Respiration Flashcards
What is respiration?
The process by which complex organic molecules, such as carbohydrates, are broken down to release energy which is then used to make ATP
Where does aerobic respiration mainly occur?
Mitochondria
Where does anaerobic respiration occur?
Cytoplasm
What requires energy?
Anabolic reactions
Movement
Active transport
What are the 4 stages of respiration?
Glycolysis
Link reaction
Kreb’s cycle
Oxidative phosphorylation
Where does glycolysis occur?
Cytoplasm
Where does the link reaction occur?
Matrix
Where does the Kreb’s cycle occur?
Matrix
Where does oxidative phosphorylation occur?
Inner membrane
What gets oxidised in respiration?
Glucose (goes to carbon dioxide)
What gets reduced in respiration?
Oxygen (goes to water)
What enzymes are used in respiration?
Dehydrogenase enzymes
What do dehydrogenase enzymes do?
Remove hydrogen
What coenzymes are used in respiration?
NAD
FAD
CoA
(ATP)
What is the diameter of a mitochondria?
0.5-1 micrometers
What is the length of a mitochondria?
2-5 micrometers
What does glycolysis mean?
Splitting carbohydrates
What type of respiration does glycolysis happen in?
Aerobic and anaerobic as it doesn’t require oxygen
What organisms do glycolysis?
Eukaryotes and prokaryotes
What does glycolysis form?
2 molecules of pyruvate from one glucose molecule
2 ATP
2 reduced FAD
What happens to glucose in the first step of glycolysis?
2 ATP is used (dephosphorylation) to form hexose bisphosphate
What happens to hexose bisphosphate is glycolysis?
Lysis as it is unstable
Forms 2 triose phosphates
What happens to the 2 triose phosphates in glycolysis?
Gets phosphorylated using phosphate in the cytoplasm to form 2 triose bisphosphate
What happens to the 2 triose bisphosphate in glycolysis?
Phosphates are used to make 4 ATP
Uses hydrogen to reduce 2 NAD
Forms 2 pyruvate molecules
What is dephosphorylated in glycolysis?
ATP, Triose bisphosphate
What is lysed in glycolysis?
Hexose bisphosphate
What is dehydrogenated in glycolysis?
Triose bisphosphate
What is reduced in glycolysis?
NAD
What is oxidised in glycolysis?
Triose bisphosphate
What is phosphorylated in glycolysis?
ADP, Glucose, Triose phosphate
What is a coenzyme?
Something that helps an enzyme to function
In respiration they are required for dehydrogenase enzymes to remove the hydrogen
What is substrate-level phosphorylation?
Using phosphate that is removed from an organic molecule to produce ATP from ADP+Pi
What is another name for the link reaction?
Oxidative decarboxylation
How does pyruvate enter the mitochondrial matrix?
Through membrane proteins by active transport. requires ATP produced by aerobic respiration
What is the name given to the process that removes carbon dioxide?
Decarboxylation
What is removed from pyruvate in the link reaction?
Carbon dioxide
Hydrogen (in order to reduce 2 NAD)
This forms acetate
What is joined to acetate in the link reaction?
Coenzyme A
This forms Acetyl CoA
What are the organic and inorganic products formed in the link reaction?
Inorganic - Carbon dioxide
Organic - Acetyl CoA
Why does glycolysis occur in the cytoplasm instead of in the mitochondria?
Glycolysis came before mitochondria
Mitochondria only came later - after endosymbiosis
How does a multi-enzyme complex increase the efficiency in a metabolic pathway?
Requires lots of different enzymes as there are lots of different substrates
All enzymes are closer together so speeds up the process (less time to get from one enzyme to another)
How many molecules of ATP are produced in the link reaction per glucose?
0
How many molecules of reduced NAD are produced in the link reaction per glucose?
2 (1 from each pyruvate)
How many molecules of carbon dioxide are produced in the link reaction per glucose?
2 (1 from each pyruvate)
How do you remember the Kreb’s cycle?
DeNA DeNA A FANA
What does DeNA DeNA A FANA mean?
Decarboxylation NAD is reduced Decarboxylation NAD is reduced ATP produced FAD reduced NAD reduced
What does the Kreb’s cycle start with?
Oxaloacetate + Acetyl CoA
What occurs to allow reduction to occur in the Kreb’s cycle?
Dehydrogenation (removed H and adds it to NAD/FAD)
Also, oxidation
How is ATP produced in the Kreb’s cycle?
Substrate level phosphorylation
Phosphate comes from substrate
What does Acetyl CoA + oxaloacetate form in the Kreb’s cycle?
Citrate (before first carboxylation)
What is Decarboxylation?
Removal of carbon dioxide
Where does the Kreb’s cycle happen?
Matrix of mitochondria
What is the main purpose of the Kreb’s cycle?
Reduce coenzymes
How many times does the Kreb’s cycle turn per glucose molecule?
2
Why is ATP counted as a coenzyme?
It is required for enzymes to work as it moves phosphate groups between reactions
Why is FAD used in one specific step of the Kreb’s cycle rather than NAD?
It is a coenzyme for a different enzyme that is used in that one specific step
What occurs to the reduced FAD/NAD in oxidative phosphorylation?
They are oxidised
What happens to ADP in oxidative phosphorylation?
Phosphorylated by chemiosmosis to produce large quantities of ATP
Where does oxidative phosphorylation occur?
Membrane in cristae in mitochondria
What happens to the electrons that are released by oxidising NADH and FADH in oxidative phosphorylation?
They go through the ETC using mobile electron carriers.
This releases energy to power proton pumps
What do the proton pumps do in oxidative phosphorylation?
Pump H+ ions from the mitochondrial matrix to the intermembrane space.
What does the pumping of protons produce in oxidative phosphorylation??
An electrochemical gradient
What is oxygen known as in oxidative phosphorylation?
The final electron acceptor
What happens to the electrons at the end of the ETC in oxidative phosphorylation?
They are accepted by oxygen. This also combines with H+ ions to form water
What happens due to the electrochemical gradient in oxidative phosphorylation?
H+ ions in the intermembrane space flow through ATP synthase into the mitochondrial matrix which joins ADP+Pi to form lots of ATP
How is anaerobic respiration different?
Doesn’t use oxygen
Doesn’t involve Link reaction, Kreb’s cycle or oxidative phosphorylation
Doesn’t involve mitochondria (in cytoplasm)
Final electron acceptor is pyruvate
Lower ATP yield as only 1 stage - glycolysis
What are the 2 types of anaerobic respiration?
Alcoholic fermentation
Lactate fermentation
What is produced it lactate fermentation?
Lactate and NAD
What happens in lactate fermentation?
Reduced NAD from glycolysis transfers hydrogen to pyruvate to form lactate and NAD
NAD is then reused in glycolysis
What are the positives of lactate fermentation?
Glycolysis can continue when oxygen is low so small amounts of ATP can be made to keep some biological processes going.
Cells can tolerate high levels of lactate
Lactate converted back to glucose by gluconeogenesis
What are the negatives of lactate fermentation?
Only small amounts of ATP are produced.
Lactate is toxic.
Where does alcoholic fermentation occur?
In yeast
What does alcoholic fermentation produce?
Carbon dioxide, ethanol and NAD
What happens in alcoholic fermentation?
CO2 is removed from pyruvate to form ethanal.
Reduced NAD from glycolysis transfers hydrogen to ethanal to form ethanol and NAD
NAD is then reused in glycolysis
What are the positives of alcoholic fermentation?
Produces some ATP by glycolysis when Oxygen is low
What are the similarities between lactate fermentation and alcoholic fermentation?
Takes place in cytoplasm
Starts with glycolysis (produces pyruvate)
Regenerates NAD
Releases less energy than aerobic respiration
No oxygen
What are the differences between lactate fermentation and alcoholic fermentation?
LF - Mammals (some bacteria), produces lactate, 1 step, No other products
AF - Yeast cells (some plants), produces ethanol, 2 steps, also produces CO2
What is the definition of respiratory substrate?
An organic molecule that can be broken down in respiration to release energy
What is the primary respiratory substrate?
Glucose
What respiratory substrate releases the most energy?>
Lipids
Why do lipids release the most energy?
They have the most hydrogen atoms per unit mass, so they produce more reduced coenzymes in respiration so more ATP is produced.
Why do organisms not respire lipids or proteins first?
They have other functions. Fats - insulation, Protein in muscles so respire glucose then fats then protein
What does the RQ value show?
What respiratory substrate is being respired and therefore what type of metabolism the organism has
How do you work out the RQ value?
Volume or moles of CO2 produced / Volume or moles of oxygen produced
What are the units for RQ?
No units
What is the RQ for carbohydrates?
1.0
What is the RQ for proteins?
0.9
What is the RQ for fats?
0.7
When can the RQ be more than 1.0?
When using carbohydrates and anaerobic respiration
With respirometers, what is used as a control test?
Glass beads with the same mass as the thing you are measuring. Makes sure any changes are due to the respiration of the thing you’re testing
With respirometers, what causes the fluid to move?
The uptake of oxygen as the CO2 is removed by the soda lime
How do you calculate the volume of oxygen used?
Measure how far the fluid moved
Pi X r squared X h
How would you calculate the rate of oxygen consumption?
Volume used / time
