Chemistry of Life Review BIO 30S– Answer Key 2011
Define the following terms:
Atom: The smallest unit of any given element.
Valence Electrons: The outer orbit electrons, which are important to bonding.
Atomic Mass: The mass of the atom = protons + neutrons.
Ionic Bond: The transfer of electrons between a metal and non-metal atom. Results in the attraction
between a positive cation and a negative anion.
Covalent Bond: The sharing of electrons between non-metal atoms.
Organic compound vs. Inorganic compound:
Organic – from living matter (plant/animal)  contains carbon
Inorganic – from non-living matter  contains a variety of elements
Monosaccharide: Simple carbohydrate  smallest unit e.g. glucose, fructose, galactose
Disaccharide: 2 monosaccharides covalently bonded together. E.g. Maltose  made up of 2 glucose
Polysaccharide: 3 or more monosaccharides bonded together. A complex carb. E.g. Starch, cellulose,
glycogen.
Starch: A polysaccharide/complex carb. Found in food such as potatoes and grains.
Glycogen: A polysaccharide/complex carb found in animals. Used in storage of carbs.
Cellulose (Fiber): A polysaccharide/complex carb that makes up the cell wall of plant cells.
Glucose: A monosaccharide most commonly used by cells for quick energy.
Dehydration Synthesis: The chemical process of removing 1 water molecules to bring substances
together, as in carbohydrates (glucose + glucose), proteins (a.a + a.a) or lipids (glycerol + fatty acid).
Hydrolysis: The reverse process of dehydration synthesis. A chemical reaction where water is added to
break substances apart.
Protein: A basic building block of all living organisms made out of amino acids joined together by
peptide bonds. Examples in the body: Hemoglobin  a protein that carries oxygen
Enzymes  carry out chemical reactions
Non-essential amino acid vs. Essential amino acid:
Non-essential  Produced in our body, creates proteins.
Essential  Required to eat them in our diet, creates proteins.
Dipeptide: 2 amino acids bonded covalently together with a peptide bond.
Peptide Bond: A covalent bond that holds amino acids together.
Polypeptide: A chain of 3 or more (up to a million or more) amino acids held together by peptide bonds.
Essentially a protein.
Protein Denaturation: At high temperatures proteins may change their shape and therefore will no
longer function. This is why high fever temperatures are dangerous.
Lipids: Commonly known as fats, oils and waxes. Lipids are made up of glycerol and fatty acid chains.
Functions include: Storage of energy, insulation, functions in cell membranes.
Triglyceride: 1 glycerol + 3 fatty acid chains  Common lipid.
Saturated Fatty Acids: A fatty acid chain that is completely saturated with Hydrogen and
therefore no C=C (double bonds). Known as “bad lipids” and can lead to Atherosclerosis.
Monounsaturated Fatty Acids: A type of healthy unsaturated fat. They have 1 C=C (double
bond).
Found in: Avocadoes, olives, canola oil.
Polyunsaturated Fatty Acids: A type of healthy unsaturated fat. Commonly called Omega-3 or Omega-6
fatty acids.
Found in: Fish, nuts, some veggies.
Steroids: A third type of unsaturated fat. Produced in the human body and eaten in meat. * Used in
hormonal function. E.g. Cholesterol.
Trans fatty acids: The worst type of fats. Hydrogenation is a process that converts unsaturated 
saturated and creates trans fats. High in fast food. Should eat less than 2 grams per day.
Atherosclerosis: The clogging of blood vessels due to eating unhealthy forms of lipids (saturated / trans
fats).
LDL Cholesterol: Low Density Lipoprotein, this is BAD cholesterol  causes Atherosclerosis.
HDL Cholesterol: High Density Lipoprotein, this is GOOD cholesterol  carries cholesterol away from
blood vessels.
Catalyst: A specific enzyme that speeds up a reaction without changing it.
Lactase: The enzyme responsible for digesting lactose found in dairy/milk.
Lactose Intolerant: A person who does not produce lactase therefore must take medicine prior to eating
dairy.
Amylase: An enzyme that breaks down carbohydrates in our mouth. Found in saliva.
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Substrate: What the enzyme acts on.
E.g.
Lactose is the substrate for the enzyme lactase
Carbohydrates are the substrate for amylase.
Active Site: The location of the enzyme that has a specific shape (lock-and-key idea) to fit directly in with
the substrate.
1. How many grams of fat are we supposed to consume a day?
It is recommended not to exceed _____20____ grams of saturated fats per day.
It is recommended not to exceed ____~1-2 ___grams of Trans fats per day.
2. What are the six characteristics of enzymes? Explain each in a sentence.
i.
ii.
iii.
iv.
v.
vi.
Specificity – All enzymes work for a specific reaction.
Concentration – The rate of a reaction will increase if there are more enzymes present.
pH – Every enzyme works best at a certain pH (acidity/alkalinity). If the pH in the surrounding
area changes, the enzyme may not work.
Temperature – Enzymes work best at body temperature (37˚C). Too much heat or too much
cold will kill enzyme activity.
 When proteins (enzymes) heat up, they become denatured  protein starts to unfold.
Activation – Energy is needed to start a chemical reaction. This is called activation energy. An
enzyme will lower the amount of activation energy needed to start a chemical reaction.
Inhibitors – Certain enzymes slow down or stop enzymes from working all together.
3. How are Trans Fatty Acids made and list three examples of foods high in Trans Fats.
Unsaturated fats

Saturated fats
Hydrogenation
(Heat, adding H’s)
Breaking double bonds 
Forming single bonds
Chemistry Review
1. How is an element different from a compound?
Element Made out of 1 specific kind of atom. E.g. Hydrogen or Oxygen
Compound  Made up of 2 or more kinds of atoms in a fixed ratio E.g. H2O2
2. Which sub-atomic particles have electric charges? What are these charges?
Protons  positive charge
Electrons  Negative charge
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3. Draw a diatom of chlorine using a Bohr Diagram (Cl2)
4. Describe two ways that an ion can be formed.
Cation  Atom that has a positive charge, it has lost electrons.
Anion  Atom that has a negative charge, it has gained electrons.
5. Explain why the equation for cellular respiration is a balanced equation.
6 O2 + C6H12O6  6 CO2 + 6 H2O + ATP
This is balanced because there is the same amount of atoms of the same kind on each side of the
reaction.
6. As you know, there are no molecules in ionic compounds. What then does the formula for an ionic
compound such as MgCl2 represent?
Ionic bond: Attraction between positive and negative ions.
Carbohydrates
1. What is a monosaccharide, and how can two monosaccharides combine to form a larger
molecule?
Monosaccharide is a simple sugar. E.g. Glucose, galactose, fructose.
2 monosaccharides can combine to form a disaccharide by the process of dehydration synthesis.
2. Name two simple sugars and two complex sugars.
Simple  Fruit, Honey, milk (monosaccharide sugars)
Complex  Starch, rice, bread (polysaccharide sugars)
3. How are complex sugar molecules broken apart for digestion?
Hydrolysis  Breaks down complex sugars by adding a water molecule.
4. Draw the ring structure of glucose.
5. What happens in the process of dehydration synthesis? Why is this an appropriate name?
Water is removed and forms a bond. Therefore the word “dehydration” is appropriate.
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6. What is your favourite carbohydrate? Is it a simple or complex carbohydrate?
*Answers will vary*
Lipids
1. What are three substances are commonly called lipids?
Fats, oils, waxes
2. How is a fat formed from glycerol and fatty acid?
Via dehydration synthesis.
3. Explain the difference between unsaturated and saturated fats?
Unsaturated  healthier, has double bonds C=C
Saturated  unhealthy, has single bonds C-C, saturated with H’s
4. What are the three types of unsaturated fats?
Monounsaturated
Polyunsaturated
Steroids
5. Where in cells do you find cholesterol (a type of steroid which is unsaturated fat)?
In cell membranes, allows membranes to be fluid for movement.
6. Is it best to consume HDL or LDL? Explain your answer.
HDL is good cholesterol which is attained by a diet with choices in unsaturated fats, actually leads
cholesterol away from blood vessels.
Proteins
1. Draw the basic structure of an amino acid.
Circle and label the groups that are found in it.
2. What do you call amino acids that you get from your diet?
Essential amino acids because it is essential that you eat them!
3. What are the important functions of protein in your body?
Repair cells
Enzymes are proteins important in chemical reactions
Hemoglobin is a protein that carries oxygen
4. What are great alternative of protein for vegetarians?
Beans, lentils, nuts, tofu, peanut butter
5. What are proteins made out of? What process forms proteins?
Long chains of amino acids brought together by dehydration synthesis.
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Identify the type of bond between the following atoms as being Ionic or Covalent:
COVALENT BOND
IONIC BOND
Identify the following compounds:
1. AMINO ACID
2. MALTOSE (DISACCHARIDE)
3. GLUCOSE
4. TRIGLYCERIDE (SATURATED)
5. WATER MOLECULE
6. UNSATURATED FATTY ACID (NOTE DOUBLE BONDS)
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Enzyme and Vitamins KEY Comprehension Questions
Bio 30S
1. Explain the relationship between an enzyme and it’s substrate.
Enzymes and substrate fit together like lock and key. Enzymes are specific to their substrate.
Enzymes break the substrate down into useable forms for the body.
2. High temperatures can weaken bonds between different parts of a protein molecule, thus changing
it’s shape. How might this change alter the effectiveness of an enzyme? Explain.
Since enzymes are very specific, a change in shape called protein denaturation could mean it may
no longer function. (The key no longer fits into the lock)
3. How does the active-site of an enzyme relate to the lock and key model?
The enzyme has an active-site, which is a specific shape for the substrate to fit in.
4. How do enzymes affect activation energy?
Enzymes lower the activation energy that is require to perform the chemical reaction.
5. What does the enzyme catalase do in the body?
Catalase breaks down H2O2 into H20 and O2 which is harmless to the body.
6. What is a catalyst?
A catalyst is an enzyme that speeds up a chemical reaction..
7. What are the 4 steps of the lock and key process?
1. Substrate and enzyme approach
2. Substrate attaches to the enzyme at the active site
3. Enzyme and products separate
4. Enzyme is unchanged.
8. What is an example of enzymes at work in our bodies?
Lactase breaks down lactose in dairy products.
9. How does Vitamin A’s function differ from Vitamin D’s function in the human body?
Vitamin A: normal night vision, mainly healthy eye functions
Vitamin D: strong bones and teeth, prevents rickets
10. Where do you get vitamin K in your diet? What are some of the symptoms of a lack of vitamin K?
Vitamin K: green, leafy veggies, tomatoes, cauliflower, liver, egg yolk
For: proper blood clotting, therefore symptoms include excessive bleeding and poor absorption of
blood from intestine.
11. If you are pursuing a vegan diet (no meat/milk/eggs) and are not responsible in eating other sources
of high protein foods such as beans and enriched wheats/grains, what complications could result?
Eye fatigue, low energy, loss of appetite, headaches, nervousness, skin eruptions, mental
depression, digestive problems, anemia, rundown feeling.
12. How are coenzymes different from cofactors?
Coenzymes are from organic living tissue Eg. Vitamins
Cofactors are from inorganic non-living matter Eg. Mineral
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