exam 3 Flashcards
- Nucleic Acids - Metabolism
types of nucleic acids
RNA and DNA
difference in types of nucleic acid
RNA: has OH on Carbon 2
DNA: has H on Carbon 2
Nucleic acid structure
DNA/RNA + phosphate backbone + base (A, G, C, T)
nucleic acid (DNA) characteristics
Structure stabilization
- stacking interactions
- H - bonding
- Hydrophobic effects
Charge-charge interactions: destabilize phosphate backbone
enzymatic cleavage in nucleic acids
responsible enzymes and nucleophile??
RNase: hydrolyze RNA, Nucleophile is 2 prime Carbon
DNase: hydrolyze DNA, nucleophile is water
protein expression in organisms
enzymeor not??
type??
restriction enzymes cleave DNA at specific sites.
Anabolic reactions
build up molecules from simpler building blocks and energy
catabolic reactions
break down molecules to form building blocks and energy
Amphibolic reaction
takes part in both catabolic and anabolic reactions depending on conditions
Metabolites
substrates or products in metabolic pathways
types of metabolic pathways
linear, cyclic, and spiral
Why are metabolic pathways regulated
-organisms can react to environmental conditions(such as energy or nutrients_
- organisms respond to genetically programmed instructions
how are pathways regulated
-steady-state concentration
-change in actual Gibbs free energy (not standard)controls flux
-feedback inhibition
-feed-forward activation
what is flux
rate of flow or movement through a metabolic pathway.
What affects flux
-decreases if conc. of initial substrate falls below a certain threshold
-decreases if the concentration of the final product rises.
- can be controlled to an extent by a regulatory enzyme
Feedback inhibition
- usually occurs at the first dedicated step of the pathway
- occurs when a product (usually the end product) controls its production rate by inhibiting an earlier step.
- product inhibits the first enzyme from working
-slows down and reverses flux.
feed-forward activation
- usually occurs when the production of a metabolite early on activates an enzyme that catalyzes a reaction further down the pathway.
- increases flux
if Gibbs controls flux, how do cells perform dis-favored reactions
- breaking pathways into smaller steps
- pairing with a favorable reaction
- cleavage cos similar energetically to ATP to ADP
How is energy from ATP made available
- phosphate group transfer
- ATP synthesis by phosphate group transfer: used in more catabolic reactions.
- nucleotide transfer: gives access to another ATP equivalent
Biochemical techniques to study Metabolism
- radiolabeling
- mutations
- invitro studies: inside test tube.
FYI: In vivo is inside the cell, In silico is calculation computer based.
