Podcast
Questions and Answers
What are the two main forms of plasmids based on their structure?
What are the two main forms of plasmids based on their structure?
Circular and Linear
What is the primary function of R-plasmids?
What is the primary function of R-plasmids?
To carry one or more antibiotic resistance genes
What is the characteristic of conjugative plasmids?
What is the characteristic of conjugative plasmids?
Ability to transfer to other bacteria
What is the range of sizes of naturally occurring plasmids?
What is the range of sizes of naturally occurring plasmids?
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What is the role of chromosomally encoded enzymes in plasmid replication?
What is the role of chromosomally encoded enzymes in plasmid replication?
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What is the purpose of the genes encoded by a plasmid?
What is the purpose of the genes encoded by a plasmid?
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Why are plasmids considered nonessential?
Why are plasmids considered nonessential?
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What is the term for the number of different plasmids present in a cell?
What is the term for the number of different plasmids present in a cell?
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What is the characteristic of transposable elements?
What is the characteristic of transposable elements?
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Where can transposable elements be found?
Where can transposable elements be found?
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Study Notes
Microbial Genetics
- MBG 3711 Lecturer: Ms. Sylvia Nafuka
- Contact hours: Timetable slot D, 4 lecture periods
- Important dates: Online quizzes and face-to-face tests
Introduction to Microbial Genetics
- The structure and organization of microbial genomes
- Microbial phenotypes are designated by a non-italicized 3-letter abbreviation
- Variation in phenotype may be designated by superscripts (e.g. "+", "-", "R", "S")
Structure of Nucleic Acids
- Nucleic acid molecules contain instructions for an organism's development, life, and reproduction
- Eukaryotic organisms store DNA in the nucleus and organelles like mitochondria
- Bacterial DNA forms a tangle known as a nucleoid
- Plasmids are small loops of DNA that can be transmitted from one cell to another
Bacteria Gene Content and Scales of Genome Organisation
- Average gene content: 3,100 genes per genome
- Lowest number of genes: Mycobacterium genitalium (480 genes)
- Highest gene content: Brady rhizobium japonicum (8,317 genes)
- Base pair composition average: 22.4% GC
- Variation in base composition between leading and lagging strands
DNA Supercoiling
- Double-stranded DNA twisted into supercoils by topoisomerases
- Positive supercoiling: DNA molecule twisted about its axis in the opposite direction
- Negative supercoiling: DNA molecule twisted about its axis in the same direction
- Type 1 and Type 2 topoisomerases: involved in DNA replication and decatenation
Plasmid Classifications
- Based on structure: Circular and Linear
- Based on function: R-plasmids, Col-plasmids, and Cryptic plasmids
- Based on ability to transfer: Conjugative and Non-conjugative
- Based on coexistence: Compatible and Incompatible
Plasmid Characteristics
- Naturally occurring plasmids range from 1 kbp to over 1 Mbp
- Almost all plasmids are circular, supercoiled, and double-stranded DNA molecules
- Own origin of replication, but rely on chromosomally encoded enzymes
- Genes encoded by a plasmid function to direct initiation of replication and partitioning of replicated plasmids between daughter cells
- Plasmids do not have an extracellular form and exist inside cells as free DNA
- Copy number is controlled by genes on the plasmid and interactions between the host and the plasmid
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Description
This quiz assesses knowledge on microbial genetics, covering topics such as genetic principles, microbial genetics, and genetic mechanisms. It is designed for students taking MBG 3711 Microbial Genetics.
