Lecture 1 - Interactions with Microbes Flashcards
How have bacteria shaped the world?
Made the world habitable by:
- providing molecular oxygen
- recycling matter
- provide nutrients
- symbiosis with other organisms
Most interactions with bacteria are…
Beneficial to the host
How is transmission of infectious disease different to say, hypertension, for example?
- Can be passed from person to person
- Passed from one to many people (amplification)
What are the general routes of invasion by microbes?
Respiratory tract Conguntiva Faecal-oral Sexual Injection Congenital
What are the different types of infectious organisms?
Bacteria Viruses Prions Protozoans Fungi
What are the features of a generalised bacterium?
- Cell wall made of peptidoglycan
- No nucleus
- Single, circular chromosome
- different ribosomes
- Plasmids
+/- Fimbriae
+/- Flagella
+/- Capsule
Describe the different types of cell wall that bacteria can have
Gram positive:
single cell membrane
thick outer layer of peptidoglycan
Gram negative:
inner and outer membrane
periplasmic space
thin layer of peptidoglycan
Which acids are found in the cell wall of Gram positive bacteria?
Teichoic acids
Which bacteria are more resistant to drying?
Gram positive
Thicker layer of peptidoglycan
What are the special features found on Gram positive and negative bacteria?
Gram positive:
Teichoic acids in the wall
Gram negative:
LPS on outer membrane
What is endotoxin
= LPS
Describe the genomes of viruses
Can be anything!!
RNA or DNA, not both
ds or ss
Circular or linear
What is the generalised structure of viruses?
Genome
Protein coat / Capsid
+/- plasma membrane envelope
What are the steps in viral replication?
Attachment Penetration Uncoating Transcription of early mRNA Translation of early proteins Replication of viral DNA Transcription of late mRNA Translation of late proteins Self-assembly Release
What are the generalised components of the immune system?
1/ Physical barriers
2/ Cells
- macrophages
- lymphocytes
3/ Humoral factors
- from leukocytes or other cells
