Respiration Flashcards
Respiration definition.
The process that occurs in living cells and releases the energy stored in glucose
Examples of uses of ATP?
Active and bulk transport
Protein synthesis
DNA replication
Cell division
What are metabolic reactions?
Chemical reactions which take place inside living cells
Difference between anabolic and catabolic reactions?
Anabolic large molecules are synthesised from smaller ones
Catabolic involves the breakdown of larger molecules to smaller ones
Structure of ATP?
Adenine
5 carbon sugar
3 phosphate groups
How does ATP release energy?
When it is hydrolysed to ADP
Structure of Adenosine?
Adenine and ribose
Difference between AMP and ADP?
AMP has 1 phosphate group, ADP has 2
How much energy is released when ATP is hydrolysed?
30.5 kJ mol-1
How much energy is released when ADP is hydrolysed?
30.5 kJ mol-1
How much energy is released when AMP is hydrolysed?
13.8 kJ mol-1
Glycolysis definition?
The first stage of respiration, a 10 stage metabolic pathway that converts glucose to pyruvate
What are the 3 main stages of glycolysis?
Phosphorylation of glucose
Spitting of hexose biphosphate
Oxidation of triose phosphate
What happens in the phosphorylation of glucose?
2 molecules of ATP are hydrolysed and the released phosphate group is added to hexose to form hexose monophosphate. ATP hydrolysed again to form hexose biphosphate
Structure of hexose biphosphate
6 carbon compound
1 phosphate group at carbon 1 and another at carbon 6
What is NAD?
A non protein molecule that helps dehydrogenase enzymes carry out oxidation reactions
Structure of NAD?
Nicotinamide
Ribose
Adenine
2 phosphoryl groups
How does NAD become reduced NAD?
By the nicotinamide accepting 2 hydrogen atoms
What is hexose biphosphate split into?
Two 3 carbon molecules called triose phosphate
Each triose phosphate has a phosphate group attached
What happens in the oxidation of triose phosphate?
Dehydrogenase enzymes remove hydrogen atoms from triose phosphate.
Why are the 4 stages of respiration?
Glycolysis
The link reaction
Krebs cycle
Oxidative phosphorylation
Which stage is anaerobic?
Glycolysis
Products of glycolysis?
4 ATP- 2 net gain
2 reduced NAD
2 pyruvate molecules
When is active transport used after glycolysis?
To transport pyruvate across the outer and inner mitochondrial membrane
What happens in the mitochondrial matrix?
Link reaction
Krebs cycle
What happens in the link reaction?
Pyruvate is decarboxylated and dehydrogenated
What enzyme catalyses the link reaction?
Pyruvate dehydrogenase
Is any ATP produced in the Link reaction?
No
Product of the link reaction?
Acetyl co enzyme A
How is acetyl CoA produced?
Carboxyl group removed from pyruvate
Produces acetyl group
Combines with Co enzyme
Where do the hydrogen atoms removed from triose phosphate go?
The two molecules of NAD accepts the hydrogen atoms. This reduces NAD
How to remember oxidation and reduction.
OILRIG
Oxidation is lost
Reduction is gained
Role of NAD in glycolysis?
Aids dehydrogenase enzymes to remove hydrogen atoms from triose phosphate.
Describe the shape of mitochondria?
Rod- shaped
Diameter of 0.5-1 micrometer
Length of 2-5 micrometers but up to 10
How many membranes do mitochondria have?
2- inner and outer
Makes up the envelope
What is the differences in the membranes of the mitochondria?
The outer membrane is smooth and the inner is folded into cristae
Inner membrane is less permeable to small ions
What is an advantage of cristae?
Gives a large surface area
What is found in the inner membrane?
Proteins that transport electrons
Protein channels associated with ATP synthase enzyme
What is the space between the membranes?
Intermembrane space
Describe the mitochondrial matrix
Semi rigid, gel like and fluid filled
What does the mitochondrial matrix contain?
Mitochondrial ribosomes
Looped mitochondrial DNA
Enzymes
What takes place in the matrix?
Link reaction and krebs cycle
Where does glycolysis take place?
In the cytoplasm
What does the matrix contain for those processes?
Enzymes
Molecules of NAD and FAD
Oxaloacetate
What is the Krebs cycle?
A series of enzyme catalysed reactions that oxidise the acetate from the link reaction
Step 1 of Krebs cycle?
Acetyl group (2c) combines with oxaloacetate (4c) to form citrate (6c)
Step 2 of Krebs cycle?
Citrate is decarboxylated and dehydrogenated producing a 5c. 2H, CO2 and reduced NAD is released.
Step 3 of Krebs cycle?
Repeat it step 2 to produce a 4c. 2H, CO2 and reduced NAD is released
Step 4 of Krebs cycle?
4c combines temporarily and is then released from Coenzyme A. Substrate phosphorylation occurs to release ATP.
Step 5 of Krebs cycle?
4c is dehydrogenated. Reduced FAD released
Step 6 of Krebs cycle?
Further dehydrogenation. 2H and reduced NAD.
How is oxalocacetate regenerated?
By rearrangement of atoms in the 4c, catalysed by an isomerase enzyme.
How much ATP is produced in the Krebs cyle?
For 1 molecule of glucose there are 2 turns of the Krebs cyle. So two molecules of ATP per glucose is produced.
What is chemiosmosis?
The flow of protons, down their conc gradient through a channel associated with atp synthase
What is oxidative phosphorylation?
The formation of ATP using energy released in the electron transport chain and in the presence of oxygen. The final stage in aerobic respiration
Where do the protons come from?
When reduced FAD and reduced NAD deliver their hydrogen atoms to the electron transport chain. They then split into protons and electrons.
What happens along the electron transport chain?
The electrons from the splitting of the hydrogen atom is passed along the electron carrier chain. As electrons are passed along the chain, some of their energy is used to pump the protons into the intermembane space.
Where is the electron transport chain?
Embedded in the inner mitochondrial membrane (cristae)
What does each electron carrier have?
An iron ion at it’s core
How is the proton gradient caused?
The accumulation of protons cause a proton gradient.
What does the proton gradient generate?
A chemiosmotic potential also known as a proton motive force (pmf)
How is ATP generates from pmf?
The inner membrane is impermeable to protons and the outer membrane has low permeability to protons. Protons can diffuse through a protein channel associated with ATP synthase enzymes.
