Bio Lab notebook Flashcards
Aseptic
area whose contamination has been minimized
What is the goal of flaming?
Gently heat the air at the bottle opening
mini-microbiological force field
air more likely to come out of bottle than to fall into the bottle when the air at the opening is heated
Bacteria are_______?
Prokaryotes the simples free living form
Difference between bacteria and viruses?
bacteria-susceptible to antibiotics
All bacteria?
Have a plasma membrane made of lipids (fats) that surround the inner workings of the bacterial cell
Cell wall of bacteria?
-collection of molecules that surround the plasma membrane and give bacteria structural strength
Can have additional lipid membrane that protects them from harsh environments
Appendages of bacteria?
-pili
-flagella
hairlike structures that protrude from bacteria-perform special functions
T/F Bacteria does not have DNA?
False, bacteria contains genetic material.
don’t have a nucleus-free DNA or chromsomes-called nucleoid
T/F bacteria contain ribosomes that translate the DNA sequence into protein
true
What is a phage?
devourer of bacteria
100-200 nm
Phages cannot replicate outside their host bacteria?
True
Phages are not susceptible to antibiotics
True
Phages are the most abundant life form
true
Phages can survive in ________
any environment
-found inside and outside bacterial cells
3 components of a phage?
- Capsid
- genetic material
- tail
What is the purpose of the capsid?
-contains genetic material
The genetic material is ______in phages
double stranded dna
What is the purpose of the tail in a phage?
- allows phage to attach to bacteria
2. DNA passes through the tail into the bacterium
“host range”of phage?
kinds of bacteria to which the phage can attach
Sterile
Free of all living microorganisms including bacteria, fungi, viruses
Who discovered phages?
Felix D’ Herelle- saw clear spots on a lawn of bacteria– plaques
added some material from a plaque to growing batch of bacteria
What happens when a phage infects a bacterium?
The phage attaches to the bacterium and injects its DNA into a bacterial structure-
the empty phage structure empty and attached to bacterium-no longer infectious- called a ghost
-using the bacterium’s replication machinery-phage genomic DNA makes and assembles copies of itself until the host bacterium lyses
To see phages?
Need a electron microscope
If a phage is present?
It will infect one of the bacterial cells-replicate within the cell- lyse the bacterium
lysis-up to 100 new phages
What is burst size?
Number of new phage released
new phage-travels through diffusion-will infect other bacteria
because of phage lysis-cloudy suspension of bacteria radiating outward from the area with the original phage.
What does the clearing zone indicate?
presence of infectious phage particle
-Plaques contain billions of infectious phage particles- all identical to original phage.
Why study phages?
Scientists would like to use phages to kill specific antibiotic resistant bacteria that causes disease
Lytic phage
lyse all bacteria they infect
Temperate phage?
- Replicate and lyse the host bacteria they have infected like lytic phages
- enter dormat state by incorporating their DNA into the DNA of the host
Majority of bacteriophages___________?
temperate
Prophage?
the phage genome incorporated into the bacterial DNA
Lysogeny
Mechanism by which a naive bacterial cell becomes infected with prophage
Lysogen
Bacterium that contains prophage
How does phage infect a host bacterium?
- absorption of the phage to the surface of the bacterium
- irreversible attachment of phage to bacterial cell
- Penetration of bacterial cell wall
- nucleic acid injection from the phage head
Injection of DNA?
DNA is linear within the phage head-it’s injected as a linear molecule-when phage DNA gets inside bacterium-circulizes
