Lecture 2 Basics: Bonds and polarity
Vocabulary:
Ionic bond
Covalent bond
Hydrogen bond
Bonding capacity
Electronegativity
Polar / Nonpolar
Hydrophobic / Hydrophilic
Solvent / solute
Dissolution/Solubility
7.1 Types of chemical bonds:
_______________
_________________
________________
7.2 Ionic bonds
Formed between:
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Bonds form:
7.3 Covalent bonds and polarity
Forms when:
Bonding capacity:
Electronegativity:
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Covalent bonds form molecules:
Polar covalent bonds:
Examples of polar and nonpolar molecules:
Hydrogen
Oxygen
Water
Methane
7.4 Hydrogen bonds
Defined as:
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7.5 Results of hydrogen bonding:
Cohesion:
Water is a solvent:
Hydrophilic vs Hydrophobic molecules:
7.6 Polarity in a cell – the plasma membrane
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Lipid Bilayers
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Lecture 2 Class Notes
Activity 1: (this page intentionally left blank)
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Activity 2:
Molecule
P/NP/A
Why?
O–C–O
H–O–H
Functional Group
Hydroxyl
Structure
P/NP and why
Carbonyl
Carboxyl
Amino
Sulfhydryl
Phosphate
Methyl
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Activity 3: Properties of a membrane protein - aquaporins
Aquaporins are channels that allow water to cross the plasma membrane. The diagram shows that
aquaporins form tetramers (groups of four, doi:10.1038/ncpendmet0980). Describe what parts of the
aquaporin channel protein are likely to have nonpolar functional
groups.
The image (shown in class) shows a cross-section through a single aquaporin channel (Nature 407, 599605 (5 October 2000) | doi:10.1038/35036519):
Are water molecules able to maintain hydrogen bonding as they travel through the channel? Why is this
important?
What does the asparagine (Asn) do?
How is the asparagine maintained in the protein, given its location in the membrane?
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