Biological Energy Flashcards
how can energy be stored?
(for reference / background knowledge)
as chemical bonds:
- sugar / far stores
- atp
- phosphocreatine
what energy stores do we have?
e.g for carb / fat?
carb stores - e.g. glycogen - medium term energy storage. stored in liver / muscle
fat stores - adipose tissue. long term storage
how is ATP formed? (simple)
how is ATP continously recycled?
formed: phosphorylation of ADP and AMP
recycled between: catabolism (synthesis) and anabolism (utilisation)
where does the energy come from in ATP?
- Charge density -> negative charge on Phosphate Group
- Resonance -> (describes type of bonding and molecules present)
- Reaction held far from equilibrium (if held far from equilibrium - get storage of energy)
how form energy from ATP?
- how does cell sense how much energy it has?
- ATP gets hydrolysed —> inorganic P, ADP and Energy
- Cellular ratio between ATP and AMP = sense how much energy has
describe the type of reactions get for the couple reaction of glucose breakdown and protein synthesis
Coupled reaction of glucose breakdown and protein synthesis
exergonic reaction: glucose breakdown -> Co2 + h20 + heat
endogonic reaction: ATP synthesis
Exergonic reaction: ATP breakdown
Endergonic reaction: protein synthesis
GET NET EXERGENIC REACTION
describe briefly synthesis of phosphocreatine
phosphocreatine synthesis:
- transfer of phosphate group to ATP
- enzyme used: creatine kinase
- anaerobic conditions
- One of the ways that this ATP supply is regenerated is through the molecule creatine phosphate (or phosphocreatine). In the process of regeneration of ATP, creatine phosphate transfers a high-energy phosphate to ADP. The products of this reaction are ATP and creatine*
what can phosphocreatine act as?
where usually found / indicator of ?
phosphocreatine: ATP buffer (can restore ATP when needed)
Location: in tissues that have high, fluctuating energy demands - muscle and brain
what is creatine kinase? what does it mean if found in blood?
enzyme that catalyses phosphocreatine synthesis
- found in blood = tissue damage
name some other types of phosphate energy stores
what can one be converted to ?
- GTP: readily converted to ATP with nucleoside-diphosphate kinase (NDK)
- UTP
what is the proton motive force?
- (proton-motive force. energy that is generated by the transfer of protons or electrons across an energy-transducing membrane and that can be used for chemical, osmotic, or mechanical work)*
- making a gradient to keep out of equilibrium.
- get an electrochemical gradient (gradient of BOTH electrical potential and chemical concentration across a membrane)
- transfer of H+ via proton pumps across membrane: get a proton electrochemical gradient of proteins: proton motive force
what is the term coupling used to describe with regards to proton motive force?
coupling: used to describe proton motive force’s role in ATP generation
(basically: electrochemical conc. gradoent of protons across a membrane can make ATP)
which are the energy convesion pathways that occur in cellular resp?
- glycolysis
- krebs cycle
- electron transport chain
:)
- where does glycolysis occur?
- what is high level overview of reaction?
a) what produced in aerobic
b) what produced in anaerobic conditions?
glycolysis
location: cytoplasm
conditons: with / without oxygen
high level overview of reaction:
glucose (6C) –> 2 molecules pyruvate (3C). uses 2ATP in reaction. BUT produces 4 ATPs overall. also produces 2 NADH2+ molecules.
THEN:
- if in aerobic conditions: pyruvate used to generate Acetyl CoA for citric cycle
- if in anaerobic conditions: pyruvate used to generate Acetyl CoA for lactic acid
regarding glycolysis, ATP is generated by what?
ATP generated by substrate level phosphorylation (transfer of phosphate group from triose sugar to ADP)
where does krebs / citric acid cycle occur?
what is used as in input? what are the main outputs of the cycle - used subsequently for?
location: matrix of mitochondria
- Acetyl-CoA (from glycolysis) used, extracts electrons for use in electron transport
- Electrons given off are harnessed by electron carrier molecules
- produces: Co2, 3NADH, 1 FADH2, 1GTP. feeds into oxidative phosphorylation pathway
- role in producing energy even in cells performing fermentation
which is the only part of cellular respiration pathway that uses atmospheric oxygen?
electron transport
where does electron transport occur?
describe it:)
- location: mitochondrial membrane
- 4 protein complexes (I to IV): electrons are passed from one complex to next, causes electrons to be released
- as electrons are released to acceptors (e.g. O2) from donors (e.g. NADH), H ions pumped out of the matrix into intramembrane space
- Proton motive force established and electrons flow down electrochem gradient through ATP synthase channel
(need to know more details?)
describe the how the different protein complexes work in electron transport
:)
why / how is cyanide a poison?
- binds to cyctochrome c oxidase (4th complex in ECT)
- cyanide attaches to iorn within protein complex and inhibits activity of the complex system
- ECT can’t pump H+ into intermembrane space = pH of intermembrane space increases -> pH gradient decreases.
- ATP synthesis stops
describe the structure of two motors in ATP synthase
what are they used for?
function: converting ion gradients to ATP
in ATP synthase:
- 2 motors - one electrical, one chemical
- one motor location: membrane - powered by flow of protons
- one motor location: intermembrane space: powered by ATP
WHEN ONE TURNS, CAUSES THE OTHER TO TURN
where else can you find a proton pump?
what used for and why?
location: membrane of lysosome organelle (also found in GA)
what? uses ATP to pump H+ - proton motive force
why? drops pH of lysosome to around 5. -> optimal Ph for acid hydrolases to digest biological molecules
why does having low pH of acid hydrolases of lysosome protect cell?
if lysosome membrane broke down -> acid hydrolases would be inactive bc cytosol has neutral pH
