BIOLOGY
CENTRAL DOGMA OF CELL BIOLOGY
CELL DIVISION (phases)
NUCLEUS, DNA-code and MUTATION
( + Cancer as problem of cell division and
mutation )
„META-BACKROUND“
for the all organels
(central dogma of cell biology of
eukaryotic cells)
• DNA is form of genetic infromation. DNA
can be replicated and exportedto
daughter cells. (in nucleus)
• DNA can be transcribed to RNA code.(in
nucleus)
• RNA code can be translated to protein.
(in Ribosomes)
• Complex scheme of transcritpiton and
translation:
• Technical details of DNA structure and
RNA structure:
Adenine(A), Guanine(G), Cytosine(C), Uracil
(U) and Thymine (T)
DNA: A, G, C, T
RNA: A, G, C, U
• !!! Different cells in the body produce
different final protein from DNA code:
How it is possible? The trasncription of many genes cen be spliced in
various ways to produce different mRNA.
How is the code of RNA recoded to amino-acid
NUCLEUS
AND CELL DIVISION
• DNA chains in nucleus are not like single molecules of water in
cup. DNA in nucleus is divided into several „macro-molecules“
which are conncetd with protein scaffolds
• this components create:
„DNA+protein“ = CHROMOSOMES
Diagram of a replicated and condensed metaphase eukaryotic
chromosome. (1) Chromatid – one of the two identical parts of
the chromosome after S phase. (2) Centromere – the point
where the two chromatids touch. (3) Short arm (p). (4) Long
arm (q).
• Human cells normally contains 23 pairs of chromosomes, for a total of
46. Twenty-two of these pairs, called autosomes, look the same in both
males and females. The 23rd pair, the sex chromosomes, differ between
males and females. Females have two copies of the X chromosome,
while males have one X and one Y chromosome.
Human somatic cells undergo cell-dividing, this somatic cell nuclear
and cell dividing is called MITOSIS --- 6 steps:
Two types of cell division
MUTATION
• A mutation is a change that occurs in our DNA
sequence, either due to mistakes when the DNA is copied
or as the result of environmental factors (Gamma
radiation, UV light and cigarette smoke…)
• Often cells can recognise any potentially mutationcausing
damage and repair it before it becomes a fixed
mutation.
• Not all mutation had to be negative (positive mutation
are axis of evolution in hisgtorical pariod)
MUTATION
• Mutation can be crated during the DNA replication:
(on the picture: one possible type of mutation, several another types
exist – overview in next pages)
(Ad. Mutation)
• Each eukaryotic cells have systems for
„error“ founding and elimination of part of
DNA (or self-killing of the whole cells)
• „The body must survive, each one single
cells had to be prepared for mutation
elimination or selfkilling“
• Types of mutation from the view of the
tissue:
Spontaneous versus induced
mutation
We can list 5 type of the SPONTANEOUS mutation
INDUCED MUTATION: some external
factor play role in increasing of mutation:
• !!There exist several types of mutation of DNA chain !!
Types and frequency of mutations
CANCER = illness conected
with mutation
Due to the mutation: „cancer cells have shifted rules of
metabolism“
And shifted expansion and dividing strateg: analogy to rational and chaotic
overgrow of cities
Rational and organised x
Overgrowing and selfkilling
LONG TERM SURVIVING:
Sustainable development vs. Unsustainable development
Cancer from antoher site:
Cell divison and chemotherapy
Cell divison and chemotherapy
(some cytostatic agent arrests the cell cycle at G1 or G2 or S or
M phase:
Global overview of „un-rational“ changes in
genetic code of cancer cells (…reason why the
selfelimination and external fighting is not easy).
Another illnesses caused by
mutation
• ANEMIA
• Goode overview: https://www.nature.com/scitable/topicpage/genetic-mutation-441/
• Some examples of single-gene
disorders include
1. cystic fibrosis,
2. alpha- and beta-thalassemias,
3. sickle cell anemia (sickle cell disease),
4. Marfan syndrome,
5. fragile X syndrome,
6. Huntington's disease, and
7. hemochromatosis.