Part 1: Gym partners
Ciara and Lucia were exercise buddies and had been since college. The women both got
up at 5 am every day and went to the gym together. Ciara preferred cardio while Lucia was a
strength-training specialist. Lucia had always been very careful about what she ate, while Celia
took a more relaxed attitude to her diet.
One day while Ciara watch Lucia make her “balanced breakfast” yet again before they
left for the gym, Ciara couldn’t help herself from asking, “Why are you so concerned about
food? You exercise almost every day!”
“You do realize that our bodies need all kinds of building blocks to stay healthy, right?”,
responded Lucia.
“You mean carbs and protein, right?”
“Not just carbohydrates and protein, but also lipids, vitamins and minerals.”
“But wait, lipids are fats. I thought those are bad for us!”
“Well, too much of anything is bad for you, but you actually need all of these things to
help build components of your cells. Your cells are made of four types of molecules; protein,
lipids, nucleic acids like DNA and RNA, and carbohydrates.”
Answer the following questions using the background resources provided on the course Latte
page.
1. Fill in the chart defining the biomolecules of the cell, their building blocks, at least two
possible functions for each, and the atoms commonly found in the molecule.
Macromolecule Building Block Function Atoms
2. How are these molecules interconnected in the cell?
3. Find or draw a simple chemical structure as an example of each of these biomolecules.
Part II: Where can I find that?
Ciara snatched Lucia’s health bar out of her hand
flipping it over to look at the label. (The label is shown
to the left.)
“I see carbs, fat and proteins. Wait a minute!
This thing doesn’t have any nucleic acids in it according
to the label.”
Patiently, Lucia took the wrapper from Ciara’s
hand and said, “That’s the cool part of your cells. They
can take all these building blocks and metabolize them.
In the process of catabolism, your body breaks down
biomolecules into smaller structures and in the process
of anabolism you make new biomolecules from these
building blocks. Nucleic acids are synthesized by
breaking down other molecules you eat and
reassembling the parts. Nucleic acids are especially
cool because DNA encodes the sequence that directs
what kind of protein will be made through an mRNA
intermediate. Proteins then do most of the “work” of
the cell performing reactions, helping with structure,
transporting molecules and even directing
communication between cells. Scientists call this the
central dogma of Biology.”
Answer the following questions using the background
resources provided on the course Latte page and/or
other web resources. Be sure to cite your sources.
1. What is the difference between dietary fiber
and sugar on this label? Why would your body
need both?
2. Specifically, what components on this label are
considered lipids?
3. Draw out the Central Dogma of Biology. Be sure to include the names of the molecules
involved, the names of the processes and explain what happens at each step below the
diagram.
Part III: How is the cell involved again?
Ciara thought back on their original conversation and was still a little confused.
“I have heard about organelles and structures of the cell, but I don’t really understand how
biomolecules are involved.”
“Well, it turns out most structures in the cell are made up of these biomolecules and/or use
these molecules in some way. The organelles in the cell wouldn’t exist if the four types of
biomolecules weren’t present! I eat a balanced diet so my cells have the biomolecules they
need to thrive.”
Answer the following questions using the background resources provided on the course Latte
page and/or other web resources. Be sure to cite your sources.
1. For each organelle or cell structure indicate why the structure would not function if the
listed biomolecule was missing.
a. Mitochondria missing carbohydrates
b. Cell membrane missing lipids
c. Cell membrane missing protein
d. Nucleus missing DNA
e. Ribosome missing mRNA
f. Rough ER missing lipids
g. Golgi missing proteins
h. Cytoskeleton missing proteins
i. Cell membrane missing carbohydrates
j. Nucleolus missing RNA
k. Lysosome without protein
l. Smooth ER without lipids
2. Redraw your diagram of the central dogma. Below the diagram, indicate where in the
cell each step occurs, and which biomolecules are involved in each process.