Download Unit 2 Test Review Answers

Unit 2 Review Sheet – Biochemistry
1. What are the three main bond types? Describe them
Covalent bonds: strongest, shared electrons, common in carbon bonds
Ionic bonds: weaker than covalent, attraction between positive and negative bonds, common in salts, acids
and bases
Hydrogen bonds: weakest, attraction between partial positive and partial negative, common in water and DNA
2. What is the pH scale? Draw it.
pH scale measures the acidity of a solution by measuring the concentration of H+ (hydrogen ions) on a scale of
0-14
3. Which end is acid? Which is base? What is neutral?
Low numbers are acidic, high numbers are basic, 7 is neutral
4. What are the characteristics of water that make it important to life?
Polar, high heat capacity, resists temperature change, ability to bond and attract other molecules (cohesion
and adhesion), ice is less dense than liquid water, universal solvent, most abundant compound in living things
5. What does it mean that water is polar?
There is a partial positive charge in one part of the molecules (the hydrogen atoms) and a partial negative
charge in another part (the oxygen). This is because of unequal electron sharing.
6. Explain the bonding within and between water molecules.
The bonds between hydrogen and oxygen atoms IN ONE water molecule are covalent bonds. The bonding
between two separate water molecules is hydrogen bonding, because of the attraction between the partial
positive and negative charges.
7. What is the difference in organic and inorganic molecules?
Organic molecules contain carbon
8. What are the 4 organic molecules and the monomer (subunit) of each?
1. Carbohydrate Monomer: monosaccharide (single sugar)
2. Lipid
Monomer: fatty acids and glycerol
3. Protein
Monomer: amino acid (this is on tests and SOLs a lot)
4. Nucleic Acids Monomer: nucleotide
9. What is the purpose of each of the macromolecules?
1. Carbohydrate Quick energy
2. Lipid
Long term energy storage, insulation
3. Protein
Structure, action, ENZYMES
4. Nucleic Acids Information storage
10. What is the difference in a monosaccharide, disaccharide, and polysaccharide?
Monosaccharide is a single sugar, disaccharide is made of two monosaccharides and a polysaccharide is made
of many monosaccharides
11. What are some examples of each of the 4 macromolecules?
1. Carbohydrate Glucose, fructose (mono); sucrose (di); starch, glycogen (poly)
2. Lipid
Fats, oils, waxes, steroids, cholesterol
3. Protein
Hemoglobin (in blood), enzymes, structural in fingernails
4. Nucleic Acids DNA, RNA (NA= nucleic acid)
12. Define catalyst
Something that speeds up a chemical reaction without being used up
13. What are 2 things that can change the rate of enzyme reaction?
High temperature and extreme pH because they denature the enzyme (make it not work)
14. What is the difference in the active site and the substrate?
The substrate is what the enzyme is acting on and the active site is the place of the enzyme that is shaped so
the substrate can fit
15. What does the “lock and key” feature of enzymes indicate?
The active site is shaped so it perfectly fits the substrate, just like a key is perfectly shaped for the lock it opens