BIO 156 Chapter 4: Cells Flashcards
Who discovered cells, and when?
Robert Hooke, 1665
Robert Hooke observed plant cells.
What are the three principles of Cell Theory?
- All living organisms are made up of one or more cells
- Cells are the smallest units of life
- All cells come from preexisting cells
Cell Theory was originally thought of in the mid 19th century.
What is the size range of prokaryotic cells?
0.1-5.0 micrometers
What is the size range of eukaryotic cells?
10-100 micrometers
What is the difference between magnification and resolution?
Resolution is the ability to distinguish two objects being separate while magnification is enlarging the apparent size of an object.
What are the two types of electron microscopes, and what are their abbreviations?
- Scanning electron microscope: SEM
- Transmission electron microscope: TEM
What is a scanning electron microscope used for?
View surfaces of objects
What is a transmission electron microscope used for?
View inside of objects by looking at thin slices
How much can electron microscopes magnify while still resolving objects?
100,000 times
What is volume?
Space inside
What is surface area?
Outside covering
What is the relationship of surface area to volume as an object increases in size?
As cell size increases, volume grows more rapidly than surface area
Why are cells limited in size?
At some point, there will not be enough surface area to move substances in and out to sustain life inside of cell (volume)
What are the four characteristics of all cells?
- Plasma membrane
- DNA
- Ribosomes
- Cytoplasm
What is the function of the plasma membrane?
Holds everything in and controls what goes in and out
Which property of life does the plasma membrane participate in?
Cellular organization
What are the three major molecular components of cell membranes?
- Phospholipids
- Cholesterol
- Proteins
Why do phospholipids form a bilayer when surrounded by water?
The polar heads of phospholipids are attracted to water while the nonpolar tails are repelled by the water
What are aquaporins?
Transmembrane channel proteins that let water molecules pass through the membrane without ions and other small molecules
What does prokaryotic mean?
A single celled organism that lacks a nucleus and membrane bound organelles
What types of organisms have prokaryotic cells?
- Archaea
- Bacteria
List the seven characteristics of prokaryotic cells.
- DNA: holds genetic instructions
- Ribosomes: Sites where proteins are made
- Cytoplasm: holds organelles and offers structural support
- Plasma membrane: regulates what molecules come in and out
- Cell wall: Structure and shape
- Capsule: Sticky layer that adheres to surface
- Flagellum: Moves the cell
- Pili: Tiny hairs that adhere to surfaces
What are the separate compartments called inside eukaryotic cells?
Organelles
What is the adaptive significance of organelles in eukaryotic cells?
Specialized structures where cell processes occur, each with a specific function
