Chapter 3 - Cellular Organization Flashcards
What is the approximate diameter of a typical cell?
0.1nm
Did Robert Hooke actually see cells?
No - just the outline of them
In what century were microscopes invented?
17th century (1665)
Name the 4 components of the cell theory
- Cells are the building blocks of all plants and animals
- All cells come from the division of preexisting cells
- Cells are the smallest units that perform all vital physiological functions
- Each cell maintains homeostasis at the cellular level. (Homeostasis at the tissue, organ, organ system, and organism reflects the combined action of many cells)
The human body contains _____ of cells
trillions
cytology is part of the broader discipline of …?
cell biology
cell biology integrates aspects of which 3 sciences?
chemistry
biology
physics
The human body contains how many general classes of cells and what are they
2 - somatic cells
sex cells (germ cells)
Name the 4 functions of the plasma membrane
- Physical isolation
- Regulation of exchange with the environment
- Sensitivity to the environment
- Structural support
What is the 1st part of the cell affected by changes in composition, pH, etc of the extracellular fluid?
cell membrane
The plasma membrane contains a variety of _______ that allow the cell to recognize and respond to specific molecules in its environment
receptors
Is the plasma membrane thin or thick? How many nm is it?
EXTREMELY THIN. ranges from 6-10nm in thickness
The cell membrane contains which 3 biomolecules?
carbohydrates, lipids, proteins
Which biomolecule makes up most of the SURFACE AREA of the plasma membrane?
lipids
What % weight is lipids in a cell membrane
42%
Why is isolation between the cytoplasm and extracellular fluid so important?
Because the compositions of the 2 are very different and the cell cannot survive if the differences are eliminated
Proteins account for about ____% of the weight of the plasma membrane
55%
Which are denser - proteins or lipids?
proteins
What are the 2 structural classes of membrane proteins?
Integral proteins and peripheral proteins
Can integral proteins be removed?
Not without damaging the cell membrane. It’s part of the membrane structure
Integral proteins are also known as …..? Why?
Transmembrane proteins because they span the width of the membrane one or more times
Can peripheral proteins be removed from the membrane?
Yes - they are bound to either the inner or outer surface of the membrane and are easily separated from it
Which are more abundant - peripheral or integral?
integral
Membrane proteins can have which 6 functions?
- Channel
- Carrier
- Anchoring
- Recognition
- Enzyme
- Receptor