respiration Flashcards
Name the four main stages of aerobic respiration and state where they occur?
- Glycolysis- in cytoplasm
- links reaction-
mitochondrial matrix - Krebs cycle-
mitochondrial matrix - oxidative
phosphorylation- inner
mitochondrial
membrane
Using example, outline the need for energy in living organisms?
organisms need energy for metabolism
ATP is universal energy for currency
Plants need energy for photosynthesis
light dependent stage detail
light independent stage detail
ATP needed for chemical energy for anabolic reactions such as protein synthesis
ATP needed for activation of glucose in glycolysis
active transport for movement against concentration gradient
ATP needed for movement such as muscle contraction
Explain why ATP is regarded as the universal energy currency in all organisms?
found in all organisms
loss of phosphate leads to energy release
ADP + Pi—- ATP (reversible reaction)
water soluble
so easily transported around the cell
small packets of energy so can be used to release energy immediately
easily hydrolysed by ATPase
can be regenerated
used in active transport, muscle contraction
Describe the structure and synthesis of ATP and its universal role as the energy currency in all living organisms? /8
it is a nucleotide
ribose + adenine + three phosphates
loss of phosphate leads to energy release
ADP + Pi —- ATP (reversible reaction)
synthesised during glycolysis and Krebs cycle by substrate level phosphorylation
synthesised during electron carriers during oxidative phosphorylation
by ATP synthase
by chemiosmosis
in mitochondria
used by cells as immediate electron donor
used for active transport
describe the process of glycolysis? /7
glucose phosphorylated by ATP
this raises energy level
forms hexose bisphosphate
lysis of hexose bisphosphate to form 2 TP molecules
dehydrogenation occurs. hydrogen accepted by NAD
2 Reduced NAD formed
4 ATP produced, net gain of 2 by substrate level phosphorylation
pyruvate produced
reduced NAD goes to oxidative phophorylation
Explain why glucose needs to be converted to hexose bisphosphate? /2
provides activation energy
for it to split
How does pyruvate from glycolysis enter the mitochondria?
via active transport (oxygen is required)
Outline the process of link reaction?
Pyruvate passes by active transport from the cytoplasm through the outer and
inner membranes of a mitochondrion
Undergoes decarboxylation and dehydrogenation of pyruvate to form acetate
Net gain of CO2 and 2 reduced NAD
Acetate combines with
coenzyme A (CoA) to give acetyl coenzyme A
Describe the process of oxidative phosphorylation in the mitochondria?/9
reduced NAD and FAD are passed to the ETC at cristae
hydrogen released from NAD and FAD reduced
hydrogen splits into protons and electrons
electrons are passed along the electron carriers on ETC
Energy used to pump protons into intermembrane space
proton gradient set up
protons diffuse through ATP synthase down the potential gradient
ATP produced by chemiosmosis
electrons gets accepted by oxygen to form water
protons also get added to oxygen to form water
outline the process of Krebs cycle?/9
occurs in mitochondrial matrix
acetyl CoA combines with oxaloacetate to form citrate
decarboxylation
dehydrogenation
reduced NAD and reduced FAD produced
ATP produced by substrate level phosphorylation
series of steps
enzyme catalyzed reaction
oxaloacetate regenrated
Describe the process of oxidative phosphorylation in the mitochondria?/9
reduced NAD and FAD are passed to the ETC at cristae
hydrogen released from NAD and FAD reduced
hydrogen splits into protons and electrons
electrons are passed along the electron carriers on ETC
Energy used to pump protons into intermembrane space
proton gradient set up
protons diffuse through ATP synthase down the potential gradient
ATP produced by chemiosmosis
electrons gets accepted by oxygen to form water
protons also get added to oxygen to form water
Outline the role of oxygen in aerobic respiration?
used in oxidative phosphorylation
oxygen is final electron acceptor
accepts hydrogen ion to form water
so ETC can continue
increases ATP production
in absence of oxygen only glycolysis occurs
describe ways in which the structure of the mitochondria is adapted for oxidative phosphorylation?
-cristae: increases surface
area
-intermembrane space:
allows accumulation of H+
-impermeability of intermembrane space to H+: maintains H+ gradient
- ATPase- channel for H+ – -linear arrangement of ETC
on inner
membrane: greater
efficiency
Name the stages in respiration that produce ATP by substrate level phosphorylation?
Glycolysis (anaerobic)
krebs cycle (aerobic)
what is respiratory quotient?
RQ= CO2 produced/ O2 consumed
