HTHSCI 2HH3 Study Guide - Winter 2018, Comprehensive Midterm Notes - Antibiotics, Pathogen, Bacteria
12 Oct 2018
School
Department
Course
Professor
HTHSCI 2HH3
MIDTERM EXAM
STUDY GUIDE
Fall 2018
Introduction to Microbiology
Structure, Function, Reproduction & Classification of Microorganisms
Medically Important Microbes
Bacteria: Prokaryotic; no nuclei, single celled organisms, live singly, in pairs, chains, clusters, most
common infection
Antibiotics: work against bacteria because they know the different between bacteria and hosts,
antibiotics are more difficult when it comes to fungi and other microbes because they get confused
between host and the microorganism
Viruses: Acellular; Not visible by light microscopy, obligatory microbes composed of genetic material
surrounded by a protein coat, do’t ake us as sik as ateia eause iuses ae aellula ad self-
limiting
Fungi: Eukaryotic; possess a nuclei and cell wall, organelles, obtain nutrients from other organisms;
yeasts (unicellular) & molds (multicellular)
Protozoa: Eukaryotic; single-celled organisms, possess a nuclei (referred to as parasites)
Helminths: Eukaryotic; multicellular, possess a nuclei, visible with the naked eye (referred to as
parasites)
Bacteria – Characteristics
Single-celled organisms
• No nucleus = prokaryotic
• Possess salle sepaate iles of DNA plasids
• Ribosomes smaller than those of eukaryotes
• Cell wall (composition can vary) and cell membrane
• External cellular structures (flagella, pili)
Differences between prokaryotes (bacteria) and eukaryotes (humans) can be exploited re: antibiotics
• Antibiotics target cell wall components (i.e.: penicillins) or the smaller ribosomal subunits (i.e.:
erythromycin) that damage/kill bacteria, but do not damage host cells
Cell morphology: Shape, arrangement, colony morphology, external structures, capsules, spore
formation- wide variety in morphology can be identified by direct examination *do’t hae to ko the
different shapes
Cell wall structure: Staining and microscopy; Gram and acid-fast stains
Growth characteristics: Oxygen and energy requirements
find more resources at oneclass.com
find more resources at oneclass.com
Metabolism: Carbohydrate utilization, fermentation end-poduts, et…
Molecular techniques: DNA sequencing
Colony Morphology: Characteristics of colonies grown on agar plates allows for a tentative
identification, shape(form) of the colony, margin/edge, elevation, surface texture, and pigmentation are
all important to identification of the pathogen
Bacteria – External Structures
Flagella: Protein filaments that extend from cell membrane- flagella are motile (rotate 360°), allowing
ioe to oe i a seies of tules ad us i espose to stiuli light, utiet desit, et…
• Number and location of flagellum can be used to classify microbes
o Polar – Vibrio spp. (single), Spirillium spp. (double)
o Peritrichous – flagellae on opposite ends, Escherichia coli spp.
Fimbriae: Straight filaments arising from bacterial cell wall – facilitate formation of biofilms
• Shorter than flagella - ot used fo populsio, ut a e used to pull the ateiu aoss a
substrate
o Used for reaching and grabbing, not movement
• Act as adhesins, binding to specific host cell receptors – important role in adherence to host
cells, a critical step in infection- bacteria must match the host in order to adhere and cause
infection
o E. coli spp. & Campylobacter jejuni bind to intestinal epithelial cells
• Conjugation Pili - used to transfer DNA from one bacteria to another
Bacteria – external Structures
Glycocalyx: Protective substance surrounding some bacteria, normally made of polysaccharides,
presence/absence can be used for classification & identifying bacteria
1. Slime Layer: Sticky and loose - prevents dehydration, allows bacteria to bind to surfaces and
form a protective layer encapsulating colony of bacteria, has ability to bind to appliances
2. Capsule: Firmly attached to cell surface, essential for adherence and can evade immune cells
through phagocytosis
Bacteria – external Structures
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Bacteria: prokaryotic; no nuclei, single celled organisms, live singly, in pairs, chains, clusters, most common infection. Antibiotics: work against bacteria because they know the different between bacteria and hosts, antibiotics are more difficult when it comes to fungi and other microbes because they get confused between host and the microorganism. Viruses: acellular; not visible by light microscopy, obligatory microbes composed of genetic material surrounded by a protein coat, do(cid:374)"t (cid:373)ake us as si(cid:272)k as (cid:271)a(cid:272)te(cid:396)ia (cid:271)e(cid:272)ause (cid:448)i(cid:396)uses a(cid:396)e a(cid:272)ellula(cid:396) a(cid:374)d self- limiting. Fungi: eukaryotic; possess a nuclei and cell wall, organelles, obtain nutrients from other organisms; yeasts (unicellular) & molds (multicellular) Protozoa: eukaryotic; single-celled organisms, possess a nuclei (referred to as parasites) Helminths: eukaryotic; multicellular, possess a nuclei, visible with the naked eye (referred to as parasites) Single-celled organisms: no nucleus = prokaryotic, possess s(cid:373)alle(cid:396) sepa(cid:396)ate (cid:272)i(cid:396)(cid:272)les of dna (cid:862)plas(cid:373)ids(cid:863, ribosomes smaller than those of eukaryotes, cell wall (composition can vary) and cell membrane, external cellular structures (flagella, pili)
