Group work to turn in for grading
Group member names Participation score ( 1, 0.75, 0.5, or 0)
1. Mele Morgan 1
2. Cameron Rodabough 1
3. Todd DeFeudis 1
INSTRUCTIONS: Complete this worksheet as a group. Turn in just one copy for the group, including each
member’s name and participation score (ranging from 0, 0.5, 0.75 or 1 for full participation) as
determined by the group. (Groups should have 3-5 people. It is ok to form groups with students from
different sections)
Part I- chemistry of water review
1. a-Draw 3 water molecules indicating both the covalent and hydrogen bonding occurring within
and between them. b- Using a chemical explanation, explain why water forms hydrogen bonds.
H
Covalent bond
O
O
Hydrogen bond
H
H
H
O
H
H
Water forms Hydrogen bonds because they are polar. There is uneven distribution of electrons
throughout each water molecule because Oxygen’s electronegativity is much stronger than
Hydrogen’s, making the electrons want to surround the Oxygen atom. This partial negative
charge attracts the Hydrogen atoms in surrounding water molecules, creating Hydrogen bonds.
2) Explain how water’s polarity accounts for its unique emergent properties. Include at least one
example.
Water is polar because its electrons gather around its Oxygen atom, giving it a partial negative
charge, attracting Hydrogen atoms of surrounding water molecules. These hydrogen bonds allow
for 5 main emergent properties. The Hydrogen bonds formed give water the emergent properties
to be cohesive; this allows water to have surface tension. Hydrogen bonds also allow water to
absorb heat when breaking and releasing heat when they form, minimizing temperature changes,
allowing water to have a high specific heat; which allows animals to have homeostasis.
Hydrogen bonds must be broken for water to evaporate, giving water a high heat of vaporization;
evaporation of water cools body surfaces. Hydrogen bonds make water molecules in ice crystals
space farther apart in ice crystals than in fluid water, giving ice a lower density; this allows the
lakes to melt in spring, allowing fish and other life underwater to survive. Polar water molecules
are attracted to ions and polar compounds, making these compounds soluble, so water has
solubility; any kinds of molecules can move freely in cells, permitting a diverse array of
chemical reactions.
3) Draw a molecule with the chemical formula C3H8. Draw another similar molecule, but with an alcohol
group attached to the second carbon. Will these two molecules behave the same in water? Explain why
or why not.
HHH
H-C-C-C-H
HHH
H OH H
H-C-C-C-H
HHH
No the two molecules will not behave the same in water because C3H8 is non polar, but when
you add the alcohol/hydroxyl group, -OH, it becomes polar.
4) Draw a polar amino acid and a nonpolar amino acid. Indicate how a condensation reaction can form a
peptide bond between them.
H CH3
H OH
H – N – C – C – OH
H – N – C – C – OH
H O
H O
H2 O
H CH3
H OH
H – N – C – C – N – C – C – OH
H O
H O
Part II- Cellular organelles and the endomembrane system review
5) List 2 ways the nucleus is involved in protein synthesis.
1. Transcription of DNA to RNA to facilitate protein construction. DNA in the nucleus
stores the information needed in protein synthesis.
2. DNA encodes the amino acid sequence of each protein in the cell.
6) What do ribosomes do? Are they found freely floating in the cytoplasm OR are they found attached to
another organelle OR both? Explain your answer.
Ribosomes are minute particles of RNA and associated proteins, binding mRNA and tRNA to
synthesize polypeptides and proteins. They are found both on organelles and in cytoplasm
throughout the cell. This is because Ribosomes synthesize proteins throughout the entire cell.
7) You are studying a drug that is known to block vesicle formation in the Golgi. You put some of it on
some cells for a few hours and then determine the localization of all the newly synthesized Na/K ATPase
(a transport protein that is normally present in cell membranes and exchanges sodium and potassium
ions across the plasma membrane). Where would you expect to see this newly synthesized protein
accumulate in the treated cells (would it be in the nucleus, cytoplasm, ER, golgi, or cell membrane)?
Explain why.
Without the vesicles from the Golgi, the Na/K ATPase would be found in the Golgi apparatus.
8) Cell City Analogy
In a far away city called Grant City, the main export and production product is the steel widget.
Everyone in the town has something to do with steel widget making and the entire town is designed to
build and export widgets. The town hall has the instructions for widget making, widgets come in all
shapes and sizes and any citizen of Grant can get the instructions and take them to a shop to begin
making their own widgets. Widgets are generally produced in small shops around the city, these small
shops can be built by the carpenter's union (whose headquarters are in town hall).
As each widget is constructed, they are sometimes placed on special carts which can deliver the widget
anywhere in the city. In order for a widget to be exported from the city the carts take the widget to the
postal office, where the widgets are packaged and labeled for export. Sometimes widgets don't turn out
right, and the "rejects" are sent to the scrap yard where they are broken down for parts or destroyed
altogether. The town powers the widget shops and carts from a hydraulic dam that is in the city. The
entire city is enclosed by a large wooden fence, only the postal trucks are allowed outside the city.
Match the parts of the city (underlined) with the parts of the cell.
a. Mitochondria Hydraulic dam
b. Ribosomes Carpenter’s union
c. Nucleus Headquarters
d. Endoplasmic Reticulum The Shop
e. Golgi Apparatus Postal Office
f. Protein Widget
g. Cell Membrane Wooden Fence
h. Lysosomes Scrap Yard
i. Nucleolus Instructions
j. vesicles Special Carts
Part III- Misconceptions for each question, identify a misconception that your group discovered while
working on this assignment. State the original misconception and include a corrected explanation in
your answer.
1) List a misconception that your group had about the formation of chemical bonds and/or the
chemistry of water.
Misconception: That CH groups were polar, but they are nonpolar ; “although C and H
differ slightly in electronegativity, this small difference is negligible, and C-H bonds are
considered nonpolar.” (p.25)
2) List a misconception that your group had about cellular structure (functions of organelles,
protein synthesis and delivery by cells, extracellular matrix proteins, cell-cell junctions, etc).
Misconception: The process of protein synthesis only happens in the cytoplasm. Proteins
can also be made into the endoplasmic reticulum.
3) List one more misconception on any topic from chapter 1-4.
Misconception: Protein shape only depend on interactions between R groups. Protein
shape depends on order of amino acids, interaction between R groups with other R
groups and backbones.