18 Questions
What is the term for the time required for a bacterial cell to divide?
Generation Time
Which phase of growth involves metabolically active cells but no increase in cell number?
Lag Phase
In bacterial fission, what is the structure that starts to divide?
Nucleoid
During which phase of growth do bacterial cells stop dividing due to limited nutrients and waste accumulation?
Stationary Phase
What term is used for the period when bacterial cells are adapting to a new environment before actively dividing?
Lag Phase
Why does binary fission double the number of cells each generation?
Due to DNA Replication
Which phase of microbial growth is characterized by a horizontal growth curve where population growth ceases?
Stationary phase
What is the term used to describe the process where new cells are made at the same rate as old cells die in a microbial culture?
Balanced growth
Which microorganism has a generation time of 9.6 minutes based on the information provided?
Beneckea natriegens
During which phase does bacterial cell death occur exponentially?
Death phase
What does a semi-log plot of growth vs. time yield according to the text?
Straight line
What does synchronous growth in microbial cultures refer to?
Growth where population doubles each generation
What is the structural backbone of living cells?
Carbon, nitrogen, and sulfur
Which component makes up half of the dry weight of a typical bacterial cell?
Proteins
What serves as a carbon source for chemoautotrophs and photoautotrophs?
$CO_{2}$
How do bacteria reproduce by binary fission?
Cell elongates and DNA is replicated.
What are common environmental factors that can affect microbial growth?
Iron, copper, molybdenum, and zinc
What are the primary organic growth factors required by microbes?
Vitamins, amino acids, purines, and pyrimidines
Study Notes
Bacterial Cell Growth and Division
- The term for the time required for a bacterial cell to divide is called generation time.
Phases of Growth
- The phase of growth involving metabolically active cells but no increase in cell number is called the stationary phase.
- During the lag phase, bacterial cells are adapting to a new environment before actively dividing.
Binary Fission
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In bacterial fission, the structure that starts to divide is the cell.
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Binary fission doubles the number of cells each generation because one cell divides into two daughter cells.
Phases of Microbial Growth
- The phase characterized by a horizontal growth curve where population growth ceases is called the stationary phase.
- During the death phase, bacterial cell death occurs exponentially.
Microbial Cultures
- A semi-log plot of growth vs. time yields a straight line.
- Synchronous growth in microbial cultures refers to the coordinated growth of microorganisms.
Cellular Structure
- The structural backbone of living cells is the cell wall.
- Peptidoglycan (also known as murein) makes up half of the dry weight of a typical bacterial cell.
Autotrophs
- Carbon dioxide (CO2) serves as a carbon source for chemoautotrophs and photoautotrophs.
Reproduction
- Bacteria reproduce by binary fission, where one cell divides into two daughter cells.
Environmental Factors
- Common environmental factors that can affect microbial growth include temperature, pH, oxygen, and nutrients.
- The primary organic growth factors required by microbes are carbon, nitrogen, phosphorus, and energy.
Explore the process of binary fission in bacteria, including the DNA replication, formation of cross-wall, and generation time required for cell division. Understand how binary fission leads to the doubling of cells with each generation and how growth curves are represented logarithmically.
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