BMCB 658 Exam 1 questions well
answered
Amino Acid Structure - ANS ✔✔Central carbon atom is bonded to a carboxyl group, an amino
group, a hydrogen, and the R group
Carbohydrates Structure - ANS ✔✔-Compounds made up of carbon, hydrogen, and oxygen
-General formula - (CH2O)n, where n is at least 3
Nucleotides Structure - ANS ✔✔Composed of a five-carbon sugar, a nitrogen- containing ring,
and one or more phosphate groups
Lipids Structure - ANS ✔✔-Poorly soluble in water because they are composed of long chains of
hydrocarbons
Functional Groups - ANS ✔✔Group of atoms that give rise to characteristic reactions of organic
compounds
Spontaneous Reaction - ANS ✔✔the change in free energy is negative (free energy decreases)
NonSpontaneous Reaction - ANS ✔✔-the change is positive (free energy increases)
-reaction will not occur unless energy is supplied from an external source
∆G - ANS ✔✔-free energy
-indicates the direction of the reaction
,∆G < 0 - ANS ✔✔spontaneous exergonic
∆G > 0 - ANS ✔✔non-spontaneous endergonic
∆G = 0 - ANS ✔✔at equilibrium
ΔG=ΔH−TΔS - ANS ✔✔-ΔH is changes in enthalpy
-ΔS is the changes in entropy
-ΔG is the changes in free energy
-T is the temperature
enthalpy - ANS ✔✔Heat of a reaction at constant pressure
intramolecular forces - ANS ✔✔-holds atoms together
-strong
-includes covalent and ionic bonds
intermolecular forces - ANS ✔✔-forces between molecules
-weak
-includes van der waals, dipole-dipole, dispersion, hydrogen, and ion dipole
Nonpolar Covalent Bond - ANS ✔✔electrons shared equally
polar covalent bond - ANS ✔✔-electrons shared unequally
-Formed because of the difference in electronegativity of atoms involved in the bond
,ionic bond - ANS ✔✔electron transferred
electronegativity - ANS ✔✔Measure of the force of an atom's attraction for electrons it shares
in a chemical bond with another atom
Intermolecular forces strongest to weakest
1=strongest
4=weakest - ANS ✔✔1. Ion Dipole
2. Hydrogen Bonding
3. Dipole-dipole
4. Dispersion
Van Der Waals Forces - ANS ✔✔-Dispersion and Dipole-dipole forces
-Noncovalent interaction between electrically neutral molecules
London Dispersion Force - ANS ✔✔-Results of fluctuations in the electron distribution within
molecules or atoms
-Key word: instantaneous or temporary dipole or transient dipole
-Shape affects strength of interaction
Dipole Induced Dipole Bonds - ANS ✔✔-Polar water is able to distort the electron cloud of a
nonpolar molecule, like oxygen, creating a momentary dipole
-Once the dipole is created, water is attracted to it.
Dipole-Dipole Interactions - ANS ✔✔-Forces that occur between molecules that are dipoles
-Partial positive side of a molecule attracts the partial negative side of another molecule
, Ion-Dipole Interactions - ANS ✔✔-Occur when ions in solution interact with molecules that have
dipoles
-ex. KCl dissolved in water
Hydrogen Bonding - ANS ✔✔- When a very electronegative atom is bonded to hydrogen, it
strongly pulls the bonding electrons toward it
- N, O, F
-The exposed proton acts as a very strong center of positive charge, attracting all the electron
clouds from neighboring molecules
(Hydrogen Bonds)--> Noncovalent attractive interactions between dipoles when the: - ANS
✔✔1. Positive end of one dipole is a hydrogen atom bonded to a highly electronegative atom
(hydrogen-bond donor)
2. Negative end of the other dipole is an atom with a lone pair of electrons (hydrogen-bond
acceptor)
Properties of Water - ANS ✔✔-Each water molecule can be involved in 4 hydrogen bonds
- Acts as a donor in 2 and as an acceptor in the other 2
- Enabled by the tetrahedral arrangement of the water molecule with bond angles of 104.3
-Both the melting and freezing point of water are significantly higher than would be predicted
for a molecule of its size
Approximate bond energy for hydrogen bond (in kJ) vs. a covalent bond (in kJ) - ANS ✔✔-
hydrogen bond = 20 kj/mol
- covalent bond = 413-460 kj/mol
Hydrophilic - ANS ✔✔- Ionic and polar substances
- dissolves in water
answered
Amino Acid Structure - ANS ✔✔Central carbon atom is bonded to a carboxyl group, an amino
group, a hydrogen, and the R group
Carbohydrates Structure - ANS ✔✔-Compounds made up of carbon, hydrogen, and oxygen
-General formula - (CH2O)n, where n is at least 3
Nucleotides Structure - ANS ✔✔Composed of a five-carbon sugar, a nitrogen- containing ring,
and one or more phosphate groups
Lipids Structure - ANS ✔✔-Poorly soluble in water because they are composed of long chains of
hydrocarbons
Functional Groups - ANS ✔✔Group of atoms that give rise to characteristic reactions of organic
compounds
Spontaneous Reaction - ANS ✔✔the change in free energy is negative (free energy decreases)
NonSpontaneous Reaction - ANS ✔✔-the change is positive (free energy increases)
-reaction will not occur unless energy is supplied from an external source
∆G - ANS ✔✔-free energy
-indicates the direction of the reaction
,∆G < 0 - ANS ✔✔spontaneous exergonic
∆G > 0 - ANS ✔✔non-spontaneous endergonic
∆G = 0 - ANS ✔✔at equilibrium
ΔG=ΔH−TΔS - ANS ✔✔-ΔH is changes in enthalpy
-ΔS is the changes in entropy
-ΔG is the changes in free energy
-T is the temperature
enthalpy - ANS ✔✔Heat of a reaction at constant pressure
intramolecular forces - ANS ✔✔-holds atoms together
-strong
-includes covalent and ionic bonds
intermolecular forces - ANS ✔✔-forces between molecules
-weak
-includes van der waals, dipole-dipole, dispersion, hydrogen, and ion dipole
Nonpolar Covalent Bond - ANS ✔✔electrons shared equally
polar covalent bond - ANS ✔✔-electrons shared unequally
-Formed because of the difference in electronegativity of atoms involved in the bond
,ionic bond - ANS ✔✔electron transferred
electronegativity - ANS ✔✔Measure of the force of an atom's attraction for electrons it shares
in a chemical bond with another atom
Intermolecular forces strongest to weakest
1=strongest
4=weakest - ANS ✔✔1. Ion Dipole
2. Hydrogen Bonding
3. Dipole-dipole
4. Dispersion
Van Der Waals Forces - ANS ✔✔-Dispersion and Dipole-dipole forces
-Noncovalent interaction between electrically neutral molecules
London Dispersion Force - ANS ✔✔-Results of fluctuations in the electron distribution within
molecules or atoms
-Key word: instantaneous or temporary dipole or transient dipole
-Shape affects strength of interaction
Dipole Induced Dipole Bonds - ANS ✔✔-Polar water is able to distort the electron cloud of a
nonpolar molecule, like oxygen, creating a momentary dipole
-Once the dipole is created, water is attracted to it.
Dipole-Dipole Interactions - ANS ✔✔-Forces that occur between molecules that are dipoles
-Partial positive side of a molecule attracts the partial negative side of another molecule
, Ion-Dipole Interactions - ANS ✔✔-Occur when ions in solution interact with molecules that have
dipoles
-ex. KCl dissolved in water
Hydrogen Bonding - ANS ✔✔- When a very electronegative atom is bonded to hydrogen, it
strongly pulls the bonding electrons toward it
- N, O, F
-The exposed proton acts as a very strong center of positive charge, attracting all the electron
clouds from neighboring molecules
(Hydrogen Bonds)--> Noncovalent attractive interactions between dipoles when the: - ANS
✔✔1. Positive end of one dipole is a hydrogen atom bonded to a highly electronegative atom
(hydrogen-bond donor)
2. Negative end of the other dipole is an atom with a lone pair of electrons (hydrogen-bond
acceptor)
Properties of Water - ANS ✔✔-Each water molecule can be involved in 4 hydrogen bonds
- Acts as a donor in 2 and as an acceptor in the other 2
- Enabled by the tetrahedral arrangement of the water molecule with bond angles of 104.3
-Both the melting and freezing point of water are significantly higher than would be predicted
for a molecule of its size
Approximate bond energy for hydrogen bond (in kJ) vs. a covalent bond (in kJ) - ANS ✔✔-
hydrogen bond = 20 kj/mol
- covalent bond = 413-460 kj/mol
Hydrophilic - ANS ✔✔- Ionic and polar substances
- dissolves in water
