In photosynthesis, electrons that travel through the electron transport chain in the thylakoid membrane come from . in cellular respiration, molecules of supply some of the electrons that travel through the electron transport chain.

In photosynthesis, the electrons that travel through the electron transport chain in the thylakoid membrane comes from water. In the process of cellular respiration, the molecules of NADH donates some of the electrons, which passes through the electron transport chain.

Explanation:

Water supply the initial electron in photosynthesis. The procedure of photolysis dissociates the water into oxygen and hydrogen and discharges electrons that are taken up by photosystem II. In the last step of cellular respiration, that is, oxidative phosphorylation, the donation of electrons is done by NADH that is used to pump ions of hydrogen against the gradient into the mitochondria's inner-membrane space. These flow back of the ions of hydrogen helps in the generation of the energy currency of the cell, that is, ATP.

1. amino acid refers to the fundamental building block of proteins, comprising of an amino group and a carboxyl group.

2. catalyst refers to any substance, which increases the rate of chemical reaction without being used up in the reaction.

3. a complex molecule containing he genetic code is dna or deoxyribonucleic acid.

4. an enzyme refers to a molecule of protein, which is unique in accelerating up a particular chemical reaction in the biological systems.

5. nucleic acid refers to an sequence of sugars, phosphates, and nitrogenous bases, for example, dna and rna.

6. a protein refers to a large, composite organic molecule comprising of a huge number of amino acids associated together with the of peptide bonds.

7. rna refers to a nucleic acid that takes part in the production of proteins.

8. substrate refers to a compound, which takes part in a chemical reaction, and is chemically modified by the reaction.