AP Biology - Unit 6: Gene Expression and Biotechnology (overview)

central dogma

DNA-transcription-RNA-translation-protein-phenotypes

RNA polymerase

enzyme that makes mRNA

mRNA

messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome

mRNA editing

done before mRNA can leave nucleus, includes removing introns, keeping exons (done by splicosome) and addition of GTP5 cap and poly-A tail

What happens when mRNA gets to the cytoplasm

ribosome reads mRNA with EPA (arrival, processing, exit) complex, read in codons (groups of 3)(start \= aug end \= uaa, uag, uga), tRNA has anti-codons and amino acid that build the primary protien structure

mutation

change in a DNA sequence

muatin to DNA

significant impact

mutation to RNA

minor impact

types of causes of mutation

induced and spontanius

induced muaiton

outside source (radiation, chemicals, infectious agent)

spontanious mutation

(inside factors(dna copying

types of mutation

silent, missense, nonsense, frameshift

silent mutation

A mutation that changes a single nucleotide, but does not change the amino acid created.

missense mutation

A base-pair substitution that results in a codon that codes for a different amino acid.

frameshift mutation

mutation that shifts the "reading" frame of the genetic message by inserting or deleting a nucleotide

nonsense mutation

A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein.

what is a virus

not considered alive, genetic info wrapped in protein coat

prokaryote virus

bacteriophage, only affects bacteria, two types: virulent and temperate

virulent bacteriophages

bacteriophages that replicate by lytic cycle and kill their host cells by copying DnA until host lyces

temperate bacteriophage

Bacteriophage that may enter an inactive phase (lysogenic cycle) in which the host cell replicates and passes on the bacteriophage DNA for generations before the phage becomes active and kills the host (lytic cycle)

eukayote viruses

affects us, can be single or double stranded, has lipid layer

Dna virus

lysogenic, doesnt mutate much, herpes, poxs

rna viruses

high mutatin, lytic cycle, common cold/covid

retroviruses

use reverse transcriptase to copy their RNA genome into DNA

why is gene expression necessary

able to turn on/off, allows or specialized cells,

operon

a group of genes that operate together by a switch

prog

Promoter, Repressor, Operator, Gene

inducable operon

usually off but can be stimulated when a specific molecule interacts with a regulator protein

repressable operon

transcription is usually on but it an be inhibited

Eukaryote gene expression

few have operon system

dna bends so regulatory box and activator protien can connect with TF and rna poly through mediator

why complex

tightly regulate, less mutation

teratoma

body cant regulate genes, tumor