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Freshman Biology Unit 5
Terms in this set (123)
what percentage of our mass do prokaryotes make up?
What were the old old large categories for bacteria?
Monera, Protista, Fungi, Plantae & Animalia
why did biologist switch from the old categories for bacteria to the new one
because they were neither prokaryotes nor Eukaryotes and had unique cells qualities
Character traits of the Archaea
- have no nucleus or organelles
- similarities in DNA and DNA synthesis as to
- unique cell membrane lipids,
- unique cell wall composition
- Some have the ability to survive extreme environments
what were the new categories of living things?
Bacteria, Archaea and Eukarya
what special traits do Archaea?
they are extremophiles
Archaea that live in extreme environments such as hot springs
T or F Bacteria are the most abundant life form
- Circular DNA
- No organelles
- 1/10th the size of eukaryotic cells
- Flagella-long hair-like structure used for
- Reproduce asexually -Binary Fission
What are the 3 main shapes of bacteria
shape of Coccus?
shape of Bacillus?
rod like / pill
live off dead organic matter
Live is and on other organisms and harm
Live in and on other organisms either them or not harming them
what group are Symbiotic, Parasites, and decomposers are part of what bacteria group?
how do bacteria produce their own food?
Process by which some organisms, such as certain bacteria, use inorganic molecules like H2S from the thermal vents to make energy for them and others
bacteria that need oxygen to survive
bacteria that need to be in oxygen free environment - are poisoned by
bacteria that can live in an oxygen rich or oxygen
what is the cell wall of a bacteria composed of?
peptidoglycan - a combination of protein and polysaccharides
Gram negative bacteria
have an additional layer of membrane that contains lipopolysaccharide. this extra layer inhibits the uptake of the `
what color does a gram negative cell turn into when in contact with the stain?
what color does a gram positive cell turn into when in contact with the stain?
Gram Positive Bacteria
a bacteria cell without the extra membrane
hairlike structures usually in Gram neg. bacteria. Help bacteria stick to surfaces. Also forms conjugation bridge
a passageway for the transfer of the genetic information
a single loop of that is folded on controls the cell's function
the region of the where the DNA is found
an accessory loop of DNA - small contains only a genes can be responsible for: conjugation, resistance, unique metabolic properties - like the ability use
Recycle dead organism releasing their nutrients back into the environment for use by other organisms
what would happen if there were no Decomposers?
elements on earth would have remained locked up in dead organisms and life would
What are the roles of bacteria in an ecosystem?
to be decomposers, nitrogen fixing bacteria, producers, mutualistic bacteria and pathogenic bacteria
Nitrogen Fixing Bacteria
bacteria that recycle nitrogen to a usable form through enzymes inside of them
What do living things use nitrogen for?
bacteria that are the producer of the environment for example in deep oceans chemosynthetic bacteria are the producers
What molecule do chemosynthetic bacteria use to convert it to energy for the ecosystem?
hydrogen sulfide next to the vents
photosynthetic bacteria which act as producers in many aquatic ecosystems
Bacteria that live on a living thing and help the host
Mutualistic Bacteria in the gut of an herbivore?
help to digest cellulose
Mutualistic Bacteria in the gut of the of humans?
Aid digestion and produce vitamins
Mutualistic Bacteria on the skin and in body openings?
help prevent infection by harmful organisms
organisms that cause disease
Are all bacteria pathogenic?
no only a small portion
What cause most disease?
toxins released by bacteria
What do the toxins released by bacteria cells do?
-poison cells and damage tissue
-interfere with cell signaling
-overstimulate cell causing them to malfunction
bacteria that convert hydrogen sulfide to energy
Do pathogenic bacteria have a symbiotic relationship with their host
No because they harm the host by giving the host disease
What does Koch's postulates prove?
proves that microorganism are what cause disease not bad air or ghost
What are Kock's postulates?
1. The microorganism must always found in individuals with the disease
2. The microorganism can be taken the host and grown in pure culture
3. A sample of the culture produces the disease when introduced to a new host
4. The newly infected host yields new pure culture of identical to those found in step 1
What challenges to pathogens face when having to infect the host?
- arrive at the body surface of a
- enter the host's body
- evade the host's defenses
- find conditions in the host that
allow it to reproduce
- damage the host
- it must be able to infect a new
a structure made of polysaccharide that is made by some bacteria can form. Once the structure is formed it traps other organism in it with it and protects the bacteria making it hard to kill
chemicals which either kill bacteria or prevent their growth and reproduction
Why do bacteria produce antibiotics?
to reduce competition with other organisms
What was the first antibiotic used to kill bacteria?
How do antibiotics attack different cells?
they only attack bacteria and not eukaryotic cells
What are the 5 ways antibiotics attack the bacteria?
- some damage the cell walls or prevent new cell
wall from forming
- some damage the cell membrane
- some prevent protein synthesis
- some prevent DNA from being copied
- some interfere with bacterial metabolism
what are the challenges faced when antibiotic resistance comes into play?
disease is harder to treat with antibiotics
What has caused bacteria resistance
-use of antibiotics to treat viral infections when
antibiotics don't affect viruses
-antibiotics in livestock
-show up the livestock then we consume it
-people take the antibiotics until they feel better, but stop before all of the bacteria are destroyed
How do bacteria reproduce?
by binary fission
Do bacteria reproduce sexually or asexually?
A way of reproducing that works for bacteria where the offspring is genetically identical to the parent
Under ideal conditions how many times does asexual reproduction occur
every 20 min
making more of something
occurs when genes are exchanged between 2 DNA molecules and makes a new genetic combination adding to the genetic diversity of the subject
allows bacteria to make clones of themselves - all are genetically identical
what are the 3 methods of a bacteria cell having genetic diversity?
Transduction, Transformation and Conjugation
When a viruses carry DNA from one bacterial cell another and on accident creates more genetic diversity
A way of bacteria can have more diversity through absorbing "naked" DNA released by dead bacteria from the environment
When two bacteria create a temporary connection and one bacteria passes on a copy of its plasmid or chromosome to the other to achieve genetic diversity
What are the steps of Transduction?
1. A virus, known as a phage insert its DNA into the host cell
2. Phage takes over the host cell and breaks the host cells DNA causing new viral parts to be formed
3. New viruses are assembled in the host cell and some random host cell bacteria gets packaged with the new virus
4. Virus-containing the part infects a new cell and accidentally inserts the DNA of the original host cell
5. The DNA of the first cell and the second join creating a new combo
What are the steps to conjugation?
1. A special Pillus forms a connection celled a conjugation bridge between the 2 bacteria
2. The donor cell copies its plasmid or chromosome and passes the copy through the conjugation bridge
3.then the cells seperate
The range of genetic material present in a gene pool or population of a species.
Why is genetic diversity important to bacteria?
So that the entire population of the bacteria cannot be killed in one blow because they are all the same
What is the size of a small Virus?
from 20 nm to 250 nm to small to see with a light microscope
What is the structure of a Virus?
What are the shapes of of Viruses?
Shape of icosahedral viruses?
Shape of a Helical virus?
Shape of a Complex virus?
obligate intracellular parasites
A virus that must reproduce inside a host
Why must viruses reproduce in a host?
Because they are so simple
A virus that can only infect one type of cell
Bacteriophages are viruses that only infect & kill bacteria and they are the virus that responsible for transduction
Steps of the Lytic Cycle
1. Virus attaches itself to host cell
2. Injects the host with its DNA
3. Viral DNA takes control of the host cell
4. Host cell creates new viral parts
5. The Viruses are assembled
6. Cell releases lyse releasing the virus
Steps of the Lysogenic Cycle
1. Virus attaches itself to the host
2. Inject the host with its DNA
3. Viral DNA inserts itself into the host DNA
4. Host cell continues to reproduce normally each time producing new cells with the viral DNA
5. After being made many times they enter the lytic
A time period when a host is infected by a virus but it is not actively showing symptoms. Sometimes referred to as dormancy and then when the conditions are correct it breaks out
A virus that has RNA and to take over the host cell it must convert its RNA to DNA through reverse transcriptase
foreign particle that triggers an immune response
Non Specific Defence
Treat all pathogens and antigens the same way
Specific Defenses aka adaptive immunity
they create a specific response to a specific antigen
First Line of Defence: Mechanical Barrier
Skin, Hair, and Mucous Membranes
First Line of Defence Chemical Barrier
Sweat, Oils, Ear wax, and Lysozyme
Second Line of Defence Inflammatory response
1. Interleukins are released as a chemical cry for help that diffuse through tissue and bind/stimulate receptors of white blood cell
2. The triggered mast cells release histamines which enter the capillaries
3. histamines cause the capillaries to expand allowing more blood and phagocytes to enter the area
Forms a physical barrier between us and the pathogen. They also shed regularly taking the pathogens with them
Found in the nose and ears prevents pathogens from entering
layers of tissue found in the respiratory system and other body opening which secrete mucus through having cilia beat upwards pushing the pathogens up so they can be sneezed,spit, or digested
contains compounds which inhibit the growth of many bacteria
glands in the skin release oils which prevent the reproduction of bacteria
found in the ear canal, traps bacteria and inhibits their growth
an enzyme found in tears which digests the cell walls of bacteria
Why is the area of the infection warm?
because there is an increase in blood flow due to stimulates and dilated capillaries
a type of white blood cell that engulf pathogens
What are the two types of phagocytes?
macrophages and neutrophils
Cells taking in large particles by engulfing them
Phagocytes that consume pathogens
short lives phagocytes that engulf pathogens then die
Second Line of Cellular Defences
1.Macrophages the main phagocyte involved in this process will engulf the pathogens but also release cytokines
2. Cytokines signal the brain to have a fever and stimulate the natural killer cells
3. The natural killer cells recognize infected cell and kill them by making the cell release chemicals that cause the cell to self destruct
Second Line of Defence: Fever
triggered by cytokines where the temperature is increased making it harder for the pathogen to reproduce and boost the immune response
Second Line of Defence: Complement Proteins (Protective Proteins)
Proteins are known as Complement proteins which attract the phagocytes to the area while some make holes in the bacteria killing them.
Second line of defence: Interferons (Protective proteins)
when the viral infection is present interferons are made sometimes by infected cells to warn other cells of the infection. Once made they interfere with the production of nucleic acid reducing the spread of the infection
Antibody Mediated Response
Creates a huge number of antibodies that immobilize the pathogens
Cell Mediated Response
Uses cytotoxic T cells to identify and destroy cells that have been infected by viruses
t or F the non specific and specific response happens at different times?
Why is it important that the immune system distinguishes between body cell and pathogens?
because the immune response is powerful and destructive
The non specific defence helps determine when what should be used
the immune system
proteins factories that specialize in producing antibodies
What does apoptosis do to a cell?
it destroys it
A harmless variant or derivative of a pathogen that stimulates a host's immune system to mount defenses against the pathogen
The resistance of a group to an attack by a disease to which a large proportion of the members of the group are immune leaving the one infected person infected to not be able to spread the virus
Measles is contagious T or F
T it last in a room for up to 2 hours