Lecture 2A: Introduction to the Microbial World Flashcards
(36 cards)
elements of microbial structure
- cytoplasmic (cell/plasma) membrane
- cytoplasm
- ribosomes
barrier that separates the inside of the cell from the outside environment
cytoplasmic (cell/plasma) membrane
matrix of macromolecules, small organics, ions, and ribosomes inside cell, with water as the major component
cytoplasm
protein-synthesizing structures
ribosomes
no membrane-enclosed compartments (organelle), no nucleus
prokaryotes (Bacteria and Archaea)
- plants, animals, algae, protozoa, fungi
- contain organelles
- DNA enclosed in a membrane-bound compartment = nucleus
eukaryotes
What is an organelle?
- sub-cellular
- specialized function
- morphologically and chemically
consistent structure across life forms
Distinguishing Features of Procaryotic Cells: DNA is
- Not enclosed within a nuclear membrane.
- A single circular chromosome.
- Not associated with histone proteins.
Prokaryotic cells:
- ___ of membrane-enclosed organelles like mitochondria, chloroplasts, Golgi, etc.
- Cell walls usually contain ___, a complex polysaccharide, or ___or S-layer
- Divide by ___
- lacks
- peptidoglycan
- pseudopeptidoglycan
- binary fission
Eukaryotic cells: DNA is…
- Enclosed within a nuclear membrane.
- Several linear chromosomes.
- Associated with histones and other proteins.
a cell’s full complement of genes
genome
(extrachromosomal DNA) that confer
special properties (e.g., antibiotic
`resistance)
plasmids
prokaryotic cell’s DNA generally have single circular chromosome that aggregates to form the __
nucleoid region
The properties of microbial cells. Major activities ongoing in cells in the microbial community
- metabolism
- growth
- evolution
- differentiation
- communication
- genetic exchange
- motility
cells take up nutrients, transform them, and expel wastes
1. genetic (___,___,___)
2. catalytic (___,___)
METABOLISM
- replication
- transcription
- translation
- energy
- biosyntheses
nutrients from the environment are converted into new cell materials to form new cells
GROWTH
cells evolve to display new properties. _____ capture evolutionary relationships
EVOLUTION
- Phylogenetic trees
some cells can form new cell structures such as a ___
DIFFERENTIATION
- spore
Cells interact with each other by ___
COMMUNICATION
- chemical messengers
cells can exchange ___ by several mechanisms
GENETIC EXCHANGE
- genes
some cells are capable of ___
MOTILITY
- self-propulsion (ex. flagellum)
- Earth is ___ years old.
- First cells appeared between ___ years ago.
- The atmosphere was __ (no O2) until ___ billion years ago.
– only anaerobic metabolisms
– first anoxygenic phototrophs ___ billion years ago - plants and animals ___ billion years ago
- 4.6 billion
- 3.8 and 4.3 billion
- anoxic
- ~2.6
- ~3.6
- ~0.5
At its origin, Earth was ___ . Cellular life was present on Earth by 3.8 billion years ago (bya). ___ began the slow oxygenation of Earth About 3bya but current levels of O2 in the atmosphere were not achieved until 500-800 million years ago.
- sterile
- Cyanobacteria
The three domains of cellular organisms are ___, ___, and ___. ____ and ____ diverged long before eukaryotic cells appear in the fossil record.
- Bacteria, Archaea, Eukarya
- Archaea, Eukarya
