Ch. 18- Viruses and Prokaryotes Flashcards
Any living organism or particle that cause an infectious disease
Pathogen (infectious agent)
Infectious particles that cause disease in plants
Viroids
An infectious particle made only of proteins that can cause other proteins to fold incorrectly which causes them not to function.
Prion
A protein she’ll that can have different shapes and in some viruses, is surrounded by a lipid envelope
Capsid
The protective outer coat of a virus from which spiky structures of proteins/sugars may stick out
Lipid envelope
Viruses that prey on bacteria
Bacteriophages
An infection pathway in which the host cell bursts, releasing the new viral offspring into the host’s system to infect other cells
Lyric infection
A phage combines its DNA into the host cell’s DNA
Lysogenic infection
The phage DNA inserted into the host cell’s DNA
Prophage
A rapid outbreak of an infection that affects many people
Epidemic
A virus that contains RNA and uses an enzyme to make a DNA copy. Double stranded DNA then enters the nucleus and combines with the host genes as a lysogenic infection. The viral DNA can remain dormant for years as a provirus with no symptoms to the human host.
Retrovirus
Prokaryotes that cannot survive in the presence of oxygen
Obligate anaerobes
Prokaryotes that need oxygen to survive
Obligate aerobes
Prokaryotes that can survive whether oxygen is present in the environment or not
Facultative aerobe
A small piece of genetic material that can replicate separately from the prokaryote’s main chromosome
Plasmid
A long whiplike structure outside of cell that is used for movement
Flagella
Helps prokaryotes stick to surfaces and other prokaryotes
- more numerous flagella
- shorter/ thinner than flagella
Pilli
Genetic material transfers between prokaryotes to produce genetic variation
Conjugation
A specialized cell with a thick, protective wall produced by some bacteria during conditions unfavorable for survival
Endospores
A process that uses microbes and other living things to break down pollutants
Bioremediation
The ability of bacteria to break down a material
Biodegradable
A poison released by an organism
Toxin
Chemicals that kill or slow the growth of bacteria by stopping them from making cell walls
Antibiotics
Archaea bacteria contain what type of cell?
Prokaryote
How many cells are found in Archaea bacteria?
One
Do archaea bacteria contain cell walls?
True
In which way do archaea bacteria obtain food?
Chemosynthesis/ some are autotrophs and some are heterotrophs
How do archaebacteria reproduce?
Asexually
Eubacteria are what type of cell?
Prokaryote
Eubacteria are composed of how many cells?
One
Do eubacteria contain cell walls and membrane organelles?
No
In which way do eubacteria obtain food?
Some autotroph/ some heterotroph
How do eubacteria reproduce?
Asexually through binary fission
What are the differences between living cells and viruses?
Living cells use energy, nutrients, and reproduce on its own. Viruses must use a host cell’s energy and machinery to reproduce and make proteins.
What do all pathogens have in common?
Causes diseases
Give 2 reasons why prions weren’t thought to be pathogens?
Prions are very small and often incubate for years before taking effect
What type of pathogen is an RNA based disease?
Viroids are made of RNA and is passed typing seeds and pollen to infect plants
Why is it difficult to make effective antiviral drugs?
- high mutation rate for viruses
- most drugs that would attack the virus and stop the replication may also kill the host cells
Give 5 facts about viruses.
- respond to their environment
- have genes and can reproduce
- can’t reproduce on their own but need living cells to help them reproduce and make proteins
- viruses are much smaller than most cells
- viruses aren’t given a place in the Linnaean system
Give 3 facts about viroids.
- made of single stranded RNA without a protein coat
- passed through seeds and pollen
- have even less to do with living things than viruses
What have had a major impact on agriculture and why?
Viroids because they stunt plant growth.
Why did Dimitri Ivanovsky do?
In 1892 he studied tobacco mosaic disease thought to be caused by bacteria. When he removed the bacteria, he found that the extract could still pass on the disease.
What did Martinus Beijerink do?
In 1898 he built up on Dimitri’s work by showing that the disease agent passed through agor gel. He proposed that the tiny particles within the extract caused infection which he called VIRUSES.
What are the spikes on the lipid envelope used for?
Helps viruses attach to host cells
What is another way to describe a virus?
Simply packaged sets of genes that move from 1 host cell to another and has no structures to maintain such as a membrane and organelles.
How do viruses identify hosts?
By fitting its surface proteins to receptor molecules on the surface of the host cell
What is the basic structure of a virus?
Genetic material surrounded by a capsid
What is some examples of structures if viruses?
Rod shaped and strand like viruses often have capsid a shaped on coils like a spring or helix.
What kind of genetic material can viruses have?
DNA or RNA but never both
How can the genetic material of viruses be structured?
Single/double stranded, linear, circular, or segmented
How do bacteriophages work?
They work like a syringe by injecting its genes into the host’s cell’s cytoplasm, where DNA is found.
Example of a bacteriophage
T. Bacteriophage
What is a difference between viruses that infect bacteria and eukaryotes?
The way they enter the host cell such as endocytosis.
What does the virus do when it is inside the cell?
Target the cell’s nucleus
What are the first line of defense for organisms against viruses?
In vertebrates it is skin, for other organisms it is outer skeleton of a tough cell wall
How do viruses penetrate skin?
Through a cut/scrape or mucus membranes/ body openings such as mouth, nose, genital area, eyes, and ears
What do viruses do when they are finally inside the body?
- The virus finds its way to target organs or tissues.
- When the virus comes to a host cell, it uses its own surface proteins as keys for the receptors to trick the cell to allow it to enter.
What do cold viruses do as they move from people?
Mutate
What can spread quickly in local epidemics?
Flu
Why is it necessary to make a new vaccine each year for the flu?
The high mutation rate of surface proteins on viral capsids
Explain SARS.
Symptoms are similar to flu such as fever/ coughing/ difficulty breathing.
And first appeared in 2002 in Asia and spread to other countries
What is an example of a retrovirus?
HIV
Explain HIV infections.
When the viruses. É one active, it directs the formation of new viruses
The new viruses leave by either budding/bursting through cell membranes and infect new cells.
This destroys white blood cells through lytic infection to cause AIDS.
Why is HIV hard to treat?
Has a high mutation rate, but there are drugs to slow the spread of virus
Explain a vaccine.
It is made from the same pathogen that is supposed to protect against.
It consists of weakened version of the virus or parts of it that’ll cause the body to produce a response to it.
Immune system is triggered by the pathogen’s surface proteins and prepares it from future attacks from the virus.
Ex. Of an obligate anaerobe
Archaea
Ex. Of obligate aerobe
Tuberculosis and leprosy
What are the similarities between archaea and bacteria?
- small, single celled
- have cell walls/ cell membranes
- prokaryotes
What can move on their own and why?
Archaea and bacteria using the flagella to glide
Where is the flagella attached to in prokaryotes?
Plasma membrane/ cell wall
What is structurally different between bacteria, archaea, and eukaryotes?
Flagellum
What are archaea more closely related to?
Eukaryotes
What are the differences between archaea and bacteria?
- archaea cell walls and membranes are chemically different than bacteria.
- archaea membranes have lipids found in no other organism
- bacteria have a polymer called peptidoglycan in their cell walls while archaea don’t
How are bacteria classified?
Into two groups based on the amount of peptidoglycan in their cell walls
What tells the 2 groups apart and is important in diagnosing bacterial diseases?
Gram stain
Explain conjugation.
Can exchange parts of their chromosomes through a hollow bridge of pilli connecting 2 or more cells.
How are endospores formed?
Bacteria copies its chromosome and produces a wall around the copy
What kind of conditions can an endospores help a bacteria survive?
Drying out, temperature change, and disinfectants
What are a key part of animal digestive systems?
Bacteria
What else can humans get from bacteria?
Fermented foods
What do Cyanobacteria and other bacteria produce?
Cyanobacteria produce oxygen through photosynthesis and other bacteria and Cyanobacteria produce nitrogen in a different from for other organisms to use through nitrogen fixation.
What is an example of bioremediation?
Oil spills
How can bacteria cause disease?
By invading tissues and attacking cells or making toxins that can be carried by blood to sites throughout the body.
Give an example of a bacteria invading cells to cause disease.
Tuberculosis
Give an example of a bacteria that produces a toxin to cause disease.
Staphylococcus aureus
Where can harmless bacteria be destructive?
When introduced to a part of th host that’s not adapted to them or in tissues they usually don’t colonize in
How are antibiotics produced?
Naturally by some species of bacteria and fungi
Why can antibiotics be used on animals?
We don’t have cell walls
Why can’t antibiotics work on viruses?
Viruses lack cell walls
What happens when you overuse antibiotics?
Make selective pressure favoring the bacteria because it becomes resistant
What happens when you underuse an antibiotic?
It can cause drug resistance and you won’t destroy all the bacteria, only the weak ones.
What are examples of misuse of antibiotics?
In agriculture to increase the animals’ growth rate. Then the food from the healthy animals have resistant bacteria in them which means the same antibiotics can’t be used on you since they’re resistant.
An infection made only of a strand of DNA or RNA surrounded by a protein coat.
Virus
