What are the characteristics common to all living organisms?
- Ordered structure
- Transformation of energy
- Growth+development
- Adaptation
- Responsiveness
- Reproduction
- Homeostasis
Define
Life cycle
Generation-to-generation sequence of stages in the reproductive history of an organism, from conception to production of its own offspring
What are the different groups that populated the Earth and when did they originate?
- Prokaryotes: 3.9 bya
- Protists/eukaryotes: 2.1 bya
- Animals: 700 mya
- Fungi: 500 mya
- Plants: 500 mya
- Viruses: multiple origin times
What groups of organisms are the most diverse?
- Animals
- Plants
- Fungi
- Protists
How many kingdoms were there originally, what were they and why did some fail?
5: Monera, Protista, Plantae, Fungi, Animalia
Some prokaryotes differ as much from each other as they do from eukaryotes, based on their rRNA sequences
Define
Horizontal gene transfer
Process in which genes are transferred form a genome to another through mechanisms such as transposition, viral infection, fusion of organisms (endosymbionts)
What is the difference between bacterial cell walls and archaeal cell walls?
Bacterial cell walls contain peptidoglycan: polymer composed of sugars crossed-link by short polypeptides
Archaeal cell walls have no peptidoglycan: they only have polysaccharides and proteins
Describe
Gram staining
- Experiment that allows for the classification of bacteria by the composition of their cell wall
- Gram-positive: stains purple, simpler walls with lots of peptidoglycan
- Gram-negative: stains pink, less peptidoglycan, more complex, outer membrane of lipopolysaccharides (carbs and toxic lipids)
Define
Fimbriae
Hairlike appendages with which prokaryotes stick to their substrate or to one another
Define
Pili
Appendage that pulls two cells together before DNA transfer
Define
Endospore
Sleeping cell containing copy of original chromosome, released after lysis. Creation due to unfavorable circumstances
Define
Flagella
Structure used by prokaryotes who move under their own power (50% of them). Allows prokaryotes to perform taxis, movement towards or away from a stimulus
Where is genetic information stored in prokaryotes?
In the nucleoid, a lighter region of the cytoplasm in which the chromosome is located or in plasmids
How do prokaryotes reproduce?
They reproduce by binary fission in favorable environments and can’t do so forever, because of exhaustion of nutrient supply, poisoning by metabolic waste or predation/competition
What are the 4 ways in which prokaryotes can obtain energy?
- Phototrophs: energy from light
- Chemotrophs: energy from chemical bonds
X - Autotrophs: only need CO2 as carbon source
- Heterotrophs: require at least one organic nutrient
First prokaryotes were chemoautotrophs
What are the factors that promote prokaryotic genetic diversity?
- Rapid reproduction and mutation: short generations and low mutation rate in huge populations
- Genetic Recombination: tranformation (uptake of foreign DNA), transduction (phage infections) and conjugation (F+ cells or Hfr cells)
Define
Extremophiles
Organisms that love extreme conditions (halophiles with salt, thermophiles with heat). They represent a small part of the Archaea domain
Define
Symbiosis
Relationship in which two species live in close contact with each other (host+symbiont). Can be mutualism (good for both), commensalism (neutral) or parasitism (bad for host)
Parasites that cause diseases are called pathogens
