Biologie Cellulaire

Question 1

Whats is pycnose

Answer 1

Altération du noyau de la cellule qui se présente sous la forme d’une masse condensée.—

Question 2

difference apoptose et necrose

Answer 2

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

Question 3

how fibrosis happen

Answer 3

— 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

Question 4

what are heavy metal

Answer 4

“metallic elements that have an atomic
mass greater than 20 and a density greater than 5 g/cm3

Question 5

Cites les metaux essentiels pour les poissons

Answer 5

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.

Question 6

Que sont les metaux non essentiels

Answer 6

in the case of deficiency or significant increase, they can become toxic.
Ag, Al, Cd, Pb, Hg, As, Sr

Question 7

Est ce eux les métaux dans l’eau se dégrade avec le temps

Answer 7

These contaminants are not naturally degraded over time,
remaining in water or sediment for a long time

Question 8

De quoi dépend l’accumulation des métaux dans les poissons

Answer 8

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 )

Question 9

Où les polluants s’accumulent dans le corps des poissons

Answer 9

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,

Question 10

Cites les ROS principaux produtis par les métaux

Answer 10

superoxide (O2●) hydroxyl (OH●), and alkoxyl (RO●) and the
non-radicals, hydrogen peroxide (H2O2) and peroxynitrite (ONOO􀀀 ).

Question 11

Comment les ROS sont produits ?

Answer 11

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. —

Question 12

How metals can be involved in oxidative
damage.

Answer 12

• 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 (

Question 13

Que sont les métaux qui n’ont pas de potentiel Redox ?
Que font ils ?

Answer 13

-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.

Question 14

Est ce que tous les métaux peuvent faire des ROS

Answer 14

No. Metals that have
redox potential (Cr, Cu, and Fe) can produce ROS through the redox
cycle and Fenton reactions

Question 15

Resume le redox cyle et Fenton Reactions

Answer 15

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

Question 16

Que sont les metal avec un potentiel redox ?
Que font ils

Answer 16

Cr, Cu, and Fe
-can produce ROS through the redox
cycle and Fenton reactions

Question 17

Que sont les mechanism de defense antioxidant des poissons

Answer 17

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)

Question 18

cite 3 metal-binding proteines. que font elles

Answer 18

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

Question 19

Comment apparait un stress oxidatif ? que sont les conséquences

Answer 19

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

Question 20

que sont les effets des metaux sur la reproduction des poissons

Answer 20

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.

Question 21

combien d’espèces dans le rio doce ? endémiques ?

Answer 21

une centaine—

Question 22

combien d’espèces dans le rio paraopeba ?endémiques ?

Question 22

En dehors du stress oxidatif, que sont les effets des metaux dans le corps

Answer 22

Dna damage, Endocrine disruption, enzyme malfundion, metabolico disorder,

Question 22

Où l’accumulation de metal est la plus importante ?

Answer 22

liver

Question 23

Que sont les métaux les plus retrouver dans les sites ? Que sont leurs effets ?

Answer 23

Mn, AL, Fe

Question 23

dans quelle saison les accumulations sont les plus improtantes

Answer 23

rainy

Question 23

Quelles sont les principales étapes de l’apoptose et quelles sont les protéines clés impliquées ?

Answer 23

L’apoptose est un processus de mort cellulaire programmée essentiel pour l’homéostasie tissulaire. Elle comprend l’initiation (activation des récepteurs de mort comme FAS ou via les dommages à l’ADN), la phase d’exécution (activation des caspases, en particulier les caspases 3, 6 et 7) et la dégradation cellulaire (fragmentation de l’ADN, dégradation du cytosquelette). Les protéines Bcl-2 et Bax régulent la perméabilité mitochondriale, une étape clé dans l’activation des caspases.

Question 23

Quelles sont les principales voies de signalisation impliquées dans la réponse au stress oxydatif ?

Answer 23

Les principales voies comprennent la voie Nrf2/Keap1, qui régule l’expression des gènes antioxydants, et la voie MAPK, qui peut conduire à l’apoptose en réponse à des niveaux élevés de stress oxydatif. La voie PI3K/Akt est également impliquée dans la protection cellulaire contre le stress.

Question 24

Comment les cellules se protègent-elles contre les dommages causés par les métaux lourds ?

Answer 24

Les cellules activent des systèmes de défense comme les protéines métallothionéines qui se lient aux métaux lourds pour réduire leur toxicité. Elles augmentent aussi l’expression des enzymes antioxydantes telles que la superoxyde dismutase (SOD), la catalase et la glutathion peroxydase pour neutraliser les ROS. La réparation de l’ADN et les mécanismes d’autophagie permettent également d’éliminer les composants endommagés.

Question 25

Comment les metaux lourds activent l’apoptose

Specifiquement pour Caspase 3

Answer 25

Via la creaiton de ROS

ROS play a central role in cell signalling as well as in regulation of the main pathways of apoptosis mediated by mitochondria, death receptors and the endoplasmic reticulum (ER).

Moreover, ROS cause mitochondrial membrane depolarisation and/or opening of Bax/Bak channels on the OMM, which allows release of AIF, Endo G, cytochrome c and Smac/Diablo into the cytosol. Cyt c then forms the apoptosome complex in the cytosol together with Apaf-1 and procaspase-9, leading to caspase-9 activation. Caspase-9 then activates effector caspases such as caspase-3, resulting in cleavage of cellular proteins and cell demise by apoptosis.

Question 26

Que sont les effets positifs des ros

Answer 26

At low to modest doses, ROS are considered to be essential for regulation of normal physiological functions involved in development such as cell cycle progression and proliferation, differentiation, migration and cell death.
ROS also play an important role in the immune system, maintenance of the redox balance and have been implicated in activation of various cellular signalling pathways.

Question 28

quel est le role de tumour suppressor p53,

Answer 28

can activate cell survival and/or cell death processes such as autophagy and apoptosi