This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: BIO1140 Study Group #6 Answer Key 1. Fill in the blanks: i. A base is a purine or a pyridimine . ii. A base + a pentose sugar = _a nucleoside . iii. A nucleoside + a phosphate = _deoxynucleoside . 2. What is the role of histones in DNA organization? How does DNA packaging differ between bacteria, viruses and eukaryotes? Histones pack eukaryotic DNA at successive levels of organization i.e. hierarchical organization Viruses: Use basic proteins that may be part of the virus particle (capsid). Bacteria: Use basic proteins such as “HU”, “IHF”, “H-NS” to form a series of loops called a nucleoid . Eukaryotes: Use basic proteins called histones AND a hierarchical organization 3. Describe the bacterial chromosome and the eukaryotic chromosome, and how they differ. Bacterial Chromosome: Closed, circular molecule of DNA packed into nucleoid Replication begins from a single origin, proceeds in both directions Plasmids (in many bacteria) replicate independently of the host chromosome Eukaryotic Chromosomes:...
View Full Document