Shanmugam Saravanakumar » Posts








  • Universe is made of atoms; atoms bonded together is a molecule;
  • Molecules bonded together is a Macromolecule or polymer
  • Macromolecules are found only in living or fossils of living things
  • Macromolecules are organic molecules- molecules with a carbon backbone (three or more carbons covalently bonded together)
  • There are 4 Macromolecules.
  • Each oneis made of monomers are building blocks


1. Polymer: Carbohydrate
Monomer: Glucose or sugar Function: Short term energy / storage
Examples: starch - stored carb found in plants; cellulose-carb in cell wall of plants- structure
Elements found in Carbs/ sugars =

CHO only in a ratio of 1 carbon: 2 hydrogen : 1 oxygen
*** Energy is stored in the C-H bonds
- energy found in C-H bonds in sugar comes from light energy harvested by plants in photosynthesis
- test for sugar/glucose is Benedict's:

If glucose is present, color changes to brick red / orange; if not, stays blue.



Test for starch is Iodine:
If starch present, color changes from light orange red to dark orange/ black

Picture of glucose:


Picture of Carb:







2. Polymer: Lipid = made of three fatty acid acids attached to 1 glycerol

Monomer: Glycerol and fatty acids (3 fatty acids attached to glycerol = lipid)

Function: Long term energy / cell membrane / gives insulation (keeps warm) and buoyancy (makes them float) to animals such as seals/ ducks
Examples: Fats, oils, butter, steroids, wax, phospholipid bilayer (part of the cell membrane)





Elements found in Lipids/fatty acids = CH (CH2 groups) only

*** Energy is stored in the C-H bonds

- test for Lipids/fatty acids = Sudan III
if lipid or fatty acids are present, the solution will have a red ring on the top; if not the solution will stay red/ clear throughout




3. Polymer: Protein

  • Monomer: amino acids- all organisms have the same 20 different amino acids
  • Elements: CHON; some also have S and C
  • Function: tools of the cell; shape determines the function
  • In high pH and Temperature, shape changes, denatures.
  • If mutation in gene, may change of the code for the protein- if shape changes, function changes
  • Examples: enzymes (end in �ase)- speed up the rate of reations; albumin in egg whites, kertain in hair
  • Test for protein = Biuret. If protein is present, will change dark purple; if not, clear or light purple







4. Polymer: Nucleic Acids

Examples: DNA, RNA

Building blocks = nucleotides- made of a sugar, phosphate ·and a base



  • DNA = has 4 bases: ACGT- A bonds with T and C with G
  • sugar in DNA = deoxyribose
  • shape of DNA = double helix
  • function = has our genetic info

Picture of DNA:


RNA: has 4 bases: ACGU- A bonds with U and C with G

  • sugar = ribose; shape = single strand
  • function= carries instructions to make proteins

Organic compounds Lab
Practice quiz for macromolecules:
Macromolecule practice quiz


Scientific Method


Scientific Method

Scientific Analysis of Data

Steps in the Scientific method:  ** given an experiment, be able to identify each step
The steps of the scientific method are to:

Each experiment must have an independent variable, dependent variable and a control.
*** Each experiment can have ONLY ONE INDEPENDENT VARIABLE tested at at time.

Independent variable: what YOU change in an experiment (X-axis).
Dependent variable:  what YOU MEASURE in an experiment (Y-axis).
Control:  a condition where the result stays the same

Example of an experiment: 
A scientist wants to test if a high protein diet will help fish spawn more; he feeds 100 fish with the high protein food and 100 fish with regular fish food with no high protein.  He finds that on average the experimental group lays about 43 eggs/day and fish fed regular food lays about 10 eggs /day.

hypothesis: more fish will spawn if given high protein fish food. 
Control group- no high protein fish food; 
experimental group = a high protein diet;  
result = experimental group lays about 43 eggs/day; fish fed regular food lays about 10 eggs /day.;   
conclusion = fish fed with high protein diet spawn more;  
inference (not actually shown in  the data, but a guess as to the reason for the conclusion) = 
the protein must increase egg production

example questions:
Sponge Bob wants to know if a special cream he has made will help build muscles.  So he asks 10 clams to smear the special cream on their muscles and 10 clams smear on mayonnaise on their muscles.  Each day he measures how many peanuts they can lift.  He finds those with the cream can lift an average of 5 peanuts and those without the cream can lift 4 peanuts.  
1. control?  mayonnaise
2. independent variable? cream or no cream
3. dependent variable? number of peanuts they can lift
4. conclusion?  cream does not give an advantage 

Practice questions for experiments

Equipment used in scientific experiments:

*** given an experiment, be able to identify the equipment that is needed
   1. beaker - a liquid-measuring container
   2. test tube - used as holder of small amount of solution
   3. graduated cylinder - measures approximate volume of liquids
   4. graduated pipette - measures solution volumes
   5. thermometer - measures temperature
   6. balance - measures mass of material
   7. pH meter - measures acidity of solutions
   8. centrifuge - separates materials of varying density
   9. pipette - used to transfer measured substances into another vessel
  10. droppers - for addition of liquids, drop by drop
  11. volumetric flasks - to measure precise volumes of liquid or to make
precise dilutions.
  12. Spring scale – measures the force of weight of an object
  13. Copier – to make large number of  copies for surveys
  14. Ruler – measure distance and length
  15. Science journals and encyclopedias – to do research or to find info on a topic
  16. Fossil records/ historical documents- to do research on genealogy,
pedigrees, paleontology, evolution
  17. Checklists and identification keys- to identify specimens of organisms
  18. Magnifying glass- very low magnification; used to view large objects
more closely; **    ex: leaf vein
  19. Dissecting microscope or stereoscope- gives a 3-D image; low
magnification and resolution
** cannot see individual cells
  20. Compound light microscope- high magnification ; low resolution- can see
cells; also can see larger organelles in the cell such as nucleus.
  21. Electron microscope- high magnification and high resolution; can see
parts inside the cell

cost to effect ratio:  the ratio of how much was spend in making the machine/experiment and how many folks did it benefit.
example: if we spend 20 dollars and it helps 100 people, then what is the C:E ratio?
it is 20:100 =1:5

how to avoid bias in an experiment?
1. must have a control
2. use a large group 
3. have other scientists repeat it.

precision- how close are several measurements taken by the same person.
accuracy- if we compare our measurement what it should be, how close is it?
** given numbers, be able to say how precise / accurate was the experiment

how to design a new machine- 
1. research       2. plan/build a model or prototype      3.  test it     4. publish results

Practice questions:
1. in the late 1800's, C.Eijkman studied a disease called beriberi, which is caused by a vitamin deficiency.  A disease similar to beriberi occurred in chickens that were fed polished rice, which is rice that has had the bran layer removed.  Chickens that ate unpolished rice did not get the disease.  
Eijkman convinced officials of  a prison experiencing an outbreak of the disease to start feeding the prisoners unpolished rice.  The rate of beriberi decreased dramatically.  Which procedure would best convince other scientists who questioned the results?
a. feed prisoners chicken    b. provide the same number of prisoners polished rice as with unpolished rice    c. study other types of animal with beriberi   d. compare chickens that ate polished rice to those who ate unpolished rice

2. to look at the wings of butterflies, the best equipment to use is:
a. triple beam balance and microscope   b. hand lens and triple beam balance
c. catch net and hand lens  d. microscope and graduated cylinder

3. a researcher shows his results for some eyedrops.  He showed over a two year period, that the eyedrops did prevent lens from drying out.  Before publishing his results, to be sure it is free of bias, he should:
a. extend his research for three more years    b. investigate similar products    
c. test a larger population of subjects    d.  have an independent research company perform the same experiment

4. an inventor has an idea for a pest control product for farms.  He proceeds to build and marker the product.  which step has he failed to do?
a. identify the need   b. define the problem    c.  narrow the research  d. test the product

5. The length of a desk is 2 ft.  Susan three measurements of the desk was:  4.6, 4.8, 4.7
Her results are:
a. accurate but not precise   b. not accurate but precise   c. accurate and precise   
d.  not accurate and not precise

answers: b.   c.   d.   d.   b.