3.5.2 Respiration Flashcards
ATP hydrolysis releases energy in small manageable amounts
so little energy is wasted when used in the cell
ATP can be rapidly re-synthesised after hydrolysis
so a continual supply is available in the cell
ATP can transfer energy to other molecules by adding one of its phosphate groups
so it can make molecules more reactive
ATP cannot cross the cell surface membrane
so it ensures that it is always available inside the cell for chemical processes
ATP is small and soluble
so it can easily diffuse through the cytoplasm and provide energy for different chemical reactions
Only one bond is broken to release energy during ATP hydrolysis to ADP
so it releases energy immediately
ATP function and properties
ATP hydrolysis releases energy in small manageable amounts
so little energy is wasted when used in the cell
ATP can be rapidly re-synthesised after hydrolysis
so a continual supply is available in the cell
ATP can transfer energy to other molecules by adding one of its phosphate groups
so it can make molecules more reactive
ATP cannot cross the cell surface membrane
so it ensures that it is always available inside the cell for chemical processes
ATP is small and soluble
so it can easily diffuse through the cytoplasm and provide energy for different chemical reactions
Only one bond is broken to release energy during ATP hydrolysis to ADP
so it releases energy immediately
What is the first stage of anaerobic and aerobic respiration?
Glycolysis
Equation for aerobic, aerobic respiration
Aerobic - requires the presence of oxygen (glucose) and produces carbon dioxide, water and a lot of ATP
● Anaerobic - takes place in the absence of oxygen (glucose) and produces lactic acid (in animals) or ethanol and carbon dioxide (in plants and fungi) and only produces a little ATP
ATP cycle
ATP hydrolase
hydrolysis
Exergonic reaction
ATP synthase
Condensation
Endergonic reaction
2 coenzyme in respiration process
NAD
FAD
Glycolysis process
Glucose is phosphorylated using 2ATP
The glucose phosphate is split into two triose phosphate molecules - LYSIS
The 2 triose phosphates are oxidised forming 2 NADH (reduced NAD), coupled to the addition of phosphate. This process is catalysed by dehydrogenase enzymes.
Substrate level phosphorylation occurs forming 4 ATP, with a net of 2ATP,
producing 2 pyruvate molecules are formed for every glucose oxidised
What substance and how they are transport into mitochondria during respiration
Pyruvate active transport
Oxygen diffusion
ADP and PI active transport
Link reaction
Pyruvate is actively transported from the cytoplasm into the mitochondrial matrix by carrier proteins on the mitochondrial membrane
The pyruvate loses a carbon atom (decarboxylation), which forms a carbon dioxide molecule The 2C compound is oxidised to acetate, losing hydrogen atoms (NAD is reduced to NADH) Acetate combines with coenzyme A to form acetyl coenzyme A.
Kerb cycle
2C Acetyl CoA combines with a 4C organic compound to produce a 6C molecule (citrate)
The 6C molecule is oxidised, with H atoms transferred to form reduced NAD and it loses a carbon as CO2 forming a 5C molecule.
The 5C molecule is oxidised, with H atoms transferred to form reduced NAD and it loses a carbon as CO2 forming a 4C molecule.
The 4C molecule is further oxidised producing reduced NAD and reduced FAD. ATP is also formed. The original 4C molecule that reacts with acetyl CoA is regenerated and the cycle continues.
Oxidative pgosphorylation
High energy electrons carried by the reduced coenzymes (NADH and FADH2) are passed to electron carriers (the coenzymes are oxidised again)
As the electrons flow down the electron transport chain (ETC), they lose energy and the energy is transferred to pump hydrogen ions out of the matrix into the intermembrane space.
Electrons are transferred onto oxygen which combines with hydrogen ions to form water (the oxygen is reduced).
Oxygen is the final electron acceptor.
Chemiosmosis
ATP synthase is located in the inner mitochondrial membrane
There is a concentration of hydrogen ions (protons) in the intermembrane space due to the movement of electrons through the ETC.
Hydrogen ions flow down their concentration gradient through the ATP synthase protein and the energy is transferred to make ATP from ADP and Pi.
Other respiratory substrate
Glycerol , fatty acid
Amino acid
Where does anaerobic respiration happen?
Cytoplasm
Can you explain how anaerobic respiration in animal works after production of pyruvate in glycolysis
The conversion of pyruvate to lactate in animals (and some bacteria) regenerates NAD (from NADH), allowing glycolysis to keep going
Can you explain how anaerobic respiration in plant and fungi works after production of pyruvate in glycolysis
Ethanol fermentation occurs in plants and some microorganisms such as yeast.
It allows NAD to be regenerated to keep glycolysis going. To produce ATP
Apparatus to measure rate of respiration
Respirometer
Limitation and solution of using methylene blue to measure the rate of respiration of organism
End point is subjective even using colour chart
Use colour perimeter which provides quantitative data as objective
Difficulty in seeing colour change in water bath
Required taking it out to see the colour lead to temperature drop
Use see thermostatic water bath, use a beaker to create mobile water bath
In practical of the methylene blue testing rate of respiration, why must both solution be left into water bath for five minute before reaction?
So the yeast and the methylene blue solution equilibrate to the test temperature in the water bath
In practical of the methylene blue testing rate of respiration, why did methylene blue solution turn colourless
deHydrogenase remove hydrogen from NADH and methylene pick up this hydrogen and reduce it to form colourless solution
In respirometer experiment why the liquid would move towards the left when the organism is in the left test tube
The respiring organism took in oxygen from the air in the experimental tube on the left. The carbon dioxide produce in the respiration is absorbed by the alkaline therefore the volume of gas decrease in the experimental tube causing a decrease in pressure and is comparatively lower than the tip, therefore the coloured liquid moved to the experimental tube on the left.
What is the purpose of soda line/ sodium hydroxide in respirometer experiment
To absorb carbon dioxide produce in respiration so the volume of oxygen absorbed by the organism can be measured
Explain why the apparatus in the respirometer experiments must be airtight
To prevent air entering or leaving as this would change the volume and therefore the pressure affecting the movement of the colour liquid and the validity off the result
Why there’s a blue rain on top of the yeast In practical of the methylene blue testing rate of respiration
Because that part of the methylene blue meets the air so it oxidised
When they mix the solution, it will reset to the starting point
suggest one explaination for higher glycerol and fatty acid concentration in blood plasma of athletes after they were given caffeine
breakdown of fat
at increased rate / by mobilisation of fat store
How inhibit kreb cycle decrease the uptake of oxygen in a rspiring cell
Less/no reduced NAD/coenzymes
Oxygen is the final/terminal (electron) acceptor;
