Biochemistry Crash Course Videos (Crash Course)
Video #1
โ Carbon. Contains 6 protons and 6 neutrons
โ Atomic weight of 12
โ Carbon is the foundation of biology
โ Forms covalent bonds
โ Electrons shared equally b/w bond โ non polar
โ Non equal, slight (+) and (-) charges โ polar
โ Ionic bond: donate/ accept electrons, a charged ion forms
โ Halogen โ needs 1 more electron for octet (Cl)
โ Alkalineโ only has 1 electron in octet (Na)
โ Become Na+ and Cl- after donation of electron โ ionic bond formation creates salt
Video #2
โ H2O uses a covalent bond: each hydrogen shares an electron with oxygen. It is thus a polar
molecule.
โ All water molecules are attracted to each other due to this polarity โ these are hydrogen bonds
(between the positive and negative poles of different molecules)
โ Hydrogen bonds in water results in high cohesion, and thus high surface tension.
โ Cohesion is the attraction between two like things (e.g. two water molecules).
โ Water has the highest cohesion of any non-metallic liquid.
โ Adhesion is the attraction between two unlike things (e.g. water and glass).
โ Capillary action is water defying gravity.
โ Water is the greatest solvents (due to its polarity).
โ Hydrophilic molecules are polar โ their polarity is stronger than the cohesive forces of water.
โ Hydrophobic molecules cannot break the cohesive forces of water because they are non-polar.
โ Solid water is less dense than liquid water due to hydrogen bonds forming crystalline structures
that space molecules apart more easily (when frozen).
โ Water has a very high heat capacity โ it is good at holding on to heat, thus oceans regulate climate
and temperature of planets.
Video #3
โ William Prout discovered that our stomachs have hydrochloric acid and discovered the chemical
composition of urea. Also discovered food is divided into carbs, fats, and proteins
โ Carbohydrates are the source of all energy
โ Carbs are made of sugars with the simplest being monosaccharides
โ Glucose, a monosaccharide, number 1 sugar that comes from the sun
โ Fructose, same chemical as glucose, but arranged differently, and is sweeter
โ Disaccharides are two monosaccharides put together
โ Sucrose, fructose and glucose connected, is a disaccharide joined by a covalent bond
โ Polysaccharides are thousands of simple sugar units
โ Cellulose is a bunch of glucose molecules
โ Bread is made of starch and amylase
