Cell Theory and Organelles

Study Notes

Mitochondria are called the "powerhouse centers" because they produce energy for the cell in the form of ATP.
Scientists believe mitochondria were once symbiotic prokaryotic organisms (helpful bacteria) that transformed into cellular organelles.
Mitochondria have their own DNA called mtDNA.

Cells contain organelles with specialized functions
Centrioles are involved in the organization of mitotic spindles for cellular movement.
Cytoplasm is the gelatinous fluid located inside the cell membrane that contains organelles.
The endoplasmic reticulum is a continuous membrane that helps transport, synthesize, modify, and fold proteins.

DNA replication is part of the cell cycle, which is a sequence of events that a cell undergoes in order to divide and create two copies of itself.
The cell cycle has several phases, including the interphase, where the cell prepares to divide, and the mitotic phase, where the cell divides.
The cell cycle is regulated by checkpoints that control whether a cell enters a new phase.
Cells will undergo apoptosis if they fail a checkpoint.

Cancer cells have uncontrolled growth and can replicate indefinitely.
Cancer cells avoid programmed death and can even maintain their telomeres, which normally shorten with time, thus preventing them from dying.

Karl Landsteiner discovered ABO blood groups in 1901.
He observed that mixing different blood types could cause agglutination (clotting).
Blood type compatibility is crucial for safe blood transfusions.
Blood cell surface antigens are proteins that coat the surface of red blood cells, and antibodies are specifically "against" or "anti" to the antigens from other blood types.
Individuals with type A blood have A antigens and anti-B antibodies.
Individuals with type B blood have B antigens and anti-A antibodies.
The discovery of the ABO blood group system allowed for safer blood transfusions.

### Human Evolution

European diseases were responsible for the population collapse of indigenous peoples of the Americas.
Europeans had a more diverse and larger population, and were more accustomed to living with domestic animals and pests.
Native Americans did not share urban lifestyles, which made them more susceptible to introduced diseases.

Aneuploidy is a condition where an individual has an abnormal number of chromosomes.
Individuals born with aneuploid sex chromosomes can have conditions such as XXY, XXX, and XO.