Flashcards in Introduction To Microbes Deck (106):
What categories can the microorganisms responsible for human disease be broken down into?
Give an example of a virus?
Human Immunodeficiency Virus (HIV)
Give an example of a bacteria
Give an example of a fungi
Give an example of a parasite
What does plasmodium falciparum cause?
What are viruses?
Obligate intracellular parasites without a cellular structure
What do viruses consist of?
Molecule(s) of either DNA or RNA (but not both) surrounded by a protein coat
May also have an envelope
What is a viruses envelope derived from?
The plasma membrane of the host cell from which its released
What do viruses do?
Hijack the host's mechanisms for creating mRNA and production of proteins to reproduce
What is the classification of viruses based on?
What structural features can viruses be classified based on?
Single or double stranded
Enveloped or not
Positive or negative strand
Icosahedral or helical
DNA or RNA
Give an example of a single-stranded, non-enveloped DNA virus
What can parvovirus 19 cause?
Mild infections in children
Fetal development issues in pregnant women
Give two examples of double-stranded, non-enveloped DNA viruses
Human papilloma virus (HPV)
What can adenovirus cause?
What does HPV induce?
Hyperplastic epithelial lesions of either cutaneous or mucosal epithelium
What do a small number of HPV virus types produce?
Lesions that have a risk of progressing to malignancy
Give an example of a malignancy that can arise from HPV infection
Give two examples of double-stranded, enveloped DNA viruses
What are the types of herpes infections?
What can primary HSV-1 infections cause?
Tonsillitis and pharyngitis in adults
Gingivostomatitis in young children with ulcer forming usually in the oropharynx
What can latent HSV-1 infections cause?
'Cold sores' to appear on or around the lips
What can primary HSV-2 infections cause?
Lesions in the genital tract, similar to those found in the oropharynx in primary HSV-1 infections
What can latent HSV-2 infections cause?
What does hepatitis B cause?
Acute hepatitis and later chronic liver disease
Give two examples of single-stranded, positive strand, icosahedral, non-enveloped RNA viruses?
Hepatitis A/E virus
How is hepatitis A/E most commonly spread?
Through fecally contaminated waters
What does the hepatitis A/E virus cause?
Hepatitis and impaired liver function
What is norovirus also known as?
The winter vomiting bug
What is norovirus the leading cause of?
Where is norovirus common?
In closed environments, such as schools, hospitals, prisons, and cruise ships
Give 3 examples of single-stranded, positive strand, icosahedral or helical, enveloped RNA viruses
How is HIV transmitted?
Exchange of blood produces
How is HIV transmitted perinatally?
During passage through the birth canal
What does HIV cause?
Acquired Immune Deficiency Syndrome (AIDS)
What does HIV and AIDS allow?
Increasingly frequent and serious opportunistic infections to occur
What does the hepatitis C virus cause?
Destruction of liver cells
How does the hepatitis C virus cause destruction of liver cells?
Through viral replication and host response
How hepatitis C transmitted?
Via the blood
How is the rubella virus spread?
Via respiratory secretions
What does the rubella virus result in?
What can the rubella virus cause in the developing fetus?
Extreme congenital defects
When can the rubella virus cause extreme congenital defects?
During the first trimester, when a pregnant woman is infected
Give four examples of single stranded, negative strand, helical, enveloped RNA viruses?
How is the measles virus spread?
What does the measles virus cause?
Eventually a rash
How is the mumps virus spread?
What does the mumps virus cause?
Swelling of the parotid glands
How is influenza spread?
What does influenza cause?
Give an example of double-stranded, icosahedral, non-enveloped RNA virus
What does rotavirus cause?
Severe viral gastroenteritis in infants and young children
What are bacteriophages?
A class of virus that infect bacteria
Where do bacteriophages play a key role?
Transmitting genetic material between different types of bacteria
What are true bacteria also known as?
What kind of organisms are true bacteria?
What common structural organelles do most bacteria share?
Nucleoid (circular DNA)
Do all bacteria possess a capsule or flagellum?
What is the classification of bacteria based on?
Their overall shape identified under a microscope
What are the classifications of bacteria?
What shape are cocci?
What shape are spirillus?
What shape are bacillus?
How can cocci be arranged?
What is the bacterium called when it has cocci arranged in clusters?
What is the bacterium called when it has cocci arranged in chains?
What is the bacterium called when it has cocci arranged in pairs?
What is used to help make bacteria visible under a light microscope?
A technique known as the Gram stain
What colour do gram positive bacteria appear with a gram stain?
What colour do gram negative bacteria appear with a gram stain?
What is whether a bacteria is gram negative or gram positive determined by?
The composition of its surrounding wall and membranes
What does the cell membrane of gram positive bacteria consist of?
What does the cell membrane of gram negative bacterium consist of?
What does the outer membrane of gram negative bacterium consist of?
Lipopolysaccharide and protein
How does the cell membrane of a gram positive bacterium differ from a gram negative?
Thicker peptidolycan wall
What is the result of the thicker peptidoglycan wall of the gram positive bacterium?
Often causes host response
How can the cell wall of gram negative bacterium cause disease?
Present of lipopolysaccharides, which often acts as endotoxins
How do bacteria vary in their oxygen tolerance?
Aerobes can survive in the presence of oxygen, whereas anaerobes can survive in the absence of oxygen
What are obligate aerobes?
Bacteria that require oxygen to survive
What are obligate anaerobes?
Bacteria that require an oxygen free environment for survival
When can obligate anaerobes survive in an oxygen rich environment?
If they can form spores
On what characteristics can a bacteria be identified?
What can be done by identifying a bacterias characteristics?
Allows clinicians to narrow down the antimicrobials that should be used
Give 6 medically important gram positive cocci
Coagulase negative staph
Give an example of a beta-haemolytic streptococci
Give 4 medically important gram negative cocci
Give 3 medically important gram positive bacilli
Give 6 medically important gram negative bacilli
How do prokaryotes and eukaryotes differ in terms of chromosomes?
Prokaryotes are circular, usually single, and extra-chromosomal DNA may also be present (plasmids). Eukaryotes have multiple chromosomes
How do prokaryotes and eukaryotes differ in terms of their nucleus?
Prokaryotes have no nuclear envelope or nucleoli, whereas eukaryotes have membrane bound nucleoli present
How do prokaryotes and eukaryotes differ in terms of membrane-bound organelles?
Prokaryotes do not have them, whereas eukaryotes do
How do prokaryotes and eukaryotes differ in terms of cell wall?
Prokaryotes usually have a cell wall present, whereas eurkaryotes only have them in plant cells
What may the prokaryote cell wall contain?
Do eukaryote cell walls have peptidoglycan?
How do prokaryotes and eukaryotes differ in terms of plasma membrane?
In prokaryotes, there is no carbohydrates and most lack sterols.
In eukaryotes, sterols and carbohydrates present
How do prokaryotes and eukaryotes differ in terms of ribosomes?
Prokaryotes have 70S ribosomes, eukaryotes have 80S (but 70S in organelles)
What are yeasts?
Give three examples of yeasts
What are molds?
Give two examples of molds
Give two examples of dematophytes
What are protozoa?
Single celled parasites
Give 4 examples of protozoa
What are helminths?
Multicellular parasites, worms