25 Cards in this Set
| Front | Back |
|---|---|
|
Nuclear Import Steps
|
1. Present NLS signal on cargo protein
2. Importin recognizes NLS and binds to cargo protein
3. Nuclear Pore complex recognizes importin and allows it to pass through with its cargo
4. Importin lets go of cargo protein when Ran-GTP binds to importin
5. Importin,…
|
|
Nuclear Export Steps
|
1. Cargo protein presents NES signal
2. Ran-GTP binds to exportin, causing the cargo protein to also bind to exportin
3. Entire complex crosses NPC into cytoplasm
4. GAP hydrolyzes Ran-GTP to Ran-GDP which releases exportin, causing the cargo protein to also separate
…
|
|
Endosymbiotic Theory of Mitochondria
|
o 16.5kb in human
o 13 protein coding genes
o Can form special mitochondrial ribosomes
§ 2 rRNA genes (1 per subunit)
· 12S: small subunit
· 16S: large subunit
o 22 tRNA
o ori in D-loop (stretch of gene-less DNA)
|
|
Mitochondrial Import
|
1. Chaperone proteins keep cargo protein with transit sequence from folding (for ease of transport through pore (translocon))
2. Receptor protein of the TOM (Translocon of Outer Membrane) recognizes transit sequence
3. TOM and TIM are brought closer together and open up
…
|
|
Proofreading
|
- DNA Polymerase is wrong 1 in 100,00bp
- DNA Polymerase III can act as an 3'-5' exonuclease and is done by it's epsilon unit
|
|
Mismatch Repair
|
1) MutS scans for incorrect base
2) MutH binds to Adenine of 5'-GATC-3' and cuts the non-methylated strand
3) DNA Polymerase III and Ligase replace the bases
*MutL holds MutS and MutH together
|
|
Nucleotide Excision Repair
|
Fixes dimers or "kinks" caused by UV radiation which create covalent bonds between pyrimadines of the same strand
|
|
Xeroderma Pigmentosum (XP)
|
Sensitivity to UV light due to inability to repair UV damage on DNA
|
|
Tandem Arrays
|
- 45S gene arrays (will be processed into 5.8S, 18S, and 28S segments that make up rRNA)
- Found on human chromosome 13-15, 21, and 22
- Chromosome 1 has 5S arrays
- Nucleolus forms around the 45S arrays, forming Nuclear Organizing Regions, or NOR
|
|
Christmas Tree Formation
|
- Formation that exists during transcription of rRNA genes.
- Very active and efficiently initiated when needed
- Looks like sideways Christmas trees threaded along a string
- “Ornaments” are Ribosomal subunits and sNoRPs
|
|
3 Sub-Regions of the Nucleolus
|
- Fibrillar region
o Lighter region inside circular dense fibrilar region
o DNA
- Dense fibrilar region
o Exists as dark rings
o All work is done here; sNoRPs Ribosomal proteins
- Granular region
o Looks like sand
o Pre-ribosomal particles
|
|
Types of Base Substitution Mutations
|
o Transition- Mutation where purine switches with another purine/pyrimidine switches with another pyrimidine
o Transversion- Purine switches with pyrimidine, vice-versa
|
|
Sickle-Cell Anemia
|
Defective Beta-globin subunit of red blood cell which changes the charge of the protein unit, making oxygen transport difficult
- Due to single-base pair substitution
- 1 in 600 blacks have it
- 1 in 12 are carries
`
|
|
Phenylketonuria (PKU)
|
- Newborns are screened for it and can be avoided with proper diet
- Caused by an amino acid change in a 451 amino acid enzyme
- Neurotoxic phenylalanine levels build inhibiting thyroxine and melanine
|
|
Truncation
|
Nonsense mutation
|
|
Cystic Fibrosis
|
- Faulty CFTR protein
- In frame deletion of Phe at 508 of 1400
- Cl- cannot pass into mucus, causing mucus to dry, and creating an osmotic imbalance
|
|
Types of Chromosomal-Level Mutations
|
o Insertion
o Duplication
o Inversion
§ Genes switch order on chromosome
o Translocation
§ Genes from sister chromatids switch between chromatids
§ “Crossing-over”
|
|
Lymphomas and Leukemia
|
Caused by translocations
|
|
Oncogenes turning cancerous
|
Duplication
|
|
Fragile X Syndrom
|
Duplication of short repeated sequences
|
|
Huntington's Disease
|
Duplication of short, repeated sequences
|
|
Infertility
|
Can be caused by inversions
|
|
Hemophilia A
|
- Loss of clotting factor VIII
- Caused by insertions
|
|
Duchenne's Muscular Dystrophy
|
Deletion
|
|
Insertion of Soluble Proteins
|
o S sequence is folded and threaded into the nuclear pore complex (N-terminus first)
o Signal sequence is cleaved off
|
MCB 150: Amino Acid Single Letter Abbreviation