Molecular Genetics Review

hell

S and R strain experiment, concluded protien was not hertible

Griffith

Used bacteriphages S35 and P32 to find DNA is hereditory

Hershey and Chase

Randomly stablize and release energy in the process. Their life times vary and is easy to see

Radiactive Isotopes

- First Black woman with pHd in US
- Isolated histones to find the diff types
- Founf that ATCG are building blocks

Marie Daly

- Took photo 51 using X rays
- helpes find shape, measurement and pairs

Rosalind Franklin

- Stole photo 51 and found sturcture of DNA
- Found that it is anti-paralell
- used trial and error

Watson and Crick

- Found AT and GC are the pairs
- Purines and Pyrmidines

Chargoff

- 2 rings
- G and A

Purine

-1 ring
-T or U and C

Pyrimidines

2nm
3.4nm
0.34nm

Diamter
Rotation
Space between base pairs

Phospshte group, deaxy or ribose, N base

Nucleotides

ATCG

Nitrogenous Base

hold backbone together, strong

Phosphodiester bonds

Hold nucleotides together, weak

Hydrogen bonds

DNA wrapped by proteins

Chromosome

The carbon sugar is labled clockwise afetr oxygen

Why is it 5' to 3' or vise versa

Each orginal starnd becomes template

Semi conservative

Template made from both strands

Conservative

dispersed bits and peices of each strand in second gen

Dispersive

Semi conservative

How does DNA replicate (type)

- Made bacteria with N^15 bases that were labeled with Heavy N isotope
- Added it medium with N^14
- Resulted in semi conservative
- Gen 0 was all 15 then gen 1 was mix and so on

Meselson and Stahl

Where replication starts and bubbles open

Origin of Replication

Unwinds DNA

Helicase

(single stranded binding protiens)
Prevents DNA from reconnecing

SSBP

Relives tension

Topoisomerse

- RNA primase adds primer
- DNA polymerase adds nucleotides

Leading Strand

- smaller segments because DNA keeps unwinding
-RNA primase added (non continous)
-nucleotides added on okazaki fragments by DNA poly 3
- DNA poly 1 removes RNA primase
-Ligase glues peices

Lagging strand

- Proofreads
-Adds bases

DNA polymerase 3

- prokaryotic
- repairs damage

DNA polymerase 2

- Methyl group tags mistake
- Exonuclease or Endonuclease enzymes cut out and repair

What happens when a mistake is made

Repairs damage near end

Exonuclease

Repairs damage in middle

Endonuclease

- repeating sewunce at end of DNA where RNA pimer was
- stops DNA loss each time cell division happens

Telomers

Adds the repeat TTAGGG to telomere

Telomerase

DNA to RNA (U and A)
- in nucleous
- TATA box upstream to determine where transcription occurs
- Region of promoter allows RNA poly to bond

Transcription

Initiation
- RNA poly binds to DNA promoter adds bases
- DNA unwound
Elongation
- mRNA synthesis
- DNA that os transcribed coils
Termination
- mRNA fully transcribed
-signals to stop RNA polymerase

Transcription steps

-Messagener
-Made in nucleous
- has codon

mRNA

- Ribosomal
- is ribosome

rRNA

-Transfer
- Has anticodon to connect with codon
- has amino acid and passes it on

tRNA

coding segmant and bond covalantly when introns removed

Exons

non coding segmant and spliced out

Introns

find where exona and intron meet to signal splicosome to cut off intron

snRNPs

Cap is methylated G added to 5' and poly A tail added to 3'. Protects from degradtion by ribosome

Cap and Tail

mRNA to protien
happens in ribosome

Translation

3 nucleotides on tRNA

Anticodon

3 nucleotides on mRNA

Codon

2 subunits
Accepter site
Peptide site
Exist site

Ribsome during translation

Initiation
- small ribo unit bonds to 5' cap upstream of AUG
-intiator tRNA sees start codon
- Large unit connects
Elongation
- tRNA enter A site
- Peptides bond form in P site
- E site is exit
Termination
-Stop codon (UAA,UAG,UGA)
-mRNA relased and polypeptide released

Translation process

Polypeptide to protien
- current chain not active
- shape and seqeunce =function
-multiple processing rxns to activate and make functional

Making the protien

- make up peptide chain
-on tRNA
-many different codon combinations can make 1 AA

Amino Acids

Griffith
Hershey and Chase
Franklin
Wilkins
Watson and Crick

Chronological order of experments

Cells with no regulatory mechanisms to keep healthy growth undercontrol. DNA has mutation that increases its life span

Cancer

- Mutated or damaged
- uncontrolled cell growth
-maligent

Oncogenes

- group of genes that control cell growth
-potention to become cancer

Proto-oncogenes

mass of cells
uncontrolled cell division

Tumor

slow growth
remians in one place
does not return if removed

benign

cancerous
chemo or radation needed

Malignat

Cancer causing agents
- Radation, Cig smoke, Viruses (HPV)

Carcinogen

enviromental agnet that alter DNA within cell

Mutagen

- error in DNA replication
- adding alkyl groups (c) to DNA (Alkylation)
- oxidized N bases (oxidation)

Spontaneous Mutation

-caused by radaition
-chemicals: CO, smoke, smoked meat

Induced Mutation

-sub,insert,deletion,inversion of base pairs
- single nucleotide changed

Point-Mutation

- nucleotide changed but no change AA

Silent Mutation

- Codon change= diff AA

Missense Mutation

- Codon change= early stop codon

Nonsense mutation

- the group of 3 disturbed
- new AA
- Multiple nonsense or missense mutations occur

Frame shift

- turn off uneeded genes to save energy
- gene regulation

How get optimal function

Transcriptional control
Post transcriptional control
Tranlational control
Post translational control

Controlling Eukaryot gene expression

- as mRNA synthesizes
- methyl groups added to promoter so uneeded genes cant be binded

Transcriptional control

as mRNA is processed
-masks protiens to bind mRNA and stop further processing

Post transcriptional control

-as and after protien is synthesized
-lengthen or shortens time protien is functional

Tranlational control and post tranlational control

- also needed to be effcient
- lactose and tryphtphan
- neg feedback

Gene Reg in Prokaryotes

- cluster of genes that code for protien
- Structural genes
- Promoter
- Operator
- Regulatory genes

Operon model

Encodes for protien

Structural genes

- upstream (TATA)
- RNA poly binds to it

Promoter

-base seqeunce controls transcription

Operator

encodes for repressor

Regulatory genes

-represses gene
-binds to operator

Repressor

breacks down lactose

B- galactosidase

Lac I - makes repressor
Lac z- makes B galactosidase
Lac Y- Galactoside primease: allows lac in

Lac operon model

- modding things to benifet us
- insterpsecies, gene transfer, cloning, dna seqeuncing

Gentic engerneering

- restriction enzyme to cut out gene of interest
- put in plasmid w/antibiotic gene marker
-vector put in bacteria and is duplicated
-antibiotic ensures only bacteria with new gene live
-load gun,shoot plant

Modded tomato

- makes theraputic drugs
-makes recombinant dna

Restriction enzyme

-enzyme purfied from bacteria
-protects cell from virus by degrading viral DNA
-each endonuclease recognises spefic sequence 4-8
-cleaves between deoxyribose and phosphate group
-bacteria dna protected by methylated A or C

Restriction enzyme (Endonucleases)

-staggerd cuts=sticky ends expose gene of interest
-sticky ends allow two DNA fragments to easily be joined together

Types of restriction endonucleases

- natural circular DNA
- extra chromosmal
-found in bacteria
-cloning
-extra genes

Plasmids

Polymerase Chain Reaction
- replicates gene of interest to amplify
- Denaturation
-Annealing
-Tag polymerase

PCR

splits double helix

Denaturation

cooled so that primer added sticks

Annealing

DNA synthesis

Tagpolymerase

- nose or throat sample
- reverse transcription bc uses RNA
- use reverse transcriptase RNA to cDNA

covid 19 PCR

-allows dna analysis
-restriction enzymes break up dna
- broken dna fragments put in wells
- gel sheet is neg by wells and pos at end
- dna is neg bc of phasphate group
- move by size (smaller goes farther)
-DNA ladder is basically ruler

Gel electrophoresis