Robbins chapitre 1 Flashcards
Which of those 2: phosphatidylinositol and phosphatidylserine gives a ‘‘eat mea’’ signal when flipped?
phosphatidylserine
2 ways plasma membrane proteins can be agreggated to form large complexes
chaperone molecules from the RER or lateral difusion
Anchoring junctions include: (3)
adherens junction, desmosomes/hemidesmosomes
Kinases phosphorylate tyrosine residue . Which protein removes those residues to modulate singaling?
phosphatase
what are major constituents of basal membrane?
type IV collagen (non fibrillar collagen) and laminin
name 1-3 adhesive glycoproteins
laminin
fibronectin
integrins
what is the job or CDK inhibitors?
enforcing the cell cycle checkpoints by modulating CDK-cyclin complex activity
Where are the 2 checkpoints in cellular cycle?
G1-S: check for DNA dammage
G2-M check for DNA dammage or unduplicated DNA.
symmetric va asymmetric division of stem cells
symmetric: both daughter cells can elf renew vs asymmetric: one of the 2 daughter cells cannot renew
Which enzyme family plays a critical role in neutralizing reactive oxygen species (ROS) by converting hydrogen peroxide into water?
A. Superoxide dismutases
B. Catalases
C. Glutathione peroxidases
D. Cytochrome P-450 oxidases
C. Glutathione peroxidases
What is the mechanism behind decreased protein synthesis during ATP depletion in cell injury?
A. Loss of mitochondrial membrane integrity
B. Detachment of ribosomes from the rough ER
C. Increased lysosomal enzyme activity
D. Fragmentation of chromatin
B. Detachment of ribosomes from the rough ER
- Which signaling mechanisms are involved in cardiac hypertrophy in response to increased workload?
A. Ion channel modulation and nitric oxide release
B. Mechanical triggers and trophic triggers
C. Protein kinase activation and lipid peroxidation
D. Free radical generation and ATP depletion
B. Mechanical triggers and trophic triggers
Which enzyme is responsible for converting hydrogen peroxide (H₂O₂) into water in peroxisomes?
A. Superoxide dismutase
B. Glutathione peroxidase
C. Catalase
D. Myeloperoxidase
Answer: C. Catalase
What is the primary role of myeloperoxidase in neutrophils during the respiratory burst?
A. Generating reactive oxygen species (ROS)
B. Producing hypochlorite (HOCl) from H₂O₂
C. Neutralizing hydrogen peroxide
D. Enhancing mitochondrial function
Producing hypochlorite (HOCl) from H₂O₂
Phospholipase is activated by an influx of what in the cell?
calcium
Which enzyme catalyzes the conversion of superoxide radicals (O₂*) into hydrogen peroxide (H₂O₂)?
Superoxide dismutase
Which enzyme generates hypochlorite (HOCl) during the respiratory burst in neutrophils?
A. Catalase
B. Myeloperoxidase
C. Glutathione peroxidase
D. Superoxide dismutase
Myeloperoxidase
Which enzyme catalyzes the breakdown of hydrogen peroxide (H₂O₂) in the cytoplasm
A. Catalase
B. Glutathione peroxidase
C. Superoxide dismutase
D. Phospholipase
Gluthatione peroxidase
What enzyme activates apoptosis by cleaving nuclear DNA?
A. Caspase-3
B. Cytochrome P-450
C. Endonuclease
D. Phospholipase
Caspase-3
What enzyme catalyzes the detoxification of drugs in the smooth endoplasmic reticulum?
A. Cytochrome P-450
B. Catalase
C. Glutathione peroxidase
D. Superoxide dismutase
Cytochrome P-450
Which enzyme is responsible for reducing oxidative stress in peroxisomes?
A. Catalase
B. Superoxide dismutase
C. Phospholipase
D. Myeloperoxidase
Catalase
Which enzyme generates reactive oxygen species (ROS) in phagocytes during inflammation?
A. NADPH oxidase
B. Glutathione peroxidase
C. Catalase
D. Ubiquitin ligase
NADPH oxidase
Which enzyme facilitates the conversion of molecular oxygen to superoxide in mitochondria?
A. NADPH oxidase
B. Cytochrome c oxidase
C. Superoxide dismutase
D. Glutathione peroxidase
Cytochrome c oxidase
Which protein promotes mitochondrial membrane permeability in apoptosis?
A. Bcl-2
B. Bax
C. Cytochrome P-450
D. Caspase-3
Bax
Which type of free radical is generated during the Fenton reaction?
A. Superoxide
B. Hydroxyl radical (*OH)
C. Peroxynitrite
D. Nitric oxide
Hydroxyl radical (*OH)
What is the main intracellular source of reactive oxygen species (ROS)?
A. Smooth endoplasmic reticulum
B. Lysosomes
C. Mitochondria
D. Golgi apparatus
Mitochondria
Which antioxidant enzyme is most active in peroxisomes?
A. Catalase
B. Glutathione peroxidase
C. Superoxide dismutase
D. Myeloperoxidase
A. Catalase
Catalase is an enzyme in peroxisomes that breaks down hydrogen peroxide ((H_{2}O_{2})) into water ((H_{2}O)) and oxygen ((O_{2})). This process helps maintain the redox balance in peroxisomes.
Which molecule is a critical component of the apoptosome in apoptosis?
A. Cytochrome c
B. Bcl-2
C. Bax
D. ATP
Cytochrome c
