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When is ATP made in glycolysis ?
When each triose phosphate is converted into a molecule of pyruvate .
How many molecules of ATP are made in glycolysis ?
4
State three adaptations of a mitochondrion .
Large surface area Outer membrane for compartmentalisation Mitochondrial DNA and ribosomes
By what method of transport does pyruvate move into the mitochondria ?
Active transport
What is the alternative name for the Krebs cycle ?
The citric acid cycle
What is the role of FAD ?
It is a hydrogen acceptor / carrier which carries hydrogen to the cristae for the electron transport chain .
How many ATP are made per turn of the Krebs cycle ?
1
Why is the Krebs cycle important ?
It reduces a large number of coenzymes ( 4 per pyruvate , 8 per glucose ) , meaning a lots of hydrogens are carried away to be used in oxidative phosphorylation .
Why is the Krebs cycle an example of substrate level phosphorylation ?
It is where ATP is produced from ADP and a phosphate from another molecule ( the substrate ) .
What is oxidative phosphorylation ?
It is the production of ATP using energy released from the electron transport chain and in the presence of oxygen .
What is the electron transport chain ( ETC ) ? And what is its function ?
It is a series of electron carrier proteins embedded in the inner mitochondrial membrane . Its function is to release the energy stored in electrons in NADH and FADH₂ and convert that energy into ATP .
What happens when reduced NAD ( NADH ) and reduced FAD ( FADH ) arrive at the electron transport chain ?
NAD and FAD are oxidised and release their hydrogens , which split into protons and electrons . HH + + e
What happens to the electrons from the hydrogens ?
They are passed down the electron transport chain from one electron carrier to the next , losing energy as they move .
Why does the electron move from one electron carrier to the next ?
Each electron carrier in the chain has a higher affinity for the electrons than the previous electron carrier .
What happens to the protons from the hydrogens ?
They are pumped across the inner mitochondrial membrane , into the intermembranal space .
How is ATP made by oxidative phosphorylation ?
The protons in the intermembranal space move down their concentration gradient and back into matrix through a stalked particle which contains the enzyme ATP synthase . ATP synthase uses this proton movement to drive the addition of ADP to Pi , forming ATP .
When hexose bisphosphate is split in half , what are these two molecules called ?
Triose phosphate
What type of reaction occurs when hydrogen is removed from triose phosphate ?
An oxidation reaction
What is the name of the hydrogen carrier ?
NAD - nicotinamide adenine dinucleotide
What type of molecule is NAD ?
A coenzyme
What is the role of NAD in respiration ?
It carries hydrogens ( protons plus electrons ) to the cristae of mitochondria for oxidative phosphorylation .
How many carbons are in one pyruvate ?
3
How many pyruvates are made from one molecules of glucose ?
2
What is the net number of ATP molecules made in t glycolysis ?
2 ( because 2 ATP are used at the start and 4 are made at the end )
What is the net number of ATP molecules made in glycolysis ?
2 ( because 2 ATP are used at the start and 4 are made at the end )
What environmental condition must be present for the link reaction to take place ?
There must be oxygen present .
Where does the link reaction take place ?
In the matrix of the mitochondrion
What is the matrix of the mitochondrion similar to in the cell ?
The cytoplasm
The link reaction takes place once for each pyruvate . How many times does the link reaction take place for each glucose ?
Twice ( 2 pyruvates are produced form 1 glucose )
When carbon dioxide is removed from the pyruvate , what is this type of reaction called ?
Decarboxylation
Which enzyme removes carbon dioxide from pyruvate ?
Pyruvate decarboxylase
When two hydrogens are removed from the pyruvate , what is this type of reaction called ?
Dehydrogenation
Which enzyme removes hydrogen from pyruvate ?
Pyruvate dehydrogenase
Which coenzyme carries the hydrogens from the link reaction ?
NAD
What form is the NAD in , if it has had hydrogen added to it ?
Reduced ( reduced NAD or NADH )
Which two carbon molecule is formed after the removal of the carbon dioxide and the hydrogens ?
An acetyl group
Coenzyme A ( COA ) is added to the acetyl group , what molecule does this produce ?
Acetyl coenzyme A
Where does the Krebs cycle take place ?
In the matrix of the mitochondrion
How many times does the Krebs cycle occur for each glucose ?
Twice per glucose ( once per pyruvate )
At the start of the Krebs cycle , acetyl coenzyme A combines with what substance to form citrate ?
Oxaloacetate
How many carbons are in citrate ?
6
How many carbons are in oxaloacetate ?
4
How many molecules of carbon dioxide are given off during one turn of the Krebs cycle ?
2
How many NAD are reduced during one turn of the Krebs cycle ?
3
Which coenzyme ( apart from NAD ) is reduced in the Krebs cycle ?
FAD - Flavine Adenine Dinucleotide
In which other stage of respiration does substrate level phosphorylation occur ?
Glycolysis
Where does oxidative phosphorylation take place ?
It occurs on the cristae of the inner mitochondrial membrane .
What is the process of protons moving back through the membrane known as ?
Chemiosmosis
What does ATP stand for ?
Adenosine triphosphate
What is aerobic respiration ?
The production of ATP in the presence of oxygen .
What is anaerobic respiration ?
The production of ATP in the absence of oxygen .
What three events happen in an oxidation reaction ?
Addition of oxygen Loss of electrons Loss of hydrogen
What three events happen in a reduction reaction ?
Loss of oxygen Gain of electrons Gain of hydrogen
Give three uses of the energy from ATP .
Any three from . Active transport . Endocytosis and exocytosis . Synthesis of biological molecules . DNA replication . Cell division . Movement . Maintenance of body temperature . Bioluminescence e.g. glow worms Production of electricity
Why is ATP the universal energy currency ?
It is found in all living organisms It is small so can be transported around the cell easily - It releases energy when it is needed by the cell It can be ' reused '
In which organelle does aerobic respiration take place ?
Mitochondrion
What are the four stages of aerobic respiration ?
1. Glycolysis 2 . Link reaction 3. Krebs Cycle 4. Electron transport chain / oxidative phosphorylation
What does glycolysis mean ?
Splitting of glucose
Where does glycolysis take place ?
The cytoplasm
Which type ( s ) of respiration involves glycolysis ?
Both aerobic and anaerobic .
Which molecule is used at the beginning of glycolysis ?
Glucose
What happens to glucose in the first stage of glycolysis ?
Glucose is activated by phosphorylation - two phosphates are added from 2 ATP molecules . This produces 2 ADP and 1 hexose bisphosphate .
What is the role of oxygen in oxidative phosphorylation ?
It is the final electron and proton acceptor . The electrons and protons bond with the oxygen to form water . 2H + + 2e + 1 / 2O2 → H₂O
What is the disadvantage of anaerobic respiration ?
It produces less ATP than aerobic respiration .
Which organisms can perform anaerobic respiration ?
Animals , plants and microorganisms
Which stage of respiration is common to both aerobic and anaerobic respiration ?
Glycolysis
Why is oxygen not needed in anaerobic respiration ?
There is no link reaction , Krebs cycle or oxidative phosphorylation , so oxygen is not needed as the final . electron / proton acceptor .
What is anaerobic respiration in mammals known as ?
Lactate fermentation
Describe the process of anaerobic respiration in mammals .
Glycolysis takes place and the pyruvate is converted into lactate ( lactic acid ) . This occurs as reduced NAD ( NADH ) donates its hydrogens to the pyruvate .
Why is the involvement of reduced NAD ( NADH ) important ?
When NADH gives up its hydrogens , it can be recycled to be used in glycolysis again .
How many ATP are made in lactate fermentation ?
2
What is anaerobic respiration in yeast , bacteria and plant roots known as ?
Ethanol / alcoholic fermentation
Describe the process of anaerobic respiration in yeast .
Glycolysis takes place and the pyruvate releases a molecule of carbon dioxide to form ethanal , the ethanol is then converted to ethanol when reduced . NAD ( NADH ) donates its hydrogens to the ethanol .
How many ATP are made in ethanol fermentation ?
2
What are the 4 advantages of anaerobic respiration ?
. It allows ATP to be generated . . It recycles NAD to be used again . • Glycolysis can take place again / continue . • In mammals , it allows ATP to be generated and muscles to contract when there is little / no oxygen .
Give 3 reasons why there is a lower yield of ATP in anaerobic respiration .
1. Only involves glycolysis which produces a net of 2 ATP molecules and only substrate level phosphorylation occurs . 2. Oxygen not available as the final electron acceptor so oxidative phosphorylation cannot take place and this is where most ATP is generated . 3. Pyruvate used to regenerate NAD for glycolysis to continue to take place , instead of leading to more ATP being produced .
What does the term respiratory substrate mean ?
An organic molecule that is used to produce ATP through respiration .
Why is more energy released from lipids than carbohydrates ?
Lipids contain more hydrogen which is used in oxidative phosphorylation to produce ATP .
When are proteins used as a respiratory substrate ?
In times of starvation .
How are proteins used as a respiratory substrate ?
Proteins are hydrolysed ( broken down ) into amino acids by proteases . The amino acids are deaminated . which produces keto acid . Keto acid is converted to acetate which can enter the Krebs cycle .
How are lipids used as a respiratory substrate ?
Lipids are hydrolysed ( broken down ) into glycerol and fatty acids by lipases . The glycerol can then be converted into triose phosphate and be used in glycolysis to produce pyruvate . The fatty acids can combine with coenzyme A and then be broken down into acetyl CoA , which is used in the Krebs cycle .
Why is the respiratory quotient ( RQ ) useful ?
It can indicate which respiratory substrate is being respired .
What is the formula for RQ ?
RQ = CO₂ produced/ O₂ consumed
What is a typical RQ for carbohydrates ?
1.0
What is a typical RQ for lipids ?
0.7
What is a typical RQ for proteins ?
0.8-0.9
Why do people confuse the RQ for proteins with a combination of the RQs for carbohydrates and lipids ?
If someone respired 50 % carbohydrates and 50 % lipids , they would show an RQ value similar to proteins .
What are the limitations of using RQ ?
● Substances are rarely completely oxidised and partial oxidation gives a different value . ● Organisms rarely respire a single food substance .
What type of RQ value would be produced for a mixture of aerobic and anaerobic respiration and why ?
A value higher than 1 , because anaerobic involves no oxygen so the value for oxygen consumer would be lower than in aerobic alone .
Give three factors that could be investigated when looking at their affect on respiration in yeast .
Temperature Substrate concentration Oxygen availability pH
What sources could be used for online research ?
Websites and their contents e.g. videos , PDFs , blogs , online journals etc.
What sources could be used for offline research ?
Textbooks , revision guides , journals
What is a citation ?
An in - text reference to the research that the information in that sentence / paragraph was found in .
What are the two main methods of citations ?
Vancouver and Harvard systems
What is a reference list ?
A full and detailed list of all the sources that you have used from your research , this includes both online and offline sources .
How are citations and reference lists linked to each other ?
The citation should appear within the text and is a link to the reference list .
What is meant by the term processed data ?
Data that has been obtained from performing a calculation e.g. the mean or standard deviation .
How do you make a procedure more repeatable ?
Conduct at least three repeats .
If there are at least three repeats , why is this beneficial ?
A mean can be calculated , the standard deviation can be calculated and anomalies can be identified .
If a result is identified as anomalous , what should a scientist do ?
Repeat that test again . If this is not possible , the anomalous result could be excluded from the mean .
