Chapter 27: Archaea and Bacteria (Part 1, Week 5) Flashcards
T/F Bacter and Archaea are examples of macroorganisms that can be seen with the naked eye?
False. They are MICROorganisms and can only be seen with a microscope.
What are, in phosphorous-rich bodies of water, some species of photosynthetic bacteria known as?
They can grow rapidly into large, visible population–known as blooms–that color the water blue-green or cyan.
Cyanobacteria
The individual cells release small amounts of toxins that help keep small aquatic animals away from eating them, but when blooms occur, toxins can rise to levels that poison humans, pets, livestock, and wildlife.
How do you prevent blooms of cyanobacteria?
People can prevent the formation of harmful cyanbacterial blooms by reducing the flow of phosphorus-rich fertilizers, manure, and sewage into bodies of water.
[Start 27.1 Diversity and Evolution]
What are all three domains of life and what structures do they have?
Eukarya, Archaea, and Bacteria.
Eurkarya have a eukaryotic structure. Archaea and Bacteria have a prokaryotic structure.
What do archeal and bacterial cells lack?
Nuclei with porous envelopes and other cellular features typical of eukaryotes.
Why can you not aggregate archaea and bacteria collectively as prokaryotes?
Definitions for Answer:
Monophyletic - consists of a most recent common ancestor and its entire descendants.
Paraphyletic - consists of a common evolutionary ancestor or ancestral group, but not including all the descendant groups.
Such an aggregation is not a monophyletic group, but rather a paraphyletic group—one that does not include all of the descendants of a single common ancestor.
That’s because domain Archaea is more closely related to domain Eukarya than either is to domain Bacteria.
Even so, archaea and bacteria display some common features in addition to a prokaryotic cell structure.
What phylum within Archaea and its close relatives are more closely related to Eukarya than to Bacteria?
Lokiarchaeota
Bacteria and Archaea are the two domains featuring prokaryotic cells. Eukarya is the domain consisting of organisms whose cells are eukaryotic.
T/F Many cases of horizontal gene transfer among phyla and domains are known.
True.
Some of these are depicted with blue bars and include the acquisition of mitochondria and chloroplasts by eukaryotes.
Since Archaea and bacteria include the smallest known cells and are the most abundant organisms on Earth, how much does half of Earth’s biomass consist of?
An estimated 10^30 individual bacteria or archaea.
Just a pinch of garden soil can contain 2 billion prokaryotic cells, and about a million occur in 1 mL of seawater.
Fun Facts about bacteria and archaea!
- Live in nearly every conceivable habitat.
- Most ancient organisms on Earth (3 bya)
- Most diverse metabolic processes
- Influence climate, atmosphere, soils, water quality, and tech.
- They have CRISPR-Cas systems that combat viruses and have proven useful in genetic engineering.
N/A
What, in DNA, is present in archaea and eukaryotes but not in bacteria? (2)
Histones!
Histones are biochemically basic proteins that provide a scaffold to wrap and condense DNA in the nucleus.
Archaea and eukaryotes share more than 30 ribosomal proteins that are not present in bacteria, and archaeal RNA polymerases are closely related to their eukaryotic counterparts.
What differences does archaea have with eukarya?
Archaea possess distinctive membrane phospholipids, which are formed with ether bonds.
Ester bonds characterize the membrane phospholipids of bacteria and eukaryotes
How do archaea withstand heat and extreme conditions?
Ether-bonded membranes are resistant to damage by heat and other extreme conditions, which helps explain why many archaea are able to grow inextremely harsh environments.
What are the key differences between the biochemical composisiton of the cell wall between archaea and bacteria?
In most bacteria, the cell wall is composed of carbohydrates that are cross-linked by peptides, forming a substance called peptidoglycan, whereas the cell wall of archaea is usually a surface layer of proteins.
Some bacterial species alsohave an outer envelope (membrane) composed of lipids and polysaccharides.
Where do most archaea occur?
In soils and surface ocean waters in moderate conditions, diverse archaea occupy habitats with very high salt content, acidity, methane levels, or temperatures that would kill most bacteria and eukaryotes.
What is an organism that occurs primarily in extreme habitats?
Extremophile
One example is the methane producer
Methanopyrus, which grows best at deep-sea thermal vent sites where the temperature is 98°C. At this temperature, the proteins of mostorganisms would denature, but those of Methanopyrus are resistant to such damage.
Methanopyrus is so adapted to its extremely hot environment that it cannot grow when the temperature is less than 84°C.
What is a type of extremophile that lives in thermal sea vents much like the Methanopyrus organism?
Hyperthermophile
What do you call the species of archaea that are able to grow in higher than usual salt concentrations?
Halophiles
T/F Archaea domain is more diverse than the Bacteria domain.
False. Bacter is CONSIDERABLY more diverse and has 50 or more bacterial phyla.
Archaea have 5.
T/F Bacteria favor moderate conditions.
True. Since they form many symbiotic associations with eukaryotes.
For Cyanobacteria, what does the blue-green pigmentation result from?
From the presence of photosynthetic pigments called phycobilins (FICO-be-lins) that help chlorophyll absorb light energy.
Cyanobacteria are the only bacteria known to generate oxygen as a product of photosynthesis.
Ancient cyanobacteria produced Earth’s first oxygen-rich atmosphere, which allowed the eventual rise of eukaryotes. The chloroplasts of eukaryotic algae and plants were derived from cyanobacteria.
Within the phylum Cyanobacteria, they have the greatest diversity of body type among bacteria… What are some examples? (3)
- Occur as single cells called unicells
- Occur as colonies held together by a thick gluey substance called mucilage
- Occur as branched and unbranched filaments
Some of the filamentous cyanobacteria display hallmarks of multicellularity: cellular attachment, specialized cells, intercellular chemical communication, and programmed cell death.
What are the five major sub groups of genera in the phylum Proteobacteria?
alpha (α), beta (β),gamma (γ), delta (δ), and epsilon (ε).
What subgroup of Proteobacteria can the ancestry of mitochondria be traced to?
Here are a plethora of more examples!
The ancestry of mitochondria can be traced to the α-proteobacteria, which also include several genera noted for mutually beneficial relationships with animals and plants.
For example, Rhizobium and related genera of α-proteobacteria form nutritionally beneficial associations with the roots of legume plants such as beans and peas and are thus agriculturally important.
Another α-proteobacterium, Agrobacterium tumifaciens, causes destructive cancer-like tumors called galls to develop on susceptible plants, including grapes and ornamental crops.
The genus Nitrosomonas, soil inhabitants important in the global nitrogen cycle, represents the β-proteobacteria.
Neisseria gonorrhoeae, the agent of the sexually transmitted disease gonorrhea, is one of the γ-proteobacteria.
Vibrio cholerae, another γ-proteobacterium, cause scholera epidemics when drinking water becomes contaminated with animal waste during floods and other natural disasters.
The γ-proteobacteria Salmonella enterica and
Escherichia coli strain O157:H7 also cause human disease, so food and water are widely tested for their presence.
The δ-proteobacteria include the colony-forming myxobacteria and predatory bdellovibrios, which drill through the cell walls of other bacteria in order to consume them.
Helicobacter pylori, which causes stomach ulcers, belongs to the ε-proteobacteria.
