Cramm Flashcards
Griffith
4 mice: S, R, S heat killed, S heat killed and R
-> transforming principle: molecules released when S cells killed=> transform R cells to virulent S form
(Permanent and heritable)
Avery MacLeod and McCarth
RNAse, PROTEase, DNAse… in cytoplasm. Of heat killed S cells (protein, RNA an DNA)… only DNAse had no change so DNA is the transformation molecule
Hershey and Chase
Infection, Blending and Centrifigutation
35S (protein)=> in detached bacteriophage (parent) but not in progeny bacteriophage (kid)
32P (DNA)=> found in detached bacteriophage(parent) AND found in progeny bacteriophage (kid)
So DNA is inheritable
Rosalind Franklin
X-ray diffraction
Concluded:cyclin drivel DNA and stacked and X shape diffraction
Watson and Crick
-> double helix (phosphate pentose backbone) (from Franklin)
-> antiparallel (3-5, 5-3)
-> Purine always pairs with Pyrimidine (from chargaff rule)
-> backbone is hydrophilic, bases hydrophobic
->semiconservative replication
-> parental strand unwind by breaking H bond
Edwin Chargaff
- % purines=% pyrimidines
- A%=T%, C%=G%
Meselson and Stahl
DNA banding…
1.15 N medium in 14 N medium (centrifuge 1)=> 100% 15N
2. replication 1 (centrifuge)=> 50, 50
3. Replication 2 (centrifuge)=>2 of them 100% daughter, 2 of them daughter and parental mix
DNA repair
- DNA poly proofreading… DNA pol III 3->5 exonuclease to remove nucleotide…. DNA pol III 5->3 new replacement nucleotide base
- MMR (DNA mismatch repair)… recognized by MutS/L, MutH endocnuclease picks hitman target… Exo1 5-3 endonuclease removes region… DNA pol III replacement nucleotide REGION… Ligase seals
DNA replication eukaryotic
- DNA helicase unwind double helix and ssBs (single stranded binding protein) prevent reannealing
- RNA primase (puts RNA primer)
- Topoisomerase (prevent twisting)
4.Sliding clamp attaches=> DNA pol III=> add n.b. - DNA Pol I removes RNA primer of Okazaki fragment and fill gap with dNTP
- DNA ligase… glues pieces together
(Stop at end of chromosome)
Read: 3->5
Synthesize: 5->3
Leading… continuous and toward fork
Lagging… chopped and away from fork
DNA replication bacteria
- Initiation: unwind and sep 2 temp. @ oriC (origin of replication site)
- Elongation: simultaneous synthesis of 2 new DNA strands from template by DNA poly
- Temrination: DNA rep. Stop at termination site
RNA B4 DNA
-> RNA is less stable
-> RNA is ss
-> RNA has enzymatic activity
->ribozyme can self synthesize and make RNA
Beadle and Tatum
1-gene-1-enzyme
Gene code enzyme and ricochet till essential nutrient
-> mutation can block metabolic pathway cause organism is auxotroph
-> if add nutrient after arrow of mutation then essential nutrient made… if b4 then will be inhibited by mutation
Life cycle SARS CoV2
- Bind
- Fuse viral RNA into host cell
3.RNA-> DNA by reverse transcriptase - Viral DNA to DNA of host and integrate by Integrase
- Replication
6.transcription
7.translation - Maturation and protease (breakup polyprotein into pieces and viral cell matures/assembles)
9.lyse and is virulent
Which structure is RNA (primary, sec, tert, quart??)
Secondary
Structure and fxn of gene
-promoter (DNA+TATA box-specify were transcription begin) at 5’ end/upstream of nontemplate/coding strand
-promoter is recognized and bound by transcriptional machinery (RNA poly and transcription factors)… initiate transcription
-transcriptional unit is part of gene copied into RNA
Type of RNA poly
- RNA pol I: rRNA
- RNA pol II: mRNA
- RNA pol III: tRNA
DNA transcription
- Initiation/RDS… general transcription factor bind to promoter and RNA poly II= low level transcription OR transcriptional activator protein bind to enhancer so DNA loop and RNA poly to promoter=high level transcription
2.Elongation:RNA poly read 3-5, synthesize 5-3 - Termination: 1. Rho indpdnt (prokaryote)- terminator in mRNA does hairpin (G-C self pairing)= RNA poly detach 2. Rho dependent (prok.)-terminator bound by RHO helicase=unwind mRNA from template DNA and RNA poly 3. Cleavage and polyadenylation specific factor (eukaryotes): poly AAAAA= cleave completed mRNA and RNA poly separates
Not everywhere at specific region
No primer
DNA translation (eukaryotes)
- .tRNA met-> P site…+ small/large (P (middle) to A (front) to E (end)) ribo subunit… ribo+mRNA+met tRNA= initiation complex… and it moves 5->3 till AUG start codon… anticodon (tRNA) from mRNA (codon)
- Elongation… a)aminoacyl tRNA added to A site by elongation factor GTP b)peptidyl tranferase from large rib makes peptide bond between carboxyl and amino c) ribosome translocates (tRNA from A->P, and uncharged tRNA from P->E)
- Termination… stop codon at end of protein coding sequence and recognized by release factor proteins… release factor bind to A site= peptidyl transferase detach polypeptide fromP-site tRNA
Aminoacyl tRNA (charging)
Add a.a. To tRNA
How do siRNA and miRNA regulate gene expression
21-23 nucleotides dsRNA repress gene expression by ,RMA deg ration or inhibition of translational initiation
Epigentics and mechanism in gene regulation
Transcriptional gene regulation by Posttranslational mod of histones and not changes in nucleotide sequence
Acetylation increase gene transcription. How? Loosen DNA
Methylation decrease transcription. How? Tighten DNA
(Chromatin remodeling)
Transcriptional gene reg
(.mRNA synthesis)
Initiation, elongation,termination,transcription factors,promoter,enhancer
Post transcription gene regulation
(.mRNA processing)
5’ capping
3’-polyadenylation
Splicing
.mRNA degradation (exoribonuclease and siRNA)
Translation gene reg
(Protein synthesis)
Initiation, elongation, termination, microRNA
Post translation gene reg
(Protein process)
Posttranslational mod:
1. Phosphorylation (add phosphate to protein by kinase=activate or inhibit activity)
2.Acetylation (looser so increase gene transcription)
3. Methylation (tighter so repress gene transcription)
4. Ubiquitination(add ubiquitin to protein=target to destruction)
5. Protein degradation (Proteolysis… cleave protein to induce activity… kill host cell=> power up virus)
Types of mutation
- Spontaneous:Lower rate by DNA rep error and base error
- InducedL chemical and environmental=damage nucleotide and base mispairing like UV damage
3.germlineL mutation in sex cell= heritable
4.somatic…in all other= not heritable
How is eukaryotic cell cycle regulated by CDK and cyclin
CDK and cycle increase cycle progression (like enzyme)… checkpoint delay cell cycle
- DNA damage checkpoint (G1->S)
- DNA replication checkpoint (G2/M)
- Mitotic spindle checkpoint (M)
- G1 (growth)
C1 - S phase (synthesis)
- G2 (growth)
C2
4.M (mitosis-nuclear division)
M - Cytokinesis (cell division)
**G0 is not in the cycle its like a garbage ready for use but on a need to use basis
Oncogene VS tumor suppressor gene
Oncogene: GOF allele of pos. Regulator in cell cycle so enhance cyclin
Tumor suppressor gene: LOF allele of neg. Regulator in cell cycle so enhance checkpoint
Mitosis VS Meiosis
Mitosis:
-daughter like parent… centromere split in anaphase (somatic cell)
Meiosis:
-parent halved in haploid daughter cell (germline cell)
-homologous chromosome and crossing in prophase I
-centromere NO split in anaphase I
-no DNA rep, between Meiosis 1 and 2
-daughter not like parent cause recombination
Binary fission
-like mitosis (daughter same as parent)
-replication begin at origin
-prokaryotes/bacteria
