RP1 BIO- common questions

How to measure the quantity of reducing sugar in a solution?

Filter the precipitate in the solution and dry

Weigh the dry mass

Why using a colourimeter would improve the repeatability of this investigation?

Quantitative results

How the active site of an enzyme causes a high rate of reaction?

Lowers activation energy

Active site of enzyme changes shape

ES complex distorts certain bonds e.g hydrogen, ionic

How raising temperature to 35C affects carbohydrase activity?

Increase to kinetic energy

Increase in frequency of collisions

Increase rate of breakdown of starch/carbohydrase activity

How decreasing pH affects carbohydrase activity?

Increase H+ ions

Distorts bonds e.g hydrogen,ionic

Changes shape of tertiary structure

Decrease carbohydrase activity

Cells lining the ileum of mammals absorb the monosaccharide glucose by co-transport with sodium ions. Explain how

Na+ actively pumped out of ileum into blood

Creates concentration gradient

Monosccharide moves into cell by faciliated diffusion

Describe how you would test a lipid sample for the presence of lipid and how you would recognise a positive result

Add ethanol, then shake then add water

If lipid present, then milky emulsion occurs

Describe how the student would show that reducing sugars were present in a solution

Heat the sample

Add Benedict’s solution

Turns from blue to red solution- reducing sugar present

Suggest two variables the biochemist controlled when investigating the effect of temperature on the rate of breakdown of a protein by the protease

Source of protein

Enzyme concentration

pH

Describe the induced fit model of enzyme action

Substrate binds to enzyme, induces shape in active site

Distorts bonds

Describe how the scientist would have produced the calibration curve and used it to obtain the results in the graph

Make maltose solutions of different concentrations

Use calorimeter to calculate light transmittance + plot on graph

Find concentration of sample from calibration curve