Campbell Biology (10Th Ed.) Chap 17

Front 1

gene expression

Back 1

process by which DNA directs the synthesis of proteins (or sometimes just RNA)

Front 2

transcription

Back 2

the synthesis of RNA using information in the DNA as a template

Front 3

messenger RNA (mRNA)

Back 3

A type of RNA that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein

Front 4

translation

Back 4

The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule

Front 5

ribosomes

Back 5

molecular complexes that facilitate the orderly linking of amino acids into polypeptide chains (protein synthesis)

Front 6

primary transcript

Back 6

An initial RNA transcript from any gene; also called pre-mRNA when transcribed from a protein-coding gene

Front 7

triplet code

Back 7

genetic instructions for a polypeptide chain written in the DNA as sets of three-nucleotide words

Hint 7

genetic instructions

Front 8

template strand

Back 8

the DNA strand that provides the pattern for the sequence of nucleotides in an RNA transcript

Front 9

codons

Back 9

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

Hint 9

nucleotide triplet

Front 10

reading frame

Back 10

On an mRNA, the triplet grouping of ribonucleotides used by the translation machinery during polypeptide synthesis

Front 11

RNA polymerase

Back 11

An enzyme that links ribonucleotides into a growing RNA chain during transcription, complimentary to the DNA template strand

Front 12

prometer

Back 12

The DNA sequence where RNA polymerase attaches and initiates transcription

Front 13

terminator

Back 13

(in bacteria) the sequence that signals the end of the transcription of RNA

Front 14

transcription unit

Back 14

A region of DNA that is transcribed into an RNA molecule

Front 15

start point

Back 15

the nucleotide where RNA synthesis actually begins

Front 16

transcription factors

Back 16

A regulatory protein that binds to DNA and affects transcription of specific genes

Front 17

transcription initiation complex

Back 17

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

Front 18

TATA box

Back 18

A DNA sequence in eukaryotic promoters crucial in forming the transcription initiation complex.

Front 19

RNA processing

Back 19

RNA modification where both ends of the primary transcript are altered, & certain interior sections of the RNA are cut out and the remaining parts are spliced together

Front 20

poly-A tail

Back 20

A sequence of 50–250 adenine nucleotides added onto the 3′ end of a pre-mRNA molecule.

Front 21

5' cap

Back 21

A modified form of guanine nucleotide added onto the 5′ end of a pre-mRNA molecule

Front 22

RNA splicing

Back 22

the removal of portions of the transcript (introns) that will not be included in the mRNA and the joining together of the remaining portions (exons)

Front 23

introns

Back 23

the noncoding segments of nucleic acid that lie between coding regions

Hint 23

intervening sequences

Front 24

exons

Back 24

the regions being that are eventually expressed by being translated into amino acid sequences (remains after RNA processing)

Front 25

spliceosome

Back 25

A large complex made up of proteins and RNA molecules that splices RNA by interacting with the ends of an RNA intron, releasing the intron and joining the two adjacent exons

Front 26

alternative RNA splicing

Back 26

the gene regulation in which different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns

Front 27

domains

Back 27

A discrete structural and functional region of a protein

Hint 27

(protein structure)

Front 28

transfer RNA (tRNA)

Back 28

An RNA molecule that functions as a translator between nucleic acid and protein by carrying amino acids to the ribosome, where they recognize the appropriate codons in the mRNA.

Front 29

anticodon

Back 29

the particular nucleotide triplet that base-pairs to a specific mRNA codon

Front 30

aminoacyl-tRNA synthetases

Back 30

An enzyme that joins each amino acid to the appropriate tRNA.

Front 31

wobble

Back 31

the flexible base-pairing between the 5' end of a tRNA codon and the 3' end of mRNA codon

Front 32

ribosomal RNAs (rRNAs)

Back 32

RNA molecules that, together with proteins, make up ribosomes

Hint 32

most abundant type of RNA

Front 33

P site

Back 33

a binding site for tRNA (on a ribosome) during translation. Which holds the tRNA carrying the growing polypeptide chain.

Hint 33

(P stands for peptidyl tRNA.

Front 34

A site

Back 34

a binding site for tRNA (on a ribosome) during translation. Which holds the tRNA carrying the next amino acid to be added to the polypeptide chain. (A stands for aminoacyl tRNA.)

Hint 34

(A stands for aminoacyl tRNA.)

Front 35

E site

Back 35

a binding site for tRNA (on a ribosome) during translation. which is the place where discharged tRNAs leave the ribosome

Hint 35

(E stands for exit.)

Front 36

signal peptide

Back 36

A sequence amino acids at or near the leading end of a polypeptide that targets it to the endoplasmic reticulum or other organelles in a eukaryotic cell.

Front 37

signal-recognition particle (SRP)

Back 37

A protein-RNA complex that recognizes a signal peptide as it emerges from a ribosome and helps direct it to the endoplasmic reticulum (ER) by binding to a receptor protein on the ER

Front 38

polyribosomes (polysomes)

Back 38

A group of several ribosomes attached to, and translating, the same messenger RNA molecule.

Front 39

point mutations

Back 39

A change in a single nucleotide pair of a gene.

Front 40

mutations

Back 40

A change in the nucleotide sequence of an organism’s DNA or in the DNA or RNA of a virus.

Front 41

nucleotide-pair substitution

Back 41

the replacement of one nucleotide and its partner with another pair of nucleotides

Front 42

silent mutation

Back 42

A nucleotide-pair substitution that has no observable effect on the phenotype

Front 43

missense mutations

Back 43

A nucleotide-pair substitution that change one amino acid to another

Front 44

nonsense mutation

Back 44

A mutation that changes an amino acid codon to one of the three stop codons, resulting in a nonfunctional protein

Front 45

insertions/deletions

Back 45

additions/losses of nucleotide pairs in a gene

Front 46

frameshift mutation

Back 46

A mutation occurring when nucleotides are inserted/deleted from a gene and the resulting number isn't a multiple of three

Front 47

mutagens

Back 47

A chemical or physical agent that interacts with DNA and can cause a mutation.

Front 48

riboenzyme

Back 48

An RNA molecule that functions as an enzyme, such as an intron that catalyzes its own removal during RNA splicing