SBI4U

• The cytoplasm is the jelly-like substance surrounding the nucleus, containing organelles such as mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, cytoskeleton, and chloroplasts.
• Water is a bent molecule with a polar covalent bond. When two H2O molecules are attracted to one another, they form hydrogen bonds. This is a property called cohesion, and why water forms droplets on hydrophobic surfaces.
• Adhesion is another property of water where H2O sticks to other polar molecules. Together, adhesion an cohesion cause capillary action. In tubes (example: phloem and xylem), water sticks to the vessel walls due to adhesion, pulling the water up. The water molecules stick to each other through cohesion, causing all the water to move upwards.
• Water is one of the only liquids that is denser than its solid form (ice). This is because when water freezes, it forms a crystalline structure that traps air within in.
• Water has a lot of surface tension due to cohesive forces. Strong H-bonds create a net-like structure, which is why small objects can rest on thin films of water. They don't have enough force to break the strong H-bonds.
• High-heat Capacity: takes a lot of energy (heat) to break H-Bonds, and must release a lot of heat/energy or absorb a lot of heat/energy to change temperature.
• High Heat of Vaporization: special type of high heat capacity. takes a lot to increase temperature so much that water vaporizes (IMFs are weakened so a change in state can occur). Evaporative cooling is an example of this.
• Water is a universal solvent.
• Autoionization: a process by which an atom or a molecule in an excited state spontaneously ionizes (self-ionization). Water undergoes autoionization at 25 degrees C (2/554 million)

  2H2O ⭤ H3O+ + OH- OR H2O ⭤ H+ + OH-
• Water has a pH of 7, meaning [OH-]=[H3O+]
• Strong acids/bases - fully ionize

  Weak acids/bases - partially ionize; most organic acids/bases
• Conjugate acid/base pair: An acid and a base which differ only by the presence or absence of a proton

  Ex. H20 (conjugate base) and H3O+ (conjugate acid)
• Bicarbonate buffer system: The system of buffers that maintains the pH of the blood.

  H2O + CO2 ⭤ H2CO3 ⭤ HCO3- + H+
• Hydrocarbon: nonpolar, symmetrical organic molecules made of carbon and hydrogen

  Alkane: single bonded carbon (C-C)

  Alkene: double bonded carbon (C=C)

  Alkyne: triple bonded carbon

  Methyl Group: hydrocarbon, CH3
• 6 functional groups: hydroxyl, carbonyl, carboxyl, amino, phosphate, sulfhydryl, ester, ether, amide

  increase solubility, many contain Oxygen and Nitrogen which are very electronegative
• Hydroxyl: -OH

  alcohols (names end in -ol), polar, hydrophilic, forms H-Bonds (increases solubility), found in carbs, proteins, lipids, and nucleic acids
• Carbonyl: C=O group (aldehyde, ketone)

  polar, soluble, positional isomers

  Aldehyde: end of molecule

  Ketone: middle of molecule

  **important for naming sugars (aldose or ketose)
• Carboxyl: -COOH

  acidic (can donate H+), negatively charged, hydrophilic, carbonyl + hydroxyl, found in amino acids and fatty acids
• Amino: -NH2

  weak base called an amine (accepts H+ to become NH3), polar (some solubility in H2O, but solubility decreases and carbons are added), high affinity for H-bonds, found in amino and nucleic acids.
• Sulfhydryl: -SH

  also called thiols, less polar and soluble than OH, strong odor, can form disulfide bridges (for proteins, this creates cross-links and stabilizes structure in tertiary structure)

  Cysteine is the only amino acid with an SH group
• Phosphate: -PO4 2-

  polar, acidic when H+ is accepted, transfers energy between molecules (ADP --> ATP), found in nucleic acid
• Ether: C-O-C

  Ester: O=C-O

  Amide: O=C-N
• Isomers: molecules with the same molecular formula but different structure

  example: glucose, fructose, and galactose (C6H12O6)
• Structural Isomers: same formula, different arrangement

  Skeletal/Chain: difference in backbone

  Positional: position of functional group changes (ex. aldehyde vs ketone)

  Functional: change in functional group
• Stereoisomers: different 3D spatial arrangement

  Geometric: molecules differ in spatial arrangement around C=C

  Cis vs trans - cis=same molecules on either side, trans=same molecules are diagonal

  Enantiomers: non-superimposable mirror images (ie. right vs left hand)

  Diastereomers: non mirror images, non identical stereoisomer (ex. glucose and galactose)
• Chemical Reactions:

  Neutralization: acid + base --> water and salt

  Dehydration synthesis: produces water to join 2 molecules (ex. formation of a disaccharide)

  Hydrolysis: uses water to break molecules apart

  Reduction-Oxidation (REDOX): transfer of electrons LEO the lion says GER (LEO- loss of e- is oxidation, GER- gain of e- is reduction)
• Carbohydrates: monosaccharides, disaccharides, polysaccharides

  formula: (CH2O)n

  contains many hydroxyls and one carbonyl- carbonyl takes priority so we start counting carbons from there

  Location of carbonyl: End=aldose sugar middle=ketose sugar
• Hexose sugar= glucose, fructose, galactose

  α vs β- if OH on C1 is on a different plane to C6 group then α, if on same plane then β

  on fructose use C5

  α + β glucose are diastereomers
• sweetest monosaccharide=fructose
• Glucose vs galactose check carbon 4 --> if C4 OH group is same plane and C6=galactose, if OH is on different plane then C6=glucose
• Pentose sugar: ribose or deoxyribose

  DNA: C5H10O4

  RNA: C5H10O5

  Ribose has an OH on C2 where deoxyribose has an H
• Polysaccharides: complex carbs that are insoluble due to size but still hydrophilic and form H-bonds with water

  bonds are easily broken between mono and disaccharides which releases energy
• Starch: linear (helical) chains of alpha glucose

  can easily be broken down and synthesized into glucose subunits

  used for slow energy release and energy storage in plants

  Amylopectin- slight branched chains

  Amylose- unbranched chains
• Glycogen: chains of alpha glucose with many branching points which allows for faster energy release (allows for rapid hydrolysis into maltose)

  energy storage in animals (mostly in liver and muscle cells)
• For glycogen and starch: branching points have an α 1, 6 glycosidic linkage

  chain has α 1, 4 glycosidic linkage
• Cellulose: straight chain of β-glucose

  due to β every other glucose monomer is inverted (results in non-helical chain)

  strength and rigidity comes from cross links formed by H-bonds b/w parallel strands

  humans cannot digest these bonds

  used for cells walls due to β-glucose and H-bonds created by linear, packed form
• Disaccharides:

  Lactose: galactose + glucose

  Maltose: glucose + glucose

  Sucrose: glucose + fructose
• Glycosidic linkage=special ether bond

  covalent bond b/w hydroxyl groups of 2 monosaccharides=disaccharide
• sugar is very soluble due to its polarity and hydrogen bonds from the many hydroxyl groups

  slightly negative O2 in H2O is attracted to slightly positive hydrogen in sucrose

  • sucrose is surrounded by H2O = hydration shell
  • sucrose=shielded from other molecules and dissolves
  • hydrophilic and soluble
• Bilayer: two layers of phospholipids stacked on top of one another with their hydrophobic tails facing each other and their hydrophilic heads facing outside