Biology 12
Assignment #1: Biological Molecules & the Chemistry of Life
A. Important Inorganic Molecules
Water
1.
Explain why water is considered a polar molecule.
2.
What holds a water molecule together? What type of bond holds
several water molecules together? Where will this bond form? How
would you describe this type of bond?
3.
List 4 functions of water in the body. Give an example of each
function.
Acids and Bases
4.
Give the major characteristics of an acid and relate acids to the pH
scale.
5.
Give the major characteristic of a base and relate bases to the pH scale.
6.
How many more H+ (in terms of concentration) would there be in a
solution of pH3 than in a solution of pH8?
Buffers
Hemoglobin in red blood cells acts as a buffer by preventing a drop in
pH of the blood. It is a tertiary protein that bonds to iron, which gives it
its red hue when carrying oxygen.
7.
a. Give another example of a buffer
b. What makes this buffer effective?
B. Some Important Organic Molecules
Look at the dehydration and hydrolysis reactions in order to answer the following
questions
8. Look carefully at the bonds formed during synthesis of a large molecule. Water is
produced, where does it come from (be specific)?
9.
When the reaction is reversed (hydrolysis) water is needed. What are the 2 roles
water molecules play in this reaction?
Biology 12
Proteins
10. Although many proteins are enzymes, there are many other types of proteins in
our bodies. Give 4 other types of proteins (HEATS: acronym to remember types)
and their role in living things.
11. Draw the structural formula of a typical amino acid. Circle the amino group,
acid group and remainder. Label them.
12. Why are there twenty types of R groups?
13. What is the difference between the amino acid cysteine and the amino acid
alanine, be specific. Think “R-group”. (You will have to look this up).
14. Diagram the joining of 2 amino acids together through dehydration synthesis to
form a dipeptide with a peptide bond. Highlight the peptide bond.
15. a)
When does a polypeptide become a protein?
b) Where does this occur in a cell (think protein synthesis from bio 11)?
16. Describe the four structures proteins can assume in terms of what they are made
of and the bonds holding them together. Make a sketch (very simple), for each,
labeling relevant bonds.
17. What is meant by protein denaturation and what is its significance in living
organisms (specifically enzymes).
Carbohydrates
18. By looking at a structural formula of a molecule, how would you know you were
looking at a carbohydrate?
19. How is a monosaccharide converted to a disaccharide? Give examples. What is
the molecular formula for glucose?
20. How are monosaccharides converted to polysaccharides?
21. Distinguish between starch and glycogen and sugars (e.g. sucrose). Why is
glucose such an important molecule?
22. How would you distinguish a cellulose molecule from a starch molecule? Why
is cellulose undigestible?
Biology 12
Lipids
23. Explain how a neutral fat (triglyceride) is synthesized (created).
24. Explain how a neutral fat (triglyceride) is hydrolyzed (broken apart).
25. Define what saturated and unsaturated fats mean. A “C – H” bond is considered
energy rich. How much more energy do fats carry per gram than carbs? You will
have to look this on up
26. Compare trans unsaturated fats to unsaturated fats and explain why one is more
healthy than the other.
Phospholipids
27. Differentiate between a lipid and a phospholipid.
28. Where are phospholipids found in our body?
Steroids
29.
a. What is the base molecule of steroids? How are steroids different from
other lipids?
b. Where are they made in the cell? In the body?
c. List 2 examples of steroids.
Nucleic Acids
DNA, RNA & nucleotides- we will be going into more detail with these polymers in the
future but you must know their basic structure and function now
30. What molecules make up the DNA backbone? Are they the same in RNA?
31. What are the 3 components of a nucleotide?
32. Which nitrogen bases are complimentary in DNA? In RNA?
33. Sketch a molecule of ATP and describe its structure.
34. What process produces ATP? How many ATP molecules can be made from a
single glucose molecule?
35. Why is ATP the “energy currency” of the cell?
36. Copy out the ATP cycle. Since this is a cycle what does this tell you about this
molecule?
37. How does our body use ATP?
Biology 12
ENZYMES: BIOLOGICAL CATALYSTS
38.
What is the general role of enzymes? How do they aid digestion?
39.
To what group of biological molecules do they belong?
40.
What process in the cell synthesizes enzymes?
41.
What is the name for the reaction type that includes all digestive reactions?
42.
Explain thoroughly why the reaction is called hydrolysis, and as part of your
answer make a diagram as given in Fig. 6.6, Pg. 107. Use a dipeptide as the
substrate, Label the active site, substrate (and its name), the actual enzyme for
dipeptide digestion, and its source in your diagram. Also label:
enzyme/substrate complex, products induced fit, “lock & key fit”, H2O, H+, OH-,
and hydrolysis.
43.
Describe what an active site is and why it is significant (lock and key)?
44.
What is meant by the term “optimal temperature”? (don’t simply use the word
“best”, but rather explain why it is the best temperature)
45.
What is meant by the term “optimal pH”? (as above)
46.
Will an enzyme catalyze a reaction if its active site is deformed? (i.e. if the
enzyme is said to be denatured). Why?
47.
Name 2 ways that an enzyme could become denatured.
48.
Once denatured, can an enzyme regain its 3D shape?
49.
What do COFACTORS do? How do they work?
50.
What is the name of organic cofactors?
51.
Contrast competitive and non-competitive inhibitors