Bittel Lectures Flashcards
What characteristics do all living things on the earth have in common?
- all cells store their heredity information in the same linear chemical cod: DNA
- all cells replicate their heredity information by templated polymerization
- all cells translate RNA into protein in the sam way
- each protein is encoded by a specific gene
- all cells function as biochemical factories dealing with the same basic molecular building blocks
- all cells are enclosed in plasma membrane across which nutrients and waste material pass
- life requires free energy
What is short telomere syndrome?
Accelerated aging syndromes often caused by inheritable gene mutations resulting in decreased telomere lengths.
Organs with high cell turnover (bone marrow, liver, lungs, immune system) are commonly affected
What is xeroderma pigmentosum?
cells in most individuals with disease are defective in nucleotide excision repair
sunlight exposure produces pyrimidine dimers in skin cell DNA which can not be repaired
results in abnormal skin pigmentation and acute sensitivity to sunlight
What is Bloom syndrome?
mutation that is usually either nonsense or frameshift mutations in the BLM gene that cause truncation of the BLM protein
What is replication stress?
the slowing or stalling in replication fork progression
What does ionizing radiation do to organisms?
Dislodges electrons in tissue causing free radicals which often damage DNA
What does UV light damage do to organisms?
Induces the formation of pyrimidine dimers: two thymine bases covalently bonded that blocks replication
What does the SOS system in bacteria do?
Allows bacteria cells to bypass the replication block with mutation prone pathway.
If UV light causes formation of a _______ dimer. Then it will ______ replication and _____ the cells unless it is broken. If dimer is repaired, it often leads to _______.
thymine; block; kill; errors (mutations)
What occurs in thymine dimer repair?
(nucleotide excision repair) The dimer is repaired by enzymes that cut out the surrounding nucleotides and fill the space back in.
What is the ATM protein?
member of the phosphatidylinositol 3- kinase family of proteins that respond to DNA damage by phosphorylating key substrates involved in DNA repair and/or cell control
What is the ATM protein?
member of the phosphatidylinositol 3- kinase family of proteins that respond to DNA damage by phosphorylating key substrates involved in DNA repair and/or cell control.
What is the function of the ATM protein?
mobilizing and regulating the cellular response to DNA double stranded breaks function is lost with people who have ataxia-telanglecatasia
What does singling in response to double strand breaks control?
cell cycle checkpoint activation
DNA repair
transcriptional and translation events
apoptosis
How does RecQ helicases protect against cancer?
maintain genomic stability by functioning at the interface between DNA replication and DNA repair
What are the three RecQ family members? What happens if there is a defect in these?
BLM, WRN, RECQ4
defect give rise to cancer predisposition disorders
What is the function of RecQ helicases?
at the interface between DNA replication and recombination to repair damage replication forks
How are BLM and BRCA1 and 2 related?
Part of the same complex
What maintains the 3D structure of RNA?
conventional base pairing
What modifies the 3D structure of RNA?
nonconventional base pairing
What is the RNA sequence the same as?
the non template strand of DNA (coding strand)
What is DNA transcribed by?
RNA polymerase
Function of mRNAs
messenger RNAs, code for proteins
Function of rRNAs
ribosomal RNAs, form the basic structure of the ribosome and catalyze protein synthesis
Function of rRNAs
ribosomal RNAs, form the basic structure of the ribosome and catalyze protein synthesis