What are the differences between eukaryotic and prokaryotic cells?
Eukaryotic: organelles, defined nucleus, plant and animals. Prokaryotic: no distinct nucleus, not membrane bound, bacteria and archaea.
What is passive transport?
Movement of small, lipid soluble molecules from high to low concentration.
What is the role of facilitated transport?
Uses carrier or channel proteins in the membrane to help with transport.
What is active transport?
Uses ATP to push molecules against their gradient.
What is the sodium–potassium pump?
It pumps 3 sodium out and 2 potassium into the cell using 1 ATP, maintaining cell volume and electrochemical gradient (homeostasis)
How do cells communicate through local signaling?
Conducted through gap junctions and direct contact.
How do cells communicate through long-distance signaling?
A cell releases a signaling molecule to a target cell with a receptor, often using the bloodstream (hormones)
What are the steps of cellular respiration?
- Glycolysis: glucose splits into 2 pyruvates, get 2 ATP
- Citric acid cycle: converts pyruvate to acetyl coA, producing ATP, NADH, FADH2 and CO2
- Oxidative phosphorylation: uses NADH in electron transport chain to make ATP.
What is endocytosis?
Cell engulfs material, forming a vesicle to move inside the cell.
What is exocytosis?
Vesicles fuse with the membrane to secrete substances outside the cell.
Atrophy
cell shrinks
Hypertrophy
cell enlarges
Hyperplasia
increase in number
Dysplasia
abnormal cell growth; always pathologic
Metaplasia
a cell more suited for action replaces (can become pathogenic)
What is hypoxia?
Decreased oxygen to the cells/tissues
Why is hypoxia so dangerous?
↓O2 -> ↓ ATP -> Na/K pump fails -> fluid imbalance; cellular swelling
What is ischemia?
Reduced blood flow causing tissue damage; most common way to lead to hypoxia
why is ischemia dangerous?
sudden oxygen rush during reperfusion introduces ROS species.
which type of ischemia is better? gradual or sudden?
gradual - the body gets used to finding ways to perfuse around it
How does oxidative stress occur?
When reactive oxygen species (ROS) exceed antioxidant defenses, leading to damage ( in plasma membrane & protein/DNA -> cell dysfunction & death)
What are common causes of cell injury?
-chemical (liver damage, ROS)
-Air pollution
-Heavy metals (lead, mercury)
-temp extremes
-pressure (decompression, blast injury, altitude)
-cellular accumulation (water, lipids, bilirubin, calcium travel into cell)
What differentiates necrosis from apoptosis?
Necrosis is unplanned cell death (injury) causing inflammation; apoptosis is programmed and does not cause inflammation.
What is hydrostatic pressure?
Pressure that pushes fluid out of capillaries
