Respiration Flashcards
What are the components of the matrix
Link reaction and krebs cycle occur.
Fluid like
Contains enzymes - for reactions - coenzymes
Mitochondrial DNA and ribosomes - to synthesise enzymes
What are the components of the outer membrane
protein channels and carriers present
phospholipid membrane
What are the components of the inner membrane
phospholipid bilayer which is less permeable to small ions
cristae - highly folded to increase SA
electron carriers- electron transport chain
What are the significance of the intermembrane space’s location
close contact with the matrix to allow for reduces NAD and FAD to deliver protons to the electron transport chain
Why may mitochondria look different in microscope images
cut across different planes of the mitochondria
Name the order of the stages of respiration
and where does each stage occur
- glycolysis -cytoplasm
- link reaction -matrix
- Krebs cycle -matrix
- oxidative phosphorylation and chemiosmosis- cristae/matrix/im space
Explain the stages of glycolysis
- PHOSPHORYLATION 6
GLUCOSE is broken down by 2 ATP into HEXOSE1,6 BISPHOSPHATE
2.LYSIS 3
HEXOSE 1,6 BISPHOSPHATE breaks down into 2 TRIOSE PHOSPHATE MOLECULES.
3.OXIDATION 3
EACH TRIOSE PHOSPHATE breaks down into PYRUVATE by 2 ATP and NAD gains 2H+ becoming REDUCED NAD
4.PYRUVATE is ACTIVELY TRANSPORTED to the LINK REACTION
Explain the stages of the Link reaction
PROCESS HAPPENS TWICE
- PYURVATE gets to the MATRIX through the outer membrane via a protein SYMPORT via ACTIVE TRANSPORT
- a CARBON gets REMOVED from PYRUVATE (decarboxylated)- then loses a H+ to NAD ( becomes reduced NAD via OXIDATION) making ACETATE
3.ACETATE combines with COENZYME A to become ACETYL COENZYME A
Explain the stages of the Krebs cycle
PROCESS HAPPENS TWICE
- ACETYL GROUP reacts with OXALOECAETAE making CITRATE
2carbon + 4carbon = 6 carbon - CARBON DIOXIDE is removed (DECARBOXYLATED) H+ and e- are removed and reduced NAD (DEHYDROGENATED) makes a 5 carbon compound. CARBON DIOXIDE is removed from the 5 C compound making a 4 C compound
6C - co2 = 5C - co2 = 4C - H+ and e- are REMOVED forming REDUCED NAD.
ATP is made via SUBSTRATE LEVEL PHOSPHYRLATION (without a membrane)
H+ and e- removed from FAD making REDUCED FAD
H+ and e- removed again from NAD forming REDUCED NAD
Explain the stages of Oxidative Phosphorylation.
- REDUCED NAD/FAD release PROTONS AND ELECTRONS into the ELECTRON TRANSPORT CHAIN via ELECTRON CARRIER PROTEINS
- ELECTRONS RELEASE ENERGY as they travel causing H+ to be ACTIVELY TRANSPORTED inti the IM SPACE from the MATRIX through the CRISTAE
3.INCREASED CONC of H+ in the IM SPACE - creating an ELECTROCHEMICAL GRADIENT.
- CHEMIOSMOSIS ( movement of protons from a high to low concentration) DOWN ELECTROCHEMICAL GRADIENT occurs INTO the MATRIX via ATP SYNTHASE.
5.Protons drive ATP PRODUCTION by supplying a PROTON MOTIVE FORCE. OXYGEN reacts with PROTONS and ELECTRONS to make WATER
How many ATP molecules can be made from 1 glucose molecule :
explain how
32
glycolysis = 7
link reaction = 5
krebs cycle = 19
Why arent 32 ATP molecules always made in aerobic respiration
ATP is used during the process of respiration :
actively transport pyruvate to mitochondrial matrix
used in ETC
ATP used to transport NAD to reduced NAD
What stage of respiration can occur in anaerobic respiration and why
Glycolysis - the only process which doesn’t require oxygen.
Why cant the krebs cycle, oxidative phosphorylation occur in anaerobic respiration
no final electron acceptor in the ETC oxidative phosphorylation
Reduced NAD and FAD aren’t oxidised by an electron carrier –> no NAD/FAD for dehydrogenation in the krebs cycle.
Describe the process of lactate fermentation
Pyruvate ( made from glycolysis) gets converted into LACTATE ( lactic acid).
Lactate dehydrogenase enzyme
Reduced NAD loses 2 electrons and becomes NAD (oxidised)
Why cant lactate be stored in the body
Toxic chemical which can form cramp in muscles.
if lactate built up , PH would decrease and would inhibit enzyme action involved in glycolysis and muscle contractions
How can lactate be removed from the body
lactate is removed from cell and travels in the blood stream to the liver to be converted back into glucose
GLUCONEOGENESIS.
Describe the process of alcoholic fermentation
- Pyruvate turns into ethanal , a carbon is lost ( decarboxylated) and is catalysed by pyruvate decarboxylase
2.Ethanal is then reduced to ethanol , it gains 2 hydrogens from reduced NAD being converted into NAD. - The NAD gets recycled to the glycolysis reaction to accept more hydrogen atoms
Why does anaerobic respiration have a lower yield then aerobic respiration
2 vs 32 ATP.
What are facuitative anaerobes and what do they do
Respires both aerobically and anaerobically
Respiratory substrates
organic substances that can be oxidised by respiration to produce ATP
What are 3 three respiratory substances and their mean energy value
LIPIDS - 39.4
PROTEINS - 17.0
CARBS - 15.8
What factor determines the amount of ATP produced
more hydrogen atoms present the more ATP that can be produced.
More H atoms =more transported by NAD/FAD= steeper the proton gradient = more ATP from chemiosmosis
How do lipids get broken down and enter the respiration sequence
- LIPIDS –> glycerol –> pyruvate in the link reaction
- LIPIDS –> fatty acids –> acetyl COA
What is the correlation between H atoms and oxygen
More hydrogen atoms present the more oxygen needed to respire that substance
What happens when we have excess proteins
- Keto acid enters the respiratory pathway as pyruvate , acetyl coA or in the Krebs cycle
- In the liver proteins gets deaminated - turned into urea which gets excreted
What does RQ stand for
Respiratory Quotient
Whats the RQ formula
Volume of Co2 produced/ Volume of O2 consumed
in a set volume of time
Whats the RQ for respiration
1
Whats the RQ for carbs , lipids and proteins
Carbs = 1
Lipids = 0.7
Proteins = 0.8 - 0.9
Why is it disadvantageous to use proteins as an energy source
It produces a lower ATP yield , as deamination of amino acids require ATP
When do we use proteins as an energy source
When lipids and carbohydrates are used up and theres no source of them
How are proteins broken down and enter the respiration cycle
Proteins –> Pyruvate / Acetyl CoA
Why do plants have a lower RQ value
CO2 is released in respiration and is used in photosynthesis - therefore its difficult to measure
If the RQ value more than 1 , is aerobic or anaerobic respiration
Anaerobic respiration
more co2 is produced than o2
Why cant proteins and lipids be aerobically respired
They cant go through glycolysis - aerobic respiration .
They enter the respiration system during the Link reaction or the Krebs cycle
