TCA cycle and oxidative phosphorylation

What are the steps in aerobic respiration and where in the mitochondria does it take place and quick summary

aim is to make ATP from glucose

1. glycolysis: glucose → pyruvate (cytoplasm)

2. link reaction: pyruvate → Acetyl-CoA  (mitchondrial matrix)

3. TCA cycle: Acetyl-CoA → 3 NADH, 1 FADH2 , 1 ATP ( per turn and theres 2 turns per glucose) (mitchondrial matrix)

4. electron transport chain- oxidative phosphiorylation: electrons from NADH and FADH2 used to pump H+ making ATP. O2 is final electron acceptor makign ATP (inner mitchondrial membrane)  

    

What is another name for the TCA cycle

kreb cycle 
cirtric acid cycle 
tricarboxcylic acid cycle
common terminal pathway 

TCA cycle

• happens in all tissues that have a mitchondria ( ot RBC ir white muscle fibres) in the mitchondrial matrix 

• the overall reaction is: acetyl-CoA → CO₂ + NADH + FADH₂ + GTP (ATP)

• trapping energy from the breakdown of acetyl Co-A into energy carrying molecules ( NADH, FADH2, ATP) 

• 1 turn = 3 NADH, 1 FADH₂, 1 GTP

• 2 turns per glucose → total 6 NADH, 2 FADH₂, 2 GTP

• ➡ Each NADH = 2.5 ATP
  ➡ Each FADH₂ = 1.5 ATP
  ➡ Each GTP = 1 ATP

• Total per turn = 10 ATP
  Total per glucose = 20 ATP

• 
  

• uses intermediates to generate energy carrying molecules

•  the intermediates are: 

• Citrate 
  Isocitrate 
  a-ketoglutarate 
  succinyl-Co-A
  Succinate
  Fumarate
  malate 
  oxaloacetate

• and can be rememberd by Can I keep selling socks for money officer  

it is an irrevrsible reaction and the irreversible steps are the fist 3 : 

• Acetyl-CoA → Citrate

• Isocitrate → α-Ketoglutarate

• α-Ketoglutarate → Succinyl-CoA

• the anaboloic processes that the TCA cycle is involevd in is: 

• producing neurotransmitters: a-Ketoglutarate -> glutamate 

• glutamate can be used to make amino acids: e.g glutamine,proline,arginine 

• oxaloacetate -> asparate 

• succinyl-CoA can go into the heme biosynthesis pathway 

Link reaction – where does it happen, what is the overall reaction, what is the catalyst, what metabolic reaction does it happen in, what is the cofactor, what is the high-energy product made

• in mitchondrial matric

• Pyruvate + Coenzyme A + NAD+ -> Acetyl CoA + CO2 + NADH + H+   
  Catalyst: pyruvate dehydrogenase

• a decarboxcylation reaction ( removing -co2) 

• cofactor: NAD+ 

• high energy product: NADH , H+

• this links glycolysis to TCA cycle by converting pyrucate to acetyl CoA it can neter the TCA cycle 

• it is an irreversible reaction as a carbon has been removed

Oxidative phosphorylation – how is the rate of oxidative phosphorylation (OP) controlled

• making ATP using energy from NADH and FADH2

• happens in the innermitchondrial memebrane

1. NADH donates electrons ot complex I, FAH2 donates electrons to complex II

2. the electrons move doen the electron transfer chains ( complexes) going to III then IV, the elctrons loose energy whilst moving between them 

3. this releases energy to pump H+ from the matrix -> intermmebrane space makign a proton graidiet, and an electrochemical graidient

4. at complex IV  e + O2 -> H2O  ( oxygen is the final electron acceptor) 

5. complex V is ATP synthase, the proton moves down the graidient makign ADP + phosphate -> ATP, this is passive  

• the two groups of proteins used are: 

• hydrogen pair acceptors 

• electron acceptors 

• if theres a high concentration of ADP there is an increased rate of OP and O2 uptake 

• if there is a high concentration of ATP there is a decrease rate of OP and O2 uptake 

What are the three ways oxidation reactions take place

- Add O2 to a molecule
- Remove one electron
- Remove 2 H

What are the 2 ways to stop oxidative phosphorylation and how are they different

1. inhibitors : block specific complexes so theres no electron flow so no ATP made

• cyanide ( inhibits complex 4)

• rotenone  ( inhibits complex 3)

• carbon monoxide ( inhibits complex 4) 

1. uncouplers :break the link between the electron transport chain and ATP synthase, so the elctrons are still moving and H+ is being transfered but no ATP made 

• dinitrophenol

• thermogenin protein in brown adipose tissues

How does oxidative phosphorylation link to dental issues and what are some examples

• oxidative phosphorylation makes reactive oxygen species which cause damage to cells and tissues 

• if you have an imbalance in ROS and antiocidant defences in the body you have oxidative stress 

• oxidativte stress can leade to oral problems and diseases

1. periodontitis and gingivitis 

2. oral cancer and lesions 

3. salivary gland disfunction 

How much ATP is made in the whole of anaerobic respiration (metabolism of glucose)

 
* depends on whether you use NADH or FADH2 in oxidative phosphorylation

What is the main energy carrier molecule in ATP synthesis

NAD

Which from NADH and FADH₂ are used in high and lower energy metabolic reactions

NADH- higher
FADH2- lower

What is the pentose phosphate pathway

• glucose 6 phosphate ( from glycolysis) to ribose 5-phosphate 

• purpose is to make NADPH which is used in fatty acid synthesiis and proctects cells from oxidative stress 

• also make riboe 5 phosphate which is used to make nucleotides and DNA/RNA