BIOLOGY SUMMARY NOTES
ATP:
- A nucleotide composed of a nitrogenous base, adenine with a pentose sugar of
ribose and three phosphate groups
- Small and soluble and can be moved quickly within the cells
- It is synthesized by ADP combining with Pi to form ATP
- Hydrolysis of ATP releases energy
- High turnover rate
- It is described as universal as it is used in all organisms and currency as it can be
use in different reactions.
- A molecule of ATP produces 30.5 kJ
- Provides energy and it is important for processes like active transport, protein
synthesis, making cellulose from many monosaccharides joined by glycosidic bonds,
making triglyceride from fatty acids and glycerol joined by ester bonds
- Linking ATP transport to ADP transport is advantageous as there is sufficient supply
of ADP so ATP synthesis can be continued
- Actual net number of ATP molecules synthesized is less than the theoretical number
because ATP is needed to transport pyruvate into the mitochondria, some energy is
lost as heat and not all glucose may be completely broken down
- ATP is needed for proteinsynthesis to provide energy to unwind the DNA strands and
to activate the nucleotides. It also needs energy to form peptide bonds to join the
amino acids
Aerobic respiration and anaerobic respiration:
- Only 2 ATP is produced per mole glucose during anaerobic respiration as only
glycolysis process occurs and cannot go on indefinitely, thus less efficient compared
to aerobic respiration
- Aerobic respiration produces more ATP than anaerobic respiration so more glucose
is needed to be broken down in glycolysis to provide the same amount of ATP from
anaerobic respiration
Respiratory quotient (RQ):
- RQ: volume of CO2 given off divided by the volume of O2 taken up
- RQ when only respiring carbohydrates is 1.0 because the volume of CO2 given off is
equal to the volume of O2 used
- RQ when respiring only fats is 0.7
- Usual RQ value for respirations in human is usually between 0.7 and 1.0 because it
respires aerobically and different tissues respires different substrates
- RQ value over 1.0 is anaerobic respiration
,Relative energy:
- Carbohydrates has less energy value per unit mass due to less C-H bonds, so there
is less reduced NAD form and less hydrogen atom to establish proton gradient. Thus
less chemiosmosis so less ATP is synthesized
- more water is produced when lipids is metabolized because it has more C-H bonds;
more hydrogen atoms available to reduce oxygen to water.
- Benefits of obtaining most of its respiratory substrates from its diet while exercising is
that substrates are immediately available to the muscles and no glycogen needs to
be broken down
Lactate:
- Pyruvate is reduced to lactate by the enzyme lactate dehydrogenase and pyruvate
acts as a hydrogen acceptor
- It is important so glycolysis can continue and produce small amount of ATP
- Lactate is transported to the liver and is then oxidized to pyruvate and pyruvate
converts to glucose, producing carbon dioxide. Carbon dioxide is then move to the
alveoli and increases the breathing rate for more oxygen. This extra oxygen is
referred to as an ‘oxygen dept’
- A person continues to breathe deeply for some time after stopping the exercise
because there is an oxygen dept and oxygen is needed to oxidise the lactate to
pyruvate and for lactate to convert to glycogen. It needs to re-oxygenate the
haemoglobin
Ethanol:
- Pyruvate is decarboxylated to ethanal, producing carbon dioxide.
- Ethanal is reduced to ethanol by ethanol dehydrogenase and reduced NAD,
regenerating NAD
- Anaerobic respiration is advantageous to the yeast because yeasts can survive in
absence of oxygen as glycolysis still continues and ATP synthesis is still made
- Using lower temperature has a similar rate of production of ethanol to higher
temperature method because same concentration of glucose is available to the yeast
and enzymes work at the same rate
- High temperature method is expensive to carry out because more electricity is
needed
Lactate in muscles vs ethanol from yeast
- Similarities: occurs in cytoplasm, NAD is regenerated, uses pyruvate, redox reaction
- One step process vs two step process
- No decarboxylation vs decarboxylation occurs
- Lactate dehydrogenase involved vs ethanol dehydrogenase involved
- Reversible vs irreversible
,Oxygen:
- Oxygen acts as a final electron acceptor and without oxygen, the electron transport
chain is inhibited as electrons have nowhere to flow. Thus proton gradient is not
established and reduced NAD cannot be oxidized back to NAD. Thus Krebs cycle
and oxidative phosphorylation stops
- Oxygen combines with electrons and protons to form water
- Concentration of oxygen decreases faster when ADP is added because there is a
faster rate of aerobic respiration as ADP is needed for ATP synthesis. Oxygen acts
as a final electron acceptor in the oxidative phosphorylation
Glycolysis:
- Phosphorylation of glucose occurs to become fructose 1,6-biphosphate and it splits
into two molecules of triose phosphate.
- TP is oxidized to pyruvate and there is a net gain of 2 ATP and 2 NADH is produced
Link reaction:
- Decarboxylation occurs as CO2 is remove from the pyruvate
- Dehydrogenation occurs as hydrogen is removed, converting to 2C
- The 2C combines with the coenzyme A to form acetyl coenzyme A
- Coenzyme acts as a carrier for acetyl group to the Krebs cycle and acetyl combines
with the oxaloacetate to form citrate
- Link reaction only occurs when oxygen is available as pyruvate is converted to acetyl
coenzyme A and NAD is needed to become reduced to reduce NAD. The reduce
NAD then goes to the ETC and oxygen is the final electron acceptor so NAD is
regenerated
- Reduced NAD produce in the link reaction goes to the ETC and released electrons
and hydrogen at ETC for oxidative phosphorylation
Krebs cycle:
- Acetyl CoA (2C) combines with the oxaloacetate (4C) to form citrate (6C). Citrate and
the 5C molecule is decarboxylated, removing carbon dioxide and is dehydrogenated,
losing hydrogens and is accepted by NAD/FAD to form reduced NAD/FAD. ATP is
produced by the process of substrate linked phosphorylation. Oxaloacetate is
regenerated
- 3 reduced NAD is formed from one acetyl group
- ATP is produced by substrate-linked phosphorylation as ADP + Pi -> ATP and this is
an enzyme-catalysed reactions.
, Oxidative phosphorylation:
- Hydrogen is released by the reduced NAD/FAD and is oxidized to NAD/FAD in the
cristae.
- Hydrogen splits into protons and electrons and the high energy electrons move along
the electron transport chain, releasing energy
- The released energy is use to pump the protons into the intermembrane space,
establishing a proton gradient
- The protons then return to the matrix, via facilitated diffusion by ATP synthase,
synthesizing ATP by chemiosmosis
- Oxygen acts a final electron acceptor to combine with the protons and electrons to
form water
- Electrons that are passed along the ETC comes from the hydrogen from the reduced
NAD by dehydrogenation in the mitochondrial matrix
Mitochondria:
- Inner membrane is folded to give large surface area to hold more etc and atp
synthase for more efficient chemiosmosis
- Inner membrane is impermeable to H+ ions to allow the establishment of proton
gradient and so H+ can only move via ATP synthase
- Intermembrane allows the accumulation of H+ to give low pH
- The membrane is separated from the rest of the cytoplasm to allow different pH
- Matrix contains enzymes to catalyse the link reaction and Krebs cycle, has oxygen to
form water, pyruvate for link reaction to make acetyl coA and water as a solvent for
reactions
- Contains linear arrangement of etc due to large surface area of cristae, increasing
chemiosmosis
- Inner membrane remains intact when organelle is placed in pure water as the
membrane is relatively impermeable of water so water does not enter the matrix by
osmosis
- Contains a high proportion of cardiopipin (makes membrane impermeable to some
ions) so that H+ only moves via the ATP synthase to maintain the proton gradient
- Pi is transported across the inner membrane together with the H+ via facilitated
diffusion when it moves through the ATP synthase
- Old and damaged mitochondria are broken down by hydrolytic enzymes and
components of breakdown is use to produce mitochondria
Calvin cycle:
- Carbon fixation occurs as carbon dioxide combines with RuBP, catalyzed by rubisco
to form unstable 6C compound which splits into two molecules of GP. GP is then
reduced to triose phosphate (TP) by reduced NADP and ATP.
- GP to produce some amino acids
- TP is then converted to other carbohydrates like hexose
ATP:
- A nucleotide composed of a nitrogenous base, adenine with a pentose sugar of
ribose and three phosphate groups
- Small and soluble and can be moved quickly within the cells
- It is synthesized by ADP combining with Pi to form ATP
- Hydrolysis of ATP releases energy
- High turnover rate
- It is described as universal as it is used in all organisms and currency as it can be
use in different reactions.
- A molecule of ATP produces 30.5 kJ
- Provides energy and it is important for processes like active transport, protein
synthesis, making cellulose from many monosaccharides joined by glycosidic bonds,
making triglyceride from fatty acids and glycerol joined by ester bonds
- Linking ATP transport to ADP transport is advantageous as there is sufficient supply
of ADP so ATP synthesis can be continued
- Actual net number of ATP molecules synthesized is less than the theoretical number
because ATP is needed to transport pyruvate into the mitochondria, some energy is
lost as heat and not all glucose may be completely broken down
- ATP is needed for proteinsynthesis to provide energy to unwind the DNA strands and
to activate the nucleotides. It also needs energy to form peptide bonds to join the
amino acids
Aerobic respiration and anaerobic respiration:
- Only 2 ATP is produced per mole glucose during anaerobic respiration as only
glycolysis process occurs and cannot go on indefinitely, thus less efficient compared
to aerobic respiration
- Aerobic respiration produces more ATP than anaerobic respiration so more glucose
is needed to be broken down in glycolysis to provide the same amount of ATP from
anaerobic respiration
Respiratory quotient (RQ):
- RQ: volume of CO2 given off divided by the volume of O2 taken up
- RQ when only respiring carbohydrates is 1.0 because the volume of CO2 given off is
equal to the volume of O2 used
- RQ when respiring only fats is 0.7
- Usual RQ value for respirations in human is usually between 0.7 and 1.0 because it
respires aerobically and different tissues respires different substrates
- RQ value over 1.0 is anaerobic respiration
,Relative energy:
- Carbohydrates has less energy value per unit mass due to less C-H bonds, so there
is less reduced NAD form and less hydrogen atom to establish proton gradient. Thus
less chemiosmosis so less ATP is synthesized
- more water is produced when lipids is metabolized because it has more C-H bonds;
more hydrogen atoms available to reduce oxygen to water.
- Benefits of obtaining most of its respiratory substrates from its diet while exercising is
that substrates are immediately available to the muscles and no glycogen needs to
be broken down
Lactate:
- Pyruvate is reduced to lactate by the enzyme lactate dehydrogenase and pyruvate
acts as a hydrogen acceptor
- It is important so glycolysis can continue and produce small amount of ATP
- Lactate is transported to the liver and is then oxidized to pyruvate and pyruvate
converts to glucose, producing carbon dioxide. Carbon dioxide is then move to the
alveoli and increases the breathing rate for more oxygen. This extra oxygen is
referred to as an ‘oxygen dept’
- A person continues to breathe deeply for some time after stopping the exercise
because there is an oxygen dept and oxygen is needed to oxidise the lactate to
pyruvate and for lactate to convert to glycogen. It needs to re-oxygenate the
haemoglobin
Ethanol:
- Pyruvate is decarboxylated to ethanal, producing carbon dioxide.
- Ethanal is reduced to ethanol by ethanol dehydrogenase and reduced NAD,
regenerating NAD
- Anaerobic respiration is advantageous to the yeast because yeasts can survive in
absence of oxygen as glycolysis still continues and ATP synthesis is still made
- Using lower temperature has a similar rate of production of ethanol to higher
temperature method because same concentration of glucose is available to the yeast
and enzymes work at the same rate
- High temperature method is expensive to carry out because more electricity is
needed
Lactate in muscles vs ethanol from yeast
- Similarities: occurs in cytoplasm, NAD is regenerated, uses pyruvate, redox reaction
- One step process vs two step process
- No decarboxylation vs decarboxylation occurs
- Lactate dehydrogenase involved vs ethanol dehydrogenase involved
- Reversible vs irreversible
,Oxygen:
- Oxygen acts as a final electron acceptor and without oxygen, the electron transport
chain is inhibited as electrons have nowhere to flow. Thus proton gradient is not
established and reduced NAD cannot be oxidized back to NAD. Thus Krebs cycle
and oxidative phosphorylation stops
- Oxygen combines with electrons and protons to form water
- Concentration of oxygen decreases faster when ADP is added because there is a
faster rate of aerobic respiration as ADP is needed for ATP synthesis. Oxygen acts
as a final electron acceptor in the oxidative phosphorylation
Glycolysis:
- Phosphorylation of glucose occurs to become fructose 1,6-biphosphate and it splits
into two molecules of triose phosphate.
- TP is oxidized to pyruvate and there is a net gain of 2 ATP and 2 NADH is produced
Link reaction:
- Decarboxylation occurs as CO2 is remove from the pyruvate
- Dehydrogenation occurs as hydrogen is removed, converting to 2C
- The 2C combines with the coenzyme A to form acetyl coenzyme A
- Coenzyme acts as a carrier for acetyl group to the Krebs cycle and acetyl combines
with the oxaloacetate to form citrate
- Link reaction only occurs when oxygen is available as pyruvate is converted to acetyl
coenzyme A and NAD is needed to become reduced to reduce NAD. The reduce
NAD then goes to the ETC and oxygen is the final electron acceptor so NAD is
regenerated
- Reduced NAD produce in the link reaction goes to the ETC and released electrons
and hydrogen at ETC for oxidative phosphorylation
Krebs cycle:
- Acetyl CoA (2C) combines with the oxaloacetate (4C) to form citrate (6C). Citrate and
the 5C molecule is decarboxylated, removing carbon dioxide and is dehydrogenated,
losing hydrogens and is accepted by NAD/FAD to form reduced NAD/FAD. ATP is
produced by the process of substrate linked phosphorylation. Oxaloacetate is
regenerated
- 3 reduced NAD is formed from one acetyl group
- ATP is produced by substrate-linked phosphorylation as ADP + Pi -> ATP and this is
an enzyme-catalysed reactions.
, Oxidative phosphorylation:
- Hydrogen is released by the reduced NAD/FAD and is oxidized to NAD/FAD in the
cristae.
- Hydrogen splits into protons and electrons and the high energy electrons move along
the electron transport chain, releasing energy
- The released energy is use to pump the protons into the intermembrane space,
establishing a proton gradient
- The protons then return to the matrix, via facilitated diffusion by ATP synthase,
synthesizing ATP by chemiosmosis
- Oxygen acts a final electron acceptor to combine with the protons and electrons to
form water
- Electrons that are passed along the ETC comes from the hydrogen from the reduced
NAD by dehydrogenation in the mitochondrial matrix
Mitochondria:
- Inner membrane is folded to give large surface area to hold more etc and atp
synthase for more efficient chemiosmosis
- Inner membrane is impermeable to H+ ions to allow the establishment of proton
gradient and so H+ can only move via ATP synthase
- Intermembrane allows the accumulation of H+ to give low pH
- The membrane is separated from the rest of the cytoplasm to allow different pH
- Matrix contains enzymes to catalyse the link reaction and Krebs cycle, has oxygen to
form water, pyruvate for link reaction to make acetyl coA and water as a solvent for
reactions
- Contains linear arrangement of etc due to large surface area of cristae, increasing
chemiosmosis
- Inner membrane remains intact when organelle is placed in pure water as the
membrane is relatively impermeable of water so water does not enter the matrix by
osmosis
- Contains a high proportion of cardiopipin (makes membrane impermeable to some
ions) so that H+ only moves via the ATP synthase to maintain the proton gradient
- Pi is transported across the inner membrane together with the H+ via facilitated
diffusion when it moves through the ATP synthase
- Old and damaged mitochondria are broken down by hydrolytic enzymes and
components of breakdown is use to produce mitochondria
Calvin cycle:
- Carbon fixation occurs as carbon dioxide combines with RuBP, catalyzed by rubisco
to form unstable 6C compound which splits into two molecules of GP. GP is then
reduced to triose phosphate (TP) by reduced NADP and ATP.
- GP to produce some amino acids
- TP is then converted to other carbohydrates like hexose
