Biology Extended Essay Enzymes Are Proteins


Some of you have asked about EE in Biology.  Biology is challenging, and statistically, grades are lower on EEs in biology than Literature, History or Korean.  having said that, it can be VERY interesting! and FUN!!  If you are considering EE in biology, here are some things students are doing now and a list of brainstorm topics they have though of below. 


2011 DP biology graduates' EE topics:

Keun Ho Choi - "Does the UV light (in a cup keeper in restaurants in Korea) really make a differnece to growth of bacteria on cups?"

Yeana Jang - "How well does benedict's reagent quantitatively measure gluose concentration in solution?"

Louis Kim - "To what degree does coriander (cilantro) oil have antibiotic action against E. coli?"

Several other projects we started but did not do:

    • When you put a plasmid into a bacteria, can you retrieve the plasmid again?
    • Does caffeine afect the metabolic rate of mice?
    • Does garlic act against stimulating affect of caffeine in mice?
    • Does eating garlic cause mice to lose weight?
    • Does amylase (enzyme) digest different starches (like potato or corn or rice of wheat) to different degrees?


Here are some other ideas for possible extended essay topics (in rough form):



    • Play rhythm then stop and have subject try to maintain rhythm.  Record their rhytm 60 s later.  Do musicians have a better internal metronome tham non-musicians (or age, or gender)?
    • Is there a relationship between eardrum tension and sensitivity to sound (hearing threshold?)
    • Does the protein content of varnish affect the tone of wood (like a cello?)
    • Does resonance of pitch of wood affected by mositrue content?  In other words, could resonance (or change in resonance) be an indicator of wood mositure (ie. related to making instruments)



  • Compare absorbance of tropical vs temperate plants to see if they have different absorbances in cholorophyll (based on receiving light of differnt wavelengths over the course of a year)
  • in Spring, leaves on end of branhces are reddish and light green while older leaves are "greener."  What are the pigment differences taht make leaves different colors with respect to leaf ages?
  • Seaweed grows under water but plants grow on land. 
    • Does seaweed have different pigments for photosynthesis? 
    • Maybe red seaweed and green seaweed have differnt pigments from each other?



  • Do different tissue have different amounts of catalase?
  • Use x-ray or UV to cause mutation in E. Coli and measure mutation rate
  • cat wrapped in foil cannot balance (does foil interefere with magnetism from earth? do cat's balance with magnetism?
  • sea urchin development
  • enzymes denature at high temperature; are all low temperature treatment reversible?


BEHAVIOR (this has to have biological basis)

  • why does one person yawning cause others to yawn?
  • when you laugh, what causes you to "lose" strength?



  • Are there factors in soap that make a bigger difference than alcohol to remove bactiera?  Surfactant? Detergents? to make water "wetter?"  What affect bacteria the most
  • Does toilet really have more gersm than desks ... since urine is sterile and poop goes into bowl ... (or does bidet have less germs since users do not touch their bottom? etc
  • Hydrogen peroxide is commonly prescribed as a topical antibiotic and applying it to an open cut produces foaming action.
    •  H2O2 foaming is result of catalase, not bacteriacidal action; how do you know it is killing bacteria?
    • Measure the effectiveness of hydrogen peroxide as bacterialicide
    • How effective does iodine kill bacteria (bacteriacide predating hydrogen peroxide)
  • Can we replicate the antibiotic affect of Fleming's famous experiment using bread mold to kill bacteria?



  • Develop a protocol for enzyme extraction from potatoes. 
  • How can you isolate catalase from potato to make a "pure" enzyme?  (ie. centrifuge, buffer, solvent separation, etc.) This is similar design to DNA isolation method.
  • Modify protocol to maximize production of DNA from published extraction method?



  • Compare commercial yeast sold for bread making with "natural" yeast in the air. 
    • Is natural yeast better for raising bread? 
    • Is your natural yeast one species or more than one species?
    • How can you tell the yeasts are different species? 
    • What conditions produce maximum respiration rate in yeast?
    • Look at process of respiration: how are yeast different? What can we experiment on with regard to yeast unique respiration method?



  • how does lack of sleep affect student performance?
  • What specific skills, if any, are affected by sleep shrotage (ie. less than 8 hours per night)
  • Is little sleep a help to students or a hindrance?


...and MORE

  • do plants growing in shade have greater varety of pigments to permit use of wider range of colors of light than plants that grow in full sun?
  • Compare pigment in red cells on bottom of leaf with pigments in green cells on top of leaf; is there a difference in absorption spectrum?
  • What temperature can proteins handle before functional denaturation?  or How cold can proteins go and still be functional?  or Does size of protein make larger proteins more succeptible to temperature dufferences than small proteins when frozen?
  • does antibiotic action of honey depend on sugar concentration or enzymes? (use heat test to see!)
  • does glucose or another carbohydrate attract ants/bees?
  • How does meat attract bees?
  • Does water stress determine the number of stomata on a leaf?
  • Does water stress determine action of mimosa plant?
  • when - if at all - should roasted meat b salted in the roasting process to prevent toughness (dehydration/denaturation)?
  • Since conifers have needles all year, do they have pigments for absorbing more low energy radiation than deciduous trees?
  • What glucose concentration produces maximum pollen tube growth rate in lillies?
  • Investigate the relationship between plant density and plant productivity (based on noticing that rice planted in May in Korea is spaced apparently widely apart; why do farmers not plant rice more densely to get more rice production?)
  • Does transpiration rate affect "leaf lifting" in bean plants (re: circadian rhythms of plants)
  • Does N or P more strongy affect plant productivity?
  • What are the limiting issues for plants growing in Korea's in-organic soil (the sandy soil that so many gardens are planted in.)
  • What nutrients, if any, are in Korea's soil (re; personal gardening)




What is the Extended Essay?

"..... the extended essay, a substantial piece of writing of up to 4,000 words, enables students to investigate a topic of special interest that they have chosen themselves.
It also encourages them to develop the skills of independent research that will be expected at university."

(The IB Extended Essay Guide 2013 p.2)

Self-directed Learning

One important aspect of the Extended essay is the possibility for self-directed learning.

Resources for students writing their Extended Essay

The IB Extended Essay Guide for 2013 - is a must for students and supervisors. Biology pages begin here

Ethical guidelines are also provided by the IB and should be shown to students.

The IB Animal Experimentation Policy should be given to all students who express an interest in an essay in Biology. There has been some new guidance from the IB during spring 2014 about the use of animals in experiments. The guidance says that in all IB work we should consider, replacing the animal with a simulation, refine the experiment to alleviate any stress on the animal or reduce the number of animals involved.

"Any investigation involving animals should initially consider the replacement of animals with cells or tissues, plants or computer simulations. If the animal is essential to the investigation, refinements to the investigation to alleviate any distress to the animal, and to reduce the numbers of animals involved, should be made.

Experiments involving animals must be based on observing and measuring aspects of natural animal behaviour. No experimentation should result in any cruelty to any animal—vertebrate or invertebrate. Therefore, experiments that administer drugs or medicines, or those that manipulate the environment or diet beyond that which can be regarded as humane, are unacceptable in IB schools."

IB teacher support material, august 2014

Ethical guidelines are also provided by the IB and should be shown to students.

Many schools have produced their own support documents for the students- here is a booklet designed for students at Munich International School.


Schools are required by the IB to provide an Extended Essay Supervisor to each student, who is responsible to guide the student through the criteria, the research process and finally the writing process. As this is most likely the first piece of research that a high school student will undertake, I feel it is important that the supervisor consider the whole learning process.

Essays in Biology

An essay in Biology needs to be based on some experimental data, either collected through a student designed investigation or primary data provided from another source. Students should avoid super-sophisticated university laboratory-based experiments as the examiner is likely to suspect that the design of the investigation, the process of data collection and interpretation of the data is not that of the student. Actually, simple investigations that students can do at home can be very successful. Descriptive essays will not be appropriate for earning higher marks.

The topic of the essay must lie clearly within Biology and not lean into other subjects. So what does this mean? Biology is the study of life,so the essay must deal with living organisms. Biochemical topics can be pursued but must be focussed on the effects on the living thing not the chemical aspects. For example, a study of enzymatic kinematics falls under chemistry but the factors that affect enzymes and how this impacts on the ecological niche of an organism becomes a Biology topic. An Essay which deals with how organisms learn to negotiate a maze is more likely to be considered as Psychology but if the behaviours are related to the survival of the organism then this falls towards Biology.

To read more about helping students choose a topic for their extended essay in Biology read  Extended Essay titles.

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