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Chapter 2 Biochemistry Practice test
1. What are the three subatomic particles and their charges? Protons (+), Neutrons (0), Electrons (-)
2. Where are protons and neutrons found in an atom? Nucleus Where are electrons found in an atom?
Electron cloud
3. Vocab review: define/explain
a. atomic number - # of Protons = # of electrons
b. mass number- # protons + # of Neutrons
c. Isotope- Atoms which have gained or lost neutrons
d. Ion - different number of electrons
e. Polarity – unequal sharing of electrons produces opposite charges on different sides of molecule
f. Cohesion - water molecule stick to water molecule
g. Adhesion - when water molecules sticks to other substances
h. Compound – Two or more elements combined
i. Solute- Sub that is dissolved
j. Solvent- Sub that does dissolving
k. suspension- Mixture that is not dissolved but remains suspended
l. solution- evenly distributed mixture/Homogeneous mixture of two or more substances (Solute is
dissolved in solvent)
m. buffer- makes small pH changes to keep a balance
n. Monosaccharide- single sugar (carbohydrate) molecule
o. Polysaccharide- large sugar(carbohydrate) molecule (monosaccharides linked together)
p. Amino acid- monomer of a protein
q. Activation energy-energy required to get reaction started.
r. Exergonic reaction - Energy is released
s. Endergonic reaction - Energy is absobrbed
4. Which element is present in all ORGANIC molecules? Carbon
5. Polymers are formed by the joining together of monomers, in a reaction called dehydration where water
is taken out to join two molecules.
6. What are the four organic compounds found in living things and what do they do?
a. Carbohydrates – Main source of energy
b. Lipids – Store energy
c. Proteins – Structure - hair nail (keratin), Transport – hemoglobin, Movement - muscle/skeletal
(actin Myocin, collagen), Defense - antibodies, toxins produced by bacteria, Regulation of cell
functions - hormone, enzymes catalyze chemical reaction
d. Nucleic acids – Transmit genetic info
7. What happens when a positive ion is formed? Electrons are lost
8. How does a ionic bond form? Transfer of electrons
9. How does a covalent bond form? Sharing of electrons
10. What are the forces called that allow a gecko to climb up vertical surfaces? Vander Waal’s
11. Weak bonds between the polar water molecules such as water are called hydrogen bonds
12. What do enzymes do? Speed up chemical reaction.
13. What is a substance with a pH of 8 or above? BASIC What is a substance with a pH of 6 or below?
ACID What has a pH of 7? NEUTRAL
14. When 2 hydrogen and 1 oxygen combine to form water, what would the product(s) be? water
What would the reactant(s) be? Hydrogen & Oxygen
15. What does the pH scale measure? Amount of H+ ions
16. In a glass of salt water, what is the solute? salt What is the solvent? Water
17. If an atom has an atomic number of 35 and a mass number of 75, how many protons does it have?35
electrons?35 neutrons?40
18. If a reaction in one direction releases energy, the reaction in the opposite direction absorbs energy.
19. Chemical reactions that ABSORB energy will not occur without a source of energy.
20. Which macromolecules (Ex wax, oil) is made up of glycerol and fatty acids? Lipids
21. Which macromolecule makes up muscles, skin, and hair ?
Proteins
22. Nucleotides consist of a phosphate group, a nitrogenous base, and a 5-carbon sugar
23. What are the two factors that affect enzymes? pH and Temperature
Practice SOL questions… (Circle the correct answer).
24. Which property of water allows many land-dwelling organisms to maintain body temperature by
eliminating excess heat?
A Water’s ability to evaporate _
B Water’s movement by capillary action
C Water’s capacity to dissolve substances
D Water’s formation of ions in solution
25. Pepsin is found in the human stomach and breaks down proteins to smaller peptides. What is pepsin?
A A mineral
C A carbohydrate
B An enzyme _
D A vitamin
26. Peroxidase is an enzyme that breaks down hydrogen peroxide in cells. It accomplishes this because of its
structure. What part of the enzyme is involved in catalytic activity?
A Binding pocket
C Active site _
B Pleated sheet
D Quaternary structure
27. Which of the following molecules is most abundant in the cells of the human body?
A Amino acids
C Lipids
B Nucleotides
D Water _
28. Enzymes only work with specific substrates because each substrate —
A has a specific active site for enzyme attachment _
B can only use a specific ionic bond with the enzyme
C destroys its specific enzyme
D actively interferes with other substrates around it
pH Values of Some Common
Substances
Substance
pH
sulfuric acid
1.2
tomatoes
4.2
rainwater
6.2
29. A change of one unit on the pH scale represents a tenfold increase in the concentration of hydrogen ions.
How much greater is the hydrogen ion concentration in tomatoes than in rainwater?100 x
Answer for #49: D (the increased acidity will kill most of the fish
Review your notes, handouts, assignments and labs for this chapter. Read the chapter.
Review pH scale. Be familiar with both acids and bases & calculations for hydrogen ion concentration.
Review structures, functions of Monomers and Polymers of carbon compounds.