Lecture 2 (Quiz 2) Flashcards
(50 cards)
Plasma Membrane
Phopholipid bilayer with proteins, lipids, and carbohydrates integrated into it at varying levels. (Fluid Mosaic) Acts as a protective membrane that regulates what enters and leaves a cell (selectively permeable),
Mitochondria
POWER HOUSE OF THE CELL. Takes oxygen and broken down components of the diet to make ATP. Houses ETC = largest ATP producer. Also utilizes proton gradient that the ETC produces to create ATP by pumping in protons.
Transport Types
Simple Diffusion
Facilitated Diffusion
Active Transport
Group Translocation
Rough Endoplasmic Reticulum
Covered in ribosomes, located directly by the nucleus, site of protein synthesis
Smooth Endoplasmic Reticulum
No ribosomes, connected to RER but further from the nucleus, site of lipid & carbohydrate synthesis as well as some detoxifying functions.
Golgi Apparatus
Final check and packaging point to send things out of cell or accept things in from out of the cell.
Categories of Cellular Stress/Injury Response (3)
- Reversible
- Adaptive
- Death
Reversible Response
Withstands assault with quick, adaptive change, then returns to normal. Short-term stress/injury
Adaptive
Changes structure/function to adapt and is USUALLY reversible when assault is gone. Longer term stress/injury
Death
Apoptosis or necrosis of cell with stress/injury is too severe
Types of Reversible Responses (2)
- Hydropic swelling
2. Accumulation of Macromolecules
Hydropic Swelling
Accumulation of water in cells that cause swelling of the organ (ex: hepatomegaly)
How does Hydropic Swelling Happen?
Sodium-Potassium pumps fail which disrupts their corresponding gradients, causing water to follow sodium into the cell.
Why do the pumps fail?
Decreased availability of oxygen (hypoxia) and increased concentrations of chemicals that inhibit the ETC cause the ETC to stop, the hydrogen gradient to not be maintained, and, therefore, ATP not to be produced. In most cells, 30% of their ATP supply goes to keeping the pumps going, even higher in organs like the brain (90%).
Issues Associated with Accumulation (3)
- Toxicity
- Inflammation
- Crowding that disrupts cellular function
Categories of Accumulation (3)
- Accumulation of Normal Substances
- Accumulation of Abnormal Proteins
- Accumulation of Indigestional Particles
Normal Substances to Accumulate (3)
- Lipids
- Carbohydrates
- Proteins
Examples of Accumulating Lipids
- Chronic Alcohol Ingestion - preferentially metabolizes alcohols over lipids leading to excess fatty vacuoles in the liver (fatty liver)
- Tay-Sachs Disease
- Gaucher Syndrome
Example of Accumulating Carbohydrates
Diabetes Mellitus - impaired uptake of glucose causes it to enter filtrate and leads to excess glycogen stores in renal tubule cells
Example of Accumulating Proteins
Renal tubules accumulating proteins due to leaky glomerular capillaries, endocytosis of escaped proteins, or excess accumulation
How Abnormal Proteins Accumulate
Stress causes protein denaturation. The denatured proteins can then be fixed and refolded by things like chaperone proteins or be “murdered” via ubiquitination. If either of these pathways are not working properly, abnormal proteins can build up and accumulate in the cell.
Types of Indigestional Particles (2)
- Exogenous - tattoos, Black Lung, etc.
2. Endogenous - Bilirubin
Bilirubin Accumulation
Example of Endogenous Indigestional Particle Accumulation. Pigmented byproduct of metabolized RBCs and heme. Lots of reasons can lead to its accumulation like bad livers, excessive breakdown of RBCs, overproduction of hemoglobin, etc. If it does accumulate it causes a yellowing of the white of the eyes (sclera) and even the skin, in high levels.
What causes brain damage in neonates?
Unconjugated Bilirubin