Biology 221: Organic Molecules

Characteristics of an organic molecule

- contains carbon

- most contain carbon-carbon and/or carbon-hydrogen bonds

- many are essential for life

- some are synthetic

vitalism

- organic molecules that are produced by living organisms

synthetic organic molecule

tefzel

Properties of carbon

- can form single, double and triple bonds

- can bond to a wide variety of other atoms

- can form linear, branched, or ring-like structures

- can bond to a variety of functional groups

polymers

subunits covalently linked together

basic subunit of polymer

monomer

reaction type for subunits in a polymer are joined

condensation

reaction type used to degrade a polymer into individual subunits

hydrolysis

4 Major classes of organic molecules

carbohydrates, lipids, proteins, nucleic acids

atoms found in carbohydrates

carbon, hydrogen, oxygen

ratio of carbohydrate atoms

1:2:1

simplest forms of carbohydrates

monosaccharides

reducing sugars

a sugar reduced by adding another sugar to it

how a sugar can be a reducing sugar

a sugar can be a reducing sugar if it has a free aldehyde group or ketone group

forms that monosaccharides can exist

can exist as linear chains or as ring stuctures

properties of glucose

- very water soluble

- highly reduced molecule: good source of energy

functions associated with carbohydrates

- body's main source of energy

- aids in cellular breakdown of glucose

Disaccharide

a polymer consisting of two monosaccharides covalently linked by a glycosidic bond

bond used to join monosaccharides

glycosidic bond

formation of disaccharides

dehydration synthesis by removing 1 net unit of water

oligosaccharides

short chains of sugar molecules

polysaccharides

polymers consisting of monosaccharides subunits joined by glycosidic bonds (more than 2)

glucose polymers

starch, glycogen, cellulose

starch

found in plants

glycogen

found in the body

cellulose

fungi, major polymer in plants and living organisms

Peptidoglycan

- found in bacterial cell walls

- base is a sugar

Chitin

- found in exoskeletons of insects, bones

Glycosaminoglycans

- found in fluid surrounding joints

- long, unbranched polymers consisting of repeating disaccharide subunits

- The disaccharide subunit contains least one amino sugar

lipids are composed of

composed primarily of carbon, hydrogen, and a little oxygen

examples of lipids

fats/oils, waxes, triglycerides, phospholipids, steroids, hormones, and vitamins

properties shared by lipids

- non polar molecules (many C-C and C-H bonds)

- highly varied in structure (no repeating subunits)

lipids that are hydrophobic

fats/oils, waxes, phospholipids, and steroids

functions associated with lipids

membranes, energy storage, signaling

fatty acids are composed of

hydrocarbon chains with a carboxyl group

saturated fatty acid

no double bonds

unsaturated fatty acid

at least one double bond

monounsaturated

one double bond

polyunsaturated

more than one double bond

triglycerides composed of

3 fatty acids covalently linked to a molecule of glycerol through dehydration synthesis

bond used in triglycerides

ester bonds

Fats

has a lot of saturated fatty acids

Oils

has a lot of unsaturated fatty acids

Phospholipids

made of a glycerol molecule, two fatty acids, and a phosphate group

classification of phospholipids

amphipathic molecule because they have a hydrophilic head (phosphate group) and a hydrophobic tail (fatty acids)

Reason for arrangement of phospholipids in water

water drives the formation of membranes because phospholipids are amphipathic molecules

subunit in protein

amino acids

covalent bond in proteins

peptide bonds

functions of proteins

- forming rRNA

- movement

- protects organisms against disease

- chemical reactions in energy balance

- strength and support structures

- movement of solutes across membranes

naturally occurring amino acids

20

general structure of an amino acid

amino group + acid group

peptide

short chain of amino acids

polypeptides

a polymer of peptide bonds

primary structure of protein

linear sequence

functional groups on an amino acid

amino group and carboxyl group

Secondary structures of proteins

alpha helix and beta pleated sheets

Tertiary structure of a protein

3D shape

quaternary structure of a protein

two or more polypeptides may bind to each other to form a functional protein

Globular protein

compact, spherical, and soluble in water

Filamentous protein

long and elongated, forming thread-like structures and insoluble in water

Glycoproteins

adding a sugar

Lipoproteins

adding a lipid

Place where information for making proteins are stored

DNA - specifically genes

forces that contribute to formation of structures of proteins

Van der Waals forces

Importance of structure of a protein to its function

the specific shape determines which other molecules it can bind with to work in the body

functional domain on a protein

independently folded region(s) on a protein that performs a characteristic function

subunits of nucleic acids

nucleotides

bond used to join nucleic acids

phosphodiester bonds

groups participating in formation of phosphodiester bonds

sugar-pentose, phosphate group, and single/double ring of carbon and nitrogen

types of nucleic acids

deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)

function of DNA

stores genetic information

how DNA stores genetic information

by sequence of nucleotides

major types of RNA

tRNA, mRNA and rRNA

three basic parts of a nucleotide

nitrogenous base, pentose sugar and a phosphate

carbon that the base is attached to

Carbon 1'

Carbon that the phosphates are attached to

Carbon 5'

specific sugar found in DNA nucleotides

DNA - deoxyribose (would not have oxygen)

specific sugar found in RNA nucleotides

RNA - ribose (would have OH attaching at carbon 2')

bases that can be attached to DNA and RNA nucleotides

adenine, guanine and cytosine

base only found in DNA

thymine

base only found in RNA

uracil

purine bases

guanine and adenine

structural feature of purines

double ring structure

pyrimidine bases

cytosine, thymine, uracil

structural feature of pyrimidines

single ring structure

orientation of a double stranded DNA molecule

5' to 3'

adenine

thymine

guanine

cytosine

form that RNA exists in living cells

single-stranded molecules

orientation of the RNA with pairs of a strand of DNA

3' to 5'

orientation of strands in double stranded RNA molecule

anti-parallel orientation

adenine

uracil (RNA)

4 ring structure, lipids have a lot of carbon-carbon and carbon-hydrogen bonds and are non polar

Why are steroids, many hormones, some vitamins, and waxes considered to be lipids?

4 ring structure

What structural feature is shared by molecules classified as steroids?

process of proteins forming

protein synthesis through dehydration synthesis