DNA and the Genome - Gene Expression Flashcards
amino acid
one of twenty different types of organic compound which are the basic building blocks of protein
antibody
type of protein made by white blood cells to defend the body against pathogens
chromatography
technique used to separate components of a mixture which differ in their degree of solubility in a solvent
enzyme
- type of protein possessing an active site which combines with a specific substrate
- they are natural catalysts which speed up reaction by lowering the activation energy
gel electrophoresis
technique used to separate electrically charged molecules by subjecting them to an electric current which forces them to move through a sheet of gel
hormone
type of protein which acts as a chemical messenger
type of bond which holds polypeptide chains into a coil
hydrogen bonds
chemicals present in all proteins
- carbon
- hydrogen
- oxygen
- nitrogen
peptide bond
stong chemical link joining adjacent amino acids in a polypeptide chain
polypeptide
chain-like molecule composed of several amino acids
protein
molecule composed of one or more polypeptides folded or coiled into a specific shape
anticodon
triplet of bases on a tRNA molecule which is complimentary to an mRNA codon
attachment site
tRNA
region of a tRNA molecule to which a specific amino acid becomes temporarily fixed
codon
unit of genetic information consisting of three mRNA bases
exon
coding region of a gene
intron
non-coding region of a gene
mRNA
type of nucleic acid which carries a copy of the DNA code from the nucleus to the ribosome
primary transcript
mRNA strand formed as the compliment of a DNA strand
ribose
sugar present in RNA
ribosome
sub-cellular structure made of rRNA and protein which is the site of protein synthesis (translation)
RNA polymerase
enzyme which controls transcription
splicing
joining of exons from a primary transcript of RNA (following the removal of introns) to form the mature transcript
transcription
definition
process by which a complimentary molecule of mRNA is made from a region of a DNA template
translation
definition
conversion of the genetic information on mRNA into a sequence of amino acids in a polypeptide
tRNA
type of nucleic acid which carries a specific amino acid to a ribosome
uracil
base present in RNA that is complimentary to adenine
replaces thymine
transcription
process
- RNA polymerase unwinds DNA exposing the bases
- mRNA nucleotides align with complimentary base pairs on the template strand (A-U G-C) - 3’ end
- strong chemical bonds form between adjacent nucleotides
- temporary hydrogen bonds between the mRNA and DNA strand are broken allowing the primary transcript to separate from the tamplate strand
- the primary transcript udergoes RNA splicing to form the mautre transcript which goes to the ribosome for translation
- DNA molecule reforms
translation
process
- tRNA nolecules receive an amino acid and carry it to the ribosome
- the first tRNA moves in by codon-anticodon complimentary pairing
- another molecule does the same; peptide bond forms between adjacent amino acids
- the first tRNA detaches from the mRNA strand for reuse
- translation continues to form a polypeptide chain
alternative RNA splicing
alternative splicing is when sections of the primary transcript can be treated as both introns and exons, different exons are spliced together to form the mature transcript
