Viruses and Bacteria Key Vocabulary and Key Questions from the text Chapter 20 Viruses and Bacteria Key Vocabulary and Key Questions from the text

20.1 Key Vocab Virus-particle made of proteins, nucleic acids, and sometime lipids that require a host cell for reproduction Capsid-protein coat around a virus Bacteriophage-a virus that infects bacteria cells Lytic infection- virus enters a cell, makes copies of itself, and causes the cell to burst Lysogenic infection- Prophage Retrovirus-

20.2 Key Vocab and Questions Prokaryote-unicellular organism where DNA is not enclosed in a nucleus Bacillus- bacteria that is rod shaped Coccus-round shaped bacteria Spirillum- spiral shaped bacteria Binary fission-asexual reproduction, where the cell splits in half, producing two identical daughter cells Endospore- thick internal wall, encloses the DNA and cytoplasm of bacteria cell, remains dormant for a period of time Conjugation- a hollow bridge that forms between 2 cells to exchange genetic ino

How are prokaryotes classified? Thy belong to either of 2 domains: Bacteria or Archaea Bacteria is the larger domain, cell walls contain peptidoglycan, and live almost everywhere What us peptidoglycan you ask…a polymer of sugars and amino acids that surround the memebrane Archaea is the smaller group, membranes have different lipids, no peptidoglycan in cell walls, and live in extreme environments

How do prokaryotes vary in their structure and function? They vary by size & shape, movement, and the way the obtain and use energy Shapes include: bacilli, cocci, spirilla Some move by flagella, some don’t move, others glide or whip Mode of nutrition include heterotrophs, photautotrophs, photoheterotrophs, and echemoautotrophs see chart page 582

What roles do prokaryotes play in the living world? Prokaryotes maintain ecological balance of the living world as decomposers, producers, nitrogen fixers, and even benefit humans! Decomposers-break down organic matter replenishing the environment Producers-huge source of oxygen b/c of photosynthesis, also a huge food source Nitrogen Fixers-organisms need nitrogen to make proteins and bacteria take gaseous nitrogen and “fix” it or convert it to more useful forms or ammonia, provide 90% of itrogen for other organisms to use

20.3 Vocab & Questions Pathogen- anything that causes a disease Vaccine- a weakened or killed pathogen or inactive toxins used to promote immunity from a disease Antibiotic-drug used to attack a bacterial infection, ex: penicillin & tetracycline Emerging disease-un unknown disease that appears in a population or a well known disease that becomes harder to control

How do bacteria cause disease? Bacteria destroy living cells and tissues, ex. Tuberculosis is inhaled and destroys tissues or Or bacteria release toxins that disturb homeostasis, ex. Diptheria that causes deadly food poisoning or botulism What is homeostasis again?

What are ways to control bacteria? See chart page 587

How do viruses cause disease? Viruses cause disease by directly destroying living cells or by affecting processes that disrupt homeostasis See chart page 588, different human viral diseases

How can we protect against viral diseases? Prevent them by vaccinations, personal hygiene, and avoiding sick individuals Treatment- Viral diseases cannot be treated with antibiotics, there are some antiviral medicines, but for the most part viruses just need to run their course

Why are emerging diseases particularly threatening to human health? Pathogens that cause emerging diseases are threatening because humans have little to no resistance and because no method for controlling them has been developed (if it is a new disease)