Worksheet 1
BY330 Summer 2014
1. List the three major components of cell theory.
All organisms consist of one or more cells.
The cell is the basic unit of structure for all organisms.
All cells arise from preexisting cells.
2. A cell is 67 micrometers in diameter. Express this value in millimeters and
nanometers.
1 millimeter = 1000 micrometers  67 micrometers = 0.067
millimeters
1 micrometer = 1000 nanometers  67 micrometers = 67,000
nanometers
3. Why do cells need to be so small? Explain using the surface area and volume
relationship.
The smaller the cell, the higher the surface area to volume ratio. This
makes it easier to diffuse essential gases across the cell membrane, as
they will have a smaller distance to travel. Cells need to be small to
enhance the ability to get materials into and out of the cell.
4. Ninety-nine percent of the cell is made up of which six chemical elements?
Oxygen, carbon, hydrogen, nitrogen, phosphorus, sulfur (CHNOPS)
5. Water is required for many chemical reactions in a cell and is perfect to serve
as a solvent for other molecules in the cell. List at least three reasons why
this is a true statement. (Drawings may be helpful!)
Water is very polar, allowing it to interact well with other molecules,
like more water. It forms a weak hydrogen bond (drawing of a
hydrogen bond interaction between two water molecules may help
here).
Has very high melting and boiling points
Has a high surface tension
6. List the four categories of small organic molecules.
Simple sugars, fatty acids, amino acids, nucleotides
7. What are the two components of a simple sugar? What is the typical formula
for a simple sugar? Name the most abundant simple sugar. List three
functions and examples of the simple sugar.
Components – at least one keto or aldehyde group and one hydroxyl
group
Formula – (CH2O)n where n = 3-8
Worksheet 1
BY330 Summer 2014
N-acetylglucosamine is the most abundant simple sugar.
Functions – Provide energy, storage (glycogen, starch), structural
support (cellulose)
10. List three functions of a nucleotide.
Provide energy (ATP)
Use as signaling molecules (cAMP)
Make nucleic acids (DNA, RNA)
Worksheet 1
BY330 Summer 2014
12. Why do macromolecules contain both covalent bonds and weak bond
interactions?
Covalent bond keep macromolecules together and provide
stability. Weak bond interactions allow macromolecules to
wiggle and move. A combination of the two provides both
stability and flexibility.
13. List and describe the four types of weak bond interactions.
Ionic – occurs between fully and partially charged groups, like
sodium chloride
Hydrogen bonds – a hydrogen atom shared between 2
electronegative atoms
Van der waals – electrons of adjacent atom shells line up and are
attracted to positively charged nuclei; fleeting and weakest
(drawing may help here)
Hydrophobic interactions – two molecules are attracted to each
other because they mutually exclude water, like two methyl
groups
14. Draw a double-stranded piece of RNA using two base-pairs. Label the
5’ and 3’ end of the molecule and the phosphodiester bonds.
Worksheet 1
BY330 Summer 2014
15. Is there more deoxyribose or ribose sugar in the cell? Why?
There is more ribose sugar in the cell because the cell has more RNA
(3-5%) than DNA (less than 1%).
16. DNA exists in the cell in the form of chromatin. Why? Describe the process of
chromatin formation. (Be specific and include ALL relevant information, i.e.
types of proteins involved, types of chromatin, etc.)
DNA needs to be organized and protected by chromatin in order to
prevent naked DNA from being eaten up by nucleases. So, DNA is
surrounded by proteins to form chromatin. The proteins used are
histones – specifically H2A, H2B, H3, and H4. Pairs of these four
proteins are bound with DNA to form a nucleosome. The DNA double
helix winds around each nucleosome 1.7 times. The exposed DNA
leftover, linker DNA, is surrounded by a non-nucelosomer H1 protein
that protects it. This wrapped DNA coils around itself to form tightly
wound chromosomes – the most condensed form of chromatin. When
chromatin is unwound a little, it becomes heterochromatin. Decondensed even further, this becomes euchromatin.