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Carbon & Large biological molecules ( Carbon and the molecular…
Carbon & Large biological molecules
Carbon and the molecular diversity of life
Carbon
Can form molecules large, complex & varied
DNA, proteins, carbs all compose of carbon bonded to each other
organic chemistry
compound containing carbon are organic
can arise only in living organisms
Friedrich Wohler
tried to make inorganic salt
made urea instead
study of carbon compounds
percentages pf C, H, O, N,S ,P are uniform from on organism to another
can form 4 bonds
carbon has 6 electrons & 4 valence electrons
shares 4 electrons to 8 electrons are present
forms single or double covalent bonds
single covalent bond- causes bonds to form tetrahedron
double bond- from a plane
Ex: Ethene C2H4
Ex: Methane CH4
electron configuration gives it covalent compatibility w/ diff atoms
Carbon skeletons
formed by carbon chains
vary in length, can be straight, branched or arranged in close rings
some have double bonds, very in number & location
Hydrocarbons
organic molecules consisting of only carbon and hydrogen
H attached to carbon skeleton where electrons available for covalent bonding
major components of petroleum
Isomers
compounds that have same # of atoms of same element s but diff structures & diff properties
Structural isomers
differ in covalent arrangements from their atom
Ex: figure 4.7
num of possible isomers increases as carbon skeleton increases in size
may differ in location of double bonds
cis-trans isomers
carbons have covalent bonds to same atom, but differ in spatial arrangement due to inflexibility of double bonds
single bonds allow atoms to rotate
if double bond joins two C and each have two diff atoms attached , the two distinct cis-trans isomers possible
Ex: Figure 4.7
Enantiomers
isomers that are mirror images of each other but differ in shape due to presence of asymmetric carbon
attached to 4 diff atoms or groups of atoms
can be arranges around asymmetric carbon in two diff ways
left-handed & right-handed versions of molecule
right-handed one won't fit into left-handed space
Chemical groups
properties depend on various chemical groups attached to skeleton
groups can participate or contribute to function indirectly
Can affect molecular shape, contributing to function
directly involved in chemical reactions
functional groups
each have certain properties; Shape and charge
7 important chemical groups:
Hydroxyl , carbonyl, carboxyl, amino, sulfhydryl, phosphate, methyl
first 6 can be chemically reactive. Methyl not reactive
ATP
adenosine triphosphate
three phosphates ended together
Structure & function of large biological molecules
molecules of life
important large molecules sorted by: Carbohydrates, lipids, nucleic acids, proteins
carbs, proteins, and nucleic acids are called MACROMOLECULES
Polymers
a long molecule consisting of many similar or identical building blocks linked by covalent bonds
monomers are building block of polymers
enzymes break down all polymers
specialized macromolecules that speed up chemical reactions
dehydration reaction
two molecules covalently bonded with the loss of water molecule
when bonds form between two monomers each contributes part of water molecules that releases during reaction
disassembled to monomers by hydrolysis
reverse of dehydration reaction
means water breakage
broken by the addition of water molecule
ex: digestion in body
carbohydrates
includes sugars and polymers of sugars
Simplest carbs are monosaccharides; monomers
has a carbonyl group
Ex: glucose
carbon skeleton can classify sugars
major nutrients for cells
disaccharides are double sugars, two monosaccharides together
consists of two monosaccharides joined by glycosidic linkage
polymers are called polysaccharides
macromolecule, polymer with millions of monosccharides
joined by glycosidic linkage
serves storage or as building material for structures the protect cell or whole organism
storage polysaccharides
both plants and animals store sugars for later
plants store starch within cellular structures, plastids
animals tore a polysaccharide called glycogen, polymer of glucose
stored in liver and muscle cells
structural polysaccharides
organisms by strong materials with it
cellulose is a major component ti the cell wall of plant cells
chitin- carb used by arthropods to build their exoskeleton
lipids
does not include true polymers, not big enough to be considered macromolecules
lipids mix poorly with water
consist mostly of hydrocarbon regions
fats
are not polymers but are large molecules assembled by smaller molecules by dehydration reaction
contracted by glycerol and fatty acids
fatty acid is long long carbon skeleton
joined by ester linkage
phospholipids
major constituents of cell membranes
similar to fat molecules but with two fatty acids
proteins
can speed up chemical reactions, others play role in defense, storage, transport, etc.
enzymatic proteins speed up metabolism
can preform is functions over and over agin
all constructed by same set of 20 amino acids
bond is called a peptide band
amino acids
the monomers of proteins
has amino group and carboxyl group
polypeptides
amino acid polymers
joined together by the removal of water
resulting covalent bond is peptide bond
nucleic acids
polymers made of monomers called nucleotides
two types: deoxyribonucleic acid (DNA) & ribonucleic acid (RNA)
DNA provides directions for its own relipication
each chromosome contains one long DNA
info of cell activity is encoded in DNA
RNA controls proteins synthesis, gene expression