Introduction to Bacteria (H&D 004) Flashcards
What is the definition of microbiology
Study of small organisms that are invisible to the naked eye
What are organisms that are studied in microbiology
Fungi, algae, protozoa, bacteria and virus
What are the three domains of a microorganism
Eukarya, Archaea and Bacteria
What are the three common shapes of bacteria cells
cocci (spherical), bacilli (rod-shaped) and spiral (spirillum)
What does it mean if bacteria are gram positive
Their cell wall consists of thick peptidoglycan hence will have no outer-lipid membrane
What does it mean if bacteria are gram negative
Their cell wall has a thin peptidoglycan in which will have a outer-lipid membrane
How is the capsule a virulence factor for the bacteria
Prevents the bacteria from experiencing desiccation, allowing the bacteria to multiply and survive longer
How is the flagellum a virulence factor for the bacteria
Allows the movement of the bacteria to move and divide from one place to another
How is the pili a virulence factor for the bacteria
Allows attachment to the host cell enabling itself to multiply
What is the definition of the ‘infectious dose”
The number of bacteria able to cause an infection
What are plasmids of the bacteria
Extra chromosomal elements in which code for traits like toxin production and drug resistance
What are endospore of the bacteria
Structure that helps bacteria survive heat, cold, chemicals, desiccation and lack of nutrients. However, not all bacteria have this structure
What is the definition of colonization
When bacteria penetrate and grow within the tissue
What contributions enable the process of colonization to occur
Must have appropriate amount of nutrients and environmental conditions as well as exo-enzymes
What is the function of exo-enzymes
Cell and tissue destruction
What are two ways that bacteria are able to cause disease
Invasiveness and toxigenicity
What is the definition of invasiveness
Rapid bacteria growth in tissue and organs before immune defenses can develop (eg. tuberculosis and rheumatic fever)
What is the definition of toxigenicity
Toxin production by bacteria in which is transported to tissues or organs in the body. Exotoxins are substances that are produced and then secreted outside of the bacterium and endotoxins are toxins that are released in the cell wall of the bacterium (eg. release of exotoxins cause cholera (permeability in the gut) and tetanus (affects muscle function)
What is the definition of microbiota
An ecological community of microorganisms that share human body space (Also known as normal flora)
What are the two types of normal flora
Resident flora and transient flora
What is the definition of resident flora
Microorganisms that are permanently with the body
What is the definition of transient flora
Microorganisms that are picked up from the environment (eg. soil when gardening working with patients in the hospital)
Why would it be bad to be a transient flora
Because some microorganisms that are picked up by the environment might be infectious. This may result in some people becoming a contact or asymptomatic carrier
Why would having a normal flora be better for the human host
Prevention of other organisms from being established and causing an infection
What are some examples of a normal flora preventing pathogens
Bacteria in the lining of intestines to prevent attachment of pathogens to the lining, or bacterium controlling the growth of potential pathogens via secretion of anti-microbial substances
