Biologie Cellulaire Flashcards
Whats is pycnose
Altération du noyau de la cellule qui se présente sous la forme d’une masse condensée.—
difference apoptose et necrose
La nécrose est une mort cellulaire non programmée souvent causée par des dommages aigus, tels qu’une blessure ou une infection, entraînant une inflammation et la destruction de larges zones de tissu. L’apoptose est une mort cellulaire programmée, hautement régulée, qui permet à la cellule de se dégrader sans provoquer d’inflammation
how fibrosis happen
— Fibrosis, or scarring, is defined by the accumulation of excess extracellular matrix components.
ibrosis is a kind of common pathological process characterized by abnormal activation of fibroblasts (A fibroblast is a type of cell that contributes to the formation of connective tissue,)and excessive deposition of extracellular matrix, which may cause organ dysfunction, or even organ failure in highly progressive cases
Persistent inflammation, or hepatitis, sends nonstop signals to repair cells to continue depositing collagen. The extra collagen stiffens around the tissue like it is supposed to in the healthy liver; but, instead of a signal being released to stop the inflammation and discard the extra collagen, the inflammation continues, and even more collagen is deposited, leading to more stiffening. This is how fibrosis develops
what are heavy metal
“metallic elements that have an atomic
mass greater than 20 and a density greater than 5 g/cm3
Cites les metaux essentiels pour les poissons
copper (Cu), zinc (Zn), chrome (Cr), nickel (Ni), cobalt (Co), molybdenum
(Mo), and iron (Fe), have important biological functions. in the case of deficiency or significant increase, they can become toxic.
Que sont les metaux non essentiels
in the case of deficiency or significant increase, they can become toxic.
Ag, Al, Cd, Pb, Hg, As, Sr
Est ce eux les métaux dans l’eau se dégrade avec le temps
These contaminants are not naturally degraded over time,
remaining in water or sediment for a long time
De quoi dépend l’accumulation des métaux dans les poissons
The accumulation
of metals in fish can vary according to à
-the degree of exposure,
(. the concentration of pollutants)
-, the duration of exposure, and water
parameters ( such as pH, hardness, organic matter, temperature, and
salinity )
- according to the
biological characteristics of the fish, ( age, length, weight, feeding
habits, habitat, and metabolic status )
Où les polluants s’accumulent dans le corps des poissons
In general, these pollutants tend to accumulate in
metabolically active tissues such as the liver, spleen, gills, and kidneys
and can affect enzymatic and metabolic activity,
Cites les ROS principaux produtis par les métaux
superoxide (O2●) hydroxyl (OH●), and alkoxyl (RO●) and the
non-radicals, hydrogen peroxide (H2O2) and peroxynitrite (ONOO ).
Comment les ROS sont produits ?
ROS can be generated both via cellular reactions and as a result of electrochemical (corrosion) and metal release reactions taking place on metallic NPs or biomaterials in biological settings. —
How metals can be involved in oxidative
damage.
- Metals that do not have redox potential (Pb, Ni, Cd, As, and Hg)
promote the depletion of sulfhydryl cell reserves, which is indirectly
linked to the production of superoxide and hydroxyl radicals, and
hydrogen peroxide. these metals can decrease the action of antioxidant defenses containing
thiol groups and enzymes
Metals that have
redox potential (Cr, Cu, and Fe) can produce ROS through the redox
cycle , like y the Haber–Weiss reaction (A), and Fenton reactions (
Que sont les métaux qui n’ont pas de potentiel Redox ?
Que font ils ?
-Pb, Ni, Cd, As, and Hg
- DÉFINITION
- promote the depletion of sulfhydryl cell reserves, which is indirectly
linked to the production of superoxide and hydroxyl radicals, and
hydrogen peroxide.
Est ce que tous les métaux peuvent faire des ROS
No. Metals that have
redox potential (Cr, Cu, and Fe) can produce ROS through the redox
cycle and Fenton reactions
Resume le redox cyle et Fenton Reactions
Oxidation and reduction (Redox) reactions represent the transfer of electrons from an electron donor (reducing agent) to an electron acceptor (oxidizing agent).
The Redox active metals (Co, Cr, Mn, Fe, Cu) are those that can damage cells by directly generating ROS by up-regulating Haber-Weiss and Fenton reactions
Fenton reaction uses ferrous ion (Fe2+) as a catalyst to catalyze hydrogen peroxide (H2O2), making it produce hydroxyl radical (·OH) to oxidize organic matter.
Fenton reaction is defined as a process that involves the generation of hydroxyl radicals using ferrous iron and hydrogen peroxide
Que sont les metal avec un potentiel redox ?
Que font ils
Cr, Cu, and Fe
-can produce ROS through the redox
cycle and Fenton reactions
Que sont les mechanism de defense antioxidant des poissons
can operate enzymatically through
superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase
(GPx), and glutathione S-dismutase (GST), and/or non-enzymatically,
through reduced glutathione (GSH) and glutathione disulfide (GSSG)
cite 3 metal-binding proteines. que font elles
In addition, metal-binding proteins such as
ferritin, ceruloplasmin, and, especially, metallothioneins (MT), play a
key role in maintaining the homeostasis of essential metals and in
detoxifying non-essential metals
Comment apparait un stress oxidatif ? que sont les conséquences
When there is an imbalance between antioxidant
defense mechanisms and ROS levels, oxidative stress occurs in the
body. High levels of ROS leads to the oxidation of macromolecules in
several tissues, peroxidation of lipid membranes, and DNA damage
que sont les effets des metaux sur la reproduction des poissons
Endocrine-disrupting chemicals”,
showing that these pollutants can also bind to specific hormone receptors,
mimicking, antagonizing, or blocking the action of endogenous
hormones in fish.
combien d’espèces dans le rio doce ? endémiques ?
une centaine—
combien d’espèces dans le rio paraopeba ?endémiques ?
En dehors du stress oxidatif, que sont les effets des metaux dans le corps
Dna damage, Endocrine disruption, enzyme malfundion, metabolico disorder,
Où l’accumulation de metal est la plus importante ?
liver
