Describe what happens in the first stage of glycolysis
Glucose enters the cells cytoplasm
Upon entry, an enzyme adds two phosphate groups to a glucose through phosphorylation
There phosphate groups are available due to the breakdown of 2 ATP molecules
Producing a new molecule of glucose phosphate
What is the reaction when an atom gains hydrogen
Reduction
What is an oxidation reaction
When a substance loses hydrogen
Which step does oxidation-reduction take place
3
What molecule is oxidised during glycolysis
Triose phosphate
What is NAD converted to in the oxidation-reduction reaction in glycolysis
NADH
Describe how oxidation-reduction is involved in glycolysis
Triose phosphate loses hydrogen in the third step of glycolysis
So Triose phosphate is oxidised
The hydrogen is transferred to a molecule called NAD forming NADH
In the third and final step of glycolysis , Triose phosphate loses hydrogen is converted to
Pyruvate
Describe glycolysis
First, glucose enters the cell’s cytoplasm. Upon entry, an enzyme adds two phosphate groups to glucose in a process known as phosphorylation. These phosphate groups are available due to the breakdown of
2
ATP molecules. As a result, this produces a new molecule called glucose phosphate.
Second, hexose phosphate breaks down into two molecules of triose phosphate.
Third, triose phosphate is converted into pyruvate. In this step,
2
molecules of NADH and
4
molecules of ATP are formed.
The overall yield of ATP within glycolysis is
2
ATP
What is an anabolic reaction
Building larger molecules from smaller molecules , requires energy as its making bonds
What is a catabolic reaction
Breaking larger molecules into smaller molecules , releasing energy as its breaking bonds
What happens to pyruvate after glycolysis
It’s actively transported into the matrix
What is pyruvate converted to in the first step of the link reaction
Acetate
What is acetate then converted to
Acetyl coA
When pyruvate loses hydrogen it becomes
Oxidised
Describe fully the link reaction, including details about all the products that are formed
takes place in the matrix of the mitochondria. In the first step of the link reaction, pyruvate is converted to a molecule called acetate as a carbon is lost in the form of carbon dioxide. A hydrogen atom is also lost from pyruvate, which is transferred to a molecule of NAD, a coenzyme, to produce reduced NAD, called NADH. In the second step of the link reaction, a molecule called coenzyme A is added, which converts acetate into a new molecule called acetyl-CoA.
What’s the 3rd stage of aerobic respiration
Krebs cycle
What other products does the krebs cycle produce
NADH
FADH2
To catalyse the production of ATP , ATP synthase needs energy
This energy is supplied by
Diffusion of protons down a proton gradient
What process occurs in anaerobic respiration but not in aerobic respiration
Reduction of pyruvate
Describe the process of glycolysis
Phosphorylation of glucose using ATP
Oxidation of TRIOSE PHOSPHATE to pyruvate
Net gain of ATP (4 produced , 2 used)
NAD reduced
Malonate inhibits a reaction in the Krebs cycle
Explain why malonate would decrease the uptake of oxygen in a respiring cell
Less / no reduced NAD/ coenzymes fewer hydrogens/ electrons removed and passed to ETC
Oxygen is the final electron acceptor
In muscles, pyruvate is converted to lactate during prolonged exercise.
Explain why converting pyruvate to lactate allows the continued production of ATP by anaerobic respiration
Regenerated / produces NAD
Oxidises NADH
So glycolysis continues
4 stages of respiration in order
Glycolysis
Link reaction
Krebs cycle
Electron transport chain
