Higher Assignment

Question 1

What is your assignment’s title?

Answer 1

The effect of inhibition on enzyme activity

Question 2

What is the aim of your assignment?

Answer 2

To investigate the effect of sodium chloride concentration on enzyme activity

Question 3

Point to mention in paragraph 1 of underlying Biology (enzyme action)

Answer 3

1: brief summary of enzyme action and specificity
2: describe substrate affinity
3: describe induced fit and resultant orientation
4: results of induced fit, such as deceased activation energy

Question 4

Points to mention in paragraph 2 of underlying biology (inhibition)

Answer 4

1: description of general inhibition
2: name two main types of inhibition
3: describe competitive inhibition
4: describe non-competitive inhibition
5: explain why competitive is reversible (and how), whilst non-competitive isn’t.

Question 5

Name all required details in your method:

a) chemicals
b) apparatus
c) measurements

Answer 5

a) varying concentration of sodium chloride solution, catalase solution and hydrogen peroxide solution
b) Eppendorf tubes, beaker, water bath, syringe, paper disc and stopwatch
c) time taken for disc to rise, volumes of each chemical

Question 6

What must you do with your internet source?

Answer 6

Number it with a figure and then reference this figure at the end, with the source’s URL. DO NOT WRITE THE URL UNDERNEATH THE SOURCE

Question 7

What type of graph will you use?

Answer 7

A line graph

Question 8

What will your… be:

a) x-axis scale and label
b) y-axis scale and label

Answer 8

a) sodium chloride concentration; 0, 0.1, 0.2, 0.3, 0.4

b) time taken for disc to rise to surface; 15 to 30 in increments of 1

Question 9

What will you include in your analysis?

Answer 9

Percentage increase of time taken, between concentrations of 0 and 0.4

Question 10

What is your percentage increase?

Answer 10

87%

Question 11

What will you then state after calculating percentage increase, in your analysis?

Answer 11

This demonstrates the increased time taken for the disc to rise, as the sodium chloride concentration increased within each Eppendorf tube - equating to a progressively decreased enzyme activity. This decrease in activity is similarly shown in figure 1.

Question 12

What is your assignment’s conclusion?

Answer 12

Overall, as the concentration of sodium chloride increases, enzyme activity decreases. This can be seen through the trend of the operational dependant variable, as the time taken for each disc to rise increased significantly as the sodium chloride concentration increased - equating to a decreased activity. This is shown in figure 1, as the graph’s downward trend indicates the steady decrease in enzyme activity as the sodium chloride (NaCl) concentration decreased

Question 13

What are your points of evaluation?

Answer 13

1) increased validity, due to the use of a control water group.
2) reliability was increased through the process of repeated measurements, before gaining an average.
3) validity was improved to a further extent through the use of water baths. However, validity was decreased by the absence of a pH buffer.

Question 14

What is the significance of a control group?

Answer 14

Allows comparison with other groups, during the experiment, as this group produces abnormal results compared to others. For example, the use of a control group of water allowed the conclusion that sodium chloride concentration was the driving factor behind this variation in time taken for discs to rise, as the control group’s disc was the quickest to do so - equating to the greatest enzyme activity.

Question 15

What is the significance of repeating measurements to gain an average?

Answer 15

This repetition and mean calculation allowed the effect of certain anomalies to be reduced, within individuals results, preventing the overall trend and relationship of the experiment from being affected.

Question 16

What is the significance of using water baths?

Answer 16

This allows the temperature of all 5 Eppendorf tubes to stay at a constant level, throughout the experiment. This prevented the variable of temperature from affecting the results, and therefore deeming them invalid, as varying temperatures often change enzyme activity or denature the molecule altogether.

Question 18

What is the significance of not using a pH buffer?

Answer 18

This reduced the validity of the experimental results, as it did not ensure a constant pH value across all Eppendorf tubes. This means that the enzyme activity of certain groups may have been altered or increased, deeming the results invalid

Question 19

What are the 4 phases of micro-organism growth

Answer 19

+ lag
+ log
+ stationary
+ death

Question 20

What is the lag phase

Answer 20

As the micro-organism adjusts to the conditions of the growth medium - it does not divide. Biosynthesis occurs as cells combine nucleus acids and enzymes.

Question 21

What is the log phase

Answer 21

When the micro-organism divides at its maximum rate, meaning the culture size doubles at regular intervals

Question 22

What is the stationary phase

Answer 22

As the micro-organisms begins to exhaust its substrate wealth and a toxic build-up of secondary metabolites forms, the death rate equals the culture growth rate.

Question 23

What is the death phase

Answer 23

When the culture fully exhausts its substrate concentration and the toxic secondary metabolites kill the cells, the death rate finally exceeds the growth rate.

Question 24

What is a primary metabolite

Answer 24

A metabolite that is produced during periods of active microorganism growth (lag or log) and concern the biosynthesis of microbes.

Question 25

What is a secondary metabolite

Answer 25

A metabolite that is not produced until cells have established themselves in the medium (log, stationary, death). They confer an ecological advantage and are often highly useful to humans. Regularly, they are similarly toxic and dangerous to cells.

Question 26

How can metabolite production be increased, at a controlled rate

Answer 26

+ introduction of precursors (increased primary metabolite conc.)
+ enzyme inducers
+ enzyme inhibitors

Question 27

What are the two methods by which wild micro-organisms are altered, for human benefit

Answer 27

+ mutagenesis

+ recombinant DNA

Question 28

What is mutagenesis

Answer 28

When micro-organism’s are exposed to mutagens (agents that increase the rate of mutation) in an attempt to alter their genome, beneficially.

Question 29

Give an example of a mutagen

Answer 29

Ultraviolet light

Question 30

What is a disadvantage of mutagenesis

Answer 30

Once mutated, the wild micro-organisms often revert to their previous state, and become dangerously harmful in the civilised environment

Question 31

What is recombinant DNA technology

Answer 31

When the DNA of a plant or animal is placed inside the plasmid of a bacterial cell, in an attempt to increase the rate of production often desired animal or plant protein - as such bacteria reproduce rapidly.