My overview of whats important in biology
Natural selection process
1. Individuals vary in their traits. 2. Inidividuals struggle to exist 3. Individuals differ in their fitness and pass the traits down to the next generation 4. Populations become adapted to the environment
What is a mutation
A change in the sequence of nucleotides in the genetic material which can change the sequence of amino acids in a protein and thus the properties of that protein
active immunity
A form of acquired immunity in which the body produces its own antibodies against disease-causing antigens.
Helper T cells
A form of lymphocyte that can recognize the combined MHC-II-antigen receptor on the macrophage. WHen this happens, it is activated and starts to divide, producing cytokines that alert the antibody mediated responses and starts the activation of cytotoxic T cells
Thimersol in flu vaccine
A preservative that may be present in some multi-dose vials of the vaccine
natural selection. Ex:
A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits. Giraffe and their neck example
How does the immune system recognize self from nonself?
A series of markers present on the plasma membrane of each cell. The plasma acts as the barrier between the interior of the cell and the exterior environment. The membrane is made of phospholipids adn within are a variety of proteins.
Cytotoxic T cells
A type of lymphocyte that kills infected body cells and cancer cells. Targets the cells of our bodies that hvae been infected by a pathogen and are presenting a specific pathogen on their surface.
Trivalent vaccine
A vaccine that protects against three strains. Contains inactivated (killed) virus particles that cannot reproduce
How do viruses infect cells?
A virus has certain molecules that allow it to attach to a specific kind of cell and the virus then injects its nucleic acid into the cell. For influenza A, it is carried out by the H spike.
What are antiviral medicines?
A way to combat a virus that has the ability to evolve rapidly. either in attachment, when vriuses are specific in the types of cells they infect so it's possible to target either the molecules on teh surface of the host cell that the virus identifies with or the proteins that the virus uses to attch to the cell; Uncoating. Once inside the cell, some viruses provide an enzyme to remove their genetic material from the capsid; Release. Many viruses provide an enzyme that interacts with specific molecules in the host cell's membrane toa llow the newly formed viruses to escape the host cell
How are flu viruses named?
According to their host, type, strain, and year of isolation
Interferon as a chemical signal of the immune response (cytokine)
Acts as a signal to nerby cells that a cell has been infected by a virus
cell-mediated immunity
Adaptive immunity form; lymphocte type of immunity produced by T cells that attack infected or abnormal body cells
Archaeopteryx
An example of a transitional species between reptiles and birds and an example of descent with modification
Tiikalik roseae
An example of descent with modification. Called "fishapod" because it is the transitional link between fish and amphibians
Formation of fossils
An orgainism dies in a marine environment and is covered by sediment, impressions of the softer parts may be made and the hard parts become mineralized fossils
Pathogen
An organism that causes disease
APC
Antigen-presenting cell; a macrophage that has a portion osf an antigen on its surface to alert the remainder of the immune system. The specific stages of the immune system will then target anything in the body that matches the antigen, be it a pthogen encountered int he fluids of the body or a cell that has been infected by the pathogen.
what does evolution tell us about how the influenza virus will change?
Antigenic shift will occur and produce new forms fo the virus that culd infect humans and because the influenza virus is an RNA virus, it must undergo reverse transcription in order for the host cell to use its genetic material to make new viruses. This has the potentail to intrudce new mutations by antigenic drift, which can produce new variants of the H and N spikes. Because our immune system often uses H spikes as an antigen, any change in a virus's structure could create problems at the individual and population level
How are antigens produced?
Antigens are produced when a macrophage engulfs a pathogen. When pathogens are ingested by the macrophages and dendritic cells of the immune system, they are digested and a small portion of the pathogen is attached to the surface of the macrophage which alerts the remainder of the immune system.
Tamiflu
Antiviral medication that disrupts the influenza virus life cycle by targetting the release stage of influenza life cycle by inhibiting a viral enzyme, called neuraminidase, that allows the virus to leave the host cell. Rapivab and Relenza have similar functions
How does the flu vaccine work?
Associated with active immunity, direct exposure to the pathogen (like influenza virus) prompts an immune response. Fortunately, by exposing an individual to an antigen that is specific to that pathogen but not the actual pathogen itself, the body begins an immyne response to the antigen and in the process generates memory B and t cells. However, when you get th flu vaccine, you don't get the fly virus because its a killed version. H spikes are unique to influenza so it is possible to build vaccinations that use these spikes as antigens and prime the immune system for future exposure tot eh actual virus. When you are exposed to the actual virus, the response of your memory B and T cells, generated during the primary response to the vaccine, is faster and more effective and generally able to protect you from getting the flu
What does the tree of life include?
Bacteria and Archaea, which are both prokaryotic, single-celled organisms, and Eukarya, which is Eukaryotic, single-celled to multicelllular organisms
Jean Babtiste Lamarck
Believed that complex life forms are descended from simpler forms. Inheritance of acquired characteristics.
analogous structures
Body parts that share a common function, but not structure. I.e. wings on birds, bats and insects
Proteins
Built from aino acids, they are the working molecules of the cells
Attachment
Capsid combines with receptor
Evolution
Changes in a species or population over time. Only occurs when heritable changes in the genetic information are passed on from generation to generation.
Cytokine symptoms and action for the Integumentary system
Chills. Restriction of blood vessels in the skin to conserve heat
Nasal Spray
Contains weakened versions of the flu virus and may produce some flu-like symptoms. It is less affective than a trivalent or quadrivalent vaccine
Chemical signals of the immune response are collevtively called ___
Cytokines
What is the genetic material of a virus?
DNA or RNA, it contains the instructions needed to make the proteins that compoase the capsid surrounding the virus and for influenza a, the H and N spikes.
What is the flow of information in all organisms except retroviruses?
DNA to RNA to proteins
Innate defenses
Defenses that act as general defenses and don't target specific pathogens. The first line of defense is the physical barriers which are structures and chemicals produced by several of the organs and tissues of the body that slow or prevent pathogens from entering
Antigenic
Describes organisms that can evade our immune defenses
Natural killer (NK) cells
Destroy cells of the body that have been infected by viruses or bacteria. Nonspecific
Macrophages, dendritic cells and neutrophils
Destroy pathogens (organisms that cause disease) by phagocytosis (surrounding and engulfing it). Nonspecific
What does influenza do that accounts for many flu symptoms
Disrupts the epithelial cells that regulate the activities of the body
antiviral drugs
Drugs that act, are effective, or are directed against viruses.
Aluminum salts in flu vaccine
Enhances the ability of the immune system to detect the virus. Some vaccinations are aluminum free
The Flu and the respiratory system
Enters through mouth or nose. Travels down the pharynx into the trachea and lungs. H spikes identify host epithelial cells. N spikes act to initiate entry of the virus into the target cell. The replication cycle begins immediately. Once inside, the virus hijacks the cellular machinery to make new viruses and produces proteins to interfere with the normal function of the epithelial cell. Fluid accumulation occurs in the lungs. As the epithelial cells lose their function, they may undergo apoptosis/programmed cell death. This may cause inflammation of the tissue which activates the immune system. The immune system sends a host of cells to the respiratory system. Chemical signals increase blood flow to these tissues and combined, this causes tissues to swell and inflammation to increase. As a result, large amounts of mucus are produces, which casues the congestion and cough.
What types of cells does influenza infect?
Epithelial cells lining the respiratory system
Georges cuvier
Father of paleontology
Directional selection
Form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve
What two components do all viruses have?
Genetic material and a capsid
Interleukin as a chemical signla of the immune response (cytokine)
Glycoprotein that is involved in regulating the general immune response
Types of Spikes on Influenza Virus
H spikes and N spikes
Cytokine symptoms and action for the Nervous system
Headache and fever. Presence of cytokines tells the hypothalamus in the brain to increase the body temperature
H spikes
Hemagglutinin, allows the virus to attach to specific host cell receptors by identifying a specific molecule on the surface of the cell
Embryonic development
Homologus structures are evident during the embryonic development of animals because the embryos look similar. The similarity in embryonic development is due to the action of a series of developmental genes called Hox genes.
How does evlution relate to the influenza virus?
Human influenza viruses originate in animal hosts like the pig and bird. When those two exchange genetic material, they evolve into new forms, which can be transmitted to humans, causing flu outbreaks
Stomach as a physical barrier for pathogens
Hydrocholoric acid (low pH) destroys bacteria and other pathogens
Where did the influenza virus originate?
In prokaryotes
Formaldehyde in flu vaccine
Inactivates any toxins from the viruses or bacteria that may have been present during production
Histamine as a chemical signal of the immune response (cytokine)
Increases the permeability of the capillaries and causes fluid to be released into the area of the wound. Responsible for the symptoms of an allergy
RNA viruses
Influenza A and HIV
Epithelial cells
Involved in regulating the movement of materials into and out of the tissues of the body, such as the respiratory tract and digestive tract. Our skin also is composed of it to isolate us from our external environment
Lymphatic system
Involved in returning fluids (called lymph) from the tissues of the body back to the circulatory system, filtering/cleaning the blood and interstitial fluids of the body, or in the production and maturation of immune system cells called lymphocytes.
alternative pathway of complement activation
It is triggered by the presence of infection but does not involve antibody. The early stages leading to cleavage of C3 involve iC3b, factor B, and factor D.
Cytokine symptoms and action for the Muscular system
Joint and muscle aches. Breakdown of muscle fibers and accumulation of fluid
Cytokine symptoms and action for the digestive system
Loss of appetite, nausea, vomiting. Reduces action of appetite centers in the brain.
What cells are directly involved in identifying pathogens?
Macrophages and dendritic cells
Major-histocompatibility complexes (MHS)
Markers present on the plasma membrane of each cell that helps the immune system recognize self from non self
Alveoli
Millions of tiny air sacs in the lungs where gas exchange occurs. They are thin walled structures lined with a single layer of epithelial cells.
Antigenic drift
Minor change in influenza virus antigens due to gene mutation. May be introduced by the acion of the reverse transcriptase enzyme, is due to minor mutations in the structure of teh H and N spikes and may result in a reduced fidelity for flu vaccines
Chicken Egg method
Most common method: inject the virus into fertilized chicken eggs, allow them to incubate for a few days while the virus begins to replicate. Then extract the liquid portion and kill the viruses in it. The virus particles are then isolated, purified and used to make the vaccines. This requires the longest development time.
Respiratory tract as a physical barrier for pathogens
Mucous membranes trap microbes; they contain chemicals that protect against pathogens; cilia
N spikes
Neuraminidase enzyme, helps break down mucous material surrounding host cells in the respiratory tract and initiates penetration of the virus into the host cell
What research is being done on a universal flu vaccine?
New vaccines are being designed t o use other proteins within the capsid of the virus as the bases for programming the adaptive responses. These proteins, core proteins, don't change at the same rate as the H and N spikes and are more similar between influenza viruses.
Release
New viruses leave host cell
Recombinant process
Newest process, only a small portion of the influenza virus is used. The portion protein of the H spike is used. The protein is added to the virus that infects insect cells and is then cultured to produce large amounts of the H spike protein. The complete virus isn't produced and the extracted H spike protein is used to make the vaccine. This is the most rapid method of producing a vaccine and allows for egg-free vaccines.
Is it possible to have an antibody on reserve for every variant of antigen? Why?
No, each B lymphocyte can produce a single form of antibody, and within are genes that allow for the production of antibodies that vary slightly in their structure and the antigen it will produce. This gives our immune system tremendous felxibility in the types of pathogens it can respond to
Skin as a physical barrier for pathogens
Normal bacteria (flora) on the surface, along with chemicals released by oil and sweat glands, inhibit bacterial growth
What happens if a mutation occurs in the DNA
Nothing, death of the cell or organism, or often the final protein assumes a slightly different shape and the result is variation in that trait.
The immune response
Our immune system has several levels of defenses, from nonspecific phsycial barriers to cellular mechanisms of protecting us from specific pathogens such as the influenza virus
Inflammatory response events
Part of innate defenses. The damaged tissue and nearby immune cells release histamine, causing fluid to leak from nearby capillaries slowing the movement of pathogens and increases blood flow to the area to deliver additional white blood cells (like macrophages) and clotting factors to repair the would. The macrophages identify and destroy any bacteria or viruses int he wound area. Neutrophils remove dead cells, woulnd debris and any pathogens in the area by phagocytosis. If additonal assitance is needed, neutrophils may release cytokines to recruit more immune cells to the area. Clotting factors close off the wound. This causes pressure to build and accounts for the red, tender appearance of inflammation
MHC-I
Present on every nucleated cell of the body. This is the general self identification tag.
Antibiotics in flu vaccine
Prevents bacterial growth during preparation and storage of the vaccine
5 characteristics to determine if something is alive or not
Process energy and materials, maintains an internal environment, responds to stimuli from the environment, reproduces, and adapts to changing environmental conditions
B lymphocytes
Produce antibodies to target specific antigens in the fluids of the body. Specific
Charles Lyell
Proposed that the Earth's surface is dynamic and constantly undergoing erosion and uplift, explining the different fossil layers
Complement proteins
Proteins in blood produced by the immune system that help destroy pathogens by coating or puncturing them. Enhanses inflammation, cell lysis and opsonization. C1-C9
Cytokines
Proteins released by white blood cells that alarm the organ systems of the body that a pathogen is present
Antibodies
Proteins that attach to antigens, keeping them from harming the body. It can clump together around an antigen, inactivating it, or it can bind to the antigen and flag it for destruction from a natural killer cell
The fossil record
Provides us with ideas of what organisms were like in the past and gives an indication of how they have evolved over time
Influenza virus uses ____ to manufacture mRNA molecules directly from the virues's RNA molecules, bypassing the need for a reverse transcriptase
RNA Polymerase
How do viruses evolve?
RNA genetic material in the influenza virus mutates and develops develops methods ot avoid our immune system
What is the flow of information in retroviruses?
RNA is converted into DNA with an enzyme called reverse transcriptatse so it can be processed by the host cell
Egg protein in flu vaccine
Remnants from the production of the vaccine. Newer vaccines that do not use eggs during production won't have these proteins present
Immune system
Responsibel for protecting our bodies from foreign pathogens like viruses and bacteria, and works closely with the lymphatic system
Cell-based method
Similar to the process with chicken eggs, except the viruses are placed into mammalian cell cultures to replicate.
MHC-II
Special identification tag. Molecules only found found on macrophages, B cells, and activated T cells that signal helper T cells. Alerts the immune system of specific pathogens.
Gelatin, sorbitol or monosodium gluamate (MSG) in flu vaccine
Stabalize the vaccine and protect it from temperature variations during storage
Thomas Malthus
Stated that populations sometimes increase at rates fater than their food supply can increase, creating competition
homologous structures
Structures in different species that are similar because of common ancestry. I.e. limbs of a mouse, bat and whale
T lymphocytes
Target cells that have been infected by a specific pathogen. Specific. White blood cells produced in thebone marrow. After being formed, they travel to the thymus where they mature. As they mature, each develops receptors that will allow it to recognize a single form of antigen.
What are the methods of producing a flu vaccine?
The Chicken Egg method, Mammalian Cell-Based method, and Recombinant method
Evidence of evolution is biology
The Fossil Record, Comparative anatomy, Embryonic development and genetic material
What are most flu symptoms a result of?
The activation of the immune system and chemical signals released in resonse to infection. The white blood cells release proteins called Cytokines which acts as an alarm to the organ systems of the body
Memory
The adaptive immune response ability to remember past exposures to pathogen. Some activated B cells are held in reserve and not used in the first response to teh antigen and wait for future exposure. This is useful if you come into contact again.
Genetic Comparisons
The closer the genetic information is between two species, the closer their evolutionary relationship
Comparative anatomy
The comparison of body structures and how they vary among species. Homologous structure.
What happens when influenza enters an epithelial cell ont eh surface of our respiratory tract?
The infected cell posts an antigen on its surface, attached to a MHC-I marker, flagging cytotoxic T cells that were just activated by the helper T cells. The cytotoxic T cell then attaches to the target cell and releases a protein called perforin, which opens a hole in the membrane. Granzymes enter the hose, casing the cell to undergo programmed cell death/apoptosis.
Thymus
The organ where T lymphocytes mature
Spleen
The organ where blood is filtered and cleaned by the action of white blood macrophages
How are flu viruses selected to make a vaccine?
The process begins a year in advance. Over 100 worldwide monitering stations send clinical samples to influenza centers in 5 countries. There, scientists review data to determine each flu virus's potential to cause a world-wide pandemic, what is known about the strain of the virus, and the ability to produce an effective vaccine against the strain.
What introduces mistakes that can cause variation in new viruses
The use of reverse transcriptase enzymes or RNA polymerase
How do animals play a role in virus evolution?
They cause antigenic shift when the virus combines inside thier cell (bird virus and human virus combining inside a pig cell)
Immune system and lymphatic system
They work closely to protect the body from pathogens. The immune system monitors the fluids from the lymphatic system for the presence of pathogens through the lymp nodes of the body. At those times when you're sick, you may feel warmth and pain from your lymph nodes as the cells of the immune system engage the pathogens
Erasmus Darwin
Thought all living things came from a common ancestor
How does the flu enter the body?
Through the mouth or nose, often from touching something where the virus is. From here it enters into the respiratory system and travels down the pharynx into the trachea and lungs.
Lymph nodes
Tissue where the interstitial fluid is filtered and cleansed by white blood cells called macrophages
red bone marrow
Tissue where the lymphocyte cells of the body are produced. The location where B lymphocytes mature
Types of flu vaccines
Trivalent, quadrivalent, and nasal spray
Antigenic shift
Two different influenza viruses infect the same host cell so a new form of the virus is made, formation of new combinations of H and N spikes on the virus, and a slower adaption by the immune system
Evolution is recognizes as one of the _____ of biology. That means that ____
Unifying theories; almost every aspect of the biological sciences may be explained by evolutionary processes and plays a role in all levels of biology.
B cell
Unlike a T cell, a B lymphocyte can bind directly to an antigen, even if it is still ont he surface of the pathogen. If a B cell recognizes the influenza virus directly it can start to produce antibodies against it. this is known as adaptive immunity.
Penetration
Viral DNA enters host
Maturation
Viral components are assembled
Retrovirus
Virus that contains RNA and uses the enzyme called reverse transcriptase to make a DNA copy
Antibody-mediated immunity
While helper T cells andcytotoxic T cells are working to target infected cells, teh B lymphocytes begin the production of antibodies.
Quadrivalent vaccine
Works by stimulating an immune response against four different antigens. Contains inactivated (killed) virus particles that cannot reproduce
inflammation
a localized response to an injury or to the destruction of tissues
Life cycle of a virus
attachment, penetration, biosynthesis, maturation and release
Opsonization
coating antigen with antibody enhances phagocytosis
classical pathway of complement activation
complement binds to an antibody that is bound to a foreign substance.
Fidelity
faithfulness; loyalty
Lysogenic cycle
following penetration, the DNA integrates into the cell's DNA and remains inactive. As the host cell divides, it divides. It remains latent until some environmental factor signals it to reenter the lytic cycle.
Disruptive selection
form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle
Stabilization selection
most common form of natural selection in which organisms with extreme expressions of a trait are removed
Macrophages
phagocytize foreign substances and help activate T cells
Phagocytosis
process in which extensions of cytoplasm surround and engulf large particles and take them into the cell
Glycoprotein
protein witha large sugar group attached, acts as identification tags
Transitional follis
represent intermediate forms, are an excellent example of descent with modification, help us understand how species have changed over time, and provide an indication of the timeline of these changes
Cell lysis
rupturing membranes of foreign cells
Antigen
substance that triggers an immune response. Usually proteins or large carbohydrates that are specific to pathogens like bacteria and viruses.
adaptive immunity
targets specific antigens associated with a pathogen and remembers past responses. able to target cells of the body that are infected with the pathogen while also responding to any pathogens that are free in the blood or interstitial fluid of the body. Must be activated to respond to a specific antigen
What accounts for the types of host species?
variations of the types of H spikes on an influenza A virus
Biosynthesis
viral components are synthesized