The document discusses glycolysis, which is the first stage of respiration. Glycolysis takes place in the cytoplasm of cells and involves splitting a molecule of glucose into two molecules of pyruvate. It has two stages - phosphorylation and oxidation. In phosphorylation, glucose is phosphorylated using ATP to form glucose phosphate, which then splits to form two triose phosphates. In oxidation, the triose phosphates are oxidized to form two pyruvate molecules while collecting hydrogen ions to form NADH, and producing a net gain of two ATP molecules.

1. Glycolysis

2. The first stage of respiration
Glycolysis

3. Respiration
• Process of respiration
is split into four parts
• By breaking it into
four parts we will
have less to learn at
any one stage

4. Glycolysis is the first stage of respiration!

5. Glycolysis is the first stage of respiration!
Glycolysis splits one molecule of glucose
into two smaller molecules of pyruvate

6. Glycolysis is the first stage of respiration!
Glycolysis splits one molecule of glucose
into two smaller molecules of pyruvate
Glucose is a hexose
(6-carbon) molecule

7. Glycolysis is the first stage of respiration!
Glycolysis splits one molecule of glucose
into two smaller molecules of pyruvate
Glucose is a hexose
(6-carbon) molecule
Pyruvate is a triose
(3-carbon) molecule

8. Glycolysis is the first stage of respiration!
Glycolysis splits one molecule of glucose
into two smaller molecules of pyruvate
Glucose is a hexose
(6-carbon) molecule
Pyruvate is a triose
(3-carbon) molecule
Pyruvate is also
known as pyruvic
acid

10. • Glycolysis takes place in the
cytoplasm of cells.

11. • Glycolysis takes place in the
cytoplasm of cells.

12. • It’s the first stage of both
aerobic and anaerobic
respiration.

13. • It’s the first stage of both
aerobic and anaerobic
respiration.
•It doesn’t need oxygen to take
place – so it’s anaerobic

14. • It’s the first stage of both
aerobic and anaerobic
respiration.
•It doesn’t need oxygen to take
place – so it’s anaerobic

15. There are TWO STAGES of GLYCOLYSIS –
Phosphorylation and Oxidation

16. Glycolysis

17. Glycolysis
1
2
A
B

18. Glycolysis
1
2
A
B
These arrows in diagrams
just mean that A goes into
the main reaction and is
converted to B.
A will normally release or
collect something from
molecule 1, e.g. hydrogen
or phosphate

19. Stage One - Phosphorylation

20. Stage One - Phosphorylation
1.Glucose is phosphorylated by
adding 2 phosphates from 2
molecules of ATP to give a hexose
phosphate.

21. Stage One - Phosphorylation
1.Glucose is phosphorylated by
adding 2 phosphates from 2
molecules of ATP to give a hexose
phosphate.
2.The hexose phosphate is split
using water

22. Stage One - Phosphorylation
1.Glucose is phosphorylated by
adding 2 phosphates from 2
molecules of ATP to give a hexose
phosphate.
2.The hexose phosphate is split
using water (hydrolysis)

23. Stage One - Phosphorylation
1.Glucose is phosphorylated by
adding 2 phosphates from 2
molecules of ATP to give a
glucose phosphate.
2.The glucose phosphate is split
3.2 molecules of triose phosphate
and 2 molecules of ADP are
created.

24. What’s the point?
• Glucose can now no
longer leave the cell.

25. What’s the point?
• Glucose can now no
longer leave the cell.
• Molecules produced
are much more
reactive!

26. Stage Two - Oxidation

27. Stage Two - Oxidation
1.The triose phosphates are
oxidised (lose oxygen), forming
two molecules of pyruvate.

28. Stage Two - Oxidation
1.The triose phosphates are
oxidised (lose oxygen), forming
two molecules of pyruvate.
2. Coenzyme NAD+
collects the
hydrogen ions, forming 2 reduced
NAD (NADH + H+
)

29. Stage Two - Oxidation
1. The triose phosphates are oxidised (lose
oxygen), forming two molecules of pyruvate.
2. Coenzyme NAD+
collects the hydrogen ions,
forming 2 reduced NAD (NADH + H+
)
A coenzyme is a helper molecule
that carries chemical groups or ions,
e.g. NAD+
removes H+
and carries it
to other molecules.

30. Stage Two - Oxidation
1.The triose phosphates are
oxidised (lose oxygen), forming
two molecules of pyruvate.
2. Coenzyme NAD+
collects the
hydrogen ions, forming 2 reduced
NAD (NADH + H+
)
3. 4 ATP are produced, but 2 were
used up at the beginning, so
there’s a net gain of 2 ATP.

31. Next in Aerobic respiration….

32. Next in Aerobic respiration….
1. The 2 molecules of reduced NAD go
to the electron transport chain
(ETC), part 4 of respiration.

33. Next in Aerobic respiration….
1. The 2 molecules of reduced NAD go
to the electron transport chain
(ETC), part 4 of respiration.
2. The two pyruvate molecules go into
the matrix of the mitochondria for the
link reaction.