Lecture 2 Notes (Part 2) Flashcards
What does Na do in the environment?
Reduces water activity
Where can bacteria survive when they can tolerate high concentrations of salt? (2)
Allows them to survive temporal and spatial change of salinity
- Ecosystems
- Saltmarsh
What is a major source of energy for the biosphere?
Light
What does light drive?
Thermic processes associated to climate
What are the 3 aspects to temperature?
- Temp as a factor that affects the rate of chemical reactions catalyzed or not by enzymes
- Temp as a key factor for the survival of organisms
- Climate is largely driven by temp
What are proteins sensitive to?
Denaturation and temps higher than their optimum range
What happens to chemical reactions and enzyme activity as temp increases?
They increase too
What is a negative aspect to too high of temp?
Breaking of bonds that can lead to denaturation and inactivation
What is high temp usually associated with? (3)
- Hot springs
- Hydrothermal vents
- Volcanoes
At what temp can phototrophic organisms no longer grow?
> 37 deg C
At what temp can only some chemolithotrophic bacteria grow?
> 73 deg C
What do prokaryotes need in order to avoid inactivation of proteins? What are 2 examples?
Special adaptations
- Subtle changes in hydrophobic interactions
- Salt bridges
What are thermophiles and hyperthermophils associated with?
Geothermic energy
Mesophil
Is an organism that grows best in moderate temp
- 20-49 deg C
Thermophile
Is an organism that thrives at relative high temp
- 41-122 deg C
Psycrophile
Is an organism that is capable of growth and reproduction in cold temp
- -20-10 deg C
How long ago did O2 appear?
2 billion years ago
What did organisms do before O2 appeared?
Most organisms were likely chemoautotrophic or fermentation
What allows glucose (or acetate) to produce more energy from the same mol of glucose?
Photosynthesis
Decrease in energy does what for growth?
Decreases it
What is population?
Requirement of communities of various species to recycle nutrients and create a growing environments
What is a very common tree on the island?
Douglas Fir
What can statistics do?
Create parameters for restrictions
How can we study a biological population? (3)
- Need to determine what constitutes an individual
- How it will be observed
- How it will be treated for statistical analysis
- eg) take a swab, culture it and count the results
Oak-Hickory populaiton
Non-linear relation that can be linearized by using a logarithmic scale that allows for a regression determination of the death rate
Unlike plants and animal, what can prokaryotes not do?
Be counted directly
What is the device called thats used to count cells?
microscope
- hemacytometer
How do you use a hemacytometer? (4)
- Use a slide with a grid and put a drop of sample on it
- Select the field of choice
- Calc the average of cells in the grids
- Calc the number of cells in the sample
What is electron microscopy measuring?
Wavelengths
What are epiflourescense used to look at?
Stains
What are petri dishes used for?
Culturing
- most common
What is a spectrophotometer used for?
Counting bacteria by looking at the density of the suspension
What is the most modern way of counting bacteria? (2)
- Quantitative PCR
2. Molecular probing
What is a negative aspect of microscopes?
Cant tell whether the cells are alive or dead
Viable count
Gives a quantitative idea about the presence of microorganisms
- counting cells that are able to grow
- eg) bacteria, yeast and mold
Direct count
Counting blood/tissue cells by using a hemocytomer can be determined the concentration of a known volume
- can detect between live and dead cells
Turbidmetry
Is the process of measuring the loss of intensity of transmitted light due to the scattering effect of particles suspended in it
Monod’s experiment
Used E.coli as an experimental modle to understand bacterial population
What was the limiting factor for growth of E.coli?
Glucose
- if ran out of glucose then they used lactose
What does a plateau on the graph indicate?
It means that the bacteria is re-engineering and creating new proteins cause it is developing new proteins
What does the presence of lactose induce?
Transcription of genes
What are the 6 growth phases?
- Lag
- Acceleration
- Exponential
- Retardation
- Stationary
- Declining
Lag phase
Growth rate null
- no cell division
- no DNA replication
Acceleration phase
Growth rate increases
Exponential phase
Growth rate is constant
- cell division
Retardation phase
Growth rate decreases
Declining phase
Growth rate is negative
What phase is used to define a population in biology?
Exponential phase
- ideal condition for cells
