enzymes and nutrition Flashcards
what are enzymes?
they are biological catalysts which means they speed up chemical reactions without being altered
how do bacteria absorb digested food into their cells?
bacteria release digestive enzymes into their environments and then absorb digested food into theri cells
digestive enzymes in humans
they turn large molecules in our food into smaller subunits they are made of and these digested molecules are then small enough to be absorbed by the small intestine
breaking down
- protein molecules are broken down into amino acids
- starch molecules are broken down into glucose molecules
- lipid molecules are broken down into 3 fatty acids and 1 glycerol
synthesis after breaking down
once small molecules are absorbed into the body they can be used to build larger molecules that are needed in cells and tissues. building larger molecules from smaller subunits is called synthesis.
enzymes
breaking down of large molecules and synthesis of smaller subunits happens much too slowly to supply all that the body needs to stay alive and be active SOOOOO a catalyst needs to be used. in this case enzymes are used as they are biologic catalysts that increase the rate of reaction. they work on substrates and the substances produced are called products.
amylase
- found in saliva and small intestine
- breaking down starch to smaller sugars, such as maltose
catalase
- found in most cells especially liver cells
- breaking down of hydrogen peroxide made in many cells’ reactions into water and oxygen
starch synthase
- found in plants
- synthesis of starch from glucose
DNA polymerase
- found in the nucleus
- synthesis of DNA from its monomers
Reducing sugars test
Food group: Reducing sugars
Components of Solution/ procedure: Equal volume of Benedict’s solution placed in a hot bath for a few minutes
Products: Reduction reaction which changes the colour of the solution and may form a precipitate.
- No colour change (blue)-no
- Slight colour change (green)-very little
- Some colour change (orange)-more
- Big colour change (red)-lots
biuret test
Food group: Protein
Components of Solution/ procedure:
Potassium hydroxide is mixed with a solution of the food. Two drops of CUSO4 solution are then added.
Products: If the pale blue solution turns purple, this indicates protein in the food
Ethanol emulsion test
Food group: Fats and oils (lipids)
Components of Solution/ procedure:
The food is mixed with ethanol and shaken. Some of that mixture is then poured into water and shaken again.
Products:
Fats and oils dissolved in the ethanol float to the surface, forming a cloudy emulsion when the mixture is left to stand
energy and calorimetry
food provides us with energy and foods that contain large amounts of sugars and fats are particularly good sources of energy.
We can measure the amount of energy in a food by burning it in a calorimeter. The amount of energy transferred from the burning food to the water can be calculated from the increase in water temperature.
