II can attach.

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transcription initiation complex

Back 21

the completed assembly of transcription factors and RNA polymerase bound to a promoter.

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RNA polymerase

Back 22

untwists the double helix, exposing DNA nucleotides for base pairing with RNA nucleotides, adn joins the nucleoptides to the 3' end of the growing polymer.

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poly-A tail

Back 23

a sequence of 50 to 250 adenine nucleotides added onto the 3' end of a pre-mRNA molecule.

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5' cap

Back 24

a modified form of guanine nucleotide added onto the nucleotide at the 5' end of a pre-mRNA molecule.

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introns

Back 25

long sections of non-coding bases, intervening sequences, occur wihtin the boundaries of eukaryotic genes.

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exons

Back 26

coding regions expressed in protein synthesis

Front 27

RNA splicing

Back 27

the removal of portions(introns) of the transcriptthat will not be included in the mRNA.

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spliceosome

Back 28

a large complex made up of proteins and RNA molecules that splices RNA by interacting wiht the ends of an RNA intron, releasing the intron adn joining two adjacent exons.

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ribozymes

Back 29

RNA molecules that act like enzymes

Front 30

alternative RNA splicing

Back 30

allows some genes to produce different polypeptides.

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domains

Back 31

functional segments of a protein, such as binding and active sites.

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transfer RNA (tRNA)

Back 32

molecules that carry specific amino acids to ribosomes, each have an anitcodon, that base-pairs with complementary mRNA, assuring that amino acids arranged in the sequence prescribed by the transcription of DNA.

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anticodon

Back 33

base triplet, a nucelotide triplet at one end of a tRNA molecule that recognizes a particular complementary codon on an mRNA molecule.

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aminoacyl-tRNA synthetase

Back 34

each amino acid has one, attaches to its appropriate tRNA molecules to create an aminoacyl tRNA, driven by hydolysis of ATP.

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wobble

Back 35

enables the third nucleotide of some tRNA anticodons to pair with more than one kind of base in the codon.

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ribosomal RNA

Back 36

the most abundant type fo RNA, which together with proteins makes up ribosomes.

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P site

Back 37

ribosomes binding site for RNA, that holds the tRNA carrying the growing polypeptide chain

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A site

Back 38

holds the tRNA carrying the next amino acid

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E site

Back 39

exit site from whihc discharged tRNAs leave the ribosome.

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iniation factors

Back 40

helps subunit of ribosome attach to small one and from translation intitiation complex.

Front 41

elongation factors

Back 41

proteins invovled in the elongation stage of protein synthesis.

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polyribosomes(polysomes)

Back 42

an mRNA can be translated simultaneously by several ribosomes in strings

Front 43

signal peptide

Back 43

if a protein is destined for the endomembrane system or for secretion.