Enzyme Action
Objective
1.Review what enzymes are and how they work.
2.Discuss the factors that affect enzyme action
3.Plan/Review an investigation that will allow us to observe/determine
how temperature and pH affects enzyme activity.
Vitamins
Primary Function:
• many vitamins participate in key
chemical reactions of the body as
components of coenzymes (which act
as enzyme helpers)
• some B vitamins are coenzymes in
cellular respiration (ENERGY
PRODUCTION)
• other vitamins are required for
synthesis of important molecules such
Vitamins (cont’d)
Other Functions:
• most vitamins are involved in
maintenance of cells & tissues in the
body
• a lack of a vitamin will lead to a
deficiency disease
Vitamins (cont’d)
• Examples of deficiencies
- Vitamin A – healthy eyes, skin and hair; deficiency
– night-blindness
- Vitamin B (niacin) – needed for cellular respiration;
deficiency - pellagra
- Vitamin C – maintenance of capillaries, bones and
teeth; deficiency - scurvy
- Vitamin D – development and maintenance of
bones and teeth; deficiency – rickets (bowed legs)
Vitamins as Antioxidants
• many vitamins protect cells from free radicals
• free radicals are molecules that are by-products of
cellular metabolism
• free radicals are unstable molecules that carry an
extra electron
– e.g. O2 - and OH-
• these extra electrons can attach themselves to other
molecules in the cell and damage them
– ( eg. lipids associated with the plasma membrane, DNA or
proteins )
• may cause inflammation or even cancer (DNA
damage)
Minerals (cont’d)
Functions:
• some minerals are components of large
molecules e.g. Iron (Fe) in hemoglobin
• some minerals form parts of cells or tissues
e.g. calcium salts form the matrix of bone
tissue
• some minerals help maintain fluid balance in
the blood e.g. Na+
• some minerals are used to create electrical
impulses in nerves and muscles e.g. Na+, K+,
Ca+
Check Point
1.
2.
3.
4.
What are vitamins and what are they used for?
What are minerals and what are they used for?
What are amino acids?
What does essential mean?
Break down of the Macromolecules
(AMYLASE)
CHO’s ------digested to------ MONOSACCHARIDES
(starch)
(glucose)
(PEPTIDASE)
PROTEIN -------digested to--------- AMINO ACIDS
(BILE)
(LIPASE)
FATS ---emulsified----digested to --- GLYCEROL &
FATTY ACIDS
ENZYMES
Enzymes biological catalysts.
They are proteins that allow chemical reactions
in the body to happen by speeding them up
and/or allowing them to occur at a lower
temperature (body temperature)
Enzymes work by lowering the amount of energy
required to start a chemical reaction within a cell.
All metabolic reactions in our cells require a
specific enzyme….
• Enzymes are specific - the active site of an
enzyme has a specific shape that matches
up with only one kind of molecule (like a
key in a lock); because they are specific
we need many thousands of them to aid in
the many chemical reactions that occur
throughout the body
‘Lock and Key’
pH
• pH is a scale that indicates how acidic or basic a
solution is.
• A pH of 0-6 indicates an acid solution, where 0 is
more acidic than 6.
– Ie: Lemon juice has a pH of 2 and hydrochloric
acid has a pH of 1
• A pH of 7 is neutral
– Ie: Distilled water
• A pH of 8-14 indicates a basic solution where 14 is
the most basic.
– Ie: Sodium Bicarbonate has a pH of 8 and milk of
magnesium has a pH of 10
8Ad
Enzymes are sensitive
The rate at which an enzyme works best is
affected by two things…
Temperature: Higher temperatures result in
greater enzyme activity…however, temperatures
which are too high can cause enzymes to
denature (Recall what this means.)
pH: Some enzymes work best at a high pH
(basic) and some work best at a low pH (acidic)
The Plan….
Tomorrow you will carry out an investigation to
determine the effect of changing temperature or
pH on the effectiveness of an enzyme
(amylase) at breaking down carbohydrates.
• Read through investigation
• Answer pre-lab questions
• Prepare a table to record results
We have limited time tomorrow so you need to be
prepared!
Go over ‘Writing up a Formal Lab Report’
Plenary
1.
2.
3.
4.
5.
Give two functions of vitamins.
Give two functions of minerals.
State two examples of vitamin deficiencies.
Explain what enzymes are and how they work.
State two variables that can affect enzyme
activity.
6. Give an example of an acidic, neutral and
basic solution.
You must answer the ‘Pre Lab’ Questions