Download Investigating starch and amylase • Starch is broken down into

Measuring the rate of enzyme reactions
Enzymes are protein molecules which catalyse specific
reactions in living organisms due to the shape of their
active site.
Hydrogen peroxide → water + oxygen
• This reaction is catalysed by the enzyme
catalase.
• We can find the rate of reaction by
measuring the foam caused by bubbles of
oxygen.
Keyword
Give the definition here.......
Enzyme
Optimum
Denature
Anomaly
Enzymes are affected by temperature & pH.
1. Every enzyme has an optimum temperature & an
optimum pH.
2. In humans the optimum temperature is body
temperature (around 40°C).
3. Optimum pH will vary dependent on where the
enzyme needs to work.
4. Above the optimum temperature or pH the
enzyme denatures and the rate of reaction falls.
Good experimental techniques (part 1)
• Change one variable – the independent variable
• Measure one variable – the dependent variable
• Keep all other variables the same – the control
variables.
Investigating starch and amylase
• Starch is broken down into simpler
sugars by the enzyme amylase.
• We can investigate this by testing how
long it takes for the amylase to
breakdown starch at different
temperatures or different pHs.
• When starch is present iodine turns
blue/black in colour.
• When all the starch has been broken
down iodine remains an
orange/brown colour.
Good experimental techniques (part 2)
• Experiments that are repeated are more reliable.
• This allows us to spot anomalies.
• An anomaly is a measurement that doesn’t fit the
pattern of the other data.
• If we get an anomaly we would ignore that reading
and not include it when we analyse our data.
• If we want more precise data we could you a
greater range of values with a smaller interval in
between.
Part of tissue
Plasma
White blood
cells
Red blood
cells
Platelets
Coronary heart
disease is when
the arteries that
supply blood to
the muscle of the
heart get blocked
with fatty
deposits. This
causes the
arteries to
become narrow
and blood flow is
restricted. This
decreases oxygen
supply to the
heart muscle
which can result in
a heart attack.
Function
Carries everything except
oxygen in the blood. E.g.
Carbon dioxide, glucose,
amino acids, urea,
hormones, antibodies,
antitoxins.
Defend against disease.
Blood
Structure & Adaptations
•Pale straw coloured liquid.
•Red and white blood cells and platelets travel within this liquid.
•Large blood cells with a nucleus.
•Can change shape to engulf microorganisms.
•Produce antibodies to fight microorganisms.
•Produce antitoxins to neutralise toxins produced by microorganisms.
Carry oxygen from the
•Biconcave shape to provide large surface area to absorb oxygen.
lungs to all the cells in the •No nucleus so they have more space to carry oxygen.
body.
•Contain a red pigment called haemoglobin.
•Haemoglobin + oxygen  oxyhaemoglobin
Help blood clot..
•Small fragments of cells.
•No nucleus.
•Help blood to clot at a wound site.
Quick check...
1. Why do we carry out experiments three times?
2. What should we do with an anomalous result in
our data in an investigation?
3. How could we investigate the effect of pH on
an enzyme?
4. What is blood made up of?
5. Name four substances that are transported in
the blood.
6. What type of tissue makes up the walls of the
heart?
7. Describe the route of blood around the body
starting at the vena cava.
8. What does coronary heart disease do to the
heart?
9. If the heart beats faster & more strongly how
can this help an athlete during exercise?
THE HEART is made of muscle which contracts to pump blood
around the body.