Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
45 Cards in this Set
- Front
- Back
|
What are the 4 distinctive properties of living systems?
|
Organisms are complicated and highly organized
Biological structures serve functional purposes Living systems are actively engaged in energy transformations Living systems have a remarkable capacity for self-replication |
|
|
What is necessary for base pairing?
|
complimentary hydrogen bonding in DNA
this allows info storage and transfer |
|
|
What make up 99+% of atoms in the human body?
|
OHCN
(63,25,9,1) |
|
|
What property unites HOC and N and renders these atoms so appropriate to the chem of life?
|
Their ability to form covalent bonds by e- pair sharing
|
|
|
What gives rise to H-bonding?
|
lone e- pairs on O and N
|
|
|
What are the varieties of C-C bond?
|
linear aliphatic (tetra)
Cyclic aliphatic and aromatic Branched Planar |
|
|
What two atoms have the greatest bond energy between them?
|
H - H
|
|
|
What are the units for building complex structures?
|
simple molecules
|
|
|
Amino acids form ?
Sugars form ? Nucleotides ? |
proteins
polysaccharides nucleic acids |
|
|
What maintains biological structure and determines biomolecular interactions?
|
weak forces
|
|
|
What are two important points about non-covalent bonds or weak forces?
|
biomolecular recognition is mediated by weak chemical forces
weak forces restrict organisms to a narrow range of environmental conditions |
|
|
What are the four types of noncovalent interactions?
|
Hydrogen bonds
ionic interactions hydrophobic interactions van der waals interactions |
|
|
Hydrogen bonds in aqueous solvent can occur between what two groups?
|
neutral groups ( H-O)
peptide bonds (H-N) |
|
|
What are the two types of ionic interactions?
|
attraction
repulsion |
|
|
What is the smallest weak force and how much energy is needed to break the bond?
|
Van Der Waals: 0.4-4 kJ/mol
|
|
|
What is the strongest weak force and how much energy is needed to break the bond?
|
Hydrophobic interactions : <40 kJ/mol
|
|
|
How much energy does it take to break a hydrogen bond?
an ionic bond? |
h-bond: 12-30 kJ/mol
ionic: 20 kJ/mol |
|
|
What are hydrogen bonds?
|
electrostatic interactions between H donors and H acceptors
|
|
|
What is a H bond acceptor?
|
lone e- pair on atom that accepts H ions
|
|
|
What is a H bond donor?
|
a hydrogen in OH or NH2
|
|
|
What can never be a H donor or acceptor?
|
C-H: C cannot have free e-pairs
|
|
|
What is the most prevalent H donor and acceptor?
|
water
|
|
|
What is the most primary example of H bonding?
|
complimentary H bonding in DNA (ex between Guanine and Cytosine)
|
|
|
What is responsible for DNA?
|
the accuracy of H bonding
|
|
|
What imposes restrictions on folding of macromolecules so that only certain figurations can be achieved?
|
the linear bond that forms between the H bond donor and acceptor
|
|
|
What is dependent upon water?
|
pH and ionic equilibria
|
|
|
What are the properties of water? 8
|
high b.p
high m.p high heat of vaporization high surface tension bent structure (polar molecu) non-tetrahedral bond angles H-bond donor and acceptor potential to form 3-4 H bonds |
|
|
What leads to the higher density of liquid water?
|
the h-bonds flicker and distances are shorter because h-bonds are not in a straight line
|
|
|
Explain the h bonds in ice.
|
h bonds are in a straight line, of equal lengths and constant angle, individual molecules are kept apart
|
|
|
How many H bonds per water does ice have?
water? |
ice: 4 H bonds, 10 microsec
water: 2.3, 10 psec |
|
|
Why is water a solvent for ions?
|
polar nature allows it to interact with both cations and anions
forms a solvent shell |
|
|
Why does NaCl dissolve in water?
|
water has a high dielectric constant
|
|
|
What is Coulomb's law?
|
E=k(q1q2)/r2D
E: force D: dielectric constant |
|
|
Why can water separate ions?
|
water has a high D, which is indirectly related to force. water molecules interact more strongly with ions than cations and anions can interact with ea other
|
|
|
What do Ions carry around when hydrated in water?
|
a hydration shell
|
|
|
what does water form with polar solutes?
|
h bonds
|
|
|
what is the secret of life?and why are they important?
|
hydrophobic interactions
important for structure or macromolecules and membranes |
|
|
What is the hydrophobic effect?
|
Nonpolar (hydrophobic) molecules aggregate so that not as many h20 molecules are organized and the final S stage is increased. Entropy drives hydrophoblic interactions
|
|
|
What are amphilphilic molecules?
|
molecules that contain both polar and nonpolar groups
ex: f.a. and biological membranes |
|
|
What is a clathrate?
|
an ordered cage that water molecules form around nonpolar molecules
|
|
|
What is the purpose of micelles
|
all hydrophobic groups are sequestered from water, the ordered shell of water molecules is min. and entropy is farther increased.
|
|
|
What does the colligative properties of water depend on?
|
number of solute molecules only
|
|
|
what is the limiting factor for det how high a tree can grow?
|
osmotic pressure
|
|
|
what is the H2O conc in water?
|
55.5 M
|
|
|
Why is water an electrical conductor?
|
Protons hop from molecule to molecule
|
