Key Terms
Cell
Smallest unit of life. Every living thing is made of one or more cells.
Scanning EM (SEM)
Beam moves across surface; shows SURFACE detail
Transmission EM (TEM)
Beam penetrates cell; shows INTERNAL structures
Three principles
1. All living things are made of one or more cells.
Cell wall
Rigid layer outside plasma membrane. Primary component is CELLULOSE (polysaccharide made of glucose).
Capsule (polysaccharide)
Allows bacteria to attach to surfaces in the environment.
Flagella
Long, few per cell; move THE WHOLE CELL (sperm cells, some bacteria). Cilia: short, many per cell; move the cell OR move
Pili
Exchange genetic material during conjugation (direct contact between bacteria).
Fimbriae
Used to attach to host cells.
Result
Surface area-to-volume ratio DECREASES as cell gets bigger.
Structure
Phospholipid bilayer with embedded proteins and cholesterol.
Function
Break down fatty acids and amino acids via oxidation; detoxify poisons (alcohol detoxified in liver peroxisomes). Struct
Phospholipid
Lipid with two fatty acid chains and a phosphate group.
Microvilli
Finger-like folds of plasma membrane in absorption cells (small intestine). Increase surface area for nutrient absorptio
Nuclear envelope
Double phospholipid bilayer surrounding the nucleus.