ElementsAtoms form molecules/compoundsBonds: covalent (atoms share electrons) or ionic (atoms give/receive electrons).
H - Hydrogen
C - Carbon
Na - Sodium
Cl - Chlorine Methane
Sodium ChlorideIons
Elements / Minerals Most frequent elements: Carbon, Hydrogen, Oxygen and Nitrogen
Other elements:
- Sulfur (S): proteins/enzymes, plant growth
- Calcium (Ca): teeth, bones, cell wall component, muscle and nerve function
- Sodium (Na+): water balance (osmoregulation), muscle contraction, nervous
impulse
- Potassium (K+): nervous impulse
- Iodine (I): thyroid hormones
- Phosphorus (P): plant growth, bones/teeth, nucleic acids
- Iron (Fe): needed for chlorophyll formation /photosynthesis, red blood cells
(hemoglobin)
Hydrogen Bonds
The water molecules attract each other
Hydrogen bonds form (not real bond – strong attraction force)
Water propertiesTransparent: allows plants/algae to survive under waterStrong cohesion forces (polar molecule) = high surface tension (force between molecules at surface) = insects can walk on it/water goes from roots to leavesGood solvent for polar molecules = good transport medium (ex. blood, plants) + medium for chemical reactions
Water propertiesThermal properties (due to high specific heat, heat of fusion/vaporization) Consequences:1) can absorb larger amounts of energy and still remain liquid. Ex: large body of water can act as a buffer2) coolant effect = water absorbs large amounts of heat and cools the body (sweat)Ice floats, protecting the water below from freezing, allowing organisms to survive
Organic and Inorganic Compounds
Organic = all molecules containing carbon found in living systems exceptions: CO2 and carbonates (salt of carbonic acid - CO3
2− - ex: calcium carbonate and carbonated water)Main organic substances (macromolecules):-Carbohydrates-Lipids-Proteins-Nucleic Acids
Inorganic = all substances that are not organic
Carbohydrates
Most abundant
Short term energy storage
General molecular formula (CH2O)n
Basic unit: monosaccharides (fructose, glucose, galactose)
Two monosaccharides: disaccharides (maltose, lactose, sucrose)
Anything larger than this: polysaccharides (starch, glycogen, cellulose)
Monosaccharides
Glucose: one of main products of photosynthesis, starts cellular respiration - cell uses it as a source of energy
Galactose: sugar in milk
Fructose: sugar found in honey, fruits, vegetables
Ribose/Deoxyribose: RNA/DNA
structure
DisaccharidesSucrose — common table sugar = glucose + fructose
Lactose — major sugar in milk = glucose + galactose
Maltose — product of starch digestion = glucose + glucose
Polysaccharides Starches: plant storage
(excess glucose)
- before starches can enter (or leave) cells, they must be digested. The hydrolysis of starch is done by an enzyme called amylase.
Glycogen: animals storage (excess glucose).
-The liver and skeletal muscle are major deposits of glycogen.
Cellulose: plant structure (cell wall). Probably the single most abundant organic molecule in the biosphere. (fibers – paper, cotton)
Starch grains in potato cells
Cellulose fibers
Condensation/Hydrolysis
Condensation: 2 molecules are joined together + loss of 1 water moleculeHydrolysis: water helps break two units (monomers)
Lipids/FatsGlycerol + fatty acid chains
Large number of C - H bonds = non-polar molecules. Insoluble in water
Functions: -Long term energy storage-Thermal insulation (Arctic animals)-Major component of the cell membrane The fatty "tail" is non-polar (Hydrophobic) The phosphate "head" is a polar (Hydrophilic)
phospholipid
FatsSaturated: full of hydrogens – solid at room temperature
Unsaturated: one or more double bonds connecting carbons – liquid at room temperature
FatsCis – Trans-Oil for frying causes some of the cis bonds to convert to trans bonds. Fatty acids with trans bonds are carcinogenic.
All steroids (testosterone, estrogen, progesterone, cortisone…) and Vitamin D need cholesterol to be made.Cholesterol = controls how fluid the cell membrane will be
Energy contentAnimals use fats for energy storageFat stores lots of calories in a small space - 9Kca/g - against carbs (4Kcal/g)
ProteinsMade of amino acidsContain nitrogenMany functions:-Structural (muscles, collagen, keratin) -Enzymes (metabolism)-Carriers (hemoglobin, albumin)-Antibodies-Hormones (ex. insulin)-Membrane pumps (ATP pumps), receptors, neurotransmitters-Movement (actin, myosin)