Lecture 3 - 011509

Lecture 3 - 011509 - DNA Replication Lecture#3 MBOC old =...

Info icon This preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
DNA Replication Lecture #3 MBOC old = 235-266 MBOC new = 263-295
Image of page 1

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

View Full Document Right Arrow Icon
Concepts When is DNA replicated? What is a replication fork? Is DNA replicated synchronously? What is the immortal strand hypothesis?
Image of page 2
DNA and Chromatin Review The nucleosome is the basic unit of the chromosome and it is composed of DNA and histone proteins DNA + histone proteins + non histone proteins make up chromatin Covalent modifications on histones are essential for cell identity and basic cell biology When DNA is replicated the proteins associated with the DNA are also inherited into the daughter cell
Image of page 3

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

View Full Document Right Arrow Icon
Cell Cycle Review
Image of page 4
What is DNA replication The mechanism whereby DNA is duplicated in preparation for cell division DNA replication requires a template strand and an enzyme for adding new nucleotides to the growing strand – DNA is always replicated from 5’ to 3’ DNA replication requires DNA polymerase and it was first discovered in 1957.
Image of page 5

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

View Full Document Right Arrow Icon
Origins of Replication Replication in eukaryotic cells is initiated in one stage of the cell cycle. In mammals S-phase lasts ~8 hours By the end of S-phase each chromosome contains an associated sister chromatid joined at their centromeres There are multiple origins of replication on a given chromosome Given that the S-phase lasts ~8 hours, not all origins of replication are initiated at the same time.
Image of page 6
How was it determined that different regions of a chromosome were replicated at different times? - Cells were synchronized - Labeled with BrdU - Pulsed with thymidine during early, middle or late S-phase - Light colored regions are sites of new replication where one strand is Brdu+ and the other strand is Brdu- Traditional method
Image of page 7

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

View Full Document Right Arrow Icon
Identifying origins of Replication by DNA microarray DNA is synchronized DNA replicated once gives a signal twice as high as unreplicated DNA For simplicity only one site of origin is shown here In reality yeast have hundreds of origins of replication DNA replication proceeds bidirectionally
Image of page 8
How are origins identified In bacteria (prokaryotes) origins of replication are defined by a DNA sequence In eukaryotes the model S. Cerevisiae (budding yeast) has been most productive in defining origins of replication.
Image of page 9

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

View Full Document Right Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern