Prokaryotes and protists Flashcards
Microorganisms (Microbes)
residing in and on your body outnumber your own cells.
Disruption of our microbial communities can:
– increase our susceptibility to infectious diseases
– contribute to chronic conditions like asthma, allergies, irritable bowel syndrome, Crohn’s disease, Parkinson, autism.
Prokaryotes
-Oldest cell type
-Small and simple
-Lack nucleus
-Lack organelles
-single-called
True or false, Prokaryotic cells are smaller than eukaryotic cells.
True
True or false, collective biological mass (biomass) of prokaryotes is
at least 10 times that of all eukaryotes.
True
True or false, Prokaryotes have an immense impact on the environment and on our health.
True
What are two very different kinds of prokaryotes?
They are classified in the domains Archaea and Bacteria.
Three of the most common prokaryotic cell shapes are:
- Spherical - cocci,
- Rod-shaped -bacilli,
- Spiral prokaryotes of two types:
– Relatively short and rigid cells called spirilla
– Longer and more flexible cells called spirochetes.
True or false, Almost all prokaryotes have a cell wall.
True
Prokaryotes can be classified by:
shape and by reaction to a Gram stain.
Gram-positive bacteria
have simpler walls with a relatively thick layer of a unique material called peptidoglycan.
True or false, The walls of gram-negative bacteria stain differently.
True
Other features for Prokaryotes:
may include a sticky capsule, flagella, or fimbriae.
Prokaryotes (bacteria and archaea)reproduction
reproduce by binary fission
The division of on cell reproduce what?
reproduces the entire organism
binary fission
The chromosome replicates (beginning at the origin of replication), and two daughter chromosomes move apart
pinches inward, dividing the cell into two
Plasma membrane
What forms endospores?
Some prokaryotes form endospores that remain dormant through harsh conditions.
What does dormant survival forms of?
Forms of bacteria
dormant survival form of bacteria resistant to?
– high temperatures
– most disinfectants
– low level radiation
–drying.
What can survive thousands of years until environmental stimuli trigger germination?
Endospores
Anthrax (Bacillus anthractis)
common soil bacteria; can be deadly
Tetanus (Clostridium tetani)
common in the environment, toxin released by the bacteria can cause severe muscle spasms.
Botulism (Clostridium botulinum)
common in soil and water; spores can be in improperly canned food, paralyzing.
True or false, Prokaryotes exhibit much more nutritional diversity than eukaryotes.
True
Two sources of energy can be used by prokaryotes.
– Like plants, prokaryotic phototrophs capture energy from sunlight.
– Prokaryotes called chemotrophs harness the energy stored in chemicals.
Prokaryotes attach to surfaces and form highly organized biofilm communities that are difficult to eradicate, causing—
both medical and environmental problems – or benefits.
Biofilms
– protection from infection
– Hard to eradicate
Microbiome
– Immense effect on health
– Provides micro-nutrition
– Possible linked to SOME forms of autism, asthma, obesity, gluten sensitivity
– Aggresion in coyotes (fusobacterium)
– Lack of biodiversity affects our health, the environment
– Immensely important role in agriculture – release and provide microcnutrients to plants
– Re-establishment of native landscapes in part dependent on the microbiome
Bioremediation
is the use of organisms to remove pollutants from soil, air, or water.
True or false, Prokaryotes are often used for bioremediation, including in sewage treatment facilities.
True
• Prokaryotes are:
– the largest biomass – Very diverse
– By enlarge useful and essential for our ecosystem and health
True or false, Advances in molecular genetics revealed that many prokaryotes are more closely related to eukaryotes than to other prokaryotes.
True
the first major split in the history of life was the divergence of…..
Bacteria, and later divergence separated the domains Archaea and Eukarya
True or false, Some of the main differences among the three domains involve the cellular machinery for gene expression
True
Domain Archaea includes
– extreme halophiles (“salt lovers”),
– extreme thermophiles (“heat lovers”), and
– methanogens, which thrive in anaerobic conditions
True or false, Sometimes archaea are referred to as “extremophiles.”
True
VIRUS
consists of either DNA or RNA, that is protected by a protein/ membrane coat called a CAPSID.
Viruses range in size
from 20 nanometers (nm) – 250 nanometers (nm)
If a cell was the size of your classroom, then an average virus would be the size of a softball.
Viruses affect bacteria, plants, animals.
Viruses cause colds, flu, warts and diseases such as measles, AIDS and cancer.
True or false, not all viruses cause disease
True
True or false, not all viruses are harmful to humans.
True
Why the world needs viruses to function
Key to ecosystems
• Phages control the populations of bacteria -> kill
about 50% of bacteria each day
• Some viruses are critical to the health of coral
reefs
• Some viruses allows infected plants to deter
aphids
Why the world needs viruses to function
Protective to human health
• Some viruses may provide immune benefits
• 8% of our genome is virally derived!
• Phage therapy
• Oncolytic viruses can specifically kill cancer cells • delivery of gene therapy, vaccines
Incredibly important in evolution/ exchange of genes
• Bacterial evolution – pathogenic E.coli – shiga- toxin producing E. coli
• Genes linked to the ability to have live births were introduced by ancient retroviruses that infected our ancestors more than 130 million years ago.
Protists
Protists are mostly unicellular eukaryotes that are found in a variety of aquatic or moist habitats.
Protists may be:
– autotrophic, called algae
– heterotrophic, informally called protozoans, or
– mixotrophic. Mixotrophs are capable of photosynthesis and heterotrophy.
