Lecture 3 Flashcards
HD
How is bacterial growth defined?
An increase in cell number
What are the 2 types of Bacterial Growth?
Anabolic and Catabolic
Anabolism grows from what to what?
Small to large
Catabolism grown from what to what?
Large to small
What is binary fission?
When a cell divides into 2 new cells
What is generation time?
Time required for cells to double structural components
What is exponential growth?
When the cells double per unit time
What are 2 approaches to the study of growth under controlled conditions?
Batch Culture & Continuous Culture
Difference between batch culture and continuous culture?
Batch - fixed substrate is added - Continuous a continuous amount of growth medium
List the 4 phases of growth
- Lag
- Exponential
- Stationary
- Death
Main Reason for the lag phase to occur?
New conditions - adaptation
Growth will remain in the lag phase until the population reaches…
10 to the 6 cells/ml
2 reasons for stationary phase
Carbon and energy source
Nutrients are used up
What is endogenous metabolism?
Growth on dead cells
Which is slower death phase of exponential phase?
Death phase
What are capnophiles?
Microbes that grow better at high CO2 concentrations
What are porins?
Part of the outer membrane - allows the passage of molecules
What are autolysins?
Enzymes that create small openings in the macromolecular structure of the wall
What is the periplasm?
Fluid filled space between the outer membrane and the plasma membrane.
What is the most important differential stain used in bacteriology?
Gram Stain
Two major groups of Gram Staining?
Gram-positive and Gram Negative
Colour of gram-negative bacteria at end of Gram Staining?
Red - pores increase so the violet colour leaves
Colour of Gram-Positive Bacteria at end of Gram Staining?
Violet - Pores shrink so the colour stays
True or false - gram staining must be performed on cultures less than 24hrs old?
True
What is peptidoglycan?
A macromolecular network making up the bacterial cell wall
Describe Peptidoglycan in Gram Positive bacteria cell wall?
Many layers
Thick
Teichoic acid
Describe Peptidoglycan in Gram Negative bacteria cell wall?
Thin
No teichoic acid
Ideal numbers on plate for a viable count?
30-300 cfu
Does Gram Positive or Gram Negative look like an ice cream sandwich?
Gram Negative
Does Gram Positive or Gram Negative look like 2 layer jello?
Gram Positive
Polymerization reactions through which macromolecules are made from monomers are the main reactions of what?
Cell Synthesis
Generation times vary widely among organisms. Many bacteria have generation times of _____ but a few very rapidly growing organisms can divide in as little as ______
1-3h, 10 m
The vessel that is used as a growth container in continuous culture is called a
Bioreactor or a Chemostat
T or F In a chemostat one can control the flow rate, maintain a constant substrate concentration, as well as provide continuous control of pH, temperature, and oxygen levels. This allows control of the rate of growth, which can be used to optimize the production of specific microbial products such as ethanol.
True
Defined as one that is able to divide and form offspring, and the usual way to perform a viable count is to determine the number of cells in a sample capable of forming colonies on a suitable agar medium.
viable count
often called the plate count, or colony count.
In this type of counting procedure is that each viable cell can yield
One colony
consists of a repeating disaccharide attached by polypeptides to form a lattice that surrounds and protects the entire cell. The disaccharide portion is made up of monosaccharides called N- acetylglucoseamine (NAG) and N-acetylmuramic acid (NAM) (from murus, meaning wall), which are related to glucose.
Peptidoglycan
The peptidoglycan is bonded to lipoproteins in the outer membrane and is in the
periplasm
T OR F - The periplasm contains a high concentration of degradative enzymes and transport proteins. Gram-negative cell walls do not contain teichoic acids.
TRUE
Part of the permeability of the outer membrane is due to proteins in the membrane called
PORINS
Staining procedures that elicit differences between bacterial cells or parts of a bacterial cell are termed
Differential staining techniques.
The coloration of bacteria by applying a single solution of stain to a fixed smear is termed
Simple staining.
