Polar: Oxygen has a partial negative charge, hydrogen has a positive charge
Hydrogen bond: Weak bond between hydrogen in a polar molecule and a small electronegative atom, forms due to the two atoms’ opposite charges
Cohesion: Hydrogen bonds hold a substance together
Adhesion: Clinging of one substance to another-- especially between water and another polar substance
Both adhesion and cohesion allow water to move against gravity
Surface temperature: How difficult it is to break or stretch the surface of a liquid, water has a high surface tension due to hydrogen bonds

High specific heat: Water is able to absorb/release a lot of heat without its own temperature changing much, water absorbs warm air and releases it to cooler air. Allows climate moderation
High heat of vaporization: Water has to absorb a lot of heat to change from a liquid to a gas and water cools when its molecules evaporate. Allows evaporative cooling

Floating ice insulates water below it

Solvent: The substance that dissolves other molecules in a solution
H2O is a versatile solvent due to its polarity
Water can carry many chemicals, nutrients, and minerals throughout an ecosystem and the organisms within it

Topic 1.2-1.6: Macromolecules and the elements of life

Carbon: Has 4 valence electrons so can form 4 covalent bonds, allowing it to be the backbone for many complex and diverse molecules
Organic compounds: Compounds containing carbon

Functional groups change function by being directly involved in chemical reactions
Hydroxyl (OH-): Alcohol, make substance more basic (raises pH)
Carboxyl (-COOH): Acid, contributes H+ (lowers pH)
Amino group (-NH2)
Phosphate group: Add negative charge to a molecule

Polymer: A molecule made of similar building blocks
Monomer: One of the units making up a polymer
Dehydration reaction: Monomers connected and covalently bonded by removing a hydrogen from both molecules and an oxygen from one (making H2O)

Hydrolysis: Bond between monomers of a polymer is broken by adding H2O

Hydrolysis example

Contain elements: Carbon, hydrogen, and oxygen
Monomer: Monosaccharide
Polymer: Polysaccharides (chain of monosaccharides linked by covalent bonds called glycosidic linkages)
Functions: Provide and store energy, provide structural support

Important polysaccharides (all are glucose polymers)

Starch: Stores glucose in plants
Glycogen: Glucose storage in animals
Chitin: Structural polysaccharide in fungi cell wells and arthropod exoskeletons
Cellulose: Cell wall component for plant cells

Trigylcerol: 3 fatty acids attached to one glycerol, energy storage

Phospholipid: Form phospholipid bilayer, have a hydrophilic head and hydrophobic tail

Cholesterol: Steroid that contributes to cell membrane integrity

Elements: Carbon, hydrogen, oxygen, phosphorus
Monomers: Nucleotides, consist of a 5 carbon sugar, a phosphate, and a nitrogenous base
Polymers: Nucelic acids, linear sequences of nucleotides
Nitrogenous base pairs: Adenine pairs with thymine (or uracil in RNA), and cytosine pairs with guanine
Purines: Have a 2 ring structure (A and G)
Pyrmidines: Have a 1 ring structure ( C and T/U)
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C and G are joined by 3 bonds, A and T are joined by 2
Directionality: Determined by orientation of sugars (hydroxyl = 3´ and phosphate = 5´)
Base pairs are joined by hydrogen bonds, nucleotides joined by covalent bonds
DNA: Antiparallel double helix (2 strands running in opposite directions), has deoxyribose
RNA: Single stranded, has ribose