respiration Flashcards
describe the process of dehydrogenation and phosphorylation in glycolysis
removal of H from triose phosphate molecules to form pyruvate and reduced NAD
explain how NAD acts as a coenzyme in glycolyisis
NAD accepts H and is reduced
during the formation of pyruvate
supplies H to enzyme involved in later stage of respiration
substrate level phosphorylation
addition of phosphate group
to ADP/ formation of ATP (using phosphate) from another molecule
outline the importance of dehydrogenation and phosphorylation in glycolysis
H removed in BD of glucose H req at later stage addition of phosphate groups destabilises large molecules/glucose leads to BD of glucose and synth of ATP
link reaction equation
pyruvate+CoA+NAD->acetyl CoA+CO2+reduced NAD
explain why the removal of CO2 in the link reaction is called oxidation
H also removed
removal of H oxidises pyruvate
name one organic compound and one inorganic compound produced in the link reaction
CO2
acetyl group
suggest why glycolysis occurs in the cytoplasm but not in the mitochondrial matrix
enz req in cytoplasm
glucose mols to large to move into mito
no transport proteins for pyruvate
mito not originally present in eukaryotic cells
compare the structures of ATP and NAD
ATP 3 phosphate groups one ribose one nitrogenous base NAD 2 phosphate 2 riboses 3 nitrogenous bases
ATP can be described as a coenzyme explain why
used to link reactions
e released as a result of the activity one enz and used by another
number of ATP mol prod by substrate-level phosphorylation after 2 rounds of the krebs cycle
1 per turn
2 in total
draw a simple diagram summarising the BD of glucose to CO2 and reduced coenzymes
glucose to triose phosphate (1); triose phosphate to
pyruvate (1); addition of two ATP (1); production of four ATP and two reduced NAD
sugg why krebs termed as aerobic despite not using oxygen at any point
H needs to be removed for cycle to continue
H removed using NAD/FAD and
reduced
then NAD/FAD are oxidised at ETC oxygen required for electron transport
suggest the reason for the involvement of FAD rather than NAD in only one specific step of the krebs cycle
enz are specific active site complim to substrates diff steps req diff enz diff enz req diff conzeymes only one step in cyle has enz which req FAD coenz
explain why H have to be acivley pumped across mem form matrix and return to the matrix by diffusion through ATP synthase
Actively pumped to increase concentration gradient (1); energy required as moving from low to high
concentration (1); membrane impermeable to ions so ions diffuse down concentration gradient (1);
ATP synthase provides hydrophilic channel (1).
explain why the e rel from re FAD lead to the synth of less ATP that the e rel form red NAD
2 Reduced NAD releases electrons to carriers at the start of the ETC (1); reduced FAD releases
electrons to carriers after the start of the ETC (1); with FAD electrons transported a shorter distance
(1); so fewer protons are actively transported (1).
suggest an expl for the toxicity of cyanide
1); so fewer protons are actively transported (1).
3 Stops flow of electrons (1); stops active transport of protons (1); proton gradient not formed (1);
(less) ATP synthesised; so less energy available for (vital) metabolic processes
discuss-
ATPase is not actually part of ETC
O2 req 4 transfer of e alng ETC
H ions return to matrix by f, diff
ATP synthase is not actually part of the electron transport chain – agree (1); not an electron carrier
(1).
Oxygen is required for the transfer of electrons along the electron transport chain – agree (1); oxygen
is final electron acceptor, required for electron transport (1) Hydrogen ions return to the matrix by
facilitated diffusion – agree (1); diffuse through hydrophilic channels (of ATP synthase) (1).
