enzymes (topic 2). Flashcards
explain why biological washing powders, containing enzymes, do not work well if you wash your clothes with very hot water (2)
- active site no longer complimentary shape to substrate
- breakdown of the substrate will not take place
which enzyme digest starch into smaller molecules
amylase
suggest why some parents might prefer to use non-biological detergents to wash their babies’ clothes (1)
- (non-bio detergents) are more gentle on skin
- (bio detergents) can cause irritation/allergies
describe how you would plan an experiment to find the best temperature for removing stains from clothing, include the laboratory equipment you would use and how you would make the investigation a fair test (4)
- (use of measuring cylinder to) measure equal volumes of detergent solution
- include unstained cloth as a control
- (use of test tubes as) containers for detergent solution + stained cloth
- use water bath to provide a range of temperatures
- cloths left in a detergent solution at each temperature
- measure time taken to remove stain
- repeat the experiment (at least 3 times)
- assess the stain removal
suggest a reason why some people think that biological washing powders are better for the environment than non-biological ones (2)
- enzymes work best at around 40°C (bio detergants most effective in a cooler wash cycle)
- fewer washes needed to remove stains
- bio detergents use less electricity
some baby foods are treated with the enzyme trypsin which pre-digests the baby food, helping the babies digest the food, suggest the effect trypsin has on the baby food (2)
- breaks down protein
- into amino acids (peptides)
name two other types of enzyme (other than protease) that break down food, along with their respective substrates (2)
- amylase: starch
- lipase: fats
list and describe two other uses of enzymes in different industries (other than protease, amylase, and lipase) (2)
- carbohydrases convert starch to glucose syrup
- isomerase converts glucose syrup to fructose syrup
- biological washing powders use enzymes to break down stains
an enzymes active site and its substrate are
complimentary
enzymes are made of
protein
suggest the optimum temperature for human enzymes
37 degrees
explain the effect of temperature on enzyme activity (6)
information relating to structure and function of enzymes (3 marks max):
- enzymes are proteins
- enzymes have a specific shape
- the substrate fits into the active site of the enzyme
- (the shape of the) active site is specific to the substrate
information relating to effect of temperature (3 marks max):
- as the temperature increases, the number of (successful) collisions between the substrate and the enzyme increases
- as the temperature increases, the rate of reaction increases
- above a certain temperature, the shape of the enzyme is changed / the enzyme is denatured
- the substrate no longer fits into the active site, so the reaction slows/stops
amylase is an enzyme that catalyses the breakdown of starch into sugars, explain how amylase breaks down starch, answer in terms of the lock and key model of enzyme activity (3)
- starch/substrate binds to active site of enzyme
- because shape of active site and substrate are complementary
- a chemical reaction occurs to produce smaller molecules (or bonds between the starch molecules are broken to produce smaller molecules)
describe how a student could investigate the effect of pH on the activity of amylase, state the variables that the student would have to control during the investigation (4)
control variables (max 2 marks):
- keep amount or concentration of starch and amylase the same
- keep temperature the same using water bath (or electric heater)
_
method (max 2 marks):
- range of at least 3 pH values
- use iodine test to make qualitative observations
- observe colour changes at different pH
- do repeats at each pH
describe how the student could extend the investigation (the effect of pH on the activity of amylase) to determine the effect of a different factor on amylase activity (2)
- keep temperature constant
- (but) change named factor
- test a range of values of named factor
