C1.2 Respiration Flashcards
ATP
‘The energy currency in cells’ it is an immediate source of energy
facts about ATP
- unstable
- cannot move outside of cell (only within)
- for synthesizing DNA proteins
- pump (active transport) molecules or ions across membrane
- move things around cells
- (chromosomes, muscle fibres; produce concentration)
ATP structure description
adenine base of RNA, 3 phosphate groups
Anaerobic Respiration (yeast)
Glucose to Pyruvate to CO2 and Ethanol
How ATP work
- once ATP used and energy released & dissipated as heat
- need to be recharged via cell respiration
- cell needs continuous supply of ATP
ATP specific mechanism
- ATP nucleotide linked to three phosphate via high energy bond
- breaking of phosphate group releases energy
- ATP -> ADP + P
- ADP is recharged back to ATP through respiration
Mechanism that turns ATP -> ADP
Hydrolysis + releases energy
Mechanism that turns ADP -> ATP
Condensatoion reaction
Measuring rate of respiration
- respirometer
- lime water and measure how cloudy it goes over time
- gas syringe
Glycolisis (quick fats)
- takes place in cytoplasm
- complex set of reactions
- Glucose makes 2 Pyruvates
- Net gain of 2ATP
- formation of NADH (reduced NAD)
How does Pyruvate move to the matrix
ATP pumps Pyruvate to matrix
* process spend ATP
What happens to the 2NADH produced from Glycolisis in the absence of oxygen
- fermentation
- NADH turns into NAD+
- produces lactate (animals & humans)
- ethanol + CO2 (yeast)
Glycolysis in detail
- Use 2ATP to phosphorylate glucose => less stable
- Phosphorylated glucose splits into two glyceraldehyde - 3- phosphate (G3P)
- Each G3P is dehydrogenated and reduces NAD to NADH
- generation of 2ATP from each G3P
Links Reaction (quick facts)
- takes place in mitcochondrias matrix
- 2 pyruvate forms 2 acetylCOA
- 2NADH formed
- CO2
Links reaction in detail
- Pyruvate from glycolisis is oxidised and decarboxylated
- In process CoA is added
- NAD is oxidising agent and is reduced to NADH by gaining H
- CO2 is produced as waste
- Acetyl CoA is produced
Krebs Cycle quick facts
- takes place in mitochondria matrix
- acetyl coa is starting point
- creates 6 NADH, 2 FADH, 2 ATP, 4 CO2 per molecule of glucose (for 2 acetyl coas)
Krebs cycle in detail
- Acetate (2C)from Acetyl coa binds with oxaloacetete(4C) to form citrate (6C)
- Remaining CoA goas back to link reaction
- Oxidative decarboxylation takes place 2x (6C->5C->4C) relasing 2CO2,2NADH, ATP
- Now 4Cmolecule reduces FAD to FADH
- Now 4C molecule reduces NAD to NADH
- Oxaloacetate is now reformed = cycle continues
ETC
Electron transport chain in which electrons are transferred across a series of proteins within the cell membrane and hydrogen protons are pumped to create a proton gradient
also called oxidative phosphorylation
ETC in detail
- Reduced NAD is delivered to the 1.Protein which splits it to NADH + H + 2e
- 2e are passed along electron carriers
- Electrons power the H+ ions being pumped across the membrane
- Reduced FAD (FADH2) works similarly but delievers to 2.Protein
ETC (quick facts)
- happens in inner mitochondrial mebrane & intermembrane space
- approx 34 ATP are generated
- produces bwater as a waste product
- 4 transmembrane proteins
- 2 Electron carriers
What directions do H+ ions go in ETC
Mitochondrial matrix -> inner mitochondrial membrane -> Intermembrane Space
Chemiosis mechanism
- H+ only have one route bacj across the IMM as it is impermeable
- through ATP synthase it rotates like a turbine
- this generates energy to convert ADP to ATP
Electrochemical Proton Gradient
- pumping of H+ across the inner mitochondrial membrane creates a conc. gradient
- since space is small; conc. gradient is high
- gradient allows function of ATP synthase
- approx. 3H+ are needed to convert each ADP to ATP
Proton motive force
represents the force used for the flow of protons across the inner mitochondrial mebrane through chemiosis
role of oxygen in ETC
- electrons come from IV Protein
- once the electrons pass along ETC => they need to go somewhere
- O2 splits to form terminal electron acceptor
- each oxzgen joins with 4e and 4H+ to form water molecules
- happens in mitochondrial matrix
What happens if there is no oxygen to accept electrons after chemiosis
NAD and FAD cannot be regenerated (usually the non reduced NAD and FAD can be recycled and reused)
* H2 carriers cannot transfer energised electrons to the chain and ATP production is halted
Factors determining the amount of ATP that can be produced
- availability of hydrogen; more H2 = more reduced NAD as an proton carrier
- more ATP can be generated
Respiratory substrate which produces most ATP
Lipids (have most hydrogens as they are long chained molecules)
1 Tryglyceride =460 ATP
Lipids as respiratory substrates
- broken down into glycerol & 3 fatty acids
- glycerol used in glycolysis
- fatty acids are broken down into acetyl groups
- go to link reaction then Krebs cycle
Proteins as respiratory substrates
- hydrolysed into amino acids
- einter in glycolysis, links reaction or krebs cycle
- very harmful as it produces urea (poisoning)
- only during starvation
Anaerobic respiration in humans in detail
- glucose breaks down in glycolysis into pyruvate
- releases 2 ATP & 2NADH
- pyruvate is reduced to lactate by NADH as enzyme
- this oxideses NADH to NAD to take part in further glycolysis
Aerobic respiration (quick facts)
- in absence of oxygen#only glucose can beused as substrate
- in cytoplasm
- produces ATP & NAD per pyruvate
- pyruvate is reduced to lactate
- net gain of 38 ATP
Aerobic respiration equation
C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP
38 ATP
Anaerobic respiration in humans equation
C6H12O6 -> 2C3H6O3 + 2ATP
Anaerobic Respiration in humans
partial breakdown of glucose to produce lactate and 2ATP + 2NADH
Mitochondria
- contains two membranes (inner and outer)
- outer membrane is permeable to small ions and molecules (contains transfer proteins)
- inner membrane is highly folded into cristae (valley)
- matrix is inside & accumulates high conc. gradient
NAD
Nicotinamide adenine dinucleotide (NAD)
* functions as co enzyme
* its ability to be reduced & oxidised allows it to perform the critical role of a hydrogen carrier
Respirometer
simple devices which measure the rate of the respiration in organisms which respire aerobically
Anaerobic Respiration in yeast word equation
Pyruvate -> Ethanal -> Ethanol
Anaerobic respiration in yeast in detail
- Glucose (6C) will first break down into pyruvates -> releases 2 ATP
- Pyruvate is converted into ethanal by decarboxylation
- Ethanal -> Ethanol (reduced by NADH)
- This happens in the cytosol (liquid in cytoplasm)
- Ethanol & CO2 produced
ATP -> ADP
- hydrolysis reaction
- add water
- exergonic reaction (spontaneous reaction; bond making releases energy)
ADP -> ATP
- condensation reaction
- removes water
- endergonic reaction (spontaneous reaction which take sin energy)
- phosphorylation
Similarities between anaerobic and aerobic respiration
- both utilise glucose
- both occur in cytoplasm
difference between anaerobic and aerobic respiration
Aerobic
* oxygen
* mitochondria
* all molecules as substrates
* 36ATP
* H20 and O2
Aerobic
* no oxygen
* 2ATP
* lactate
When does a reaction release energy
when it loses the ability to carry electrons
like ATP -> ADP, NADH->NAD
Function of ATP synthase
- protons build up in intermembrane space due to ETC
- atp synthase utilises proton gradient as protons flow down concentration gradient
- this catalyses formation of ATP
Chemiosis & ETC
- NAD reduced by gaining electrons
- NADH & FADH2 produced in Krebs cycle
- e carriers deliver electrons to ETC in inner mitochondrial membrane
- electrons release energy as they travel through proteins (carriers)
- proteins act as proton pumps
- protons pumped from mitochondrial matrix to intermembrane space
- generates proton gradient
- protons move down their conc. gradient through ATP synthase
- generates energy to catalyse/phosphorylate ADP to ATP
role of coenzyme A
(CoA)
* binds to acetate and catalyses links reaction
* aids acetate group to enter Kreb’s cycle
Which reaction is the sole linear metabolic pathway in respiration
glycolysis
Where do the products of the ETC go? How does this relate to where the proton gradient is built?
- products of ETC need to be used in Krebs Cycle => in mitochondrial matrix
- protons are pumped into intermembrane space
- protons move down conc. gradient through ATP synthase into mitochondrial matrix where they are used
