Where enzymes produced and what are are they for?

Enzymes are produced in cells via a process called protein synthesis, coded for by strands of DNA which are copied via transcription on to mRNA which then leaves the nucleus of the cell and goes to the Ribose on the Rough endoplasmic reticulum where the tRNA brings in amino acids which are coded for by three nucleotides called a codon. The amino acids are now lined up and they join via a peptide link creating a protein which can be anything from an enzyme to a hormone depending on the sequence of codons.

Enzymes act as a catalyst speeding up reactions by lowering activation energy or by forcing molecules into the correct orientations in the active site. Basically enzymes speed up metabolic processes such as respiration.

Enzymes are catalysts. Most are proteins. (A few ribonucleoprotein enzymes have been discovered and, for some of these, the catalytic activity is in the RNA part rather than the protein part. Link to discussion of these ribozymes.)

Enzymes bind temporarily to one or more of the reactants of the reaction they catalyze. In doing so, they lower the amount of activation energy needed and thus speed up the reaction.

It enables red blood cells to transport carbon dioxide from the tissues to the lungs. [Discussion]

One molecule of carbonic anhydrase can process one million molecules of CO2 each second.

Acetylcholinesterase. It catalyzes the breakdown of the neurotransmitter acetylcholine at several types of synapses as well as at the neuromuscular junction — the specialized synapse that triggers the contraction of skeletal muscle.

One molecule of acetylcholinesterase breaks down 25,000 molecules of acetylcholine each second. This speed makes possible the rapid "resetting" of the synapse for transmission of another nerve impulse.

Jelly is fine with the toast, and the milk should be fine. But make sure you can have only 1200 calories a day.. that's a bit low. The best way (!) to lose weight is to do exercise with your diet. Walk (or jog) for 10 minutes at least 3 times a week.