Ap Bio - Chemistry of Life Flashcards
Ap Biology Unit one
What are the 4 Essential Elements of life?
What percent of living mass is made from them?
- Oxygen
- Carbon
- Hydrogen
- Nitrogen
Makes up 94% of all living things.
Other elements like calcium, phosphors, potassium, sulfur, sodium, chlorine, and magnisum are also present.
How / Why do Ionic Bonds form?
Which atoms become positivly and negativly charged?
- Ionic Bonds form when one atom’s outermost electron(s) are permanently transferred to another
Na + Cl react, and become Na(+) and Cl(-)
The atom that loses the electron(s) becomes a positively charged Ion, and the atom that gains the electron(s)becomes a negatively charged Ion.
How / Why are Covalent bonds formed?
How does a Covalent bond become Polar?
- Covalent bonds are formed when electrons are shared between atoms
- When one pair of electrons is shared between two atoms, it is a single covelent bond. When two pairs are shared it is a double covelent bond. When three pairs are shared, it is a tripple covelent bond.
H+O+H, a polar covelent bond. (H+)(O-)
When electrons are shared evenly, the bond is non-polar (No charge).
When they are shared unevenly, the bond is polar covelent.
What is a Hydrogen Bond?
How are they formed?
- Hydrogen bonds are weak chemical bonds that form when a hydrogen atom (that is covalently bonded to an electronegative atom), is attracted to an electronegative atom.
The hydrogen in H2O being atracted to the oxygen in H2O.
Hydrogen bonds are weaker than Ionic and Covalent bonds, but strong when present in large numbers.
Hydrogen Bonding gives water special proprties.
What are these special properties?
- Cohesion/ Adhesion
- Surface Tension
- High Heat Capacity
- Freezing Expansion
What is Cohesion and Adhesion?
What is its purpose? what makes it special?
- Water tends to stick to itself, which exhibits a cohesive force.
- Water likes to stick to other substances, they’re Adhesive.
- The two forces together allow water to rise up roots, trunks, and branches of trees
This phenomenon is called Capillary Action.
Durring trasparation, water molecules evaporate from a leaf, pulling on their neighbors, bringing the others up behind it.
Water will stick to the sides of beakers, adeasing itself to the surface.
Why does water display High Heat Capacity?
What is Heat Capacity?
- The Hydrogen Bonds are weak by themselves but strong in large numbers
- It takes a large amount of kinetic energy (a higher temperature) to break the hydrogen bonds between molecules.
- When they are broken, molecules escape as steam
When something has low heat capacity, it is easy to heat.
Heat Capacity is the quantity of heat required to change the temperature of a substance.
What makes a solution Acidic or Basic?
Why/how does this happen?
- The Acidity of a solution is determined by the number of hydrogen ions present
- The Basicness of a solution is determined by the number of Hydroxide ions present
H2O can be broken into a Hydrogen Ion [H+]and a Hydroxide Ion [OH-]
Hydrogen atoms in polar covalent bonds with a more electronegative atom may have their proton pulled away from them. Hydrogen bonding pulls on the proton even more and is sometimes pulled off the atom entirely.
For water, this process is essentially temporary, but for other molecules, it is not.
What is the difference between organic and Inorganic compounds?
- Organic Compounds:
- Are derived or produced by living organisms
- Have Carbon-Hydrogen covalent bonds
- Inorganic Compounds:
- Generally have Ionic bonds, and lack Carbon-Hydrogen bonds
- Rarely contain Carbon atoms
What is Dehydration Synthesis?
Dehydration synthesis is a chemical reaction where two smaller molecules are joined together to make a lerger molecule following the relese of water from said molecule.
It’s called that because of the removal of water from the molecule.
When two monosaccharides are brought together, the hydrogen [-H] from one molecule combine with the hydroxyl group [-OH] of the other. Water is created as a bi-product, and we get two monosaccharides, or a Disaccharide.
What is Hydrolysis?
Hydrolysis is a chemcial reaction where water is used to break down the chemical bonds that exist between a particular substance.
Hydrolysis is just Dehydration Synthesis in reverse.
Hydrolysis means “Water” (Hydro-) and “Breaking” (-lysis). The bond between the sugars is broken up with water.
What are the 4 importaint groups that make up an Amino Acid?
How does the R-group effect the Amino Acid its connected to?
The R-group effects:
Composition of elements,
Polarity/ Charge,
Shape/ Size,
What is a peptide bond?
How are peptide bonds formed?
Peptide bonds are the bond between two amino acids.
By joining the carboxyl group of one amino acid to the amino group of another.
Peptide bonds are formed via Dehydration synthesis.
What are the 4 levels of protine structure?
What are the two main types of Secondary structure?
- Primary
- Secondary
- Tertiary
- Quaternary
When polypeptide chains form a coil, we call them alpha helix’s
When polypeptide chains form a zigzag pattern, we call them beta-pleated sheets.
