BIOLOGY 12 UNIT TEST – BIOCHEMISTRY Name:
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PART I: MULTIPLE CHOICE (Total: 50 marks) CIRCLE the best answer.
1. The atomic number of oxygen is 8. The atomic mass of oxygen is 16. Which of the following statements is true about a neutral oxygen atom?
A. An oxygen atom has 8 protons, 8 electrons and 8 neutrons. B. An oxygen atom has 16 protons, 16 electrons and 16
neutrons.
C. An oxygen atom has 8 protons, 8 electrons and 16 neutrons.
D. An oxygen atom has 16 protons, 16 electrons and 8 neutrons.
________________________________________________________________________ __________
2. A water molecule is capable of forming hydrogen bonds because:
A. the oxygen atom gives up an electron to a hydrogen atom. B. the electrons are shared at an equal distance between the
hydrogen atoms and the oxygen atom.
C. both the hydrogen atoms and the oxygen atom have the same number of protons.
D. there is an unequal sharing of electrons between the oxygen atom and the hydrogen atoms.
________________________________________________________________________ __________
3. What type of compound releases OH- ions in solution?
A. acid B. base C. protein D. buffer ________________________________________________________________________ __________
4. Which of the following is an example of hydrolysis?
C. absorption of fatty acids and glycerol D. formation of amino acids from proteins
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5. Which of the following are lipids?
A. ATP B. DNA C. steroids D. glycogen
6. If a protein loses its three-dimensional configuration, it is said to have become: A. dysfunctional B. two-dimensional C. unsaturated D. denatured ________________________________________________________________________ __________
7. What property of water allows it to form hydrogen bonds?
A. It has a neutral pH. B. Its molecules are polar. C. It is an excellent solvent. D. Its molecules can dissociate.
________________________________________________________________________ __________
8. A substance which helps maintain a constant pH in a solution is a(n): A. salt B. acid C. base D. buffer ________________________________________________________________________ __________
9. Which of the following is a protein?
D. cholesterol
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10. How are starch and cellulose similar?
A. Both are polymers of glucose B. Both are produced in human cells.
C. Both are components of the cell membrane.
D. Both can be digested by enzymes produced in the pancreas.
________________________________________________________________________ __________
11. Which of the following is not a component of a nucleotide?
A. sugar
B. phospholipid C. phosphate group D. nitrogenous base
________________________________________________________________________ __________
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12. The level of protein structure represented by the alpha-helix shape is:
A. primary B. secondary C. tertiary D. quaternary ________________________________________________________________________ __________
13. If the pH of a solution changes from 2 to 5, then the solution has:
A. become a base B. lost hydrogen ions C. become more acidic D. gained hydrogen ions
15. Fructose, glucose and galactose are:
A. triglycerides B. monosaccharides C.nucleotides
D. amino acids
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16. The functioning of a protein is determined by its:
A. size B. length C. weight D. shape
________________________________________________________________________ __________
17. The molecule shown below is part of:
A. ATP B. DNA
C. a steroid hormone D. an enzyme
________________________________________________________________________ __________
18. Which of the following refers to primary protein structure?
A. the helical shape of the protein B. the linear sequence of amino acids
________________________________________________________________________ __________
19. What is the empirical formula of a carbohydrate?
A. CH4 B. CHO C. CH2O D. C6H12O6 ________________________________________________________________________ __________
20. How are carbohydrates, lipids, proteins and nucleic acids similar?
A. They act as catalysts.
B. They are made up of carbon atoms.
C. They have a tertiary shape held together by hydrogen bonds. D. They form part of the phospholipids bilayer in the cell
membrane.
________________________________________________________________________ __________
23. Which element is present in proteins but not in most carbohydrates? A. carbon B. oxygen C. nitrogen D. hydrogen ________________________________________________________________________ __________
24. If four monosaccharides joined together, how many water molecules would be produced?
A. 1 B. 2 C. 3 D. 4 ________________________________________________________________________ __________
A. oxygen B. glycerol C. hydrogen D. fatty acids
________________________________________________________________________ __________
26. A large molecule of repeating subunits is called a(n):
A. polymer
B. monosaccharide C. amino acid D. fatty acid
________________________________________________________________________ __________
27. The backbone of DNA is composed of an alternating strand of ___________________ and _________________________________ molecules.
A. nitrogenous bases and deoxyribose B. phosphates and 5-carbon sugars C. nitrogenous bases and phosphates
D. adenosine triphosphate and nitrogenous bases
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28. The hydrolysis of a neutral fat will produce:
A. amino acids
B. glucose molecules C. nucleotides
D. fatty acids and glycerol
________________________________________________________________________ __________
29. Neutral fats do not dissolve in water because:
A. water is non-polar
B. water is polar and neutral fats are non-polar
C. Neutral fats are polar and form hydrogen bonds with water D. Neutral fats break down into ions when combined with water ________________________________________________________________________ __________
A. peptide bonds B. hydrogen ions
C. equal sharing of electrons D. unequal sharing of electrons
________________________________________________________________________ __________
32. Hemoglobin and antibodies are all composed of:
A. lipids B. proteins
C. carbohydrates D. polysaccharides
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Use the following diagram to answer question 33.
33. What occurs when the bond labeled X is broken?
A. Energy is released. B. Water is produced.
C. The molecule is denatured. D. Carbon dioxide is produced.
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38. Which of the following processes can produce maltose?
A. the addition of water during the hydrolysis of a disaccharide B. the bonding of two saturated fatty acids and the addition of
glycerol
D. the bonding of two monosaccharides and the removal of one water molecule
________________________________________________________________________ __________
39. In the human body, steroids can act as:
A. buffers B. vacuoles C. hormones D. coenzymes ________________________________________________________________________ __________
40. Which of the following are components of a phospholipid?
A. cholesterol, glycerol, fatty acids
B. fatty acids, phosphate group, glycerol C. glycerol, amino acids, phosphate group
D. phosphate group, cholesterol, monosaccharides
________________________________________________________________________ __________
41. Which of the following describes hydrolysis?
A. taking up excess hydroxide ions B. making a polymer by removing water
C. making water by combining an acid and a base D. adding water to break a polymer into unit molecules
________________________________________________________________________ __________
42. Glucose in cells is used primarily:
A. as an energy source B. to produce membranes C. to store genetic material
D. to produce enzymes that catalyze reactions
________________________________________________________________________ __________
A. glucose B. enzymes C. fatty acids D. nucleotides
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45. Which of the following would be found in RNA but not in DNA?
A. uracil B. adenine C. guanine D. thymine
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46. An unsaturated fat is characterized by
A. a helical structure B. four fused carbon rings
C. double bonds between the carbon atoms D. phosphate groups substituting for fatty acids
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47. What is the molecule illustrated above?
A. glycogen B. a nucleotide C. an amino acid D. a disaccharide
Which of the following diagrams correctly represents a solution with a pH greater than 7?
END OF MULTIPLE CHOICE SECTION
PART II: WRITTEN SECTION (Total: 38 marks) You may use point form for this section.
Make sure that your answers are clear and sufficiently detailed. Watch spelling!
1. What is meant by the statement that “water is a polar molecule”?
2. Describe THREE functions that water performs in living things. For each of the functions, list the property of water that allows it to perform this function.
(6 marks)
3. Use a labeled diagram to explain the processes of DEHYDRATION SYNTHESIS and HYDROLYSIS. Use a SPECIFIC EXAMPLE (or
(6 marks – 0.5 marks per box)
Biologically important macromolecule
Subunit molecule
5. a) Draw the basic structure of an amino acid and label its parts. (4 marks)
b) How many different amino acids are there in the human body?
__________________________________________ (1 mark)
6. Use the following table to compare saturated and unsaturated fats. (List three differences between them.)
3 marks – 0.5 marks per box
d) List TWO biological functions of polymers of this molecule. (Hint: the function can be in animals or plants.)
(2 marks)
i)