Prokaryotes
Single-celled organisms that make up domains Bacteria andArchaea
What is Prokaryotes?
A polymer made of modified sugars cross-linked by short polypeptides.
• Can be used to identify different types of bacteria:
Gram-positive bacteria
Gram-negative bacteria
What is petidoglycan?
Share some traits with bacteria and other traits with eukaryotes
• However, because they have many unique characteristics on their own, we expect that they have followed a separate evolutionary path for long
What is Archaea?
The evolutionary history of a species or group of species
What is phylogeny?
Organisms present in most eukaryotic lineages, mostly unicellular
What is Protists?
They are known to be able to thrive in a wide range of extreme
environments. They are also adapted to the “normal” habitats, too.
Their ability to adapt to a broad range of habitats explains why they
are the _____.
What is the most abundant organisms on Earth?
Stain purple, Very thick peptidoglycan layer, less structurally complex
What is Gram-Positive Bacteria?
Can be divided into halophiles (high salinity environments) and thermophiles (high temperature environments)
What is extremophiles?
All phylogenetic trees have these. They signify a common ancestor between groups.
What is branching points?
Protists are very diverse in _____. Some are photoautotrophs (chloroplasts), heterotrophs (absorb organic molecules), mixotrophs (combine photosynthesis and heterophic processes)
What is Their Nutrition?
Bacilli, Cocci, Spirrilli
What are the shapes of prokaryotes?
Dense and well-defined (or a slime layer), Sticky outer layers enable them to adhere to their substrate or other individuals in a colony, allowing bacteria to survive in harsh enviroments
What is capsules?
Release methane as a by-product of how they obtain energy
• Because they are strict anaerobes, they get poisoned by oxygen
• Most of them live in swamps and marshes where other microorganisms have
already consumed all the oxygen
• They cause the ‘marsh gas’
What is Methanogens?
Phylogenies are constructed using homologous or analogous features.
What is homologous features?
Homologous features- Phenotypic and genetic similarities due to shared ancestry
Analogous Features- occurs when similar environmental
pressures and natural selection produce similar (analogous)
adaptations in organisms found in different evolutionary
lineages. Convergent evolution
Plastid-bearing lineage gave rise to 2 lineages of photosynthetic protists (algae)
What is Green and Red Algae?
Maintains cell shape
• Protects the cell
• Prevents it from bursting or shriveling
What is cell wall?
Certain bacteria can develop these resistant cells when they lack water or
essential nutrients, are extremely durable that they can survive in boiling water
What is endospores?
3 types of symbiosis
What is mutualism (both species benefit), commensalism (One benefits while the other is not harmed or helped), and parasitism (one harms the host)?
Consists of an ancestral species and SOME, but not all, of its descendants
What is paraphyletic?
Large groups of organisms that share a common ancestor and share unique characteristics.
• Each supergroup has smaller groups within it.
What is supergroups?
A cell is placed in a hypotonic environment. What happens to the cell?
What is it burts?
The cell has more solute so water floods into the cell in an effort to equalize it.
In prokaryotes, it occurs via:
• Transformation
• Transduction
• Conjugation
What is Genetic Recombination?
In transformation, the genotype (and possibly phenotype) of a
prokaryotic cell is altered by the uptake of foreign DNA from its
surroundings.
In transduction, phages (or bacteriophages; viruses that infect
bacteria) carry prokaryotic genes from one host cell to another
During conjugation, DNA is transferred between two prokaryotic cells (usually the same species) that are temporarily joined
• Occurs unidirectionally only (donor and recipient)
Our well-being depends on _____
What is Mutualistic Prokaryotes?
The most recent common ancestor is not part of
the group.
What is polyphyletic?
Super groups covered in class.
**Will be going over these alot on Thursday
Excavata, SAR