Summary
Summary Microbiology Notes for medstudentsonamission
- Module
- Institution
- Book
Microbiology Notes for medical students.
[Show more]
Connected book
Book Title:
Author(s):
- Edition:
- ISBN:
- Edition:
Seller
Follow
elisajohanna
Content preview
1. Introduction of Medical Micorbiology- History and subject.Microbiology is the study of microorganisms, a large and diverse group of microscopic organisms that exist
as single cells or cell clusters; it also includes viruses, which are microscopic but not cellular.
Microorganisms have a tremendous impact on all life and the physical and chemical makeup of our planet.
They are responsible for cycling the chemical elements essential for life, including carbon, nitrogen, sulfur,
hydrogen, and oxygen; more photosynthesis is carried out by microorganisms than by green plants.
Humans also have an intimate relationship with microorganisms; more than 90% of the cells in our bodies
are microbes. The bacteria present in the aver- age human gut weigh about 1 kg.
Robert Hooke: microscope in the 17th century
Antonie van Leeuwenhoek: rst one to observe microorganisms
Lazzaro Spallanzani in the 18th century: identi ed that boiling uids would sterilize and kill
microorganisms
Pasteur: could not grow spontaneously, have to travel via spores
Ferdinand cohn: classi cated bacteria into 4 groups
Robert Koch: link certain microbes with diseases
2. Bacterial taxonomy: classi cation, nomenclature and identi cation.
Classi cation Example
Identi cation
- Growth media
- microscopy
- Biochemical tests
- immunologic tests
- genetic analysis
- motility
- staining characteristics
- morphology
Nomenclature
fifi fi fi fi fi fl fi
, 3. Bacterial morphology.
Bacteria are less than 3 micrometer and only visible under microscope.
Basic forms:
- spheres- coccus
- Ball shape
- Rod saped
- cylindrical shape
- Spiral shape
- Twisted two or more times along the axis
The basic rms can further be arranges in di erent ways:
Cocci arrangement:
cocci- single
diplococci- double
streptococci- chain
staphylococci- piramide
Rod arrangement:
Bacilli- single
Diplobacilli- double
Streptobacilli- chain
Bacteria are all prokaryotic and therefore:
- dont have membrane bound organnels
- have cell wall with peptidoglycan
- have single supercoiled circular chromosome
- have plasmids
- 70S ribosomes
fi ff
, 4. Bacterial Ultrastructure- eukaryotes and prokaryotes. Cytoplasmic structures.
Eukaryotes and Prokaryotes
5. Bacterial Ultrastructure- Cell wall, structure and Biosynthesis of bacterial cell wall.
The cells wall is located outside the cell membrane and found in plants, fungi, bacteria, algae and archaea.
It is a peptidoglycan cells wall composed of disachharides cross linked by amino acids, sitting outside the
cellular membrane to provide bacterial structural support.
The disaccharides are made up of two sugars that are glucose derivatives, N- acetylglucosamine and N-
acetylmuramic acid ( NAG and NAM). Stages of their synthesis:
1. addition of ve amino acids to NAM
2. NAG is added to NAM
3. these three units are hen transported across the cell membrane by bactoprenol to the periplasm
4. once in the periplasm , they bind to cell wall accepted and are extensively cross linked
5. transpeptidases are the enzymes responsible for the cross linking
In Gram positive bacteria there is no additional cell membrane while there is one in gram negative. Gram
positive will stain dark purple and gram negative will stain red.
fi
, As well as di ering in relation to the outer membrane, they have some other key di erences:
- di erent agellar structure ( + has two rings in basal body
- + has higher resistance to physical disruption
- + has a thicker wall
- + is more susceptible to antibiotics
- teichoic acids are only found in + cells
6. Bacterial ultrastructure- external structures.
Fimbriae
- protein tubes
- attachment to surfaces
- sometime motility
- short
- + and -
Pilli
- long
- conugation
- attachment
- + and -
S- layers
- surface protein
- only in -
- unknown function
Glycocalyx
- extracellular polymers comprised of polysaccharides and proteins sometimes
- protection
- capsule
Flagella
- motility
- can be
- monotrichous
- lophotrichous
- amphilotrichous
. peritrichous
- lament, hook, basal body
ff
flfi ff ff
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller elisajohanna. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £6.44. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
75323 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now