Molecular Biology and Chromosome Structure Flashcards

Vocabulary flashcards covering bacterial genome structure, chromosome compaction, supercoiling enzymes, and related antibiotics based on the lecture transcript.

Nucleoid region

The region in a bacterial cell lacking a membrane-bound nucleus where the circular chromosome is located.

Directed assembly

A process in complex viruses, such as T4, where specific non-structural enzymes or gene products are used to assist in building the viral particle rather than self-assembling.

Origin of replication

A specific site containing a few hundred nucleotides in a circular bacterial chromosome that is recognized by DNA polymerase to begin copying DNA.

Loop domains

Compacted DNA structures created when highly repetitive sequences in the bacterial chromosome bind to single-stranded DNA binding proteins, achieving a tenfold reduction in size.

Supercoiling

The process of twisting DNA loop domains into tight coils or knots to achieve additional compaction and generate mechanical tension for strand separation.

DNA gyrase

An enzyme, also called topoisomerase II, that uses energy to add negative supercoils into bacterial DNA to increase compaction and strand separation tension.

Topoisomerase I

An enzyme in bacteria that relaxes negative supercoils and reduces structural tension in the DNA chromosome.

Quinolones

A class of antimicrobial drugs that inhibit bacterial DNA gyrase function, disrupting bacterial replication and survival.

Coumarins

A class of chemical compounds that act as bacterial topoisomerase inhibitors to disrupt DNA supercoiling.

Ciprofloxacin

A powerful antibiotic, also known as Cipro, that targets bacterial DNA gyrase and is effective against severe bacterial infections like anthrax.

Chromatin

The complex of DNA and protein in eukaryotic cells that undergoes multi-step compaction to fit linear chromosomes inside the cell nucleus.