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Flashcards in Section 4 Deck (31)
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1

Transitions vs Transversions

-Point mutations
Purines= A,G (single ring) Pyramidines= C,T,U (double ring)
-Transitions= Py-->Py or Pr-->Pr
-Transversions= Py-->Pr or vice versa
-Transitions= more frequent even though transversions= more probable

2

Missense Mutation

-Nonsynonymous mutation
-Diff AA
-Neutral, detrimental, or beneficial

3

Nonsense Mutation

-Stop codon
-Detrimental

4

Silent Mutation

-Synonymous Mutations= same AA
-No effect usually

5

Spontaneous mutations

-Abnormalities by biological process

6

Strand Slippage

-Spontaneous Mutation
-DNA pol temporarily dissociates during replication and stem loop forms
Ex: ALS GGGGCC

7

Germline Mutation

-Occurs in egg or sperm
-Passes to offspring

8

Somatic Mutation

-Occurs in somatic cell
-Passed w/in organism (mosaicism), but not from parent to offspring

9

Mismatch Repair

-Corrects misincorperation of bases after replication
-Detects bulge in helix and fixes based on parent strand's methylation

10

Base Excision Repair

-Corrects single damages nucleotides
-Ex: AP sites

11

Nucleotide Excision Repair

-Corrects thymine-thymine dimers
-Repair of UV damage

12

Repair in CRISPR

-Homologous Recombination
---Exonuclease trims back DSB
---Sister chromatid atcs as template to repair damaged strand
-Non-homologous endjoining
---Exonuclease trims back DSB
---Ligase seals back together (deletion results)

13

Depurination

-Removal of purine base from deoxyribose
--Creates apurinic site
-DNA pol places adenine opposite if not repaired b4 next replication

14

Deamination

-Loss of NH2 GROUP
-Affects mthylated CpG islands
-Changes C-G to A-T

15

Restriction Enzymes

-Nucleases that cut put DNA at specific recognition sequences

16

Transformation and Plasmid Vectors

-T= uptake of exogenous DNA into host cell
-MCS= Location for gene insert
-Ori= enables plasmid to replicate
-LacZ= way to screen for insertion of gene
----If white, gene inserted (X-gal not converted by B-gal)
----Blue pig if no gene
-Antibiotic resistance gene= provides selectable marker which plasmids recieved gene
-Prok= shine dalgarno
-Euk= TATA

17

DNA library

-Collection of cloned fragments of DNA
-Single source

18

CRISPR-Cas9

-Guide RNA= engineered to be complimentary to target DNA
-Cas9 nucleade= cuts target DNA bound to guide RNA
-Cut fixed by HDR or NHEJ

19

PCR

-Uses principles of natural DNA replication to artificially synthesize target region of DNA
1. Denature DNA
2. Anneal primers
3. Synthesize new strand
4. Repeat 1-3 for 20-40
5. Amount of target DNA doubles each cycle

20

Genetic Maps

-Order and distance of genes based on map units/ cM
-Done using controlled crosses and genetic markers

21

Physicla Maps

-Order and distance of genes from bp units
-Sequencing and assembling genome
-Physical distances SOMETIMES correspond to recombo frequencies

22

Map-Based Sequencing

1. determine map order of clones
--using restriction enzymes
2. Assemble clones into contigs
3. Sequence contigs using sanger

23

Whole Genome Shotgun sequencing

-Generates frags of diff sizes from genomic DNA by random sheering
1. Genomic DNA cut into overlapping frags and cloned in bacteria
2. Frags sequenced
3. Overlap is used to order clones and entire genomic sequence is assembled

24

Homologous

Similiar
-Orthologs= arrise from a specification event, 1 ancestral gene
-Paralog= genes that arrise from duplication event

25

Cell Determination

-Process by which cell commits to developing
-Totipotent= cell can develop into anything
-Pluripotent= cell can become certain type of cell, already has determined cell line
Multipotent= cells have capacity to divide into multiple cells

26

Hox genes

-Code for transcription factors that regulate other genes

27

Cancer

-Genetic cuz due to genes, but not always heredetsry cuz can be influenced by environmental factors
-Over proliferation of cells

28

Red Flags of cancer

-Early onset
-Ashkenazi jewish
-Rare types of cancer
-Multiple gen. affected by cancer

29

Genes in cancer

-KRAS--> gain of fxn leads to quicker cell proliferation= cancer
-BRCA2--> loss of fxn leads to cell proliferation
-TP53--> If cell ungergoes stress, no longer works--> cell proliferation

30

Knudson's multistep model of cancer

-1st somatic mutation--> 2nd somatic mutation in same cell---> single tumor (sporadic)
OR
-Predisposed person inherits 1st mutation-> only 2nd mutation required for cell proliferation (hereditary)

31

Clonal Evolution of Tumors

-Cell predisposed to proliferate at high rate
-2nd mutation causes cell to divide rapidly
-3rd= structural changes
4th= divide uncontrollably and invade other tissues