lecture_18v2

lecture_18v2 - Lecture18: GrowthRatecontrol,and Homeostasis

Info iconThis preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 18: Growth Rate control, and Homeostasis Reading: Chapters 2, and 15
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
What can effect the growth rate of bacteria? Quality of nutrients (talk about this later) Carbon source Nitrogen source Etc. pH Salt conditions Temperature?
Background image of page 2
Bacteria can live in a variety of pH ranges Neutrophiles Acidophile Alkaliphiles
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
While bacteria can live in a broad pH range, Any one species has its limits! pH gradients effect the growth rate Neutrophiles Acidophile Alkaliphiles
Background image of page 4
Homeostasis: pH pH out pH in Δ pH Neutrophiles 6 87 . 5 8+ Acidophiles 1 46 . 5 7+ Alkaliphiles 9 12 8.4 9 What are the implications for bacteria that live in alkaline environments???
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Osmotic Homeostasis An experiment from high school What happens to cells if they are placed in a hypo osmotic solution? What happens in a hyper osmotic solution?
Background image of page 6
Osmotic Homeostasis Osmotic Homeostasis: How do cells keep turgor pressure: cells keep osmotic pressure higher inside then out. This is done by increasing the internal concentration of solutes called osmolytes Osmolytes or Compatible solutes : some are produced by the cell some are not and are accumulated via transport. Osmoprotectants : are osmolytes that are accumulated via transport, such as K+ or Betain (except for cyanobacteria) Others include: glutamine glutamate, proline and betaine as well as Treholase a disaccharide of glucose
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Therefore cells must regulate in the influx of solutes and production of osmoprotectants in response to changes in the environment.
Background image of page 8
What about temperature
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
How do you change the growth rate At kmax, change the nutrient composition Otherwise use a chemostat!
Background image of page 10
The concept of μ μ is the number of doublings per hour; and is often referred to as the growth rate.
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/02/2009 for the course MIC 140 taught by Professor Meeks,singer during the Spring '09 term at UC Davis.

Page1 / 31

lecture_18v2 - Lecture18: GrowthRatecontrol,and Homeostasis

This preview shows document pages 1 - 12. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online