Respiration Flashcards
What is the energy stored in complex organic molecules?
Potential energy
What can ATP be used for?
Active transport
Endocytosis
Exocytosis
Synthesis of large organic molecules
DNA replication
What are heterotrophs?
Consumers and decomposes e.g animals and fungi
Why is ATP referred to as a universal energy currency?
It occurs in all living cells and can by used by cells in small amounts.
How much energy is released in the breakdown of ATP?
30.5KJ when ATP to ADP and ADP to AMP
But 13.8KJ when AMP to adenosine
What is glycolysis?
The first stage of respiration
A 10 stage metabolic pathway that converts glucose into pyruvate.
Were does glycolysis occur?
In the cytosol
What are the three main stages of glycolysis?
Phosphorylation
Splitting
Oxidation
What is the role of NAD?
It oxidises substrate molecules during glycolysis, the link reaction and the kerbs cycle.
Oxidation of triode bisphosphate to pyruvate?
Dehydrogenase enzymes coupled with NAD remove hydrogen from triode phosphate.
The two NAD molecules become reduced
What is the Cristae ?
Inner highly folded mitochondrial membrane
What is the matrix?
Fluid filled inner part of the mitochondria
Where do the link reaction and kerb cycle take place?
The matrix
What is inside the matrix?
Enzymes that catalyse the stages of these reactions
Molecules of the coenzymes NAD and FAD
Oxyloacetate
Mitochondrial DNA
Ribosomes
Difference in permeability between outer and inner membrane of a mitochondrion
Inner membrane is less permeable to small ions such as hydrogen ions
Decoarboxylation
Removal of a carboxyl group from a substrate or molecue
Dehydrogenation
The removal of hydrogen atoms from a substrate molecule.
Substrate level phosphorylation
Production of ATP during glycolysis and the crebs cycle
what is pyruvate converted to during the link reaction?
A two carbon acetyl group during the link reaction.
This acetyl group is oxidised.
The link reaction?
Pyruvate is decarboxylated and dehydrogenated by the enzyme pyruvate dehydrogenase.
What are the products of the link reaction?
2CO2
2 reduced NAD
2 acetyl CoA
The Krebs cycle?
A series of enzyme catalysed reactions that oxidise the acetate from the link reaction to two molecules of CO2, while conserving energy by reducing the coenzymes NAD and FAD.
What is the actual cycle for the knobs cycle?
Refer to google.
Products of the kerbs cycle?
6 reduced NAD
2 reduced FAD
4 CO2
2ATP
Will the kerbs cycle and link reaction work in the absence of oxygen?
No
What other substrates can be respired?
Fatty acids
Glycerol
Amino acids (delaminated first)
What is chemiosmosis?
Flow of protons down their concentration gradient, across a membrane, through a channel associated with ATP synthase.
What is oxidative phosphorylation?
The formation of ATP using energy released in the electron transport chain and in the presence of oxygen. It is the last stage of aerobic respiration.
The process of oxidative phosphorylation
Reduces NAD and reduced FAD are re oxidised when they deliver their hydrogen atoms
The atoms split into protons and electrons
The protons go into a solution in the mitochondrial matrix
How does the electron transport chain function?
Electron carrier proteins have an iron ion core which can be reduced
What is the proton gradient called?
The proton motive force
How is ATP synthesised?
As protons move down their respective gradients they move through ATP synthase which causes it to have a conformational change in shape. This allows ATP and a Pi to combine forming ATP
What is the roll of oxygen in oxidative phosphorylation?
It is the final electron acceptor.
It combines with electrons coming off the e.t.c and with protons from ATP synthase forming water.
Without the presence of oxygen what are the two main ways for reduces NAD to be reoxidised?
Ethanol pathway used by fungi and plants
The lactate pathway used by mammals
Ethanol fermentation pathway.
Pyruvate
Ethanal
(Reduced NAD is oxidised)
Ethanol
Lactate fermentation pathway
Pyruvate
(Reduced NAD oxidised)
Lactate
What is the fate of lactate?
Converted to Pyruvate which may enter Krebs
Recycled into glucose and glycogen
What is the ATP yield from anaerobic respiration?
Neither ethanol or lactate fermentation produces ATP so the total yield is only that of which was produced during glycolysis.
what is a facultative anaerobe?
A bacteria that can grow in the presence or absence of oxygen
How does yeast respire in the presence of oxygen?
If oxygen is available then the yeast cells respire aerobically using glycolysis, the link reaction, the Krebs cycle and oxidative phosphorylation.
Without the presence of oxygen how does yeast respire.
Anaerobically using the glycolysis and the ethanol pathway
What is needed to investigate the rate of reproduction of yeast cells under aerobic and anaerobic conditions.
Microscope, Haemocytometer, conical flasks, elastic bands, culture of yeast, dry cider.
How do you prepare for the investigation into the rate of yeast replication under aerobic and anaerobic conditions.
The conical flasks have to be clean and sterilised.(can heat in microwave)
What would the procedure be to investigate the rate of reproduction of yeast cells under aerobic and anaerobic conditions.
Pour cider into conical flasks
One drop of yeast suspension into each conical flask
Mix
Four layers of material over each conical flask
Leave in warm place
Mix and extract contents onto haemocytometer
Count number of yeast cells in the centre square of each corner square.
What is the second investigation using a haemocytometer?
Refer to textbook page 149.
How can the rate of respiration be measured with the rate of evolution of carbon dioxide?
Measuring the PH with a PH meter (as CO2 dissolves in culture medium it lowers PH)
What is a respiratory substrate?
An organic substance that can be oxidised by respiration releasing energy to make ATP.
How can fructose and galactose be changed to glucose?
By isomerase enzymes
Why do fats produce far more ATP than equivalent mass of carbohydrate?
They are long chains of hydrocarbons so there are many hydrogen atoms and carbon atoms within the. This provides a lot of potential protons for oxidative phosphorylation.
When will protein from muscle be hydrolysed?
When fasting, starving or during prolonged exercise.
How do amino acids enter the Krebs cycle?
They are converted to Piruvate or acetate.
What is the mean energy value per gram of different respiratory substrates?
Carbohydrate - 15.8KJ/g
Lipid - 39.4KJ/g
Protein-17.0KJ/g
How can the respiratory quotient be calculated
RQ=CO2produced/o2 consumed
What are the units for respiratory quotient?
There are no units
What is the RQ of glucose?
1
What is the RQ of fatty acids?
0.7
What is the RQ of amino acids?
0.8-0.9
