module 5 - 18.1 glycolysis & 18.2 linking glycolysis and the Krebs cycle Flashcards
what do cells require energy for?
- synthesis of molecule
- transport of molecules or ions
- cellular movement
what is ATP?
the intermediary between energy-yielding and energy-requiring cellular reactions
what is MRS NERG?
M - movement
R - respiration
S - secretion
N - nutrition
E - excretion
R - reproduction
G - growth
what is respiration?
making ATP from glucose
how des ATP function as the universal energy currency?
- energy is required to break bonds
- energy is released when bonds are broken
- ATP + H2O ⇌ ADP + Pi
- living cells maintain the ratio of ATP to ADP with conc. five-fold higher than conc. of ADP
- phosphate to phosphate bonds are high energy bonds
what is released from ATP + H2O ⇌ ADP + Pi?
30.6kJmol-1
what is PI?
an inorganic phosphate
what is glucose?
a respiratory substrate
where does glucose have energy stored?
in its carbon to carbon and carbon to hydrogen bonds
how is the energy from glucose transferred to ATP?
by cellular respiration
what is chemiosmosis?
when glucose molecules are broken down in stages and the released energy is used to convert ADP and Pi to ATP
what is cellular respiration?
a multi-step and multi-stage process and each reaction is controlled by an enzyme
what is aerobic respiration?
with free oxygen
what is glycolysis and where does glycolysis occur?
- first stage of cellular respiration
- cytoplasm (mitochondria not involved)
what happens during glycolysis?
- 2 ATPs are consumed to phosphorylate glucose into hexose bisphosphate
- hexose bisphosphate is split into 2 molecules of triose phosphate
- each triose phosphate has a phosphate added to it using Pi from cytoplasm to make triose bisphosphate
4a) the 2 triose bisphosphates are oxidised by removal of hydrogen (dehydrogenation) and forms 2 pyruvate. hydrogen atoms are accepted by NAD to form reduced NAD
4b) the 2 triose bisphosphate molecules have their phosphate groups removed, they’re used to reform ATP from ADP (substrate level phosphorylation)
what is the net production of ATP molecules for every glucose?
2 ATP molecules which isnt enough so cant survive on anaerobic respiration alone
what do phosphates do?
lower the activation energy
which has a lower activation energy: triose bisphosphate or glucose?
triose bisphosphate
what happens in the matrix?
contains enzymes for the Krebs cycle and the link reaction
- also contains mitochondrial DNA
what happens in the outer mitochondrial membrane?
separates contents of mitochondrion from the rest of the cell, creating cellular compartment with ideal conditions for aerobic respiration
what happens in the inner mitochondrial membrane?
contains elctron transport chains and ATP synthase
what are cristae?
projections of the inner membrane which increase the surface area available for oxidative phosphorylation
what is the intermembrane space?
proteins are pumped into this by electron transport chain
- small space to conc. builds up quickly
why is the membrane of the mitochondria folded?
- larger SA
- packs more enzymes
what is a link reaction?
links glycolysis to krebs cycle
what happens during the link reaction/oxidative decarboxylation?
- pyruvate pumped into matrix by carrier proteins
- pyruvate is put through oxidative decarboxylation
- carbon dioxide is removed by oxidation reaction
- hydrogen atoms are accepted by NAD to produce reduced NAD (reduction)
- this produced a 2-carbon group tat gets bound to coenzyme A to produce acetyl CoA
how is ATP used to help pyruvate?
ATP is used to pump pyruvate against a concentration gradient from cytoplasm so has carrier proteins in mitochondrial membrane
