week 1: basic chemistry Flashcards
What are atoms?
Smallest stable units of matter.
Define elements.
A pure substance, consisting only of atoms of the same type (i.e. with the same atomic number).
What are molecules and compounds?
Substances consisting of atoms of one or more elements, joined together by a chemical bond.
What is a chemical bond?
An attraction that links atoms and ions together.
What are covalent bonds?
Involve the sharing of valence electrons between atoms to fill their outer electron shell.
What is a polar covalent bond?
When the electrons are distributed unequally, creating an asymmetrical (polar) molecule.
What occurs in a water molecule regarding polar covalent bonds?
The 8 protons of the O atom have a much stronger attraction for the shared electrons than the single protons of the H atoms.
What is a non-polar covalent bond?
When the electrons are equally shared between the atoms and there is no net electrical charge difference across the molecule.
What are ionic bonds?
Involve the transfer of valence electrons between atoms, forming a stable ionic compound with a neutral charge.
What characterizes metallic bonds?
Metallic atoms share their electrons, creating a sea of freely-moving electrons.
List three properties of metallic bonds.
- Very strong (high tensile strength)
- Malleable and ductile
- Good conductors of electricity and heat.
What are Van der Waals bonds?
Attractive forces between a positively charged region on one molecule and a negatively charged region on a neighbouring molecule.
What are London dispersion bonds?
Occur between non-polar molecules due to momentary dipoles created by moving electrons.
What are dipole-dipole bonds?
Occur between polar molecules when their -ve and +ve regions interact.
What are hydrogen bonds?
Attractive bonds between a hydrogen atom covalently bonded to a very electronegative atom and another.
What is one significant role of hydrogen bonds in biology?
Responsible for secondary/tertiary/quaternary protein structure.
How do hydrogen bonds affect the physical properties of water?
- High boiling point
- High surface tension
- Ice floats due to less dense structure.
What are intramolecular bonds?
Hold molecules together.
What are intermolecular bonds?
Occur between molecules.
supports organelles and cell shape & plays a role in cell motion
cytoskeleton
tube of protein molecules present in cytoplasm, centrioles, cilia and flagella
microtubules
intertwined protein fibres that provide support and strength
intermediate filament
twisted protein fibres that are responsible for cell movement
actin filament
complex assembly of microtubules that occurs in pairs
centriole
