Study Guides (400,000)
US (230,000)
UC-Irvine (3,000)
BIO SCI (300)
Moreno (10)
Midterm

BIO SCI 99 Study Guide - Midterm Guide: Nucleosome, Histone H2B, Chromatin


Department
Biological Sciences
Course Code
BIO SCI 99
Professor
Moreno
Study Guide
Midterm

This preview shows half of the first page. to view the full 1 pages of the document.
Lecture4. DNA Packaging
DNA packaging What’s the problem?
1. Human cells contain 46 chromosomes. Their combined length is nearly two meters. All of
this DNA must be packed into a nucleus with a diameter as small as 7 microns, while
ensuring organized access to its information.
2. Do prokaryotes and viruses have the same problem?
Levels of DNA compaction
1. Terminology: chromatin.
2. Technique: DNA gel electrophoresis and SDS-PAGE. Just know the general concepts and how
to interpret the gels.
3. Nucleosome level
i) The basic unit of condensation.
ii) What are the components of a nucleosome?
iii) Be able to interpret the chromatin digestion experiment (Figure 10-1).
iv) What are the functions of: the core histones (H2A, H2B, H3, H4), the histone octamer,
the linker histone (H1), the histone N-terminal tails?
v) Acetylation of the N-terminal tails is generally associated with opening chromatin and
allowing transcription. It is thought that acetylation weakens nucleosome-nucleosome
interaction (which are mediated through interactions between N-terminal tails).
4. 30 nm filament level
i) What is the relationship between the core histones, the linker histone and the 30 nm
filament?
5. Next level: Looping of the 30 nm filament along a chromosomal protein scaffold.
6. And higher levels of compaction that are still being worked out…rosettes?
7. Top level: the chromosome
8. What effect does DNA packing have on gene expression?
9. Compare the gene transcription levels between genes on naked DNA, beads-on-a-string
DNA (DNA bound with core histones), and 30 nm filament DNA.
10. Be able to interpret Figure 10-10.
11. How do prokaryotes compact their DNA? Looking for two main points here
You're Reading a Preview

Unlock to view full version