Stuff you missed Flashcards
What is the function of DNA pol a?
Contains primase and initiates DNA synthesis
What are three diseases linked to mitochondrial DNA depletion?
Alper’s Syndrome
Progressive External Ophthalmoplegia
Ataxia-neuropathy syndrome
What is the significance of high ratios of NADH to NAD in mitochondrial DNA depletion?
Decreases mitochondrial beta oxidation and impairs fatty acid oxidation
What is the red flag clinical presentation of mitochondrial disorders?
Multi-organ disturbance, with highly energy-demanding organs most commonly involved
What type of repair is photoreactivation?
Direct repair mechanism in bacteria for repairing pyrimidine dimers
What are examples of illegitimate DNA recombination?
Unequal crossing over
Integration of virial genomes
Rearrangement of Immunoglobulin genes during differentiation in precursor cells and B lymphocytes
Movement of transposons (Alu sequences)
Why are salvage pathways preferable to de novo synthesis?
De novo synthesis is energy expensive – every step adding an amino acid and closing the ring requires ATP
Why does Adenosine deaminase (ADA) deficiency cause SCID?
Results in excess ATP and dATP, causing negative feedback of ribonucleotide reductase, inhibits deoxy- purines and pyrimidines for DNA replication
What are two features of euchromatin?
Open structure, Active
Subject to DNAase 1 cutting
What is the Lyon hypothesis?
Methylated sections of chromosome are Barr bodies, however the same chromosome is not always the one methylated
What is responsible for maintaining methylation status in eukaryotic cells?
DNMT1 - dna methyltransferase
What enzymes are responsbile for denovo methylation
DNMT3A
DNMT3B
What are five characteristics of enhancers?
- turn on transcription
- can be upstream or downstream, location doesn’t matter
- can be on an intron
- sequence can be backward
- Can be tissue specific
What are the three proteins involved in ubiquitination?
U-activating enzyme
U-conjugating enzyme
U-ligase
What is a proteasome?
Large protein-degrading structures that bind ubiquitin-labeled proteins and remove the ubiquitin.
Central channel hydrolyzes peptide bonds, ATP-dependent
