Respiration

HideShow resource information

Glycolysis

Phosphorylatied glucose is broken down into 2 Triose Phosphate molecules (both of these contain 3 carbons). These molecules are oxidised, meaning excited electrons are "lost". NAD is converted into reduced NAD, as hydrogen is removed from TP, turning it into pyruvic acid.

All of this happens in the cytoplasm.

The net production of ATP produced is 2. 2 ATP is used in the breaking down of glucose.

This is the only stage of respiration that does not require oxygen.

1 of 6

Link Reaction

Pyruvate loses a carbon (decarboxylation), releasing carbon dioxide. Pyruvate turns into Acetyl, which binds to coenzyme A, froming Acetyl coenzyme A. During this, NAD isconverted into reduced NAD. Acetyl seperates from the coenzyme and is recycled.

This stage can only occur if oxygen is available.

No ATP is produced at this stage.

2 of 6

Krebs Cycle

Acetyl binds with 4C to form 6C. Carbon is lost in the form of carbon dioxideto from 5C, and then to form 4C. 4C binds to Acetyl, and the process is continuous. Reduced NAD and Reduced FAD are created here.

This stage doesn't require oxygen.

ATP is made when C5 is converted to C4.

3 of 6

Oxidative Phosphoylation/The Electron Transport Ch

Reduced NADnd reduced FAD are reoxidised to NAD and FAD. Electrons move along the electron transport chain, losing energy at each carrier. The energy is used to move protons by active transport from the mitochondrial matrix into the intermembrane space. This creates a chemiosmotic/electrochemical gradient. Protons diffuse back into the matrix via ATP synthase converting ATP from ADP and inorganic phosphate (Pi) The protons (H+ ions) combine with oxygen to form water.

Oxygen is said to be the final electron acceptor

Most ATP is formed during this stage.

4 of 6

Anaerobic Respiration - Plants

Due to a lack of oxygen, pyruvate cannot form acetate/ acetyl. To allow respiration to continue, the electrons, hydrogens and NAD must be recylced. Pyruvate forms ethanol, and releases Co2. This allows the recycling of the molecules, so ATP can still be produced, albeit in much smaller quantities.

Ethanol is a 2 carbon molecule.

This reaction also happens with yeast (and this is often mentioned in exams).

Ethanol is poisonous.

5 of 6

Anaerobic Respiration - Animals

Due to a lack of oxygen, pyruvate cannot form acetate/ acetyl. To allow respiration to continue, the electrons, hydrogens and NAD must be recylced. Pyruvate forms lactate. This allows the recycling of the molecules, so ATP can still be produced, albeit in much smaller quantities.

Lactic Acid/Lactate is a 3 carbon molecule.

This reaction also hsappens with some bacteria.

 Lactate is poisonous.

6 of 6

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Cellular processes resources »