Assignment-4 (Exam-4 review question)
The three types of symbiotic relationships are mutualism, commensalism and parasitism. Mutualism is a relationship where both partners benefit. An example is the relationship between a bee and a flower. The bee gets nectar out of the flower that is used in making honey while the flower benefits because pollination will have taken place. On the other hand commensalism involves a relationship where one species benefits and the others are neither helped nor harmed. An example is the existence of the normal flora bacteria in the human body. Most of them benefit by getting nutrients from the body but do not help or harm the body. Parasitism is a relationship where one organism gains while the other suffers. An example is the infestation of ticks in a cow. The ticks will benefit because they have a host and nutrients while the cow will be harmed because it loses blood.
Transient microbiota is present in a period of time then disappears while resident microbiota colonizes the host permanently. Most transient microbiota are disease causing while resident microbiota do not cause any disease in the host.
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Breached immunity, change in location of resident, Exposure to conditions eg breached mucosal wall, Increase in their numbers
Microbial antagonism is the inhibition of the action of one bacteria by the other.
Reservoirs of infection: Animate or inanimate objects that serves as the host for an infectious agent.
Contamination is the process of polluting an environment or a surface with a disease causing organism. Infection is the invasion of a disease causing agent into the body of an organism. A disease is a failure in the structure or function in an organism with an exhibition of signs and symptoms.
Mucous membrane, skin and respiratory tracts.
Through signs and symptoms. Signs are the phenomenon that can only be detected by someone else other than the sick individual. Symptoms are the phenomenon that are experienced by the individual affected by the disease.
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Pathogenicity is the ability of an organism to cause disease while virulence is the severity of the disease in the infected organisms.
Adhesisns,invasions, antiphagocytics, toxins, hemolysins and proteases.
Extracellular enzymes are produced by a cell but are only effective outside the cell eg in the digestive system. Specific toxins are produced by organs such as the skin to counter microbial infestation. Antiphagocytic factors are produced in the process of phagocytosis.
Incubation stage-prodromal stage-acute stage-convalescent stage-Resolution stage
Direct transmission involves the travelling of the disease agent from the infected organism to the non infected organism. Indirect transmission occurs when an inanimate object serves as a reservoir for the disease agent.
Direct contract does not require an intermediary while in indirect contact there is. Airbone transmission uses the air while water borne transmission makes use of the water. Biological vector are living organisms while mechanical vectors are non living.
Mode of transmission, severity, mode of treatment and time to heal.
Acute disease develops rapidly but lasts shortly. A chronic infection develops slowly but symptoms persist for long. Latent involves pathogens that remain inactive for a long time. Communicable disease are easily transmissible while non communicable are not. Incidence is the number of new cases of a disease while prevalence is the total number of cases at a time. Exogenous nosocomial infections are as a result of infection from other patients while endogenous involves infection as a result of body weakness.
Prevalence, incidence, endemic, pandemic
Age, gender, occupation, level of education
Invasive methods used, health workers contact, hospital hygiene, food handling
Chapter 15
Adaptive immune system involves the host’s mechanism to protect itself from pathogens and toxins. Innate immunity is the body’s natural way of preventing infection.
The first line involves the skin, mucous membranes, saliva and washing wax. The second line involves the phagocytes and inflammation process. The third line involves the immune system.
The skin is keratinized with dead cells that provide mechanical strength. It has two layers, the epidermis and the dermis.
The acidity of the skin kills microbes.
They compete with the infectious bacteria for nutrients and some exhibit microbial antagonism.
Components of blood include white blood cells, plasma, red blood cells and platelets.
Phagocytosis is the process of ingestion of bacteria and other infectious organisms. Begins with recognization of the bacteria. Attachment of white blood cell membrane to that of the bacteria via surface receptors. Membranes stick up together. Engulfment occurs resulting into a phagosome and the bacteria is hence destroyed via apoptosis.
Opsonization is the destruction of microbes by phagocytes.
Eosinophils fight parasitic infection and are important in allergic reactions. NK cells play a role in host rejection of tumors and virally infected cells. Neutrophils release cytokines and also amplify inflammatory reactions.
Histamine, prostaglandins, kinines, complement and cytokines.
Interferons are naturally occurring proteins released by cells of immunity. Types include interferon alpha, beta and gamma.
They interfere with viral replication hence preventing viral infection. It also upregulates MHC comlex 1 and 2 for tumour and graft rejection.
Complement is a system that enables cells of the immunity to clear bacterial infections. Pathways involve the classical pathway, alternative pathway and the lectin pathway.
Vasodilation leads to increased blood flow to the area of inflammation, resulting into increased redness and heat. Vascular permeability leads to endothelial cells to become permeable. Exudation involves the escape of fluids, proteins and red blood cells to escape from intravascular space. Then vascular stasis which involves slowing down of blood in vessels with vasodilation.
Assignment-3 (Exam-4 review question)
What are the six basic shapes of prokaryotic cells?
Coccus, Bacillus, Coccobacillus, Vibrio, Sprillum and Spirochetes.
What is an endospore? What is its function?
This is tough, and non-reproductive is a dormant , structure produced by certain bacteria from the Firmicute phylum.
Explain briefly the three common types of reproduction in prokaryotes
There are those which grow as the cytoplasmic membrane elongates (lengthens), it moves the daughter molecules of the DNA apart.
The cell forms a cross wall which invaginates the cytoplasmic membrane.
The cross wall divides the daughter cells ids produced.
How does budding differ from binary fission?
Binary fission is a sexual reproduction her parents split to form new organism and the parent organism die. While in budding, a bud develops from the parents an outgrowth and later detach after maturity.
Know the different arrangements of cocci and bacilli
In Cocci, cells are arranged either in diplococci, streptococci, staphylococci, tetrads or sarcina during multiplication, while in the Bacilli are arranged either in diplobacilli, streptobacilli and coccobacilli
List the common features of Archaea that distinguishes them from bacteria
They are Thermophiles, Halophiles and Methanogens:
What are the two kinds of extremophiles? Compare and contrast those two kinds with examples.
First which likes acidic environments is Acidophile, while Alkaliphile, likes alkaline environments (high pH).
What are methanogens? List their roles in the environment
They produce methane as a metabolic byproduct in anoxic conditions. Responsible for marsh gas , in wetlands and in the digestive tracts of animals such as ruminants
Based on what features, the phototrophic bacteria are classified? List all the types with examples
The purple phototrophic bacteria are Rhodospirillaceae and Chromatiaceae
What is known as nitrogen fixation? Which bacteria fix the nitrogen?
This is Process of nitrogen conversation into ammonia (NH 3 ). The process is naturally carried out in the soil by nitrogen fixing bacteria such as Azotobacter .
What is known as heterocyst? Describe how it is formed.
Transparent thick-walled cell found in the filaments of some cyanobacteria. It serves as the site of nitrogen fixation
In what ways the green & purple bacteria differ from cyanobacteria?
What are the three groups of bacteria with low G + C content Gram+?
cocci, bacilli and clostridium.
Compare and contrast Clostridia and Mycoplasmas
Compare the following bacterial genera (shape, habitat, beneficial or pathogenic etc) in other low G+C Bacilli and cocci group. Include the name of the diseases they cause
Bacillus
Listeria
Lactobacilli
Streptococcus and Enterococcus
Staphylococcus
List the significant beneficial or detrimental properties of the following genera in 'high G+C Gram+ bacteria"
Corynebacterium
Mycobacterium
Actinomycetes
List the three important genera of Actinomycetes and the disease caused by them
What is the common feature among all the Gram-negative proteobacteria?
What are the five classes of Gram-negative proteobacteria? List at least 1 or 2 characteristic feature that groups them as separate class.
What is known as prosthecae? What is its function?
Which class of the proteobacteria the 'nitrogen fixers' belong to? How do they fix nitrogen? Give examples of nitrogen fixers
What is the difference between 'nitrogen fixers' and 'nitrifying bacteria'?
What does Nitrification means? Which bacteria is involved in this process?
Give the name and the disease caused by pathogenic Alphaproteobcteria.
Which Betaproteobacteria is involved in Nitrification? In sulfur recycling? In sewage treatment?
Which Betaproteobacteria is (are) pathogenic? What disease(s) they cause and what part of the body they inhabit?
Which one of the Gmmaproeobacteria acts as Intracellular pathogens? What disease they cause?
What is known as 'Methane Oxidizers'? Which bacteria is involved in this process?
List the diseases caused by Pseudomonads bacteria
Which Deltaproteobacteria is involved in sulfur recycling? In killing other bacteria? In decaying?
Which bacteria cause blood poisoning? Ulcer?
What are the unique features of chlamydias and spirochetes?
chlamydias are Small , Gram-negative , Reduced amount of peptidoglycan in cell wall while spirochetes are Orienta , Ehrlichia and Anaplasm spirochetes.
List the ecological importance of bacteriods
Earthworms improve the quality of the soil
