1. Introduction to bacteria 1 & 2
April 16th, 2014

2. Introduction to Bacteria (3)
Biology 11
Mr. McCallum

3. Exit slip (previous class)
Number of bacterial cells in/around us
Communication between bacteria – Multi-lingual
“chemical words”
Bacteria do good things for our bodies (digestion, educating immune system, etc.)
Bacteria wait to attack – need numbers
Complexity – not solitary
Vibrio fischeri – bioluminescence
Adaptation of squid – relationship?
Scope of medical application
Impede signalling/communication enzymes
Enhance current functioning of good bacteria
WE DO NOT KNOW IT ALL – SO MUCH MORE TO DISCOVER
Students are the engine of modern research

4. Reproduction (Binary fission)
Cell division (but not technically Mitosis… why??)
Doubles in size, replicates DNA, divides in half
Producing clones/identical copies
Example of exponential population growth
Asexual reproduction

5. Binary Fission VS. MITOSIS

6. Reproduction (Binary Fission)
BOTH start with one cell and result with two genetically identical cells Binary Fission: Prokaryotic organisms only. Single stranded RNA/DNA. Does not include “steps” of mitosis (does not involve centromeres, kinetochores, sister chromatids, spindle fibres, etc.) Mitosis: Eukaryotic organisms only. Does not occur in single celled organisms – rather in somatic cells or multicellular organisms

7. reproduction (Conjugation)
Simple sexual reproduction – uncommon
Way to introduce genetic variety
Exchanging of genetic material
Hollow bridge forms

8. Reproduction (Conjugation)

9. Reproduction (Spore formation)
Some species can form an endospore in unfavourable conditions
Dormant phase
Heat resistant
Hard to destroy

10. Reproduction (Spore formation)

11. Benefits of bacteria Benefits outweigh harmful effects
Essential for decomposition and recycling matter into nutrients for living things
Three examples of beneficial bacteria:
Intestinal bacteria help us digest and synthesize vitamins!
Streptococci and lactobacilli are responsible for dairy production (cheese, buttermilk, and yogurt)!
Streptomyces are a source of antibiotics!

12. Harmful effects of bacteria
Best known for causing disease
Tuberculosis, diphtheria, typhoid fever, bubonic plague (black death), and E. coli
Impact of bacterial infection
Sheer number = burden on host
Destroy cells and tissues
Produce poisons (toxins)

13. Bacterial resistance to antibiotics
There are more than 2500 naturally occurring antibiotics
Over the last 50 years, bacteria have slowly developed resistance to common antibiotics
Resistance develops from variations/mutations within a bacterial population
Weakest bacteria die out, those with variations/mutations can reproduce  pass on this resistance
Their plasmids contain R (resistance) factors  have special genes that code for enzymes that inactivate specific drugs
Have R factors always existed, or have they evolved with the introduction of antibiotics?