Unit 2: Molecules

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Carbon: - Since it has 4 valence electrons, It can form 4 single bonds and is thus suited for being the backbone due to its stability - It allows carbs, lipids, proteins, and nucleic acids to form

Monomer: - Molecules that join to other similar molecules to form a polymer OR one unit of something EX: DNA’s monomers are nucleotides + Polymer = DNA Carbohydrates: - Their monomers are monosaccharides + polymer = carbs

Process: - Polypeptides are made via condensation reactions which release a water molecule - The OH/hydroxyl group is from both of the monosaccharide leaves. Leaving the molecule w one oxygen between them - Bonds are usually formed between 1 and 4 prime carbon of diff. monosaccharides

Monosaccharides: - Defined as a single sugar molecule - Atoms C,H,O are always in a 1:2:1 ratio EX: C6H12O6 - hydrogen to oxygen ratio is 2:1

Carbs: - are broken via hydrolysis reactions - Are defined by an addition of water to split apart the bond of a large molecule

Classification: - is classified based on the # of sugar molecules - one sugar are called monosaccharide, two are disaccharides, and many are polysaccharides + poly are the energy for organisms

Hexose: - are monosaccharides with 6 carbon EX: Glucose, galactose, fructose Pentose: - monosaccharide w 5 carbons EX: deoxyribose and ribose

Glucose: - are types of glucose and hexose sugars - alpha: at the one prime carbon, the hydroxyl group is pointed up -Beta: at the one prime carbon, the hydroxyl group is going down

Glucose: 1. is Soluble in water because it’s polar and can be dissolved in a polar solvent such as water 2. can be easily transported EX: in the bloodstream 3. relatively stable compound and doesn’t degrade as its being transported cause strong cov bonds 4. Yields a great amount of energy when the covalent bonds break

Starch: - Starch is made of amylose amylopectin - Amylose: long chains of alpha glucose molecules - Amylopectin: long chains of alpha glucose + branching of alpha glucose - Starch is not soluble in water due to the size which allows for compact storage of starch grains w out affecting osmotic pressure - After 20 glucose units, amylopectin has a branch - They are bonded w glycosidic bonds - are compact due to branching and coiling Note: Starch is made of glucose molecules

Glycogen: - is defined as a polysaccharide for short-term energy - has cov bonds between 1 + 4 carbon and has branches of alpha glucose bonding to 6 prime carbon - Its insoluble, and compact due to branches and coiling Note: Glycogen is made of glucose molecules

Cell wall: - cellulose has long chains of beta glucose molecules which are unbranched - molecules bonded between 1 + 4 carbon - every second beta glucose molecule is flipped resulting in a straight chain - Cellulose forms groups called microfibrils held together by hydrogen bonds - Microfibrils have high tensile strength to maintain the structural integrity of cell wall

Fatty acids: - Contain a carboxyl group (-COOH) and a methyl group (-CH3) - can be saturated: only contains single bonds between hydrocarbon chain - can be unsaturated which means they have double bonds that are bent and are called kinks - Amongst unsaturated, it can be monounsaturated or polyunsaturated meaning one or many double bonds

Mem proteins: - glycoproteins have a carbohydrate chain - the carb has a specific shape that can act as an antigen: the molecule that binds to a receptor on a cell surface for cell to cell communication (ID card)

Glycoproteins: - cell to cell adhesion: interact with other glycoproteins to form tissue - receptors: when hormones bind = changes metabolism in cell - cell-cell communication: neurotransmitters bind to glycoproteins - immune response: act as markers on cells allowing the immune system to distinguish outside cells - act as an antigen which simulates an immune response = production of antibodies to remove pathogens

Fats: - fats are triglycerides which are solid at room temperature - they have a higher MP and are usually saturated - used by animals Oils: - oils are triglycerides that are liquid at room temperature w a lower MP - fatty acids are unsaturated because the kinks mean they are more spread out so they turn liquid - Oils are used by plants and fish

Triglycerides: - made of one glycerol molecule (a sugar) and 3 fatty acids Phospholipids: - made of one glycerol molecule + 2 fatty acids + one phosphate • both are formed via condensation reactions

• triglycerides are good insulators cause they have a low thermal conductivity

Steroids: - they are lipids with 4 carbon rings +. a hydrocarbon chain - They can diffuse through the cell mem cause they dissolve in fatty acid tail EX: Oestradiol and testosterone

Water: - is polar, covalent, w weak charges at poles - is dense as a liquid than a solid EX: ice floats in water - can bond with 4 other water molecules Examples: - water makes up the cyto and is also found between cells as interstitail fluid because metabolic processes work best in an aqueous environment

Electronegativity: - the strength of attraction between an atom and its valence electrons Water: - oxygen has a more positive nucleus than hydrogen atoms and has greater attraction for the elctrons - So electrons are shared unequally - the hydrogen bonds of water are weak

Water: - it dissolves stuff well EX: anyt polar will dissolve - water forms hydrogen bonds with anything polar and pulls it apart

Xylem: - a thin narrow tube that transports water and the nutrients in the water from the roots of the plant to the leaves - This is due to capillary action: the ability of water to flow against gravity in a narrow space + the co/adhesion of water - water sticks to the plant and also to other water molecules