exam 3 review sheets

• Genome Arrangements

  Bacterial genome can be arranged in various ways, including a single circular chromosome, linear chromosomes, or plasmids
• Transmission Types

  Vertical transmission is the passing of genetic material from parent to offspring, while horizontal transmission involves the transfer of genes between unrelated individuals
• Structural Genes vs. Control Sequences

  Structural genes code for proteins, whereas DNA control sequences regulate the expression of those genes
• Conjugation


  Process where bacteria transfer genetic material to one another through direct contact
• Non-coding DNA

  Eukaryotes have more non-coding DNA compared to prokaryotes, possibly due to the complexity of eukaryotic organisms
• Gene, Operon, Regulon

  • Gene is a DNA sequence that codes for a protein, an operon is a group of genes regulated together, and a regulon is a collection of operons controlled by a single regulatory protein
• DNA Structure

  DNA consists of nucleotides, base pairs, and complementary base pairing, with purines and pyrimidines as the bases
• RNA vs. DNA

  RNA is single-stranded, contains ribose sugar, and uracil instead of thymine
• Antiparallel Double Helix

  The two strands of DNA run in opposite directions, one 5' to 3' and the other 3' to 5'
• DNA Interior Stability

  Hydrogen bonds between base pairs and hydrophobic interactions stabilize the DNA interior
• Protein Contact

  Proteins contact nucleotide bases typically through the major groove of DNA
• Denaturation

  Denaturation is the separation of DNA strands by breaking hydrogen bonds, which is reversible, and A/T-rich regions require lower temperatures to denature
• DNA Supercoiling

  Supercoiling occurs when DNA overwinds or underwinds, and enzymes like topoisomerases manage this process
• Loop Relaxation

  Specific enzymes can relax one loop of the chromosome without affecting others
• Bacterial Supercoiling

  Bacteria typically have negatively supercoiled DNA
• Topoisomerases Types

  • One that cuts one strand of DNA and another that cuts both strands
• Supercoiling in Thermophiles

  Supercoiling helps thermophiles withstand high temperatures by stabilizing their DNA
• DNA Gyrase as Antibiotic Target

  DNA gyrase is essential for bacterial DNA replication and is targeted by antibiotics to inhibit this process
• DNA Replication

  Process by which DNA makes a copy of itself
• Semiconservative Replication

  Each new DNA molecule consists of one old and one new strand
• Replication Fork

  Site where DNA unwinds to be replicated, and there are typically two in a replicating DNA molecule
• DNA Synthesis Direction

  DNA is synthesized in the 5' to 3' direction
• Lagging vs. Leading Strand

  The leading strand is synthesized continuously, while the lagging strand is synthesized in fragments due to the antiparallel nature of DNA
• DNA Replication Parts

  • Initiation, elongation, and termination
• Replication Components

  • oriC (origin of replication), ter (termination site), DnaA (initiator protein), and other proteins and enzymes involved in replication
• Methylation Role

  Methylation helps in the regulation of DNA replication and the timing of initiation
• DnaA Binding

  DnaA binds to the oriC and initiates replication by unwinding the DNA
• Deoxyadenosine Methylase


  Enzyme responsible for adding methyl groups to DNA
• E. coli DNA Polymerases

  E. coli has several DNA polymerases, but not all are involved in replication
• Replisome

  Complex of enzymes and proteins that carries out DNA replication
• DNA Gyrase Role

  DNA gyrase relieves strain while double-stranded DNA is being unwound by helicase
• Termination Site

  More than one termination site in bacterial chromosomes
• Termination Utilization Substance

  Substance that helps in the termination process of DNA replication
• Plasmid

  Small, circular DNA molecule found in bacteria and some eukaryotes
• Plasmid and Chromosome Replication

  Plasmid replication can be linked to or independent of chromosome replication
• Plasmid Replication

  Plasmids replicate through a variety of mechanisms, often involving a specific origin of replication
• High vs. Low Copy Number Plasmids

  High-copy number plasmids are present in many copies within a cell, while low-copy number plasmids are few
• Plasmid Information

  Plasmids can contain genes for antibiotic resistance, metabolism, and other functions
• Plasmid Transmission

  Plasmids can be transmitted between cells, but not all plasmids are capable of this
• Archaeal Genomes

  Archaeal genomes share similarities with both bacterial and eukaryotic genomes and have unique features as well