Although it was not specified whether or not we should have done question number 1, I still took the initiative to do it (in an attempt to become more acquainted with the world of microbes... who are we kidding, I was scared that there would be a question on it). Chapter Five of Survival of the Sickest is probably one of the best reminders of how compellingly cruel nature can be. "Enslaved spiders and suicidal grasshoppers?" (Moalem 104) yeah that's some pretty hardcore stuff. Then I read about the pin worms that live in humans, and lets be honest, that part made me cringe (I absolutely despise thinking about what other living organisms thrive and survive in my body, eurgh). All in all, chapter 5 was a great read (I couldn't stop thinking about brain hijacking parasites. Like seriously, I think a zombie apocalypse might happen soon).

These brain hijacking parasites totally reminded me about a video on zombie ants:


Below are my answers for the Unit Objectives (Part 1/2)

1. Describe how life is based on survival and reproduction with the use of examples (multiple) from Chap 5 Survival of Sickest.

2. Distinguish between quantitative and qualitative data.
Quantitative data: Deals with numbers and data, which can be measured. Involves quantities.
Qualitative data: Deals with descriptions / data which can be observed but not measured.

3. Describe what is meant by a controlled experiment.
A scientific investigation in which both the control group and experimental group(s) are kept under similar variables apart from the factor under study so that the effect or influence of that factor can be identified or determined. A good example would be the Double Blind experiment.

4. Distinguish between an element and a compound.
An element is a pure chemical substance, which cannot be broken down into simpler substances by chemical reactions. A compound contains atoms of different elements chemically combined together in a fixed ratio and mass of atoms of elements. Compounds consist of different elements in different ratios, are joined by chemical bonds and can be broken down into simpler substances through chemical reactions.
 
5. Explain how the atomic number and mass number of an atom can be used to determine the number of neutrons.
The atomic number of an atom is equivalent to the number of electrons within the atom, which is equivalent to the number of protons in the electron (considering that they are in a neutral state). The atomic mass is the total mass of protons and neutrons within the atom. To find the number of atoms, simply subtract the atomic mass by the atomic number.

6. Describe two biological applications that use radioactive isotopes.
Chemotherapy (treatment for cancer).
Chromium-51 is used in research about red blood cell survival studies.
Cobalt-60 Used to sterilize surgical instruments (and cancer treatment)
Iodine-131 Used to treat thyroid disorders. (Graves’s disease)
Selenium-75 Used in protein studies in life science research

7. Explain why strong covalent bonds and weak bonds are both essential in living organisms.
Strong Covalent bonds link atoms to form a cell's molecules. Weak bonds can be broken down and can be made again easily.
DNA is held together by covalent bonds (phosphodiester bonds) along the backbone and its held to the other strand with hydrogen bonds. The covalent bonds are necessary to support the strand and the hydrogen bonds are strong enough to hold the two strands together(double helix) but weak enough to unzip so the DNA can be duplicated (DNA>RNA>Protein) and passed on to the next generation(cell, organism, etc). Hydrogen bonds are a form of non-covalent bonds or as you called them weak bonds. Protein is also similar with a peptide chain held together with peptide (covalent) bonds and the protein folds and forms different shapes(conformations) through the use of several types of non-covalent (weak) bonds like hydrogen bonds and van der waals interactions. Of course these are large molecules (polymers) and the individual atoms in these molecules are held together with covalent bonds.

8. With the use of a diagram or diagrams, explain why water molecules are:
a. polar
Water is polar because of the difference in electronegativity (unequal sharing) between hydrogen and oxygen. The highly electronegative oxygen atom attracts electrons or negative charge to it, making the region around the oxygen more negative than the areas around the two hydrogen atoms.

b. capable of hydrogen bonding with four neighboring water molecules
Hydrogen bonds can be formed because of waters (polar covalent) ability to take a positive side hydrogen and a negative side oxygen to create a hydrogen bond inbetween.
 
Define cohesion and adhesion. Explain how water’s cohesion and adhesion contribute to the movement of water from the roots to the leaves of a tree.
   Cohesion is the ability of water molecules to be able to bond to each other. Cohesion creates surface tension in water.
   Adhesion refers to the joining of two different substances due to attractive forces that hold them. For instance, cohesion causes water to form drops and adhesion keeps the water drops on the surfaces of leaves and flowers in place.
   Capillary action is the ability of water molecules to do adhesion and build themselves up the straw. This is how plants get water from their roots to leaves and other parts (through the xylum. Food and nutrition through phylum). The water uses adhesion to get up, and cohesion to build up a train to bring up more water to the leaves. Water can consequently escape or evaporate through the pores of the leaves, but this in turn enables more water to go up the tree.

Rachel Putri Utomo
Block F, Honors Biology
Mr. Kevin Quick
Academic Year 2013-2014