Quiz 3- 4( Mechanism of cell injury )

Which process is the hallmark of irreversible cell injury?

• Cellular swelling

• Fatty change

• Membrane damage

• Ribosomal detachment

What is the consequence of ATP depletion during cell injury?

• Increased pH

• Decreased intracellular calcium

• Failure of ion pumps

• Stabilization of lysosomes

Which of the following is a key mechanism by which ischemia-reperfusion injury exacerbates cell damage?

• Decreased ATP synthesis

• Enhanced lipid peroxidation due to ROS burst

• Increased glycolysis

• Impaired protein synthesis

During oxidative stress, which molecular event contributes most significantly to mitochondrial dysfunction?

• Leakage of lysosomal enzymes

• Opening of the mitochondrial permeability transition pore (mPTP)

• Accumulation of misfolded proteins in the cytoplasm

• Depletion of NADPH

Calcium-mediated cell injury activates which of the following enzymes, leading to cytoskeletal damage and membrane breakdown?

• Phospholipases

• RNA polymerase

• DNA helicase

• Glycogen synthase

Which of the following pathways of free radical generation involves the Haber-Weiss reaction?

• Conversion of O2 to superoxide (O2•−)

• Conversion of H2O2 to hydroxyl radicals (•OH)

• Fenton reaction in the presence of Fe2+

• Formation of nitric oxide (NO) from arginine

Protein misfolding due to ER stress in cell injury is primarily sensed by which pathway?

• Autophagic degradation

• Ubiquitin-proteasome system

• Unfolded Protein Response (UPR)

• Caspase-3 activation

What role does the antioxidant glutathione (GSH) play in cellular protection against injury?

• Neutralizes hydroxyl radicals directly

• Acts as a cofactor for catalase

• Detoxifies hydrogen peroxide via glutathione peroxidase

• Stimulates superoxide production to counteract ROS

Which structural feature of lipids makes them particularly susceptible to peroxidation by reactive oxygen species (ROS)?

• Saturated hydrocarbon chains

• Unsaturated double bonds

• Polar head groups

• Phosphodiester linkages

Which one of the following is not a microscopic feature of cell injury?

• increased eosinophilia

• Karyorrhexis

• increased synthesis of protein by endoplasmic reticulum

• Swelling of mitochondria