3. Biotechnology

DNA helicase

unwinds and unzips DNA by breaking hydrogen bonds between the bases

DNA polymerase

adds new DNA nucleotides using the complementary base pairing rules

DNA ligase

seals breaks in the sugar-phosphate backbone

rRNA

joins with proteins to form the subunits of ribosomes

mRNA

produced in nucleus, where DNA serves as template; carries genetic info from DNA to ribosomes in cytoplasm

tRNA

transfers amino acids to the ribosome during protein synthesis

transcription

first step of gene expression; DNA is read to make a mRNA in the nucleus of the cell

translation

second step of gene expression; reading the mRNA to make a protein in the cytoplasm

introns

segments of DNA that interrupt genes and they don’t code for a functional protein

exons

portions of the gene that are expressed; result in a protein product

primary mRNA to mature mRNA

one end of RNA is capped, introns removed, poly-A tail added

anticodon

3 base sequence that complementary base pairs with codons of mRNA

initiation

mRNA binds to the small ribosomal subunit and causes 2 ribosomal units to associate

elongation

polypeptides lengthen; tRNA picks up an amino acid, tRNA anticodon binds to the codon and drops off the amino acid growing the polypeptide

termination

a stop codon on the mRNA causes the ribosome to fall off the mRNA

transcriptional control (nucleus)

regulates which genes are transcribed and the rate; uses transcription factors

posttranscriptional control (nucleus)

mRNA processing

translational control (cytoplasm)

differential ability of mRNA to bind ribosome

posttranslational control

changes to the protein to make it functional

proteomics

the study of the structure, function, and interactions of cell proteins

ex vivo therapy

stem cells are removed for a person altered and then returned to the patient

in vivo therapy

a gene is directly inserted into an individual through a vector or directly injected to replace mutated genes or to restore normal controls over gene activity

recombinant DNA

contains DNA from more than 1 source

genome editing

the targeting of specific sequences in DNA for removal or replacement

denaturation

DNA is heated to become single stranded

annealing

DNA is cooled and a primer attaches to each of the DNA strands

extension

DNA polymerase adds complementary bases to each of the single DNA strands, creating 2 double-stranded DNAs

transgenic organisms

organisms that have had a foreign gene inserted into them