BIOL 189 Final Exam Review Questions and
Answers (Professor Ray Thweatt)
Protons - -- positive charge
- in the nucleus
- 1.7 x 10^-24 grams
- important because it's how we identify elements
-Neutrons - -- neutral charge
- in the nucleus
- 1.7 x 10^-24 grams
- important because it determines the atomic mass of an element
-Electrons - -- negative charge
- exist in orbits (energy levels) surrounding nucleus
- 2,000 times lighter than protons and neutrons
- Important because its position determines how/why one element interacts with another
element
-Atomic number - -# of protons
-Atomic mass - -# of protons + # of neutrons
-Isotopes - -same atomic number but different atomic mass.
same # of protons but a different # of neutrons
-Electron Pairing Rule - -1) electrons like to be paired
2) orbits like to be full.
1st energy level = 2 e-
2nd energy level = 4 sub-orbits = 8 e-3rd energy level = 8 e-
-Why do we like carbon, oxygen, nitrogen, and hydrogen? - -because they make up most of
any biological cell of living things.
H = 1 unpaired e- = 1 bond
O = 2 unpaired e- = 2 bonds
N = 3 unpaired e- = 3 bonds
C = 4 unpaired e- = 4 bonds
-Ionic bond - -complete transfer of electrons between a metal (loses e-) and a nonmetal
(gains e-).
, Ex: NaCl
-polar covalent bond - -unequal sharing of electrons
-nonpolar covalent bond - -equal sharing of electrons
-Hydrogen bond - -interaction between a negative atom and hydrogen, in which that
hydrogen is already part of a polar covalent bond.
* a single H2O molecule CANNOT have a H bond
* Covalent bonds are the STRONGEST * Hydrogen bonds are the WEAKEST
-What does any property of water depend upon? - -*Hydrogen bonds*
Properties of water = cohesive, stabilize temperatures, ice floats, solvent of life
-Carbohydrates - -CxH2xOx
-Cellulose - -- polysaccharide
- cell wall of plants
-Glycogen - -- polysaccharide
- how humans/animals store sugar
-Starch - -- polysaccharide
- how potatoes store sugar
-Chitin - -- polysaccharide
- exoskeleton of insects
- cell wall of fungi
-Lipids - -CmanyHmanyOfew
-Triglycerides - -- lipid
- glycerol + 3 fatty acids
-Phospholipids - -- lipid
- glycerol bound to two fatty acids and a phosphate group.
- half hydrophobic, half hydrophilic (amphipathic)
- hydrophilic phosphate head + 2 hydrophobic fatty acid tails
-Steroids - -- lipid
- 4C ring structure
- cholesterol
- sex hormones (testosterone and estrogen)
Answers (Professor Ray Thweatt)
Protons - -- positive charge
- in the nucleus
- 1.7 x 10^-24 grams
- important because it's how we identify elements
-Neutrons - -- neutral charge
- in the nucleus
- 1.7 x 10^-24 grams
- important because it determines the atomic mass of an element
-Electrons - -- negative charge
- exist in orbits (energy levels) surrounding nucleus
- 2,000 times lighter than protons and neutrons
- Important because its position determines how/why one element interacts with another
element
-Atomic number - -# of protons
-Atomic mass - -# of protons + # of neutrons
-Isotopes - -same atomic number but different atomic mass.
same # of protons but a different # of neutrons
-Electron Pairing Rule - -1) electrons like to be paired
2) orbits like to be full.
1st energy level = 2 e-
2nd energy level = 4 sub-orbits = 8 e-3rd energy level = 8 e-
-Why do we like carbon, oxygen, nitrogen, and hydrogen? - -because they make up most of
any biological cell of living things.
H = 1 unpaired e- = 1 bond
O = 2 unpaired e- = 2 bonds
N = 3 unpaired e- = 3 bonds
C = 4 unpaired e- = 4 bonds
-Ionic bond - -complete transfer of electrons between a metal (loses e-) and a nonmetal
(gains e-).
, Ex: NaCl
-polar covalent bond - -unequal sharing of electrons
-nonpolar covalent bond - -equal sharing of electrons
-Hydrogen bond - -interaction between a negative atom and hydrogen, in which that
hydrogen is already part of a polar covalent bond.
* a single H2O molecule CANNOT have a H bond
* Covalent bonds are the STRONGEST * Hydrogen bonds are the WEAKEST
-What does any property of water depend upon? - -*Hydrogen bonds*
Properties of water = cohesive, stabilize temperatures, ice floats, solvent of life
-Carbohydrates - -CxH2xOx
-Cellulose - -- polysaccharide
- cell wall of plants
-Glycogen - -- polysaccharide
- how humans/animals store sugar
-Starch - -- polysaccharide
- how potatoes store sugar
-Chitin - -- polysaccharide
- exoskeleton of insects
- cell wall of fungi
-Lipids - -CmanyHmanyOfew
-Triglycerides - -- lipid
- glycerol + 3 fatty acids
-Phospholipids - -- lipid
- glycerol bound to two fatty acids and a phosphate group.
- half hydrophobic, half hydrophilic (amphipathic)
- hydrophilic phosphate head + 2 hydrophobic fatty acid tails
-Steroids - -- lipid
- 4C ring structure
- cholesterol
- sex hormones (testosterone and estrogen)
