Au Biology 110 Chapter 16

Front 1

promoter

Back 1

A short sequence of DNA that facilitates the binding of RNA polymerase to enable the transcription of downstream genes.

Front 2

transcription

Back 2

The process by which RNA polymerase makes RNA from a DNA template.

Front 3

RNA polymerase II

Back 3

One of three RNA polymerase enzymes that catalyze the synthesis of RNA from ribonucleotides in eukaryotes, using a DNA template.

Front 4

DNA (deoxyribonucleic acid)

Back 4

A double-stranded, double-helix molecule of deoxyribonucleotides that contains the genetic information of a cell. Each nucleotide contains the sugar deoxyribose, a phosphate group, and one of four possible nitrogenous bases: adenine, guanine, cytosine, or thymine.

Front 5

RNA (ribonucleic acid)

Back 5

A usually single-stranded polymer consisting of a string of ribonucleotides. It may be a structural component of ribosomes (rRNA), a transporter of amino acids (tRNA), or a translator of the message of the DNA code (mRNA).

Front 6

initiation phase

Back 6

The first stage of transcription, in which RNA polymerase and other proteins bind to the promoter, forcing the DNA double helix in the transcription region to separate into two single strands.

Front 7

template strand

Back 7

The strand of DNA that is read by RNA polymerase and used as a pattern to synthesize the new RNA chain. Which strand of the separated DNA becomes the template strand is based on the orientation of the regulatory sequences in the DNA.

Front 8

nontemplate strand

Back 8

The strand of DNA that is not transcribed by RNA polymerase. Which strand of the separated DNA becomes the nontemplate strand is based on the orientation of the regulatory sequences in the DNA.

Front 9

elongation phase

Back 9

The second stage of transcription, in which the RNA polymerase molecule begins to travel in one direction along the template strand, catalyzing the addition of complementary ribonucleotides and thus elongating the RNA chain.

Front 10

ribonucleotide

Back 10

A nucleotide that contains ribose as its sugar and occurs as a constituent of RNA.

Front 11

antiparallel

Back 11

The characteristic of strands of DNA or RNA that run in opposite directions: One strand runs in the 5' to 3' direction; the other is oriented 3' to 5'.

Front 12

termination phase

Back 12

The third and final stage of transcription, in which transcription termination signals at the end of the gene direct the RNA polymerase to end transcription.

Front 13

transcription termination signal

Back 13

A stretch of DNA sequence that codes for a stretch of RNA that leads to formation of a hairpin in the RNA. The hairpin disrupts the transcription complex and ends transcription.

Front 14

transcription

Back 14

The process by which messenger RNA is made from a DNA template.

Front 15

messenger RNA (mRNA)

Back 15

An RNA molecule that carries encoded information, transcribed from DNA, for the synthesis of one or more proteins.

Front 16

translation

Back 16

The process by which proteins and peptides are synthesized from messenger RNA molecules.

Front 17

ribosome

Back 17

A complex of specialized ribosomal RNA (rRNA) and proteins that mediates protein synthesis from messenger RNA strands, facilitating placement of transfer RNA, and catalyzing formation of the peptide bonds between amino acids.

Front 18

ribosomal RNA (rRNA)

Back 18

A class of specialized RNA molecules that forms part of the structure of a ribosome.

Front 19

transfer RNA (tRNA)

Back 19

A class of specialized RNA molecules responsible for matching amino acids to messenger RNA codons during translation. They have a cloverleaf shape, with the amino acid binding site at one end and an anticodon at another site.

Front 20

aminoacyl tRNA

Back 20

A tRNA molecule that is covalently linked to an amino acid.

Front 21

initiation

Back 21

The first stage of translation, which begins when a section of rRNA in the small subunit of the ribosome binds to a complementary sequence on the mRNA.

Front 22

5' cap

Back 22

A structure consisting of the molecule 7-methylguanylate and three phosphate groups.

Front 23

start codon

Back 23

The messenger RNA sequence AUG, which induces the beginning of protein synthesis and codes for the amino acid methionine.

Front 24

anticodon

Back 24

Three bases of a transfer RNA molecule that bind to a messenger RNA codon with a complementary sequence.

Front 25

elongation

Back 25

The second stage of translation, during which polypeptide chains lengthen to build the protein.

Front 26

P site

Back 26

The site in a ribosome where peptide bonds are formed between amino acids.

Front 27

A site

Back 27

The site in a ribosome at which an aminoacyl transfer RNA pairs with a messenger RNA codon, in preparation for adding its amino acid to the growing peptide chain.

Front 28

E site

Back 28

The site in a ribosome into which an empty transfer RNA is shunted after addition of its amino acid to the growing peptide chain.

Front 29

translocation

Back 29

A process that occurs during elongation when the ribosome moves down the mRNA in the 5' to 3' direction. It moves the empty tRNA into the E site; moves the tRNA containing the growing polypeptide into the P site; and opens the A site to expose a new mRNA codon.

Front 30

termination

Back 30

The last stage of translation, during which three stop codons signal the end of protein synthesis.

Front 31

stop codon

Back 31

One of three messenger RNA triplets (UAG, UGA, or UAA) that cause termination of protein synthesis.

Front 32

release factor

Back 32

A protein that fits tightly into the A site during translation because its size, shape, and electrical charge are extremely similar to a tRNA.