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Biology 30-Unit 1: The Chemical Basis of Life

Unit Test

Time: 60 min. 

Total Marks: 60

Before you start, please note:

1. Check to see that you have all seven (7) pages.

2. Answer all questions on the exam paper in the space provided. Circle the correct letter when answering the multiple choice questions.

3. Be sure you understand the question before you attempt to answer it. Ask if you do not understand.

4. Write legibly. You may use a pen or a pencil.

5. Budget your time! The marks for each question are indicated.

6. Good luck!

Section 1: Multiple Choice. (15 marks)

1. The five most common elements in living organisms are:

            A. C, H, O, Na, Cl

            B. C, H, O, Na, Ca

            C. C, H, O, N, Ca

            D. C, N, O, Na, Cl

2. Substances that enter into a chemical reaction are known as:

            A. Reactants

            B. Products

            C. Catalysts

            D. Isotopes

3. Which of the following is not a polysaccharide?

            A. Sucrose

            B. Branched starch molecules

            C. Cellulose

            D. Glycogen

4. Which of the following are purines?

            A. Thymine and guanine

            B. Adenine and cytosine

            C. Adenine and guanine

            D. Thymine and cytosine

5. The atom sodium contains 11 electrons, 11 protons, and 12 neutrons. What is the mass number of sodium?

            A. 1

            B. 11

            C. 22

            D. 23

6. Fatty acids with double bonds between some of their carbons are said to be:

            A. Unsaturated

            B. Saturated

            C. Triglycerides

            D. Completely hydrogenated

7. Enzymes:

            A. Function as catalysts

            B. Are carbohydrates

            C. Are not affected by temperature

            D. Are not affected by substrate concentration

8. Genetic information is encoded in the:

            A. Quaternary structure of a protein

            B. Sequence of nucleotides in DNA

            C. Degree of saturation of fatty acids

            D. Length of glycogen

9. In the equation 2H₂ + O₂  2H₂O,

            A. H₂, O₂, and H₂O are all compounds

            B. H₂, O₂, and H₂O are all molecules

            C. Only H₂O is a compound

            D. Both b and c

10. Glucose molecules are to starch as __________ are to proteins.

            A. Fatty acids

            B. Amino acids

            C. Waxes

            D. Nucleic acids

11. Characteristics of carbon that contribute to its ability to form an immense diversity of organic molecules include its:

            A. Tendency to form covalent bonds

            B. Ability to bond with up to four other atoms

C. Ability to bond together to form extensive branched or unbranched “carbon skeletons”

            D. All of the above

12. Which list below consists only of molecules that are all polymers?

            A. Sugars, amino acids, nucleic acids, lipids

            B. Proteins, lipids, nucleic acids, sugars

            C. Proteins, lipids, nucleic acids, sugars

            D. Proteins, lipids, amino acids, nucleic acids

13. Water molecules stick to other water molecules because

            A. Water molecules are neutral, and neutral molecules are attracted to each other

B. Hydrogen bonds form between the hydrogen atoms of one water molecule and the oxygen atoms of other water molecules

C. Covalent bonds form between the hydrogen atoms of one water molecule and the oxygen atoms of other water molecules

            D. The hydrogen atoms of adjacent water molecules are attracted to one another

14. Which, if any, of the following choices does not properly pair an inorganic compound with one of its building blocks (subunits)?

            A. Polysaccharide–monosaccharide

            B. Fat–fatty acid

            C. Protein–nucleic acid

            D. All of these are paired correctly

15. Which of the following sequences best describes the flow of genetic information in a eukaryotic cell?

            A. RNA DNARNAprotein

            B. DNARNAprotein

            C. ProteinRNA DNA

            D. DNAamino acidRNAprotein

Section 2: Short Answer. (35 marks)

1. A basic principle of electricity is “like charges repel and opposite charges attract”. Describe the subatomic particles found in the atom (include charge, mass, and location). How does their organization illustrate this basic principle of electricity? (4 marks)

2. List six (6) actions that you can take to conserve water in the home. Why is it important to conserve water (use the magical properties of water in your explanation)? (6 marks)

3. Along one strand of a double helix is the nucleotide sequence GCCATCGAAT. What is the complementary sequence for the other DNA strand? (1 mark)

4. Compare and contrast eight (8) of the following ten (10) pairs of terms. If you answer all ten (10) questions, only the first eight (8) will be marked. (3 X 8 = 24 marks)

a) synthesis reaction/ decomposition reaction

b) inorganic compound/ organic compound

c) fatty acid/ amino acid

d) ionic bond/ covalent bond

e) monosaccharide/ polysaccharide

f) DNA/ RNA

g) endothermic reaction/ exothermic reaction

h) saturated lipids/ unsaturated lipids

i) peptide bond/ dehydration synthesis

j) reactants/ products

Section 3: Long Answer. (10 marks)

Choose one of the following:

1. Explain how genetic information is passed on from one generation to the next. Be sure to discuss the ingredients, the process, and the final product. Use labelled diagrams in your explanation.

OR

2. Describe the role polymerization plays in the formation of carbohydrates, proteins, and nucleic acids.

OR

3. What are enzymes? Discuss two factors that affect the action of enzymes. Include labelled graphs in your answer.

Bonus Question: List the five most abundant elements in the Earth’s crust. (1 mark)

1.

2.

3.

4.

5.

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