Modification of RNA transcripts, including splicing out of introns, joining together of exons, and alteration of the 5' (mG cap) and 3' ends (poly A tail); only in eukaryotes
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translation
the process whereby genetic information coded in messenger RNA directs the formation of a specific protein at a ribosome in the cytoplasm
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RNA polymerase
An enzyme that links together the growing chain of RNA nucleotides during transcription, using a DNA strand as a template.
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antisense strand
DNA strand acting as template for transcription
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sense strand
strand that has the same base sequence as the mRNA
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rRNA
RNA that is combined with special protein that makes up a ribosome
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ribosome
Cytoplasmic organelles at which proteins are synthesized during translation
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tRNA
transfer RNA; type of RNA that carries amino acids to the ribosome
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DNA triplet
complimentary to mRNA codon; found in DNA
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codon
A specific sequence of three adjacent bases on a strand of mRNA that provides genetic code information for a particular amino acid.
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anticodon
group of three bases on a tRNA molecule that are complementary to an mRNA codon
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AUG
start codon
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methionine
first amino acid in most proteins
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UGA, UAG, UAA
stop codons
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nucleolus
A specialized structure in the nucleus, formed from various chromosomes and active in the synthesis of ribosomes
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TATA box
A DNA sequence in eukaryotic promoters crucial in forming the transcription initiation complex.
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promoter
A specific nucleotide sequence in DNA (TAC) that binds RNA polymerase and indicates where to start transcribing RNA.
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transcription factors
A regulatory protein that binds to DNA and affects transcription of specific genes
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TTATTT
The terminator sequence for transcription
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primary mRNA
eukaryotic RNA before it has been processed.
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mG cap
added to the 5' end of mRNA during RNA processing; prevents destruction of the mRNA
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poly A tail
The modified end of the 3' end of an mRNA molecule consisting of the addition of some 1000 to 250 adenine nucleotides.
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RNA splicing
process by which the introns are removed from RNA transcripts and the remaining exons are joined together
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introns
A segment of a gene situated between exons that is removed before translation of messenger RNA and does not function in coding for protein synthesis.
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exons
A coding region of a eukaryotic gene. Exons, which are expressed, are separated from each other by introns.
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spliceosome
A complex assembly that interacts with the ends of an RNA intron in splicing RNA, releasing the intron and joining the two adjacent exons.
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charged tRNA
a transfer RNA molecule to which the appropriate amino acid has been attached to the acceptor stem
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A site
site in the ribosome that holds the tRNA carrying the next amino acid to be added to the polypeptide chain.
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P site
site in the ribosome where peptide bonds are formed between amino acids on a growing polypeptide chain
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E site
site in the ribosome where uncharged tRNAs leave the ribosome.
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frame shift
mutation that shifts the "reading" frame of the genetic message by inserting or deleting a nucleotide
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operon
A segment of DNA containing adjacent genes including structural genes and an operator gene and a regulatory gene
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inducible gene
Genes whose expression is turned on by the presence of some substance. Regulate catabolic pathways.
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repressible gene
A gene that is regulated by a corepressor or inhibitor, which are small effector molecules that cause transcription to decrease.
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lac operon
a gene system whose operator gene and three structural genes control lactose metabolism in E. coli
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trp operon
Group of genes that are used or transcripted together that codes for the components for production of tryptophan
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virus
ultramicroscopic particles that contain nucleic acids, proteins, and sometimes lipids
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capsid
Outer protein coat of a virus
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lytic infection
Process in which a virus enters a cell, makes a copy of itself, and causes the cell to burst.
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lysogenic infection
process by which a virus embeds its DNA into the DNA of the host cell and is replicated along with the host cell's DNA
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retrovirus
An RNA virus that reproduces by transcribing its RNA into DNA and then inserting the DNA into a cellular chromosome; an important class of cancer
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reverse transcriptase
An enzyme encoded by certain viruses that uses RNA as a template for DNA synthesis.
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duplication
Change in chromosome structure in which a particular segment is present more than once in the same chromosome
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translocation
Change to a chromosome in which a fragment of one chromosome attaches to another part of a chromosome
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inversion
a kind of mutation in which the order of the genes in a section of a chromosome is reversed
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missense
A point mutation in which a codon that specifies an amino acid is mutated into a codon that specifies a different amino acid.
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nonsense
Name the type of mutation where the new codon specifies for a stop codon
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silent
A type of mutation where there is no change in the resulting polypeptide.
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beta
galactosidase
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permease
a protein that aids in the movement of lactose across the cell membrane
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regulatory gene
A gene that codes for a protein, such as a repressor, that controls the transcription of another gene or group of genes.
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promoter region
1st region of a gene, turns gene on and off, informs the gene when protein synthesis must begin
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operator region
Binds repressors and inducers (start and stop transcription). Located between the promoter region and the start site.
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tryptophan synthetase
enzyme encoded by the trp genes; made up of 5 different proteins
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miRNA
functions in RNA interference and post
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antiparallel
The opposite arrangement of the sugar
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siRNA
use in degrading mRNA
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chaperone proteins
Assist in folding other proteins into secondary and tertiary structure
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germline mutation
mutation that occur in gametes (sperm & egg); passed onto next generation
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somatic mutation
a mutation that occurs in a body cell; not passed onto next generation
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vaccine
A weakened or inactive version of a pathogen that stimulates the body's production of antibodies which can aid in destroying the pathogen
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viroid
An infectious particle that consists solely of a strand of RNA and is capable of causing disease in plants
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prion
Any of various infectious proteins that are abnormal forms of normal cellular proteins, that proliferate by inducing the normal protein to convert to the abnormal form; causing mad cow disease, kuru, and CJD