Quiz 1 - Biochem (Basics) Flashcards
What is Biochemistry?
A field that bridges bio and chem, studying the chemistry of the molecules that make life possible
What are the chemical foundations of life?
Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur
What do the six important elements provide?
Provides the underlying structure of the biological molecules (carbohy, proteins, lipids, nucleic acids)
Explain the classifications for InTRAmolecular bonds
-Covalent Bonds (sharing); polar (unequal), non-polar (equal)
-Ionic Bonds (transfer)
What are organic molecules?
Organic molecules are CARBON BASED, (involve carbon atoms bonded to each other and to Hydrogen (also maybe N,O,P,S)
What are chemical bonds?
The attraction between atoms
What are the types of chemical bonds
-InTRAmolecular bonds (within mol)
-InTERmolecular bonds (between mol)
What is the difference between Covalent and Ionic Bonds?
Covalent bonds involves the sharing of electrons to achieve stable valence shells, and this is between non-metals. Whereas Ionic bonds involves the transfer of electrons between atoms to achieve stable valence shells. metal-nonmetal.
Define Electronegativity
A measure of how strongly an atom attracts electrons.
What are the electronegativity rules?
If the electronegativity difference is:
0 - 0.5 = non-polar cov
0.5 - 1.7 = poalr cov
> 1.7 = ionic
What factors determine polarity?
- Geometry; sym vs asym
- Bond Polarity (elecneg diff)
Explain a water molecule in terms of polarity
in a water molecule, the oxygen atom is much more electronegative than the hydrogen atom, thus the electron pair is pulled more towards oxygen, making the O partially negative, leaving the H partially positive.
Why is Polarity important in bio?
-It affects physical properties of a substance - eg. solubility “LIKE DISSOLVES LIKE”
- Determines strength and type of intermolecular attraction between molecules
How do you determine polarity?
It depends on bond polarity and molecular shape
-Sym arrangement of polar bonds will result in a nonpolar mol (dipoles will cancel)
-asym arrangement of polar bonds will result in polar mol
explain the number of bonds an atom forms
- Relates to the number of electrons needed to fill the valence shell
Single = 1 shared pair of val elec
Double = 2 shared
Triple = 3 shared
Do ionic bonds have structural diagrams? Why or why not?
Ionic compounds do not share electrons, there is no covalent bonds- so NO structural diagrams
How is Lewis-d-d diff from bohr?
It only shows the valence electrons
What are the type of INTERmolecular bonds?
-London Forces (van der)
-Dipole-dipole
-Hydrogen Bonds
Give 4 points to explain INTERmolecular bonds
-Bonds BETWEEN molecules
-Responsible for many biological properties
-Weaker than intramolecular bonds within molecules
-Sometimes referred to as “van-der-waals interactions” (distance-dependent
Explain London forces
- Weakest intermolecular force
-Due to temporary equal distribution of electrons as they randomly move about nuclei forming temporary dipoles
-only forces that hold non-polar molecules together
Explain Dipole-dipole interactions
-Stronger than London Forces (weaker than ionic of covalent bonds)
-partial positive of one molecule attracts partial negative of adjacent molecule
-only has a significant effect if molecules are close together
Explain hydrogen bonds
-Strongest force
-due to dipole-dipole forces that form between partially positive hydrogen of one polar molecule and the partially negative atom (usually N, O or F) of an adjacent polar molecule
What is the chemistry of water?
-Colourless, odourless, tasteless
-Exists as a solid, liquid, and gas at normal temperatures
-Highly polar
What is the difference between hydrophilic and hydrophobic
Hydrophilic means water LOVING, whereas hydrophobic is the opposite (non polar mol)
