gene expression

transcription

the process where the genetic information in a DNA sequence of a gene is copied into mRNA

translation

the process where genetic information coded in mRNA is used to create a polypeptide/protein

mRNA

type of RNA that carries genetic information from DNA in the nucleus to the ribosome in the cytoplasm

tRNA

type of RNA that carries amino acids to the ribosome

codon

sequence of three consecutive bases on a strand of mRNA

anticodon

group of three bases on a tRNA that are complementary to an mRNA codon

complementary base pairing

In DNA, T pairs with A and G pairs with C; in RNA, U pairs with A and G pairs with C

ribosome

organelles in the cytoplasm where proteins are made

nucleus

a part of the cell containing DNA

amino acid

building block of protein

polypeptide chain

a chain of amino acids linked together by peptide bonds

protein

a molecule that is made of one or more chains of amino acids that has an essential role in all living things

nitrogenous bases

adenine, guanine, cytosine, thymine, uracil

deoxyribose

5-carbon sugar in DNA

ribose

5-carbon sugar in RNA

nucleotide

consists of a phosphate group, sugar, and nitrogenous base

triplet

a sequence of three consecutive bases found on a DNA strand

rRNA

ribosomal RNA; type of RNA that makes up part of the ribosome

peptide bond

bonds that connect amino acids in a polypeptide

nuclear pores

holes in the nuclear membrane that allow materials to pass in and out of the nucleus

RNA polymerase

enzyme that links together the growing chain of ribonucleotides during transcription

mutation

permanent change in the DNA sequence of a gene

mutagen

an environmental agent that causes a permanent change to the DNA

point mutation

gene mutation in which a single base pair in DNA has been changed

substitution

one nucleotide replaces another

insertion

base/s are added to the DNA base sequence, causing a reading frame shift

deletion

base/s are removed from the DNA base sequence, causing a reading frame shift

frameshift mutation

mutation that shifts the reading frame of the triplet code by inserting or deleting a base

silent mutation

a mutation that changes a single base but does not change the amino acid because of degeneracy

nonsense mutation

a substitution mutation that codes for a STOP codon

missense mutation

a substitution mutation that results in a codon that codes for a different amino acid

degeneracy

two or more codons code for the same amino acid

metabolic pathway

a series of enzyme-controlled reactions where the product of one reaction becomes the substrate for the next reaction