Ch 7 - From DNA to Protein: How Cells Read the Genome

Question 1

alternative splicing

Answer 1

the production of different mRNAs (and proteins) from the same gene by splicing its RNA transcripts in different ways

Question 2

aminoacyl-tRNA synthetase

Answer 2

during protein synthesis, an enzyme that attaches the correct amino acid to tRNA molecule to form a ‘charged’ aminoacyl-tRNA

Question 3

anticodon

Answer 3

set of three consecutive nucleotides in a transfer RNA molecule that recognized, through base-pairing, the three nucleotide codon on a messenger RNA molecule; this interaction helps to deliver the correct amino acid to a growing polypeptide chain

Question 4

codon

Answer 4

group of three consecutive nucleotides that specifies a particular amino acid or that starts or stops protein synthesis; applies to the nucleotides in an mRNA or in a coding sequence of DNA

Question 5

exon

Answer 5

segment of a eukaryotic gene that is transcribed into RNA and dictates the amino acid sequence of part of a protein

Question 6

gene

Answer 6

unit of heredity containing the instructions that dictate the characteristics or phenotype of an organism; in molecular terms, a segment of DNA that directs the production of a particular protein or functional RNA molecule

Question 7

gene expression

Answer 7

the process by which a gene make s a product that is useful to the cell or organism by directing the synthesis of a protein or an RNA molecule with a characteristic activity

Question 8

general transcription factors

Answer 8

proteins that assemble on the promoters of eukaryotic genes near the start stie of transcription and load the RNA polymerase in the correct position

Question 9

genetic code

Answer 9

set of rules by which the information contained in the nucleotide sequence of a gene and its corresponding RNA molecule is translated into the amino acid sequence of a protein

Question 10

initiator tRNA

Answer 10

special tRNA that initiates the translation of an mRNA in a ribosome. it always carries the amino acid methionine

Question 11

intron

Answer 11

noncoding sequence within a eukaryotic gene that is transcribed into an RNA molecule but is then excised by RNA splicing to produce an mRNA

Question 12

messenger RNA (mRNA)

Answer 12

RNA molecule that specifies the amino acid sequence of a protein

Question 13

polyadenylation

Answer 13

the addition of multiple adenine nucleotides to the 3’ end of a newly synthesized mRNA molecule

Question 14

promoter

Answer 14

DNA sequence that initiates gene transcription; includes sequences recognized by RNA polymerase and its accessory proteins

Question 15

protease

Answer 15

enzyme that degrades proteins by hydrolyzing their peptide bonds

Question 16

proteasome

Answer 16

large protein machine that degrades proteins that are damaged, misfolded, or no longer needed by the cell; its target proteins are marked for destruction primarily by the attachment of a short chain of ubiquitin

Question 17

reading frame

Answer 17

one of the three possible ways in which a set of successive nucleotide triplets can be translated into protein, depending on which nucleotide serves as the starting point.

Question 18

ribosomal RNA (rRNA)

Answer 18

RNA molecule that forms the structural and catalytic core of the ribosome

Question 19

ribosome

Answer 19

large macromolecular complex, composed of RNAs and proteins, that translates a messenger RNA into a polypeptide chain

Question 20

ribozyme

Answer 20

an RNA molecule with catalytic activity

Question 21

RNA (ribonucleic acid)

Answer 21

molecule produced by the transcription of DNA; usually single-stranded, it is a polynucleotide composed of covalently linked ribonucleotide subunits. serves a variety of information, structural, catalytic and regulatory functions in cells

Question 22

RNA capping

Answer 22

the modification of the 5’ end of a maturing RNA transcript by the addition of an atypical molecule

Question 23

RNA polymerase

Answer 23

enzyme that catalyzes the synthesis of an RNA molecule from a DNA template using ribonucleoside triphosphate precursors

Question 24

RNA processing

Answer 24

broad term for the modifications that a precursor mRNA undergoes as it matures into an mRNA. it typically includes 5’ capping, RNA splicing and 3’ polyadenylation

Question 25

RNA splicing

Answer 25

process in which intron sequences are excised from RNA molecules in the nucleus during the formation of a mature messenger RNA

Question 26

RNA transcript

Answer 26

RNA molecule produced by transcription that is complementary to one strand of DNA

Question 27

RNA world

Answer 27

hypothetical period in Earth’s early history in which life-forms were thought to use RNA both to store genetic information and to catalyze chemical reactions

Question 28

small nuclear RNA (snRNA)

Answer 28

RNA molecule of around 200 nucleotides that participates in RNA splicing

Question 29

spliceosome

Answer 29

large assembly of RNA and protein molecules that splices introns out of pre-mRNA in the nucleus of eukaryotic cells

Question 30

transcription

Answer 30

process in which RNA polymerase uses one strand of DNA as a template to synthesize a complementary RNA sequence

Question 31

transfer RNA (tRNA)

Answer 31

small RNA molecule that serves as an adaptor that ‘reads’ a codon in mRNA and adds the correct amino acid to the growing polypeptide chain

Question 32

translation

Answer 32

process by which the sequence of nucleotides in a messenger RNA molecule directs the incorporation of amino acids into protein

Question 33

translation initiation factor

Answer 33

protein that promotes the proper association of ribosomes with mRNA and is required for the initiation of protein synthesis