Exam 1

1. Selenium is a component of the ____ a free radical scavenging system that limits the damage free radicals cause

• 1. Glutathione peroxidase

• 1. Selenium peroxidase

• 1. Cytosolic phospholipidase

• 1. Enzymatic redoxase

1. How is cell injury different from cell death?

Answer explanation

Cell injury 

• Reversible changes that occur in a cell as a result to a stimulus that is too great and the cell can no longer adapt to the changes in the environment

Cell death

• A cell that is exposed to persistent or severe stimulus and is irreversibly damaged

1. Select all of the key mechanisms of cell injury or death

   2. Decreased intracellular calcium

   3. Permeabilization of cell membranes

• 1. Damage to DNA and proteins

• 1. Permeabilization of cell membranes

• 1. Disruption of biochemical pathways

• 1. Decreased intracellular calcium

• 1. ATP depletion

1. The major causes of ATP depletion are…

• 1. Hypoglycemia

• 1. Free radical damage

• 1. Hypoxia

• 1. Mitochondrial damage

• 1. Necrosis

1. Which of these are the correct sequence of events leading to cell injury or death due to ATP depletion?

• 1. Switch to anerobic glycolysis→Decrease O2→ Results in decreased ATP production→ Decreased function of Na+/K+ pumps → Increased influx of Ca2+, H20 and Na+ → Cellular swelling

• 1. Decreased function of Na+/K+ pumps→ Increased influx of Ca2+, H20 and Na+ → Cellular swelling→ Decrease O2→ switch to anerobic glycolysis→ Results in decreased ATP production

• 1. Cellular swelling→Increased influx of Ca2+, H20 and Na+ → Decrease O2→ Decreased function of Na+/K+ pumps→Switch to anerobic glycolysis→ Results in decreased ATP production

• 1. Decrease O2→ Switch to anerobic glycolysis→ Results in decreased ATP production→ Decreased function of Na+/K+ pumps→ Increased influx of Ca2+, H20 and Na+ → Cellular swelling

Which of these does mitochondrial damage NOT lead to?

• Formation of mitochondrial permeability transition pore

• Abnormal oxidative phosphorylation leading to the formation of ROS

• Phospholipase activation

• Leakage of pro-apoptotic proteins from the mitochondiral membrane leading ot cellular death by apoptosis

Increased Cytosolic Ca2+ activates what?

Answer explanation

Activation of cellular enzymes

-Phospholipases

• -Proteases

-Endonucleases

-ATPases

Formation of MPTP

Induction of apoptosis by directly activating caspases

Select all the ways there can be an increase in cytosolic Ca2+ as a response to ischemia and toxins

• Release from intracellular stores in mitochondrial and ER membranes

• Anerobic glycolysis causing the release of Ca2+ intracellularly

• Formation of the mitochondrial permeability transition pore

• Increased influx of Ca2+ across the plasma membrane late in cell injury

What are free radicals?

Answer explanation

Chemicals that have a single unpaired electron in outer orbit

-Extremely unstable and reactive chemicals

-Includes chemicals like Nitric Oxide, hydrogen peroxide etc.

Which of these are not sources of free radicals?

• Redox reactions that occur during ATP production

• Bursts produced in activated leukocytes during inflammation

• Nitric Oxide

• Glutathione peroxidase