Unit 7 Flashcards
Examples of pathogens:
Bacteria, malaria from mosquitoes, fungi like ringworm, protists.
Why do we categorize pathogens?
Because there are different ways to treat them.
What is the top killer?
Acute respiratory infection, like influenza.
What are five modes of transmission?
Air, water/food, physical contact, bodily fluids, insect/animal bites.
What are some eubacteria diseases?
Tuberculosis, bubonic plague, cholera, leprosy, lyme disease, chlamydia.
How is tuberculosis spread?
Air or water.
How is the black death/bubonic plague spread?
Fleas.
How is cholera spread?
Contaminated water from dead organisms dying in the water.
How is leprosy spread?
Personal contact.
How is lyme disease spread?
Ticks.
How is chlamydia spread?
Personal contact.
What are some viral diseases?
Chicken pox, measels, flu, hepatitis, polio, AIDS, West Nile, Hanta virus.
Mode of transmission: Chicken pox
Air
Mode of transmission: Measels
Air
Mode of transmission: Flu
Air
Mode of transmission: Hepatitis
Contaminated food or water
Mode of transmission: Polio
Contaminated food or water
Mode of transmission: AIDS
Sex/bodily fluids, contaminated needles
Mode of transmission: West Nile
Mosquitoes
Mode of transmission: Hanta virus
Mouse droppings
What is a prion?
It is a protein fragment that can cause disease. It is neither a virus nor a bacteria. Even after cremating a victim, the prion can still survive.
How is Mad Cow disease spread?
When cows died, they were fed to other cows, continuing the disease. Also, Altoids mints from England.
What is an emerging disease?
It’s new (relatively); ex. West Nile, HIV, Lyme disease, Ebola, Sars
What is a re-emerging disease?
Basically under control, but it still pops up now and then; ex. tuberculosis, malaria, measles.
What is an endemic?
Always around, hard to make a vaccine for it. Ex. Flu, pneumonia, plague, strep throat.
What is the first line of defense against pathogens?
Also called nonspecific defense. Your skin, hair, mucus, enzymes, salt, acidic secretions, wax, normal flora (symbiotic bacteria).
What is the second line of defense?
The inflammatory response, when it gets past skin
What happens during the inflammatory response?
Redness, swelling, high temperature in a localized area.
What does the swelling in the inflammatory response do?
It prevents more pathogens from entering and prevents blood loss.
What does the redness in the inflammatory response do?
It indicates that blood is flowing to the area.
What does the temperature in the inflammatory response do?
It can kill off some pathogens because of increased temperature.
What are capillaries?
They are the smallest type of blood vessel.
Why do the capillaries dilate in the inflammatory response?
When they swell, they make cracks to let the white blood cells through. The white blood cells engulf the bacteria (phagocytosis).
What is the complement system?
It’s when white blood cell proteins latch onto the cell membranes of the pathogens and punch holes in them.
What happens to combat a viral infection?
Interferons are released, which interferes with viral reproduction in neighboring cells.
What is the third line of defense?
The immune response. If a pathogen takes hold, the Helper T cells recognize foreign antigens.
What is an autoimmune disease?
It’s when the helper T cells feel the antigens of the body (good antigens) and don’t recognize them as belonging. They attack.
What are examples of autoimmune diseases?
HIV, multiple sclerosis, arthritis, diabetes type 1.
What do Helper T cells do to foreign antigens?
They engulf it and present it to other WBCs y releasing interleukins 1 and 2 to chemically attract other WBCs to the infection.
What makes antibodies?
B cells.
What are antibodies?
They are proteins that perfectly match an antigen. They bind to an antigen (they have two spots to connect to an antigen) and cause cells to agglutinate.
How do B cells produce antibodies?
They match with the antigens, clone themselves into plasma cells which produce antigens and memory B cells.
What are memory B cells?
WBCs that fight off the antigen if it comes back.
How do you get a different strain of bacteria?
The antigens change slightly, leaving the WBCs unprepared for the new adaptations.
What are cytotoxic T cells?
They are killer cells. They are called in by interleukins 1 and 2. They release proteins that punch holes and kill the infected cells.
When does a phagocyte show up?
In the inflammatory response.
What does a phagocyte do?
It is a WBC that engulfs the agglutinated antigen and antibody cells.
What do Suppressor T cells do?
They stop the release of histamines, decrease the number of WBCs around the infection, and finish off the process.
What are the two types of prokaryotic bacteria?
Archea and eubacteria
What are archea?
They are the oldest bacteria, the “earliest form of life,” and they use H2 to reduce CO2 to methane, producing marsh gas and biogas.
What are the three types of archea?
Methanogens, thermophiles, and halophiles.
What are methanogens?
They live deep underground, they are anaerobes, they feed on methane, and oxygen kills them.
Where do archea usually live?
The harshest environments.
What are halophiles?
They live in salty environments with salinity from 5-20% (compared to the 3% salinity of the sea).
What are thermophiles?
They live in super hot environments- 60-80 degrees Celsius. They feed on sulfur by oxodizing it. They are found in hot springs.
What are eubacteria?
They are the newer bacteria that can grow in Petri dishes with different nutrients and different conditions.
What are the three bacterial/eubacteria shapes?
Bacilli (rod-shaped/hot-dog shaped), spirilla (spiral-shaped), and cocci (spherical).
What are some examples of cocci?
Diplococci (comes in pairs), staphlococci (clusters), and streptococci (long chains).
Many eubacteria are…(how they get food), but some are…(another way to get food.)
Heterotrophs (find food), autotrophs (make food).
What are the two types of autotrophic eubacteria?
Photosynthetic and chemosynthetic.
What was “the first organism to photosynthesize?”
Blue-green algae, which likely made most of our oxygen and killed many anaerobic organisms.
What are the three kinds of heterotrophic bacteria?
Obligate anaerobe, obligate aerobe, facultative anaerobe.
Obligate anaerobe
Has to live without oxygen, ex. Clostridium botulinum (lockjaw).
Obligate aerobe
Needs to live with air/oxygen, ex. streptococcus.
Facultative anaerobe
Can live with or without oxygen, ex. E. coli.
What is binary fission?
Asexual reproduction in bacteria. The cell makes a copy of its DNA and splits into two cells. There is no genetic variation, which means that the clones are likely to die off from an antibiotic.
What is conjugation?
Sexual reproduction in bacteria. DNA is exchanged: The smaller of the two chromosomes moves to the other bacteria cell. The bacteria form a conjugation bridge to do this and absorb DNA. This creates genetic variation and makes it harder for the antibiotic to kill the bacteria.
What is an endospore? How does it form?
A bacterial cell that has shrunk and lost water and formed a hard outer layer in order to survive harsh conditions. It’s like hibernation. Some endospores can survive space.
What is an example of an endospore?
Anthrax
How do you turn an endospore back into bacteria?
Add water.
Bacterial toxin definition and example
Bacterial waste. Ex. Salmonella produces waste as it feeds inside you.
What are antibiotics?
They are medicines that kill only bacteria (no viruses) by preventing them from producing vital organelles such as a cell wall, membrane, enzymes, or DNA.
What likely occurred if the antibiotic stopped working?
The bacteria developed adaptations. For example, some strains of tuberculosis are resistant to all antibiotics.
Controlling bacteria and avoiding dangerous types
Use proper temperature (cooking thoroughly, heating and cooling appropriately), washing hands, cleaning surfaces,, canning food, refrigeration, freezing, preservatives (salt, vinegar, sugar, chemicals), antiseptics (alcohol and bleach), radiation.
Helpful roles of bacteria
Decomposers, nitrogen fixation, fermentation, genetic engineering, digestion, mining, prevents pathogenic invasion, makes O2, bioremediation, antibiotics.
Harmful roles of bacteria
Disease, spoils food.
Allergy
Immune response to a non-pathogen. Includes swelling, redness, temp. increase. Treated with antihistamines.
Active immunity
Pick up immunity during your life from vaccine or infection.
Vaccine
Weakened, killed pathogens or chemicals produced by microorganisms that is injected or swallowed to build memory B cells for the antigens.
Passive immunity
From pregnancy or lactation (breast feeding). Protects the babies from disease.
SCIDS
Severe combined immunodeficiency disease. It’s genetic and it means you lack B cells and T cells. Patients typically live in a sterile bubble and go through gene therapy treatment.
What is used to prevent an immune response to an organ transplant?
Anti-rejection drugs
What can antihistamines do as a side effect?
Make you drowsy as they calm the immune response.
Why don’t we typically get the same infection twice?
After this: pathogen shows up, immune response, 1st infection neutralized, then the memory B cells can shut down the infection faster next time if the pathogen shows up.
What are two ways to decrease rejection of an organ transplant?
Use antirejection drugs to slow or prevent immune response or use an organ from your family because the antigens will be similar.
What is one negative side effect of antirejection drugs?
They weaken your immune system.
What is a virus?
A nucleic acid surrounded by a protein coat. It is an obligate parasite, but it is not a living creature because it requires a host cell to reproduce.
What two nucleic acids could a virus contain?
DNA and RNA.
What is a retrovirus?
A virus containing RNA, which must convert RNA to DNA once inside host cell.
Why is a retrovirus unusual?
It was always thought that DNA made RNA which made proteins, but in a retrovirus, the RNA would convert to DNA.
What are the two paths of a viral life cycle?
Lysogenic and lytic.
What happens during a lytic infection?
Attachment: The virus attaches to the host cell. Then it injects its own DNA into the cell. Duplication: The viral phages/chromosome duplicates. Release: The host cell wall ruptures, or lyses, releasing new viral particles called phages. These can infect new cells now.
What happens during a lysogenic infection?
Attachment/injection: virus attaches and injects its DNA into the cell. Incorporation: viral DNA is added to the cell’s DNA. The cell splits. multiplying the viral DNA, during mitosis.
What can trigger the lysogenic infection to turn into a lytic infection?
Stress or chemicals, lysogenic infections aren’t noticed as much as lytic infections.
What is AIDS?
Acquired immunodeficiency syndrome. Few Helper T cells.
What is HIV?
Human immunodeficiency virus, a type of retrovirus that attacks Helper T cells. It can take a very long time to actually kill its victim.
How is HIV transmitted?
Through cuts and tears, often during intercourse, but also anytime blood can be shared. Dirty needles, blood transfusion, passed down by birth, placenta, or lactation.
How many people are infected with HIV and/or AIDS each year?
5 million.
How many people die from HIV or AIDS each year?
3 million.
What specifically do HIV and AIDS viruses attack?
The Helper T cells.
What kind of virus is HIV?
A retrovirus.
What is the process of reverse transcriptase?
It is the process of converting RNA to DNA for the HIV virus. It is a major source of error with a high mutation rate, which allows for adaptations that can help the virus survive.
What is transcriptase?
It is the enzyme that lowers the activation energy for converting RNA to DNA.
What receptors does HIV bind to?
CD4 and CCR5.
What happens if you have a defective CCR5 receptor, like some people?
You may be resistant or immune to HIV.
What are three forms of HIV treatment?
AZT, integrase inhibitors, and protease inhibitors.
What is AZT?
The initial drug given for HIV that prevents reverse transcriptase.
What are integrase inhibitors?
They prevent HIV DNA from integrating into the host cell’s DNA.
What are protease inhibitors?
They prevent the transcription of viral proteins.
What is the Nef gene?
It is the gene that allows the HIV virus to enter without the Helper T cells displaying the antigen. The HIV “sneaks in.””
What does a defective Nef gene do?
It allows the HIV antigen to be presented so that the white blood cells attack it. Common in certain Australian populations.
How many HIV viruses can be made in one person’s body each day?
Up to 5 billion.
How many Helper T cells can be destroyed by HIV each day in one person’s body?
Up to 2 million.
At what amount of Helper T cells is a person considered to have AIDS?
If they have 200 or fewer Helper T cells per mililiter of blood, they have AIDS.
How many Helper T cells does a healthy person have?
1000 per mililiter.
What is the main risk from AIDS?
The immune system becomes so compromised that it can’t prevent opportunistic infections such as pneumonia and sarcoma.
Helper T cells vs. Cytotoxic T cells
Helper T cells engulf foreign antigens and present them on their surface. They are the “alarm bells.” Cytotoxic T cells are killers that have proteins to punch holes in infected cells.
