Lecture 5- Symbiosis, bacteria

Question 1

What is symbiosis?

Answer 1

Relationships that have evolved between individuals

Question 2

Parasitism

Answer 2

A relationship between individuals where one benefits (parasite) to the harm of the other (host)

Question 3

Commensalism

Answer 3

A relationship between individuals where one benefits and the other is unaffected (fish+ sharks)

Question 4

Mutualism, co evolution

Answer 4

A relationship between individuals (usually different species) where both benefit (pollinators +flowers)

Question 5

Explain microbiome and human mutualism:

Answer 5

Each person is their own ecosystem
-bacteria is useful because it influences: metabolism, immune system, behavior, energy…

Question 6

Where do bacteria come from?

Answer 6

-the gut can be repopulated with good bacteria by the appendix

Question 7

Urbanization and the effect of mutualism

Answer 7

-increased population density=sanitation hygiene issues
-unfamiliar bacteria in the wrong place

Question 8

Cholera:

Answer 8

-infection transmitted through water, bacteria grows in small intestine
-gives infected people diarrhea
-easily spreads when sanitation is poor

Question 9

Penicillin:

Answer 9

substance that killed a number of disease causing bacteria

Question 10

resistant bacteria

Answer 10

bacteria with genes that enable them ti survive and reproduce in the presence of an antibiotic
-mutations that protect them against antibiotics

Question 11

3 classes on antibiotics based on what they interfere with:

Answer 11

-Cell wall synthesis: Bacteria build protective cell walls for protection

Nucleic acid synthesis: bacteria must copy DNA to reproduce

Protein synthesis: bacteria need proteins to do things

Question 12

Drug modification, drug degradation, reduced drug accumulation within bacteria are all adaptations that make bacteria resistant. Describe them

Answer 12

Modification: bacteria alter the antibiotics so they don’t work properly

Drug degradation: bacteria produce substances to break down antibiotics

Reduced accumulation: bacteria prevent antibiotics from getting inside

Question 13

How can bacteria gain antibiotic resistance genes

Answer 13

• from other bacteria
  -from viruses
  -from dead bacteria
  -from environment
  -pass on genes when they reproduce

Question 14

name some cases for rapid evolution of antibiotic resistance

Answer 14

-spread in the absence of reproduction
-reproduction is asexual (all offspring will have resistance alleles)
-Reproduction is fast

Question 15

selective pressure, what and who provides it

Answer 15

-Antibiotics provide selective pressure: only bacteria with genes for antibiotic resistance survive

Question 16

What is the issue regarding drug/ antibiotic development? How can we reduce selection?

Answer 16

-no cost effective to create antibiotics
-not used for very long

-Limiting the use of antibiotics