Transcript The necessary introduction to histology_TK

The necessary introduction to histology
or
What is the composition of the living
matter?
Doc. MUDr. Marie Jirkovská,CSc
Institute of Histology and Embryology
Physical and chemical features of the components of
living mass determine their visualization on histological
slide.
DNA- deoxyribose, phosphate, bases (adenine,
guanine, thymine, cytosine - A,G,C,T)
less
stable
more
stable
nucleotide
R.J.Epstein: Human Molecular Biology, 2003
dinucleotide
DNA molecule – hydrogen-bonded
base pairs
From DNA to chromosome
Levels of DNA structure
R.J.Epstein: Human Molecular Biology, 2003
RNA- ribose, phosphate, bases (adenine, guanine, cytosine, uracil A,G,C,U)
mRNA – messenger RNA (transfer of information
from nucleus to cytoplasm)
rRNAs – together with certain proteins form ribosomes
tRNAs – match aminoacids to codons in mRNA
R.J.Epstein: Human Molecular Biology, 2003
ATP (adenosine-triphosphate), GTP (guanosine-triphosphate) ribonucleotides containing high-energy bonds.
Proteins
long chains of L-aminoacids, each linked to its neighbor through peptide
bond
Aminoacids: essential (from food only)
nonessential (synthetized in the organism)
According to features of aminoacids side chains (R) polypeptides
form three-dimensional conformation and have electrical charge.
Polypeptides may bind oligosaccharide chain (glycoproteins).
R.J.Epstein: Human Molecular Biology, 2003
Various shapes of
protein molecules
Alberts B et al. Essential Cell
Biology, 1998
Lipids – water insoluble
(fatty acids, triacylglycerols, steroids, glycolipids)
Fatty acids
a) saturated

b) unsaturated (one or
more double bonds ).
Components of
glycolipids,
phospholipids and
triacylglycerols.
Triacylglycerols esters of glycerol
and fatty acids
Steroids cholesterol and its
derivatives (steroid
hormones, biliary
acids)
Glycolipids -
Essential fatty acids – from food only
(e.g. linoleic acid, linolenic acid).
composed of two long
hydrocarbon chains
and a polar region
containing one or more
sugar residues.
Alberts B et al. Essential Cell Biology, 1998
Sugars (mono-, di-, oligo-, polysaccharides)
Monosaccharides - e.g. components
of nucleic acids (ribose, deoxyribose),
energy source (glucose).
Disaccharides - energy source,
absorbed after breaking down into
monosaccharides.
Alberts B et al. Essential
Cell Biology, 1998
Oligosaccharides and
polysaccharides - linear and
branched molecules made from
monosaccharides, e.g. glycogen
(made entirely of glucose units).
Enzymes
determine all of the chemical transformations that occur in cells. Each
of thousands of those transformations is catalysed by a special
enzyme. The name of enzyme is characterized by suffix -ase (e.g.
phosphatase, dehydrogenase).
Enzyme consists of a big protein molecule which conformation forms „active site“ there is bound molecule of substrate (S). Enzyme catalyses its transformation to
product.
Lock and key model of
enzyme mechanism.
Elliot H, Elliot D: Biochemistry
and molecular biology, 2001
In addition to protein molecule (apoenzyme), the function of some enzymes
requires cofactors ( Mg+2 , Zn+2) or coenzymes (e.g. vitamine derivatives).
Temperature and pH influence the activity of enzyme.