Ferns carry out aerobic respiration because they have chloroplasts. Thy use both respiration and photosynthesis. The steps of aerobic respiration are the following.
First is the Krebs Cycle;
1. two carbon molecules combine with oxaloacetic acid(four-carbon compound) and they make a six-carbon compound known as citric acid. This regenerates co enzyme A.
2.CO2 is released by citric acid and a hydrogen atom. A hydrogen atom forms a five-carbon compound. Citric acid is oxidized and the hydrogen electron reduces NAD+ to NADH.
3. The five-carbon compound releases 1 CO2 and hydrogen atom. Now, a four-carbon compound is produced. NAD+ is released to NADH. ADP becomes ATP.
4.The four carbon compound releases a hydrogen atom to form another four carbon compound. FAD is reduced to FADH2.
5. The four-carbon compound release a hydrogen atom to regenerate oxaloacetic acid which keeps the Krebs cycle going. 10 NADH molecules and two FADH2 molecules that are produced drive the next stage of aerobic respiration. The next stage is Electron Transport chain.
1. NADH and FADH2 give the electron transport chain electrons.
2. Electrons are passed down the chain and they move from molecule to molecule, loosing energy.
3. Lost energy pumps protons and builds a high concentration gradient.
4. This drives the synthesis of ATP. ATP synthase molecules are embedded in the inner membrane and Protons move along the chain and ATP is made from ADP and phosphate.
5. Oxygen accepts electrons and some protons. The protons, electrons and oxygen combine and form water.
Source: PG 139, 156 and 140 Modern Biology
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