ANSWER KEY-- EXAM 1 Review: Chapters 2, 3, 4, 5 Part 2.: Practice Questions

1. What occupies energy levels and orbitals around the nucleus?a. Neutronsb. Protonsc. Electronsd. Ions

2. A change in the number of electrons results in __________.a. An isotopeb. An ionc. A hydrate d. A change in atomic number

3. An element that loses electrons becomes more (negative / positive) and is considered a(n) (cation / anion), whereas an element that gains electrons becomes more (negative / positive) and is considered a(n) (cation / anion).

4. The _# of neutrons (and atomic mass)_ of isotopes vary, but the __# of protons (atomic number) and electrons_ remains constant.

5. A(n) _______ is an atom that has given up an electron to eliminate a valence shell.a. Compoundb. Anionc. Polar moleculed. Catione. Ionic bond

6. A bond that is characterized by an unequal sharing of electrons is called aa. Covalent bondb. Ionic bondc. Hydrogen bondd. Polar covalent bonde. Nonpolar covalent bond

7. How many electrons does carbon have, and how many are in the valence shell?a. 6, 2b. 8, 4c. 12, 4d. 4, 6e. 6, 4

8. Magnesium has an atomic number of 12, how would its atomic orbitals be filled?

a. 1st=2 electrons; 2nd=6 electrons; 3rd=4 electronsb. 1st=2 protons; 2nd=8 protons; 3rd=2 protonsc. 1st=2 electrons; 2nd=8 electrons; 3rd=2 electronsd. 1st=8 electrons; 2nd=4 electrons

9. If an electron jumps from the 2nd to 3rd which of the following was most likely the cause?a. A release of energyb. Gaining an electronc. Absorbing energyd. Release of lighte. Losing an electron

10. Which of the following is least like the others?a. Ionic bondsb. Nonpolar covalent bondsc. Hydrogen bondsd. Polar covalent bonds

11. Hydrogen bonds are always found between:a. Two partially- charged moleculesb. Two oxygen atomsc. Two positive ionsd. Any compounds containing hydrogene. Water and any nonpolar molecule

12. Each water molecule can form up to four ___hydrogen___ bonds with adjacent water molecules.

13. The __hydrophobic__ portion of a molecule avoids contact with water.

14. Which of the following is not a unique property of water?a. Surface tensionb. Cohesionc. Evaporative coolingd. Adhesione. Low specific heat

15. Which of the following will not dissolve in water?a. Ionic compoundsb. Nonpolar compoundsc. Hydrophilic compoundsd. Polar compoundse. Hydrophobic compounds

16. An acid is a:a. Proton acceptorb. Electron acceptorc. Proton donord. Electron donor

17. Which of the following would be basic?a. pOH= 12b. pOH= 4c. pH= 8d. Both A and Ce. Both B and C

18. What is the property that allows ice to be less dense than liquid water?a. Cohesionb. Hydrogen bondingc. High specific heatd. Adhesion

19. Which of the following is true?a. pH determines acidity by measuring the H+ concentrationb. pOH determines acidity by measuring the H+ concentrationc. pOH determines acidity by measuring the OH- concentrationd. pH determines basicity by measuring the H+ concentratione. pH determines basicity by measuring the OH- concentration

20. If the pH is 6, what is the hydrogen ion concentration? [H+]= 10-6

21. If the [OH-]= .000001, then what is the pOH? pOH=6

22. If the [OH-]= .000001, then what is the hydrogen ion concentration? [H+]= 10-8

23. Last week the pH tested at 3 in the lake, today the retested pH= 7, what was the change in the pH? What was the change in the hydrogen ion concentration? What was the change in the hydroxide ion concentration?pH changed by 4[H+] decreased by 104

[OH-] increased by 104

24. What makes up 96% of the elements in living things?a. Calcium, Potassium, Sulfur, Hydrogenb. Nitrogen, Oxygen, Hydrogen, Carbonc. Calcium, Hydrogen, Oxygen, Nitrogend. Phosphorus, Oxygen, Nitrogen, Carbon

25. Isomers have the same molecular formula, but different ___structure___.

26. What are the following images depicting?

structural

enantiomers

structural

geometric (cis/trans)

27. Which of the following represents a carboxyl functional group?a. –COb. –CH3

c. –COOHd. --PO4

28. Identify the functional groups in the following images.

Blue NH2’s are amino groupsOrange COOH’s are carboxylsGreen OH are hydroxylsBlack =O is a ketone (carbonyl)

29. Which functional group incorrectly paired with its characteristics?a. Methyl; effects function of sex hormonesb. Phosphate; chemical energy stored in cellsc. Sulfhydryl; forms alcohold. Amino; acts as a basee. Hydroxyl; causes molecule to be hydrophilic

30. What are the four major classes of macromolecules in living systems?a. Carbohydrates, lipids, proteins, and amino acidsb. Carbohydrates, sugars, fats, nucleotidesc. Carbohydrates, lipids, proteins, nucleic acidsd. Carbohydrates, sugars, proteins, amino acids

31. What type of macromolecule is most abundantly found in the body?a. Carbohydratesb. Nucleic Acidsc. Amino Acidsd. Lipidse. Proteins

32. A hydrolysis reaction creates ___monomers___ by __adding___ water, while a

condensation reaction creates polymers by __removing____ water

33. Fill in the chart below.Macromolecules: Subunits: (monomers) Type of linkage:1. carbohydrates (mono) saccharides Glycosidic2. lipids ----- Ester3. nucleic acids Nucleotides Phosphodiester4. proteins Amino Acids Peptide

34. Most biological polymers are assembled through _dehydration synthesis_ which occurs between two of the monomers.**Dehydration synthesis= condensation reactions

35. The simple sugar, ___glucose___ ,is an important and common fuel molecule in living cells.

36. What are the differences between starch and cellulose structures?Starch= alpha => glucose repeated in same positionCellulose = beta => glucose in alternating positions

37. What are the 3 classes of lipids? List an example for each1. Fatty Acids

a. Saturated—butterb. Unsaturated—oil

2. Phospholipid—cell membrane3. Steroids—cholesterol, hormones

38. Proteins are polymers of a. Amino acidsb. Carbohydratesc. Nucleic acidsd. Lipidse. Any hydrocarbon

39. A ___peptide__ bond joins two amino acids together in a protein.

40. The ___secondary__ structure of protein consists of hydrogen bonds within the backbone.

41. Draw a generic amino acid structure.

42. At what structure level is a protein not considered a protein?a. Primaryb. Secondaryc. Tertiaryd. Quaternary

43. What can denature a protein?a. Salt concentrationb. Temperaturec. pHd. All of the above

44. What are the general function of each macromolecule, and where might we find them?1. Carbs= store energy2. Lipids= protection, storage, (energy)3. Proteins= protection, defense, signaling, transport, structure, contractile, storage

45. In what structures do nucleic acids store genetic information? DNA and RNA

46. What are the 3 components of nucleic acids?5 carbon sugar + phosphate group + nitrogenous base

47. What are the nitrogenous bases? How can they be categorized?

Bond with 2 H bonds--

Bonds with 3 H bonds

Purines V V Pyrimidines

A T/U

G C

48. Identify the different structures below. Describe the components of each.

Left: Secondary protein (alpha helix)

Right: Quaternary protein (hemoglobin)