BIOL 2401 Unit 3 Lecture Notes PDF

BIOL 2401 - Unit 3 3.1a – Eukaryotic Pathogens (Fungi) Describe the defining characteristics of fungi, and the two basic forms of fungi Main role of fungi is to act as ___________ decomposes and also used in the production of foods Structural...

BIOL 2401 - Unit 3 3.1a – Eukaryotic Pathogens (Fungi) Describe the defining characteristics of fungi, and the two basic forms of fungi Main role of fungi is to act as ___________ decomposes and also used in the production of foods Structural components: o Fungal cell membranes contain __________ ergosterol o Fungal cell walls contain ______ chitin Two forms: o Multicellular forms: ____ molds  Filaments that contain hyphae  A network of these filaments are called _________ mycelium Fig 3.1 – mold o Unicellular form: _______ yeast Fig 1.5 Fungi can reproduce through: o Sexual reproduction through the production of ________ gametes o Asexual reproduction through:  ___________ mitosis : equal division  ___________ budding : unequal division cell has a little growth coming off the cell new organism fragmentation  ______________ : part of the structure breaking off  _______ spores : specific cell types used for reproduction (BIOL 2401) – Weissy Lee (Unit 3) Page 1 of 19 Describe the five types of mycoses and describe a common type of fungal skin infection A disease caused by fungi is called a mycosis myo=fungal; cosis=infection/disease Fungal pathogens also tend to grow more ________ slowly (in comparison to bacteria or other types of microbes) Those that cause skin infections can directly affect the _____ skin , enter through a ______ wound , or be part of the ____________ resident microbiota o The transmission of these fungal pathogens can be promoted through ____ moist environments (e.g., sweaty shoes, communal showers, etc.) and spread through _________ physical contact ___________ superficial mycosis is a fungal infection of the epidermis, hair and nails with no keratin digestion. ____________ cutaneous mycosis (aka: _______ tinea ) is a fungal infection of the epidermis, hair and nails with keratin digestion. Examples of tineas: ring worm, athlete’s foot Microbes that cause this type of mycosis are called _______________ dermatophytes ringwom, athlete foot; fungal infection ________________ subcutaneous mycosis is a fungal infection into the deeper tissues (past the dermis) __________ systemic mycosis is a fungal infection that has spread throughout the body (e.g., from the respiratory system) _____________ opportunistic mycosis is a fungal infection that occurs when a patient is immunocompromised (e.g., yeast infections) (BIOL 2401) – Weissy Lee (Unit 3) Page 2 of 19  Practice! Dermatophytes are responsible for: a) Superficial mycosis b) Cutaneous mycosis c) Subcutaneous mycosis d) Systematic mycosis e) Opportunistic mycosis Name two toxins that are produced by fungi, and their effects ______ ergot toxin is produced from Claviceps purpeurea, a fungus that grows on rye Do not need to and grains; two possible effects: remember o __________ gangrenous ergotism, leading to vasoconstriction and eventually organism names, just gangrene toxin names o __________ convulsive ergotism, targets the central nervous system leading to mania and hallucinations _________ aflatoxin is produced from Aspergillus, an opportunistic fungal pathogen that can be ________ consumed (leading to cancer) or ________ inhaled (leading to chronic pulmonary disease aspergillosis) 3.1b – Eukaryotic Pathogens (Algae) Describe the defining characteristics of algae All algae are classified as ______________ photoautotrophs , meaning that they are capable of photosynthesis o Contain specific _________ pigments in their chloroplasts leading to different colours redseaweed is sourec of Multicellular algae (__________ seaweeds ) are sources of food, and solidifying agents (e.g., agar)agar plates in lab o Similar to plants in structure, but do not have ______________ roots nor leaves Some unicellular algae can produce ______ toxins and when they ______ bloom (sudden increase in population), can lead to high concentrations of toxins (BIOL 2401) – Weissy Lee (Unit 3) Page 3 of 19 Name and describe two diseases caused by unicellular algae Diatoms Dinoflagellates Fig 1.3 Fig 3.3 Key cell Cell wall = silica Cell wall = cellulose structures Flagella Transmission As algae are consumed by shellfish in the ocean, there is accumulation of the toxin. method Shellfish are then consumed by other animals, leading to further accumulation of the toxin (______________________ bioaccumulation ) Outbreaks are uncommon in humans, but can lead to death in animals that rely on shellfish for their main source of diet Toxin name domoic acid saxitoxins Disease name paralytic shellfish poisoning domoic acid toxicosis ocean turns red cause of alot of (occurs during red tide) dinoflagellates Signs and _____________ numbness , dizziness, nausea, diarrhea symptoms memory loss (targets CNS) _____________ vomiting, headaches & paralysis Practice! Which of the following characteristics are DIFFERENT between diatoms and dinoflagellates? a) Toxin produced b) Transmission c) Symptoms d) Disease e) Cell wall component f) Location of algae (BIOL 2401) – Weissy Lee (Unit 3) Page 4 of 19 3.1c – Eukaryotic Pathogens (Protozoa) Describe the defining characteristics of protozoa A metabolically-diverse group, and can live in a variety of environments Some are free-living and some are parasitic In hosts, the _____________ trophozoite is the form where growth and feeding occurs. when they Some species can form a ______ cyst , which is a cell with a protective wall and allows them to survive become dormant harsh environmental conditions Cysts = protozoan equivalent of bacterial endospores Different reproductive methods are possible, including: o Sexual reproduction through the production of __________ gametes (meiosis) o Asexual reproduction through: Protozoan binary fission is different  ___________ binary fission : equal division into two cells from prokaryote binary fission – do not need to know details  ___________ Budding : unequal division into two cells Schizo means multiple, (starts with one  ___________ Schizogony : multiple fission into several cells. and then divide into a lot) The products of these are called __________ merozoites and stored in _______ schizonts Several parasitic species require multiple hosts for a complete life cycle: o The ________ definitive host is the primary host OR where sexual reproduction of the parasite occurs o The ___________ intermediate host is the secondary host OR where asexual reproduction of the parasite occurs Describe the life cycles of three pathogenic protozoa and the illnesses they causes as per prof; do not learn the A. Entamoemba histolytica causes the disease amoebiasis or _________________ amoebic dysentery scientific names but tthe diseases name   fecal.oral route ______ feces containing ___________ food/water Contaminated amoebic cysts contaminated with feces food/water _______ ingested Symptoms include _____________ diarrhea , mucus, pain, flatulence Complications: formation of __________ cysts , which can spread to other organs; chronic infection is also possible (BIOL 2401) – Weissy Lee (Unit 3) Page 5 of 19  species B. Plasmodium spp. causes the disease ________ malaria “spp.” = species genus name Anopheles _____________ mosquitoes (warmer environment), cant be any mosquito but a aspecific type (Definitive host) 3. Trophozoites can also form 1. Mosquito bites a human and injects ___________ gametes , which are picked up Plasmodium by another mosquito biting the human _____________ sporozoites The gametes then develop into sporozoites in this mosquito into the human __________ humans (Intermediate host) 2. Effects on humans: red blood cells liver Sporozoites undergo Merozoites infect RBC to form schizogony to form ______________ trophozoites _____________ merozoites Trophozoites ______ lyse RBC, leading to the release of _________ toxins Trophozoites then form more merozoites Key signs and symptoms: extreme fever and chills, __________ anemia (cause of destruction of RBC) (BIOL 2401) – Weissy Lee (Unit 3) Page 6 of 19 C. Toxoplasmosis gondii causes the disease _______________ toxoplasmosis ________ cat 1. _______ oocysts are (Definitive host) shed in cat feces 5. Cats can be ________ re-infected if they consume infected intermediate hosts (birds, rodents) or ingest infected 2. Feces contaminate food/water food/water fecal-oral route fecal/oral ________ 3.a) route or deeer 3.c) Transfer of 3.b) ___________ consuming cysts through the meat of infected ________ placenta ________ humans ______________ birds, rodents etc. animals if pregnant, can (Intermediate host) pass the infection to (Intermediate host) fetus 4. Effects on intermediate hosts: Oocysts become ____________ tachyzoites , which travel to (brain) neural and muscle tissue to form __________ cysts , which can persist for years Key signs and symptoms in humans: Typically ___________________ asymtomatic in healthy individuals; can lead to various diseases (e.g., encephalitis) in immunocompromised individuals brain infection (BIOL 2401) – Weissy Lee (Unit 3) Page 7 of 19 3.1d – Eukaryotic Pathogens (Helminths) Describe how parasitic helminths differ from free-living helminths Parasitic helminths rely on a host for survival, and compared to their free-living counterparts, will have reduced: o _________ digestive systems because they do not need to digest their own food use their host for food and digestion o ________ nervous systems because they do not need to search for food or regulate body temperature o __________ locomotor abilities because they do not need to run from predators However, they will have increased ___________ reproductive systems compared to their free-living counterparts to ensure survival of their species Describe the defining characteristics of helminths 2 types Platyhelminths Nematodes Alternative flat worms round worm name Reproduction _____________ monoecious = male and female reproductive __________ dioecious , = separate organs in a single individual individual worms with either Reproduction occurs when two worms of the same male or female organs species fertilize each other Both a male and a female worm is required for reproduction Characteristics flukes = tape woms = Unsegmented (no specific sub- (noodle type) nonsegmented worms segmented worms types) with an oral sucker Segments = _________ proglottids Head = _________ scolex , which contains Fig 3.9 _________ hooks eggs In general, all helminthic infections are treated with specific _________ drugs , and may need ________ surgery in more extreme cases. (BIOL 2401) – Weissy Lee (Unit 3) Page 8 of 19 Describe the life cycle and characteristics of two flatworm species 1. Schistosoma spp. is a ______ fluke that causes the disease Schistosomiasis or _____________ snail fever 1. Urine/feces containing eggs are released into freshwater 2. Eggs hatch in the water and develop to the miracidia form, which infects snails Human (Definitive host) 4. The cercariae form can Snails penetrate the skin of swimmers (Intermediate host) and migrate to the bloodstream 3. Inside the snails, the miracidia mature to 5. Effects on humans: the cercariae form, which leaves the snail The worm then matures to adult form, mates and and enters the water then releases eggs The eggs travel through the bloodstream and enters various organ systems such as the bladder or intestine, and then excreted in urine or stool Key signs and symptoms: rash at site of penetration, muscle pain, chronic infections (BIOL 2401) – Weissy Lee (Unit 3) Page 9 of 19 2. Taenia solium is a __________ tapeworm that causes the disease taeniasis or ________________ pork tapeworm 1. Feces containing _____ eggs are released and contaminate food/water 2. Both hosts can become infected when they _______ ingest contaminated food/water (fecal-oral route) 4. Transmission can occur when humans ____________ pigs _________ (Intermediate host) ____________________ infected, undercooked pork (Definitive host) meat is ingested. 3. Eggs hatch and move to the 5. Effects on humans: ________ muscle tissue of the pig to form Inside humans, the eggs hatch and the scolex attaches _______ cysts ; the worm does not develop any to the _______ intestine ; further development occurs to form further the adult worm, which produces eggs. In some cases, the larva can form _____ cysts in other tissues, such as in the muscle, eye, or brain leading to ___________ cysticercosis Key signs and symptoms: Usually asymptomatic or mild GI symptoms; larvae can form _____ cysts which embed in muscle, eyes, or brain, which can lead to pain (BIOL 2401) – Weissy Lee (Unit 3) Page 10 of 19 Describe the life cycle and characteristics of two roundworm species 1. Enterobius vermicularis is a ____________ roundworm that causes enterobiasis or __________ pinworms   fecal/oral _________ feces _____________ food/water route Contaminated containing eggs contaminated with feces food/water _______ ingested More common in _____________ young children Key signs and symptoms: itching in anal region and insomnia (occurs when female worm leaves the colon at night to lay eggs on the perianal region 2. Ascariasis lumbricoides is a round worm that causes ______________ ascariasis   fecal/oral ________ feces/soil ____________ food/water route Contaminated containing eggs; also contaminated with feces food/water common in soil ____________ ingested Key signs and symptoms include: asymptomatic; shortness of breath, diarrhea, abdominal pain, intestinal ____________________ blockage o Worms ___________ mature by migrating around the body (including the circulatory system, respiratory system, and ending up at the digestive system) Complications include a buildup of _______________ worm masses which needs to be surgically removed Fig 3.12 (BIOL 2401) – Weissy Lee (Unit 3) Page 11 of 19 3.2 - Viruses A quick reminder on units: Describe the characteristics of viruses 1 cm = 10 mm __________ acellular (no cell structure) 1 mm = 1000 µm 1 µm = 1000 nm Small – measured in ___________ nanometres o Cannot be viewed using a light microscope (requires an electron microscope) Explain why viruses are classified as obligatory intracellular parasites Relies on a _____ host for replication; cannot survive without one Viruses have been found to infect every type of host cell, but A common error is to mix up most viruses can only infect specific hosts and specific cell types virion characteristics with within the hosts phage characteristics – be sure you can distinguish the For the context of this course, the following terminology is used: virsuses two! o _______ /virions can infect eukaryotes o ___________________ bacteriophage/phage can infect bacteria Describe the general structure of a virion and a bacteriophage 1. Virion structure a) Nucleic acid: _____ DNA or _____ RNA DOUBLE or _______ ________ SINGLE stranded b) Capsid: Fig 3.15 A ________ PROTEIN coat that surrounds the nucleic acid, which is made up of smaller subunits called ______________ CAPSOMERE Capsid shape can vary between different viruses, and are typically categorized as: Fig 3.16 o _______ HELICAL _________ (polygon with 20 sides) o ICOSAHEDRAL o _________ COMPLEX (BIOL 2401) – Weissy Lee (Unit 3) Page 12 of 19 c) Envelope: Some viruses have a ____________ PHOSPHOLIPIDS layer surrounding the capsid; these are called _________ ENVELOPED viruses o Embedded in this envelope are _______ SPIKES Viruses that do not have this envelope are called _____________ NON-ENVELOPED viruses 2. Phage structure Bacteriophages have their genome (DNA) in the polyhedral _______ CAPSID (head) The head is then connected to a _______ SHEATH The _________ TAIL FIBRES are attached to the sheath, and are involved in _________ ATTACHMENT Fig 3.13 Practice! Draw an annotated diagram illustrating the following: Enveloped virus Non-enveloped virus NUCLIEC ACID CAPSID SPIKES ENVELOPES Describe characteristics that are used to classify viruses 1. Official classification and naming of viruses Example - Classification of viruses based on genetics, chemistry, Family: Retroviridae morphology, and mechanism of multiplication Genus: Lentivirus Family names tend to end with the suffix “-viridae” Common name: Human Immunodeficiency virus Genus names tend to end with the suffix “-virus” ________ COMMON names are often used for viruses, and these are not italicized 2. Unofficial/informal group of viruses based on shared characteristics: Type of nucleic acid (DNA/RNA; single-stranded/double-stranded) Capsid morphology Presence of envelope (BIOL 2401) – Weissy Lee (Unit 3) Page 13 of 19 Describe the various life cycles of animal viruses The main steps between the different life cycles are the same, but the details will vary depending on whether the virus is enveloped/non-enveloped and whether its genome is DNA/RNA On an exam setting, make sure you include only the relevant details for the specific virus type mentioned – this is important to demonstrate understanding of the material and the question! Attachment The animal virus (virus) attaches to the target cell type by hijacking a specific ________________ surface receptor on the cell. a) Enveloped viruses will attach using _______ spikes b) Non-enveloped viruses will attach using _______ fibres Entry The virus enters the host cell a) Enveloped viruses will enter the host cell through ______ fusion , where the viral envelope fuses with the plasma membrane, pushing the capsid into the cell. For understanding… pink- host component; blue-viral component Draw a diagram for fusion: host cell membrane cytoplasm outside b) Non-enveloped viruses will enter the host cell through ____________ endocytosis , where the host cell is forced to engulf the virus forming a vesicle. Eventually, the capsid breaks free of the vesicle. For understanding… Draw a diagram for endocytosis: (BIOL 2401) – Weissy Lee (Unit 3) Page 14 of 19  Uncoating The capsid breaks into capsomeres, __________ exposing the genome Biosynthesis The virus replicates its genome and proteins using _____________ a) DNA viruses – the viral DNA is _________ replicated , then __________ transcribed to form mRNA and then __________ translated to make viral proteins. (i.e., follows central dogma). For understanding… Draw a flow diagram for the biosynthesis of DNA viruses. host host viral Ddrp ribosomes viral viral proteins dna rna host DNA polymerase b) RNA viruses – the RNA genome needs to be replicated, but host cells do not have the right enzyme for this. RNA viruses must bring their own enzyme for RNA replication – _________________________________________ RNA Dependent RNA polymerase (RdRp) Following RNA replication, ____________ translation occurs to make viral proteins DNA is not involved for these viruses (i.e., partially follows central dogma) For understanding… Draw a flow diagram for the biosynthesis of RNA viruses. host ribosomes viral viral RNA proteins viral RdRp RNA retroviruses – the viral genome is made of RNA Viral RNA is first converted to DNA. Host cells do not have this enzyme, so viruses must bring their own enzyme for reverse transcription called ________ reverse ________________ transcriptase Viral DNA is then integrated (enzyme called _________ integrase ) into host DNA to form a ________ provirus (this integration is permanent) (BIOL 2401) – Weissy Lee (Unit 3) Page 15 of 19  Viral DNA hibernates Upon a specific ________ trigger , the DNA genes are _________ activated , and become transcribed to form mRNA and then the mRNA is used for translation to form proteins for HIV pt, that trigger is getting sick, cold, etc etc For understanding… Draw a flow diagram for the biosynthesis of RNA retroviruses. viral viral (starting point) DNA viral RNA RTase viral integrase trigger host DNA viral viral proteins provirus host DNA host Ddrp ribosomes Assembly The capsid and genome spontaneously ___________ assemble Release / exit Viral exit from the host cell Enveloped viruses exit the host cell through _______ budding or just remember __________ exocytosis where the host plasma membrane is used one out of two terms to form the viral envelope. The host cell may or may not die from this process. Non-enveloped viruses exit the host cell through ___________ cell lysis , leading to host cell death. Sources of images: Dimitrov, D. S. (2004). Virus entry: molecular mechanisms and biomedical applications. Nature Reviews Microbiology 2: 109-122) Fig 3.20, 3.22 (OpenStax) https://www.khanacademy.org/science/high-school-biology/hs-human-body-systems/hs-the-immune-system/a/intro-to-viruses Practice! Outline the steps for the replication of an enveloped RNA virus. 1. Attachment- spikes 2. entry - fusion (define) 3. uncoating 4. biosynthesis - RdRp 5. assembly 6. Exit or Release - budding or exocytosis (BIOL 2401) – Weissy Lee (Unit 3) Page 16 of 19 Contrast acute and persistent viral infections, and provide examples for each type Acute viral infection: the virus _______ rapidly reproduces, causing symptoms over a _____ brief period of time o Examples include: ______________ cold, influenza Persistent viral infection: the virus cannot be _______ cleared from a person; two types: o ______ latent viral infection: the virus becomes hidden or dormant in the host cell  Examples include: ______________ herpes simplex virus o _______ chronic viral infection: the symptoms are recurrent as the virus inactivates the immune system  Examples include: ______________ hepatitis C Describe how viruses can cause cancer A key characteristic is that cancer cells grow _____________ uncontrollably Some viruses can cause cancer by transforming a normal cell to a malignant cell This can be done by: o _________ inserting the viral genome into specific genes (called tumour suppressor proteins) which control _____________ cell division o Enhance genes (called oncogenes) to ________ increase cell division 3.3 - Prions Define the term “prion” and briefly explain how they can be infectious Proteinaceous infectious particle or prion are ________ proteins that can cause diseases (no cell structure, no genome) Prions are _________ misfolded versions of a normal protein (PrPc) in the cell When a prion is in contact with the normal protein, it causes the normal protein to also misfold and ____ loses its function Fig 3.23 Aggregates of the misfolded protein form, leading to neuron ______ death (BIOL 2401) – Weissy Lee (Unit 3) Page 17 of 19  Transmission: o Between animals, or from animals to humans by _______ ingesting contaminated meat o Between humans through __________ inherited , or by _______ contact with contaminated tissues (e.g., organ transplant) Diseases – various forms of ___________________ transmissible spongiform ________________ Encephalopathy o _________ mad cow disease, scrapie, chronic wasting disease o Inherited form is called Creutzfeldt-Jakob disease (CJD) Fig 3.24 Unit 3 Review questions – see if you can answer without using your notes! (for studying purposes only and not for marks) Unit 3.1 - Fungi 1. Describe the structure of multicellular fungi and unicellular fungi. 2. Describe the possible modes of reproduction in fungi. 3. Identify the five types of mycoses and describe the affected area for each. 4. Identify two fungal toxins and their effects in humans. Unit 3.1 - Algae 1. Identify the typical metabolic diversity of algae. 2. Describe the structure of multicellular algae. 3. Identify and describe the transmission of the disease caused by diatoms. 4. Identify and describe the transmission of the disease caused by dinoflagellates. Unit 3.1 - Protozoa 1. Describe the function of a protozoan cyst. 2. Identify and describe the possible modes of reproduction in protozoans. 3. Define definitive and intermediate hosts. 4. Identify the disease and describe the transmission of Entamoeba histolytica. 5. Identify the disease and describe the transmission of Plasmodium spp. 6. Identify the disease and describe the transmission of Toxoplasmosis gondii. (BIOL 2401) – Weissy Lee (Unit 3) Page 18 of 19 Unit 3.1 - Helminth 1. Compare parasitic helminths vs. free-living helminths in their digestive, nervous, locomotor and reproductive systems. 2. Compare the structure and reproduction of platyhelminths with nematodes. 3. Identify the two types of platyhelminths, and compare the structure of these two types. 4. Identify the disease and transmission of Schistosoma. 5. Identify the disease and transmission of Taenia solium. 7. Identify the disease and transmission of Enterobius vermicularis. 8. Identify the disease and transmission of Ascariasis lumbricoides. Unit 3.2 - Viruses 1. Identify the difference between an animal virus (virus) and a bacteriophage (phage). 2. Describe the three main parts of an animal virus. 3. Describe the structure of a phage. 4. Describe the specific life cycle for the following animal viruses: Non-enveloped DNA viruses very important; need to know all of them! Enveloped DNA viruses Non-enveloped RNA viruses Enveloped RNA viruses Enveloped RNA retroviruses 5. Describe the difference between acute and persistent viral infections. 6. Identify and differentiate between the two types of persistent viral infections. 7. Identify two ways in which some viruses can cause cancer. Unit 3.3 – Prions 1. Identify the nature of prions. 2. Describe how prions can cause disease. 3. Identify how prions can be transmitted. 4. Identify two examples of diseases caused by prions. (BIOL 2401) – Weissy Lee (Unit 3) Page 19 of 19 Unit 3.1 - Helminth 1. Compare parasitic helminths vs. free-living helminths in their digestive, nervous, locomotor and reproductive systems. 2. Compare the structure and reproduction of platyhelminths with nematodes. 3. Identify the two types of platyhelminths, and compare the structure of these two types. 4. Identify the disease and transmission of Schistosoma. 5. Identify the disease and transmission of Taenia solium. 7. Identify the disease and transmission of Enterobius vermicularis. 8. Identify the disease and transmission of Ascariasis lumbricoides. Unit 3.2 - Viruses 1. Identify the difference between an animal virus (virus) and a bacteriophage (phage). 2. Describe the three main parts of an animal virus. 3. Describe the structure of a phage. 4. Describe the specific life cycle for the following animal viruses: Non-enveloped DNA viruses Enveloped DNA viruses Non-enveloped RNA viruses Enveloped RNA viruses Enveloped RNA retroviruses 5. Describe the difference between acute and persistent viral infections. 6. Identify and differentiate between the two types of persistent viral infections. 7. Identify two ways in which some viruses can cause cancer. Unit 3.3 – Prions 1. Identify the nature of prions. 2. Describe how prions can cause disease. 3. Identify how prions can be transmitted. 4. Identify two examples of diseases caused by prions. (BIOL 2401) – Weissy Lee (Unit 3) Page 19 of 19