Lesson 1: Biochemical Interactions Flashcards
INTRAmolecular Forces:
The chemical bonds/forces within a molecule
a) ionic bonds
b) covalent bonds
These include covalent bonds, ionic bonds, and others.
Define covalent bonds.
Electrons are SHARED between atoms
What does electronegativity refer to?
How strongly an atom attracts electrons.
What are polar molecules?
Molecules that have an unequal sharing of electrons, resulting in partial positive and partial negative regions.
What determines the polarity of a molecule?
Electronegativity of the atom and bonding angle.
How do asymmetrical and symmetrical molecules differ in terms of polarity?
Asymmetrical molecules are generally polar, while symmetrical molecules are generally non-polar.
What are ‘lone pairs’ in the context of molecular polarity?
Free electrons that can affect the bond angles in a molecule.
Define ionic bonds.
The bond between a cation (positively charged ion) and an anion (negatively charged ion).
What happens to ionic compounds like NaCl in water?
They tend to readily dissociate in water.
What are intermolecular forces?
Forces occurring between molecules, generally weaker than intramolecular forces.
Name the two types of intermolecular forces important for biological processes.
- Hydrogen bonding
- Hydrophobic interactions
What is hydrogen bonding?
A weak association between H+ and the partial negative part of a molecule.
What role do hydrogen bonds play in adhesion?
They contribute to the capillary action of water moving up narrow class tubes and paper.
When do hydrophobic interactions occur?
Between non-polar molecules, which tend to clump together.
What are London Dispersion Forces?
Weaker, momentary interactions of electrons of one molecule to another.
What are hydrocarbons?
Molecules only containing H and C that are generally non-reactive (non-polar).
What is the significance of functional groups in biological molecules?
They are involved in the chemical properties and reactivity of biologically important molecules.
List some CHARACTERISTIC properties of water.
- Cohesion
- Adhesion
- High specific heat capacity
- High specific heat of vaporization
- Solid water is less dense than liquid water
What is the highest density of water?
At 4°C.
Fill in the blank: Water is _______.
Cohesive
True or False: Non-polar molecules are hydrophilic.
False
What should be considered when analyzing the behavior of powders in water?
Water’s polarity and how it interacts with the powders.
Hydrophobic:
Water fearing
Hydrophilic
Water loving
Why is water cohesive?
H20 molecules H bond w/ each other, causing high surface tension (ex. water spider walking on water).
Why is water adhesive?
H20 molecules H bond w/ other polar materials, causing capillary action (ex. water creeping up paper or narrow glass tube)
Why does water have a high heat capacity?
H bonding causes H20 to absorb a lot of heat before the temp increases, and lose a lot of hear before the temp decreases, causing temperature moderation (ex. organisms maintaining their body temp).
Why does water have a high hear of vapourization?
H bonding causes H20 to absorb a lot of hear to become vapour/gas, causing evaporative cooling [Ex. organisms can dissipate body heat from surfaces such as skin (sweating), or tongue (panting)]
Why is waters highest density @ 4 degrees Celsius?
H20 molecules form crystal lattice when frozen, and the H bonding btween the v-shaped molecules spread the molecules apart reducing the density (Ice is less dense than water), causing Ice to float on water. This helps aquatic life to survive through winter.
Water absorbs thermal heat, causing…
High specific heat capacity and High specific heat of vapourization
Water clings, causing…
Cohesion and Adhesion
Solid water is less dense than liquid water, causing…
The highest density to be 4 degrees Celsius.
