Proteins Flashcards
What are proteins made from?
Proteins are made from long chains of smaller molecules called amino acids. These long chains are folded into particular shapes.
What happens if the shape of an enzyme changes?
If the shape of an enzyme changes, it may no longer work (it is said to have been ‘denatured’)
What are enzymes?
Enzymes are biological catalysts. There are optimum temperatures and pH values at which their activity is greatest. Enzymes are also proteins.
What are proteins?
Proteins are polymers. They are built up in cells in monomers called amino acids join together end to end.
What is glycine?
Glycine is an amino acid
What is alanine?
Alanine is an amino acid.
How many naturally occurring amino acids are there?
There are only about 20 different amino acids. However, each protein molecule has hundreds, or even thousands, of them joined together in a unique sentence (this gives each protein its own individual properties)
What is particularly important for antibodies and enzymes?
The particular shape that a protein molecule has allows other molecules to fit into it.
What is the name of the place where substrate molecules fit?
The active site
How can enzymes be denatured?
Enzymes can be denatured by high temperatures or extremes of pH.
Why is it wrong to say that enzymes have been killed?
It’s is wrong to say that an enzyme has been killed. Although enzymes are made by living things, they are proteins and not alive. You must say ‘denatured’.
What happens to enzymes as the temperature increases?
As the temperature increases, so does the rate of reaction. But very high temperatures denature enzymes.
How can changes in pH affect enzymes?
Changes in pH alter an enzyme’s shape. Different enzymes work best at different pH values. The optimum pH for an enzyme depends on where it normally works.
Which enzymes work best inside cells?
The enzymes involved in respiration, photosynthesis and protein synthesis work inside cells. Other enzymes are produced by specialized cells and released from them.
Where is amylase produced?
Salivary glands, pancreas and small intestine
Where is protease produced?
Stomach, pancreas and small intestine
Where is lipase produced?
Pancreas and small intestine
What is the function of amylase?
Amylase catalyses the breakdown of starch into sugars in the mouth and small intestine.
What is the function of protease?
Proteases catalyse the breakdown of proteins into amino acids in the stomach and small intestine
What is the function of lipase?
Lipase catalyse the breakdown of fats and oils into fatty acids and glycerol in the small intestine.
What acid does the stomach produce?
It produces hydrochloric acid.
How is the stomach producing hydrochloric acid useful?
It helps begin digestion, and it kills many harmful microorganisms that might have been swallowed along with the food.
When do the enzymes in the stomach work best?
The enzymes in the stomach work best in acidic conditions - in other words, at a low pH.
When do the enzymes in the small intestine work best?
The enzymes in the small intestine work best in alkaline conditions, but the food is acidic after being in the stomach.
