Chemical structures
Molecular Formula
Shows the number of each atom in an element or compound
Structural Formula
Shows how the different atoms are bonded together, on a 2-dimensional plane
Organic Chemistry
The study of carbon based compounds
Organic compounds usually contain primarily carbon and hydrogen, but we’ll also see some containing other elements
hydrocarbons:
Molecules containing only carbon and hydrogen atoms
Because of their symmetric nature, large hydrocarbons are non poluar
Functional groups
Hydroxyl (-OH)
Polar due to the electronegative oxygen atoms
Water molecules are attracted to hydroxyl group, making it highly soluble (dissolves) in water
Sugars and alcohols are highly soluble in water because they contain hydroxyl groups
Names usually end in -ol (ie. Ethanol)
Carbonyl (-CO)
Carbon is joined to the oxygen by a double covalent bond
Polar (hydrophilic)
Aldehyde
Ketone
Carboxyl (-COOH)
Carbon atom double bonded to an oxygen atom and single bonded to a hydroxyl group (-OH)
Polar (hydrophilic)
Source of hydrogen ions (H+), which makes a molecule acidic. These organic acids are called carboxylic acids.
Amino (-NH₂)
Nitrogen atom bonded to a hydrocarbon radical and two hydrogen atoms
Polar (hydrophilic)
Molecule is basic. These molecules are organic bases called amines.
Act as a base, picking up protons (H+) from the surrounding solution.
5) Sulfhydryl (-SH)
Sightly polar (hydrophilic)
Help stabilize structures of proteins
Phosphate (PO₄⁻³)
Polar (hydrophilic)
Negatively charged
Found in molecules that make up the cell membrane, as well as DNA and RNA
Transfer of energy between organic molecules (ATP)
always contain Carbon, Hydrogen, and Oxygen
They store energy in a way that is easily accessible by the body
simple and complex carbohydrates
Monosaccharides = simple sugars (between 3 to 7 carbon atoms)
Mono = one
Saccharide = sugar
Examples:glucose, frutose, galactose
How are these 3 monosaccharides similar and different from one another?
Different:
Arrangement of atoms differ
Similar:Same molecular formula: C6H12O6
Glucose, fructose and galactose are isomers of each other
Disaccharides: 2 monosaccharides can join through a glycosidic linkage (between hydroxyl (OH) groups on each monosaccharide) to form a disaccharide
Examples:
Glucose + Fructose = Sucrose (table sugar)
Polysaccharide = many monosaccharides joined together by glycosidic linkages
Poly = many
Saccharide = sugar
Examples: starch, glycogen, cellulose
Plants store glucose as starch
Animals store glucose as glycogen
Cellulose provides structural support in plant cell walls
Composed of carbon, hydrogen, and oxygen atoms
types of lipids
triglycerides: Made up of 1 Glycerol + 3 Fatty Acids
Three types:
Saturated fatty acid (no double bonds)
Mono-unsaturated fatty acid (1 double bond)
Poly-unsaturated fatty acid (2 or more double bond)
Humans cannot synthesize polyunsaturated fats (“healthy fats”); they must be consumed in our die
The double bond makes a “kink” or a bend in the structure that prevents the fatty acids from packing tightly
Phospholipids
About them: Main components of cell membranes
Head is polar (hydrophilic) – glycerol, phosphate, choline
Tail is non-polar (hydrophobic) – fatty acids
other lipids
Waxes: lipids made of long carbon-based chains that are solid at room temperature
Steroids: a lipid made of 4 carbon-based rings
Each differs depending on the arrangement of atoms in the rings & the functional groups attached
Higher proportion of non-polar C-H (high energy) bonds makes lipids extremely hydrophobic (insoluble in water)
Lipids yield more energy than carbohydrates
The energy in the lipids hydrocarbon chains is less accessible to cells than carbs → lipids provide longer-term energy and are processed by the body after carbs have been used up
Extremely diverse type of macromolecules
Ex of functions ...Catalyzing chemical reactions (enzymes)
Providing structural support (bones, skin, hair, nails)
Transporting substances in the body (blood- hemoglobin) :
Monomer: amino acids
Amino acids contain a central carbon atom bonded to a:
Hydrogen atom
Amino group
Carboxyl group
R group (side chain)
levels of protein organization
Primary Structure
Linear sequence of amino acids
2. Secondary Structure
A polypeptide can form:
Alpha helix: coil-like shape
Beta pleated sheet: folded, zig-zag shape
3. Tertiary Structure
Protein folding to create 3D structure
Folding occurs as the different R groups in a polypeptide
4. Quaternary Structure
In proteins with multiple polypeptide chains, these separate polypeptides are arranged into a 4th level of organization
two types
2 types:
DNA (deoxyribonucleic acid) → contains the sugar deoxyribose
RNA (ribonucleic acid) → contains the sugar ribose
DNA and RNA are polymers of thousands of repeating nucleotide monomers
About nuecleotides
A nucleotide is made up of 3 parts covalently coned together:
A phosphate group
A 5-carbon sugar
A nitrogenous base
Complementary base pairing (DNA): nucleotide bases always pair together in the same way:
T pairs with A
G pairs with C
A polymer of nucleotides is referred to as a strand
The covalent bond between nucleotides is a phosphodiester bond → between the phosphate group on one nucleotide and a hydroxyl group on the sugar of the next nucleotide
Strand backbone: alternating phosphates and sugars
Bases are projecting from the strand
Passive Transport
* cell does not require energy
* substances move [high] → [low]
Diffusion
Simple Diffusion = random movement of particles from an area of high concentration to an area of low concentration
down a concentration gradient [high] → [low]
Osmosis
Osmosis = simple diffusion of ONLY water across a selectively permeable membrane
Water is so small and there is so much of it, it can freely cross the membrane
Water is transported down a concentration gradient [high] → [low]
A cell can find itself surrounded by one of 3 different types of solutions:
Hypertonic - more solute, less water
Hypotonic - less solute, more water
Isotonic - equal solute, equal water
Facilitated Diffusion
Facilitated Diffusion: diffusion of specific particles through transport proteins found in the membrane
Some molecules (large or polar molecules) cannot easily diffuse directly through the cell membrane, so they are “helped along” with a special protein
Transport proteins are specific - it recognizes and “selects” only certain molecules to cross the membrane based on shape, size, or charge
Molecules move down a concentration gradient through transport protein [high] → [low]
Active Transport
* cell does require energy
* substances move [low] → [high]
Primary Active Transport
Uses ATP directly to move molecules or ions from one side of the membrane to the other side, AGAINST the concentration gradient
Requires the use of carrier proteins (not channel proteins)
Example: Na+/K+ pump (sodium potassium pump)
Secondary Active Transport
Uses an electrochemical gradient (created by primary pump) as a source of energy to transport molecules or ions across a cell membrane
The energy is then used to transport another solute against its concentration gradient
Requires the use of transport (carrier) proteins
Bulk Transport (Endocytosis & Exocytosis)
Moving large molecules into & out of cell through vesicles
examples: proteins, polysaccharides, hormones
requires energy
ENDOCYTOSIS (bring material inside)
phagocytosis = “cellular eating”
pinocytosis = “cellular drinking”
EXOCYTOSIS (release material outside)