6-3 Vocab Flashcards
Okazaki Fragments
A short segment of DNA synthesized away from the replication fork on a template strand during DNA replication. Many such segments are joined together to make up the lagging strand of newly synthesized DNA
Nucleosomes
The basic, beadlike unit of DNA packing in eukaryotes, consisting of a segment of DNA wound around a protein core composed of two copies of each of four types of histone
Bacteriophages
A virus that infects bacteria; also called a phage
Euchromatin
The less condensed form of eukaryotic chromatin that is available for transcription
Transfer RNA
(tRNA) An RNA molecule that functions as a translator between nucleic acid and protein languages by picking up a specific amino acid and carrying it to the ribosome, where the tRNA recognizes the appropriate codon in the mRNA
TATA Box
A DNA sequence in eukaryotic promoters crucial in forming the transcription initiation complex
Ribozymes
An RNA molecule that functions as an enzyme, such as an intron that catalyzes its own removal during RNA splicing
Terminator
In bacteria, a sequence of nucleotides in DNA that marks the end of a gene and signals RNA polymerase to release the newly made RNA molecule and detach from the DNA
Transcription Factors
A regulatory protein that binds to DNA and affects transcription of specific genes
Wobble
Flexibility in the base-pairing rules in which the nucleotide at the 5’ end of a tRNA anticodon can form hydrogen bonds with more than one kind of base in the third position (3’ end) of a codon
Aminoacyl-tRNA Synthetases
An enzyme that joins each amino acid to the appropriate tRNA
RNA Polymerase
An enzyme that links ribonucleotides into a growing RNA chain during transcription, based on complementary binding to nucleotides on a DNA template strand
Insertions
A mutation involving the addition of one or more nucleotide pairs to a gene
Poly-A Tail
A sequence of 50 to 250 adenine nucleotides added onto the 3’ end of a pre-mRNA molecule
RNA Splicing
After synthesis of a eukaryotic primary RNA transcript, 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)
Exons
A sequence within a primary transcript that remains in the RNA after RNA processing; also refers to the region of DNA from which this sequence was transcribed
Promoter
A specific nucleotide sequence in the DNA of a gene that binds RNA polymerase, positioning it to start transcribing RNA at the appropriate place
Alternative RNA Splicing
A type of eukaryotic gene regulation at the RNA-processing level 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
RNA Processing
Modification of RNA primary transcripts, including splicing out of introns, joining together of exons, and alteration of the 5′ and 3′ ends
Reading Frame
On an mRNA, the triplet grouping of ribonucleotides used by the translation machinery during polypeptide synthesis
