Download (DNA) and ribose (RNA)

The DNA-language consists of the ”letters” (bases) A, T, G og C
Uracil in RNA,
thymine in DNA
The bases in DNA (A) and RNA (B) are coupled to each other via deoxyribose
(DNA) and ribose (RNA), and with phosphate
A
B
The structure of DNA (one strand shown) and RNA
Note that the strands are antiparallel and have
a 5’ (5-merket) and a 3’ (3-merket) ende
Most DNA molecules are right-handed twisted
DNA-molecules can be visualized by elektron microscopy, here
illustrated by a particularly small molecule (plasmid, see later)
DNA can replicate itself by the help of numerous proteins. This is perhaps
the most important characteristic of life! Life anywhere (in the universe!)
without copying is difficult to envision
Proteins consist 20 different amino acids (R varies)
Covalent sulfur bridges can occur in proteins. This can have a major effect on
protein
3D structures and therebye functionality
S
u
l
p
h
u
r
b
r
i
d
g
e
s
The acid-base properties of amino acids have a big effect on protein functionality
The amino acids in proteins are held together by covalent peptide bonds.
Note that this defines the carboxyterminal and amino-terminal ends of
proteins. Polymerization occurs such that the amino acid at the amino
terminal end is the first to become incorporated.
The penta-peptide Ser-Gly-Tyr-Ala-Leu (SGYAL)
Monosaccharides are aldoses or ketoses
Many monosaccharides are epimers of each other
The monosaccharides can (and will) also be found in ring form
Monosaccharides can be linked to each other and become carbohydrate
storages (starch) or have structural functions (cellulose, chitin etc.)
The stiff ”skeleton” of this insect contains a lot of chitin, also in shrimps, crabs etc
Fungi can ”eat” the cellulose, which is a major component of wood. Cotton is
almost pure cellulose. What would happen if no organism could utilize
cellulose (like humans)?
Lipids typically have long chains of carbon atoms, but exist in many forms,
also linked to polysaccharides (lipopolysacchariders), phosphate
(phospholipids) and as triglycerides. They are typically found in cell membranes
and as stored fat (do you see it on yourself?). Candle-lights are composed of
long chain fatty acids
Different triglycerides (note the double bonds, which are interesting in
relation to human health)
Central Dogma
genetic information in DNA is passed
to next generation (heredity)
DNA
storage of genetic information
RNA
carrier of genetic information
Proteins
carry out the functions of the cell
This is probably the most important of all slides in the course!
An alternative way of illustrating the central dogma