Week 4: Enzymes

Enzymes are proteins, composed of amino acids. They speed up chemical reactions in cells, but remain unchanged. A catalyst.

Two types of chemical reactions that may occur:

Anabolic - Building up: Protein Synthesis, Photosynthesis
Catabolic - Breaking down: Respiration

Enzyme processes inside cells are called Intracellular. Enzyme processes outside of cells are called extracellular.


Enzymes have an optimum temperature at which they work, beyond which they function less well, or break completely. Enzymes that have been heated up too much are said te be 'de-natured' and they cannot be used again.


Here are some locations in the body and the enzymes that work there.

Mouth: Amylase

Stomach: Protease

Pancreas: Amylase, Protease, Lipase

Small intestine: Amylase, Protease, lipase


Here is what those particular enzymes do

Amylase > Starch to sugars

Protease > Proteins to amino acids

Lipase > fats to glycerol


Catalase is the fastest known enzyme. It converts hydrogen peroxide to water and oxygen.



Test, Fast Froth.

1. Cut two pieces of liver (from a lamb) to the same size
2. Put 1 into a boiling tube containing 5cm3 of hydrogen peroxide
3. Use a ruler to measure the highest point of the resulting froth and the time it took to reach that point.
4. Do the same with the second piece of liver, but this time cut it into small pieces

Which test causes froth to rise the quickest, highest? Why?
Where is the enzyme found in this test? Was the enzyme a breaker or a builder, a catabolic or an anabolic?


Recap with bullets

Enzymes

• Are proteins
• Made of Amino Acids
• Biological Catalyst - Speeds up reaction, remains unchanged
• Will be damaged at too high a temperature, or the wrong ph - De-natured
• Can be used again and again
• Human enzymes tend to work best at 37 degrees
• Fulfill one specific role - reaction or process
• Anabolic process builds
• Catabolic process breaks down

Enzymes in metabolism

• Intracellular -eg photosynthesis
• Extracellular - eg digestion
• anabolic - Protein synthesis, photosynthesis
• Catabolic - respiration

So, Photosynthesis is an intracellular anabolic enzyme process.