9th Grade Bio - Protein Synthesis

central dogma

a theory that states that genetic information flows in one direction, from DNA to RNA to proteins

RNA nitrogenous bases

Adenine, Guanine, Cytosine, Uracil

messenger RNA

transcribed segments of DNA that leave the nucleus and are translated into proteins

Ribosomal RNA

molecules that make up ribosomes

Transfer RNA

identifies matching amino acids to the corresponding mRNA nucleotides

polypeptides

chains made by joining amino acids together (protein polymer)

codon

a segment of 3 consecutive nucleotides that code for one amino acid

start codon

AUG

what is transcription?

when DNA is copied into mRNA

RNA polymerase

a protein that unzips DNA and copies it into RNA

template strand

the strand of DNA that is copied into RNA

coding strand

the DNA strand that doesn’t get copied

pre-mRNA

newly transcribed RNA that has not gone through RNA splicing

RNA splicing

when pre-mRNA removes the pieces of the strand that don’t code for proteins

introns

pieces of pre-mRNA that don’t code for proteins and are spliced out.

exons

pieces of pre-mRNA that code for a protein and are spliced together, creating mature RNA

what is translation?

when the mRNA strand is read and translated into a polypeptide chain, which forms a protein

how does translation start?

when the mRNA enters the cytoplasm, ribosomes bring large and small subunits to translate the RNA into amino acids

anticodon

at the end of the tRNA, identifies the type of amino acid being coded for by the codon

epigenetics

how your behaviors/environment cause changes that affect how your genes work. does not alter genetic code, but determines what genes are turned on/off

mutation

change in genetic material of a cell

mutagins

chemical/physical agents in the environment that interact with DNA and may trigger mutations

wild type

a gene without a mutation

when do mutations generally occur

DNA replication due to faulty DNA polymerase

point mutations

alters a single nucleotide

nonsense mutation

early stop codon. protein denatures

silent mutation

changes codon but amino acid remains the same. protein is unaltered and functions normally

missense mutation

changes the amino acid and results in a different protein being formed

frameshift mutation

alters the structure of DNA by adding/deleting nucleotides

insertion mutation

caused by insertion of one or more nucleotides that shifts the reading frame

deletion mutation

caused by deletion of one or more nucleotides that shifts the reading frame

chromosomal mutation

results in the change of an entire chromosome

types of chromosomal mutations

inversion, deletion, insertion, duplication, translation