Enzyme Action

Objective1.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.

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 as DNA

Vitamins

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 (cont’d)

• 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)

Vitamins as Antioxidants

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+

Minerals (cont’d)

Check Point

1. What are vitamins and what are they used for?

2. What are minerals and what are they used for?

3. What are amino acids?

4. 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 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

• 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

Enzymes are sensitiveThe 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)

8Ad

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 resultsWe have limited time tomorrow so you need to be

prepared!Go over ‘Writing up a Formal Lab

Report’

Plenary

1. Give two functions of vitamins.

2. Give two functions of minerals.

3. State two examples of vitamin deficiencies.

4. Explain what enzymes are and how they work.

5. 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 before you start the investigation tomorrow!