HW #19 - AP Biology Period 4 #22 Liem Nguyen 11/24/09...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
AP Biology Period – 4 #22 Liem Nguyen 11/24/09 Homework #19 (0912104: Chapter 19 (due Friday 091204 ) Total points: 20 for Attempt on all questions ONE Concept Map: 10 points Objectives The Structure of Eukaryotic Chromatin 1. Compare the structure and organization of prokaryotic and eukaryotic genomes. eukaryotic genomes are larger cell specialization chromatin: DNA-protein complex The eukaryotic genome and the prokaryotic genome are similar in expressing genes, but two main differences are that eukaryotic genomes are organized into chromatin and are much larger, and that cell specialization in eukaryotes is extremely important. 2. Describe the current model for progressive levels of DNA packing in eukaryotes. lots of DNA histones nucleosome 30 nm fiber looped domains chromosome There are the histones that make up the nucleosomes. Then the 30-nm fiber is made up of many nucleosomes. The looped domains are made up of 30-nm fiber, and finally, those condense to become a chromosome. 3. Explain how histones influence folding in eukaryotic DNA. histone: proteins responsible for the first level of DNA packing in chromatin Histones hardly leave the DNA; only sometimes during transcription. Histones are wrapped around DNA. Also, histones make up the nucleosome, which is an important part of DNA packing. It helps compact the nucleosomes. 4. Distinguish between heterochromatin and euchromatin. heterochromatin: interphase chromatin visible as irregular clumps euchromatin: “true chromatin” Heterochromatin is more compact than euchromatin. Heterochromatin DNA is usually inaccessible to transcription enzymes and is usually not transcribed.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The Control of Gene Expression 5. Explain the relationship between differentiation and differential gene expression. cell differentiation: results in many differentiated cell types differential gene expression: expression of different genes by cells with the same genome Cell differentiation is a difference in specific cells. Meanwhile, differential gene expression is the difference of the expression of the genes in the same genome. 6. Describe at what level gene expression is generally controlled. gene expression can be turned on or off, accelerated, or slowed down gene expression: transcription Gene expressions generally controlled are mostly found in the transcription step in both prokaryotic cells and eukaryotic cells. 7. Explain how DNA methylation and histone acetylation affect chromatin structure and the regulation of transcription. histone acetylation: acetyl groups attached to positively charged histone tails DNA methylation: methyl groups added to bases in DNA genome imprinting: methylation permanently regulates the expression of either the maternal or paternal allele of certain genes In histone acetylation, positive charges are neutralized, disabling it from binding with other nucleosomes. This way, transcription proteins have easier access to the genes in the acetylated area. In DNA methylation, it inactivates certain genes for a long time in
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/06/2011 for the course AP BIO 101 taught by Professor Chan during the Fall '05 term at JFK.

Page1 / 8

HW #19 - AP Biology Period 4 #22 Liem Nguyen 11/24/09...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online