Micro ch 7--The Blueprint of Life from DNA to Protein

DNA structure

deoxyribose nucleic acid in an alpha helix

made up of sugars and phosphates

antiparallel

the two strands of DNA run in opposite directions

what is RNA

single strand of DNA, consists of single bases

made of sugars (ribose) and phosphates

no thymine, instead there is uracil

messenger RNA/mRNA

coded by an enzyme as a complimentary copy of the gene

ribosomal RNA/rRNA

coils to make a ribosome

binds to mRNA when trying to make a polypeptise chain

transfer RNA/tRNA

carries a different amino acid to the codon to code for things

gene

a section of a chromosome that codes for one characteristic

DNA replication

in the S phase of cell life, the amount of DNA doubles

semiconservative

2 new strands are made to pair with the 2 old strands

helicase

an enzyme that separates the two strands of DNA

DNA polymerase

adds bases to each of the old strand and makes two new paired strands

endonuclease

proofreads the new DNA stand

exonuclease

cuts out anything in the new DNA strand put their by mistake

ligase

connects broek pieces of the DNA strand together

protein synthesis stages

transcription and translation

transcription

inside of the nucleus, DNA unwinds and separates

RNA polymerase puts a copy of the gene onto the mRNA

mRNA leaves the nucleus

translation

mRNA binds to a ribosome

tRNA carries different amino acids to the ribosome to mae the protein coded by mRNA

ribosome rease the codons in threes

genetic code

based on the 3-base sequence of the mRNA

eukaryotic gene expression

a cap is placed on one end of the mRNA and a tail is put on the other end

DNA contains introns and exons

prokaryotic gene expression

do not have introns, only contain exons

introns

sections within a gene that code for nothing and are cut out

exons

genes to code the message

quorum sensing

when bacteria releases a molecules that helps ot determine how big their population is together

helps them survive and form biofilms

antigenic variation

altering surface proteins help them evade the immune system

operon

a group of genes that work together and a control section that turns them on and off

two kinds: lac operon and trp operon

lac operon

consists of three genes for making an enzyme to break down lactose and a control sections to activate and deactivate themselves

trp operon

5 genes and a control section

code for making the amino acid tryptophan

the genes are always on and making tryptophan, but if there are too many the control section shuts down