Respiration Flashcards
What are the products of glycolysis?
2x atp molecules
2x pyruvate
X2 receded NAD
Where does glycolysis occur?
Glycolysis occurs in the cytoplasm
Does glycolysis require oxygen?
NO glycolysis doesn’t require oxygen
Explain the stages of glycolysis [5]
- Glucose reacts with 2 molecules of ATP in a phosphorylation reaction forming hexosebisphosphate
- Hexosebisphosphate splits into two molecules of TP in a lysis reaction
- Two molecules of TP reacts with a phosphate group to make triosebisphosphate in a phosphorylation enzyme
- Dehydrogenation reaction occurs where triosebiphosphate lose H ion recusing NAD to reduced NAD
- The phosphate groups on each molecule leave to form 4 molecules of ATP
- The final product is 2 molecules of pyruvate
What is the link reaction equation?
Pyruvate + coenzyme A turns to acetyl coenzyme A + carbon dioxide
What is the name of the links reaction? And why?
Oxidative decarboxylation
It is called oxidative decarboxylation because an oxidation reaction occurs when NAD is oxidised to reduced NAD and pyruvate loses a carbon atom which is decarboxylation
How many times does the link reaction occur per glucose molecule?
2 times per glucose molecule
What are the products of the links reaction per glucose molecule?
X2 carbon dioxide
X2 acetyl coenzyme A
X2 reduced NAD
Where does the links reaction occur?
The links reaction occurs in the mitochondrial matrix
Does the links reaction require oxygen?
Does not require oxygen
Where does the kerbs cycle occur?
In the mitochondria
Does the Krebs cycle require oxygen?
No, it does not require oxygen
What are the products of the Krebs cycle per glucose molecule?
2x ATP
6x reduced NAD
2x reduced FAD
4x carbon dioxide
What does acetyl coenzyme A react with in the Krebs cycle and what does this form?
What happens to the coenzyme A?
Acetyl coenzyme A reacts with OXALOACETATE 4 carbon molecule, making a 6 carbon molecule called CITRATE
The coenzyme A is released back to the links reaction
In the Krebs cycle what happens to citrate to make it a 4 carbon atom?
2 rounds of decarboxylation and dehydrogenation remove 2 carbons and reduce 2 NAD molecules
The 4 carbon atom is recycled to make OXALOACETATE
What happens in the Krebs cycle following the decarboxylation reactions?
2 dehydrogenation reactions occur producing another reduced NAD and 1 reduced FAD
In oxidative phosphorylation what does reduced NAD donate to the proteins in the electron transfer carriers to start the process?
What does this do to the protein in the chain?
The reduced NAD gives its hydrogen atom which splits into H+ ion and 2 high energy electrons to the first protein in the electron transfer chain
This reduced the protein in the chain
What happens in oxidative phosphorylation when the electrons pass through the proteins in the electron transfer chain?
As the electrons pass through they lose energy energy as they are used to pump hydrogen ions into the inter-membrane space of the mitochondria
What happens to the electrons once they reach the end of the electron transfer chain?
2e- + 1/2O2 + 2H+ is converted into water
What does reduced FAD do differently to reduced NAD in oxidative phosphorylation?
Reduced FAD starts in the middle of the electron transfer chain rather than the start
How is ATP produced from oxidative phosphorylation?
The protons in the intermembrane space travel through the ion channel in ATP SYNTHASE (located in inner mitochondrial membrane) and the enzyme uses the gradient to make ATP from ADP + Pi
What is the name of the reaction that forms ATP in oxidative phosphorylation?
Chemiosmosis
What are electron transfer proteins also named as?
Cytochromes
When do eukaryotes anaerobically respire? [2]
- In the absence of O2
- When oxygen cannot be supplied fast enough to respiring tissues
What are obligate anaerobes?
Cannot survive in the presence of oxygen (usually prokaryotes)
What are facilitative anaerobes?
Can switch between anaerobic and aerobic respiration if required
For example yeast
What are obligate aerobes?
Organisms that can only synthesise ATP in the presence of oxygen
How does anaerobic respiration work in mammals?
Pyruvate accepts hydrogen from reduced NADP and becomes lactate (lactic acid)
What is lactic acid converted to and where?
Lactic acid is converted into glucose in the liver when oxygen is available
Why is anaerobic respiration not sustainable in mammals? [2]
- Not enough ATP is made to maintainTain vital processes
- Accumulation of lactic acid will result in a drop in pH which can be detrimental to the function of enzymes in the body
What is the process of alcohol fermentation in yeast? [2]
- Pyruvate is converted into ethanal by Pyruvate carboxylase enzyme
- Ethanal is converted into ethanol by accepting a H+ atom from reduced NAD
Is ethanol toxic to yeast?
Yes if it reaches above 15% concentration
What is a respiratory substrate?
Organic molecule that are broken down in respiration to produce ATP
How are lipids broken down as respiratory substrates?
E.g glycerol and triglycerides are broken into Pyruvate before undergoing oxidative carboxylation into acetyl groups to be picked up by coenzyme A
How are proteins turned into ATP as a respiratory substrate?
Proteins are hydrolysed to amino acids and then deaminated (removal of amine group)
What is RQ? What is the RQ equation?
Respiratory quotient = CO2 produced / O2 consumed
What equipment measures RQ?
Respirometer
What are the RQ values of carbohydrates, lipids and proteins?
Carb = 1.0
Lipid = 0.7
Protein = 0.9
