BY 123 (Dr. Cusic) – SI Session 2
Marlee
9/4/2015 1pm
First we will finish the questions from worksheet 1 .
Notes on the blood pH question: As pH gets smaller it means we are increasing the amount of
H+ ions…. This is an acid
As pH gets larger it means that we are increasing the amount of OH- ion concentration. This is
more basic.
The thing about logs is how many more H+ ions does a pH of 2 have than a pH of 4? 1000 times
more H+ ion the 2 than the 4!
pH of blood 7.4 and needs to be stable in order for our bodies so we have the presence of
buffers.. combinations of h ion acceptors and donors, they are actually weak acids and weak
bases..
1. Define
A. Hypothesis - a tentative answer to a well- framed question… am explanation on trial
Narrower in scope than a theory
B. Theory – an explanation that is broad in scope that generates new hypothesis and is
supported by a large body of evidence.
C. Law – Observations are so regular and consistent that you can express them in a
mathematical formula, expresses a fundamental principle of science.
D. Science – a body of information about the material world which has been collected by
rigorous, critical observational methods and has been subjected to continuous testing and
retesting
E. Biology – The study of life
F. Molarity – The number of moles solute per liter of solution. For example, 342 grams of
sucrose added to one liter of water would create a 1 molar solution.
2. Name if the following Domains and Kingdoms contain:
Multicellular, Unicellular, or both 2. Photoautotrophs, Chemoautotrophs, or Heterotrophs
Archea
Bacteria
Protist
Fungi
1. Uni
1. Uni
1. Both
2. all 3
2. All 3
2. H & P
Plants
1. Multi
1. Multi
Animals
1. Multi
2. Hetero 2. Photo
2. Hetero
*There are some exceptions, like yeast which is a fungi but unicellular.
3. Write the chemical (energy) equation for photosynthesis?
What organelle drives this process?
Light + C02 + water  glucose + O2 ,
Chloroplast
4. Write the chemical (energy) equation for cellular respiration?
What organelle drives this process?
O2 + glucose  H20 + ATP + Co2
Mitochondria
5. T or F the role of science is to answer ethical or moral questions? FALSE
6. Name the 2 cells types, then determine which cell type contains membrane bound
organelles?
Eukaryotic and Prokaryotic, Eukaryotic
7. Describe negative and positive feedback systems.
Negative feedback – Series of chemical steps, final product negatively feedsback on an enzyme
further upstream in the chemical cascade of reactions causing the pathway to stop… cells are
like students they don’t do something if they don’t have too…. “I need to make product D,
when I’ve made enough D, D will go back to a specific enzyme and shut off the pathway that
produces D”
Positive feedback – a product stimulates an enzyme in the reaction sequence, in turn increasing
the rate of production of the product…… turns on or speeds up the production of a certain
product
8. What’s the big deal about cilia being found in both the human windpipe and on the surface
of a Paramecium?
Evolution claims that we all came from a common ancestor. Even organisms as different as
paramecium and humans are unified by the presence of cilia. This demonstrates that the
unifying principle of Biology is evolution. Both examples of cilia have the same basic structure
which is remarkable. Form drives Function.
9. What is the chief cause of genetic variation? Genetic Mutation
***Mutation is just change, mutation is not necessarily a bad thing at all
10. Why are noble gases inert or unreactive?
Every atom longs to be happy, the way to make an atom happy is to make sure their outer most
energy level to be full…. First energy level can hold 2 electrons…. The 2nd and 3rd energy levels
can hold 8 electrons… The noble gases naturally have 8 valence electrons (or electrons filling
their outermost shell) therefore they are already happy and do not need to react in order to fill
their outer shell.
11. Describe electronegativity.
Electronegativity is the atoms attraction for an electron. The more electronegative the atom is
the more strongly it pulls shared electrons toward itself. For example, the greater
electronegativity of an oxygen atom in a water molecule pulls electron density from the
hydrogen’s to the oxygen molecule. This causes a polar covalent bond and partial charges on
each of the elements that make up water.
12. Hydrogen bonding involves interactions between partial positives and negatives. T or F
True
Definition – A Hydrogen bond is formed when a hydrogen atom covalently bonded to once
electronegative atom is also attracted to another electronegative atom, usually oxygen or
nitrogen.
13. Name the 8 specific chemical properties that water possesses that help sustain life here on
Earth.
1.Hydrogen bonding – different that convalent bonds found within a water molecules
2. Cohesion- the ability of water to stick to itself (water dripping out of a faucet.)
3. Adhesion- the ability of water to cling to hydrophilic objects (Xylem in a plant and water
clinging to it)
4. Surface tension – measure of how difficult it is to stretch or break the surface of a liquid…
result of waters ability to do cohesion…
5. High Specific Heat – Water stabilizes air temperature … The amount of heat that must be
absorbed or lost in order for one gram of water to change temp by one degree Celsius… waters
ability to absorb and relase heat.. measured in calories… If you live near water you have more
moderate temperatures because water absorbs energy, which stabilizes the temperature
6. High Heat of vaporization – gotta break bonds in order to change water from a liquid to a gas
state, water requires a lot of heat in order to break these bonds… evaporative cooling – when
molecules evaporate they take heat with them.. means we have a lot of liquid water here on
the earth.. not many places on earth where it gets hot enough to evaporate water..
7. Water is unusual when it freezes
- Less dense than liquid, serves an an insulator so the oceans and lakes wont freeze all the way
down to the bottom
8.Water is a great solvent- we know that like dissolves like… therefore polar substances will
dissolve in water which is also polar…. Helps us separate sodium chloride into separate ions.
14. What is a hydrocarbon? Name the 4 characteristics of Hydrocarbons?
A compound where carbons and hydrogens are attached to each other.
Length
Branching
Double Bong Location
Presence of a Ring
15. What is the ratio of Hydronium ions to Hydroxide ions in pure water? What is the pH of
pure water?
1 :1
or
H30+ = OH- , therefore the pH is 7 or neutral.
16. If NaOH is added to pure water what will happen to the pH of the water?
Na+ and OH- will ionize… an increase in hydroxide (OH-) concentration will cause the solutions
pH to rise (more basic).
17. What will happen if HCl is added to pure water? How will this affect the pH of the pure
water?
H+ and Cl- will ionize… this will lead to a decrease in pH (more acidic) of the solution caused by
the increase in Hydronium ions (H30+).
18. How many more (H+) ions are present in a solution with a pH of 2 when compared to a
solution with a pH of 4? Each pH level (1-14) is multiplied by a factor of 10, therefore, a
solution with a pH of 2 would have 10^2 (100) times more H+ than a solution with a pH of 4.
19. How many less (OH-) ions are present in a solution with a pH of 7 when compared to a
solution with a pH of 10? 1000 times less (OH-) would be present …… 10^3 = 1000.
20. An Acid donates an H+ and makes a solution more acidic. T or F
True
21. A base donates an OH- or accepts an H+, which in turn makes a solution more basic. T or F
22. What is a functional group? What are some common functional groups? Can you draw the
chemical composition of each? Can you identify them if attached to a molecule?
DON’T GET CAUGHT UP IN THE DETAILS… JUST BE ABLE TO IDENTIFY THE GROUPS ON
STRUCTURES
Hydroxyl- AKA alcohols have an Oxygen which causes the molecule it is attached too to be
polar.. this means since like dissolves like that molecules with hydroxyl groups play well with
water (is polar). -OH
Carbonyl - know the difference between a key tone and an aldehyde. Aldehyde is on the
“outside”.. see that rhymes!! Carbon double bonded to an Oxygen.
Carboxyl - contains 2 O’s so it is highly polar! has 2 ionized forms because it acts as an ACID!
Found on amino acids.
Amino - Also found on amino acids, acts as a BASE. Know its 2 ionized forms - NH2 ——> NH3+
Sufhydryl - AKA Thiol… used to stabilize protein structure.. Can covalently bond with another
thiol group… when this occurs this is called a cross link- R-SH
Methyl- CH3… recently methylation has been discovered to silence genes and has developed a
new field called epigenetics.
Phosphate - important in energy and found in nucleic acids… contributes a negative charge to
molecules… When water cleaves off a phosphate group from an ATP lots of energy is released.
Functional units are important because even a single change in functional group can change a
molecule as drastically from estradiol to testosterone
Ether= Oxygen bonded to two R groups and is not terminal as in a carbonyl.
Ester= Carboxyl except the Oxygen single bonded to the Carbon is attached to some R group
rather than a Hydrogen