exam 2 Flashcards
types of DNA damage repair
- base excision repair (BER)
- nucleotide excision repair (NER)
- DNA double strand break repair (DSBR)
- mismatch repair (MMR)
- single strand break repair (SSBR)
- interstand crosslink repair (ICR)
steps of DNA damage repair
- DNA damage recognition
- enzymatic removal of DNA lesions
- DNA synthesis
- DNA ligation
what are the two types of DNA double strand break repair?
- homologous recombination (HR)
- non-homologous end-joining (NHEJ)
what type of DNA damage repair is involved with multiple repair pathway?
interstand crosslink repair (ICR)
what DSB repair requires sister chromatid as template, is error free, and happens primarily in late S/G2?
homologous recombination (HR)
what DSB repair does not need sister chromatid as template, is fast and efficient, error prone, active throughout all cell cycle phases, predominant in mammals?
non-homologous end-joining (NHEJ)
during DNA replication, replication forks may stall when they encounter
- secondary DNA structures,
- repetitive sequences,
- certain protein-DNA complexes, or
- lesions generated by DNA damaging agents
what are the 3 major regulatory checkpoint in cell cycle?
- start/restriction point
- G2/M transition
- metaphase to anaphase transition
describe start/restriction point
point at which cells become committed to entering the cell cycle. depending on internal and external conditions, the cell can either delay G1, entering G0, or proceed past checkpoint
G2/M transition
ensures that the cell has undergone all the necessary changes during S and G2 phases and is ready to divide
metaphase to anaphase transition
control system stimulates sister chromatid separation
cell cycle
an ordered sequence of events that occur in a cell in the preparation for cell division
cell cycle is a 4 stage process in which the cell
- increases in size (G1 stage)
- copies its DNA (S stage)
- prepares to divide (G2 stage)
- divide (M stage)
what stages make up interphase (accounts for the span between cell divisions)?
stages G1, S, and G2
4 classes of cyclins
- G1/S cyclins
- S-cyclins
- M-cyclins
- G1-cyclins
what is responsible for recognizing and binding to the TATA box sequence in the DNA?
TBP (subunit of TFIID)
what does transfer RNA serve as?
it serves as the adopter molecule that binds to a specific codon and brings with it an amino acid for incorporation into the polypeptide chain
what is the most important cycle?
TCA (tricarboxylic acid)
what accounts for over 2/3 of the ATP generated from fuel oxidation?
TCA
how many ATPs does TCA generate from one glucose?
24
how many ATPs does glycolysis generate from one glucose?
8
only one type of fuel can enter TCA cycle
2 carbon acetate
acetate cannot enter TCA cycle on its own. what is it carrier?
Coenzyme A (CoA)
once acetate binds to CoA, it is called
acetyl CoA
what needs to be converted to acetyl CoA before they can be utilized as fuel by TCA cycle?
glucose, fat, amino acids
what cannot be used by TCA cycle without glycolysis?
glucose
first cellular source of immediate energy in muscle is
creatine phosphate (CP)
the second immediate energy source in muscle involves an enzyme called
adenylate kinase (which in muscle referred to as myokinase)
how does insulin lower blood glucose?
insulin lowers blood glucose by increasing the rate of glucose uptake and utilization
how does glycogen raise blood glucose?
glycogen raises blood glucose by increasing the rates of glycogen breakdown and glucose manufacture by the liver
what phosphates glucose to trap inside the cell?
hexokinase (every cell) and glucokinase (liver)
can phosphorylated glucose escape the cell?
no
what are the 3 options for glucose after phosphorylation?
glycolysis (energy production), pentose phosphate pathway (NADH, nucleotide production), glycogen synthesis (storage)
