BI111 Lecture Notes - Lecture 3: Plant Cell, Hemoglobin, Pentose
Biology Unit test 1 Grade 12
Isotopes: Atoms with differing number of neutrons. Giving off extra energy
• If unstable and decays to another form, it is a radioisotope- each having specific half
lives
Ions: Elements that have gained/lost electrons
Ionic bonds: between metals and non-metals
Covalent bonds: form between non-metals sharing electrons
• Based on difference in electronegativity (how strongly they attract electrons)
• Bonds with electronegativity between 1.7-4.1 have ionic characteristics and bonds
below 1.7 have covalent characteristics
Polar molecules: slightly charged (exp. Water)
Non-polar molecules: uncharged (exp. Oil)
*Water + oil= do not mix
Polar covalent: elements with different electronegativity values
Non-polar covalent: elements have the same electronegativity vales. Also has a
symmetrical shape that cancels out electronegative differences.
• Linear (polar and non-polar)
• Bent Linear (polar)
• Pyramidal (polar)
• Tetrahedral (polar and non polar)
Hydrophilic: dissolves, mixes in water- aka likes water
Hydrophobic: fails to mix with water- aka doesn’t like water
Intermolecular Forces: weaker attractions between different molecules, often due to
different functional groups, ions or hydrogen bonds
• Hydrogen bonding is in charge of DNA structure
Intramolecular Forces: the covalent bond that holds the atoms of a molecule together and
the ionic bond that holds ions together in a salt
Neutralization: reaction between a base and acid, leaving water and an ionic salt.
• With weaker acids and bases there is often a balance between conjugates to create a
buffer system
o Buffer: Chemical systems containing a substance that can donate H+ ions
when they are required and containing a substance that can remove H+ ions
when there are too many in a solution. Used to resist significant changes in
pH
• An acid is a proton donor and a base is a proton acceptor
Chemicals of life→
Carbon: all key molecules of life are based on carbon atoms
• Forms up to 4 stable covalent bonds
• Forms large structures with other carbon atoms (chains, branches, rings)
o Example: Hydrocarbon (octane, ethanol)
• Forms 1-3 bonds between each atoms in these chains:
1. Alkane: has only C-C bonds
2. Alkene: has at least one C=C double bond
3. Alkyne: has at least one C=C triple bond
• Creates many different organic compound life depends on (exp. Fructose)
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Other influences→
• Presence of different functional groups will influence how the molecule works
o Groups of other elements that attach
o Can result in intermolecular forces or change solubility of a molecule
Group
Chemical formula
Structural formula
Found in
Hydroxyl
OH
Alcohols (Ethanol)
Carboxyl
COOH
Acids (Vinegar)
Amino
NH2
Bases (ammonia)
Sulfhydryl
SH
Rubber
Phosphate
PO4
ATP
Carbonyl
COH
CO
Aldehydes
Ketones
Making Macromolecules→
Anabolic reaction: Building larger molecules from smaller pieces requires energy and
results in water production
• Condensation reaction (or dehydration synthesis)
• One H and one OH (H2O) are removed
• Can be reversed in a hydrolysis reaction (catabolic) – adding water and releasing
energy
• Requires enzymes
Carbohydrates→
• Most common organic compound
• Products of photosynthesis
• Source of energy and a building material for cells
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
If unstable and decays to another form, it is a radioisotope- each having specific half lives. Covalent bonds: form between non-metals sharing electrons: based on difference in electronegativity (how strongly they attract electrons, bonds with electronegativity between 1. 7-4. 1 have ionic characteristics and bonds below 1. 7 have covalent characteristics. Non-polar covalent: elements have the same electronegativity vales. Also has a symmetrical shape that cancels out electronegative differences: linear (polar and non-polar, bent linear (polar, pyramidal (polar, tetrahedral (polar and non polar) Hydrophilic: dissolves, mixes in water- aka likes water. Hydrophobic: fails to mix with water- aka doesn"t like water. Intermolecular forces: weaker attractions between different molecules, often due to different functional groups, ions or hydrogen bonds: hydrogen bonding is in charge of dna structure. Intramolecular forces: the covalent bond that holds the atoms of a molecule together and the ionic bond that holds ions together in a salt.
