16 Questions
What is the key difference between pyrimidines and purines in DNA bases?
Pyrimidines have a single-ring structure, while purines have a double-ring structure
What structural feature in RNA makes it less stable compared to DNA?
Presence of a 2’-hydroxyl group
What is a typical characteristic of prokaryotic chromosomes?
Circular shape and extensive supercoiling
How many circular chromosomes do bacteria and archaea typically have?
One
What distinguishes the genomes of eukaryotic microbes from higher eukaryotes?
Smaller and more compact genomes
What components make up prokaryotic genomes?
Protein-coding genes, RNA genes, and non-coding DNA
What is a characteristic of the genomes of endosymbionts and parasites?
Small genomes
What is the first step in cell division?
DNA replication
What is the relationship between genome size and specialized functions in prokaryotes?
Larger genomes contain more genes for specialized functions
What is the function of non-coding RNAs like ribosomal RNA (rRNA)?
They serve their cellular function as RNAs
What is included in the core genome of a lineage?
Genes present in all members of a lineage
What type of bond connects nucleotides in DNA?
Phosphodiester bond between 5’-phosphate groups and 3’hydroxyl (OH) groups
What do genomic islands and islets contain?
Horizontally acquired genes that confer unique properties to lineages
What is the composition of nucleotides in DNA?
Strings of nucleotide monomers comprised of 4 different nucleobases attached to a deoxyribose
What are the nitrogenous bases found in DNA?
Adenine (A), cytosine (C), guanine (G) and thymine (T)
What is the cellular function of open reading frames from messenger RNA (mRNA)?
They are converted to proteins via translation
Study Notes
Genetic Information and Genome Organization
- DNA bases are divided into pyrimidines (C/T) and purines (A/G), with different hydrogen bond interactions
- RNA contains a 2’-hydroxyl group absent in DNA, making it less stable and prone to hydrolysis
- Prokaryotic chromosomes are usually circular and extensively supercoiled, requiring proteins for structuring
- Bacteria and archaea typically have one circular chromosome, but some, like Vibrio cholerae, have two
- Eukaryotes have multiple linear chromosomes, with eukaryotic microbes having smaller and more compact genomes than higher eukaryotes
- Prokaryotic genomes consist of protein-coding genes, RNA genes, and non-coding DNA
- Endosymbionts and parasites have small genomes, while free-living bacteria/archaea have larger genomes
- Larger prokaryotic genomes contain more genes for specialized functions and environmental adaptation
- Core genome includes genes present in all members of a lineage, while pan genome includes all genes present in any member
- Genomic islands and islets contain horizontally acquired genes that confer unique properties to lineages
- Prophages, integrated into bacterial genomes, can carry cargo genes unrelated to phage biology and encode important bacterial toxins
- Bacteriophages, or phages, are viruses that infect bacteria and can integrate into bacterial genomes as prophages
Test your knowledge of genetic information and genome organization with this quiz covering DNA bases, RNA, chromosome structure, types of genomes, gene composition, and genomic elements.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
