Topic 1 Cell Biology Flashcards
Cell origin, ultrastructure, and division
Cell theory
Cells have membranes
Cells contain genetic information
Cells have their own energy release system
Unicellular organism functions
Nutrition Metabolism Growth Response Reproduction Homeostasis Excretion
Limitation of cell size - surface area and volume ratio
As sizes of cells increase, the ratio between surface area and volume decreases making the cell less efficient at exo and endocytosis
Emergent properties
Properties that arise from the interactions of the component parts of a complex structure; the whole is greater than the sum of its parts
Cell differentiation
Cells specialize for specific functions as a result of gene expression in DNA.
Stem cell properties
Can divide through mitosis to rapidly increase numbers
Can differentiate into any type of cell
Embryonic stem cell usage
Pros:
- can differentiate into any type of cell
- unlimited growth potential
- less chance of genetic damage
Cons:
- more risk of developing into tumor
- ethical concerns of killing embryos for stem cells
Adult stem cells
Pros:
- fully compatible with adults tissue - less chance of malignant tumor formation
- removal does not kill the cell donor
Cons:
- limited differentiation capacity
- less growth potential than embryonic
- difficult to obtain
Electron Microscopes
Have a higher resolution than regular light microscopes due to light microscopes relying on visible light wavelengths (400-700nm)
Prokaryotic cell structure
- free ribosomes
- cell wall
- plasma membrane
- cytoplasm
- nucleoid region containing naked DNA
- pilli
- flagella
Cell division in prokaryotes
Divide through binary fission. Single chromosome is replicated, move to opposite poles, and the cell divides.
Eukaryotic cell structure
Compartmentalized structure:
- nucleus
- rough ER
- golgi apparatus
- lysosome
- mitochondrion
- free ribosomes
- chloroplasts and vacuoles (plant cells)
Davson-Danielli model of phospholipid bilayer
‘Ice cream sandwich model” showed proteins on either side of phospholipid bilayer.
Proven wrong via electron micrographs showing transmembrane proteins
Fluid mosaic model membrane structure
The accepted model for phospholipid bilayer membranes. Shows phospholipid heads facing out and tails inwards, integral proteins, peripheral proteins, and cholesterol
Cholesterol in animal cell membranes
Reduces membrane fluidity and permeability to some solutes:
Disrupts regular packing of hydrocarbon tails, preventing them from crystalizing.
