Nucleosomes disassembled as replication begins and proteins form

Breakdown of nuclear membrane, spindle fibers appear, chromosomes condense

Spindle fibers attach to chromosomes and chromosomes condense

Centromeres divide and sister chromatids move to opposite sides of the cell

When does the spindle fiber dissapear?

Colchicine (Colcrys) keeps spindle fibers from forming

Spindle fibers are also known as

Packed nucleosomes condensed during mitosis

ds helix wrapped around an octamer of histones

ds helix wraps up around histone

coiling of ds chain

2 complete chaines H-bonded in antiparallel orientation

polymers of nucleotides

nucleoside + 3 phosphates

base + sugar

Deoxyribose is a ___ carbon sugar molecule

Where does phosphate group of DNA attach?

Adenine and Guanine

Thymine and Cytosine

Ribose-5-phosphate is formed in

which one?

Which one?

Which ones are 2 ring structures?

Which ones are one ring structures?

What is the only difference in thymine and uracil?

Select the features of nitrogenous bases.

DNA is neutral at pH of 7.

beta-glycosidic linkages link the pentose sugar and the

B-glycosidic linkages form on C1 of sugar and ____ in purines.

B-glycosidic linkages form between C1 of sugar and ___ of pyrimidines.

All sugars are oriented in the same direction on both DNA strands.

2 ester bonds being formed using phosphoric acid

phosphodiester linkages repeat in the ___ direction

Adenine with Thymine

Cytosine with Guanine

Which part of DNA is exposed to the solvent?

Which part of DNA is NOT exposed to the solvent?

hydrophobic part of DNA

After every ___ basepairs there is a twist.

base pairs in the core of the helix have e's that interact with one another to generate

pi-pi stacking stabilizes the helix.

site of DNA replication in prokaryotes

How many sites of origin to prokaryotes have?

how many sites of origin are in eukaryotes?

For each origin, there are 2 replication forks.

DNA has a "bubble appearance" at the replication forks

Prokaryotes have ___ DNA than eukaryotes

unwinds DNA

Prevent the two unwound DNA strands from coming back together during replication

Cuts both strands and helps with the strain that is placed on the DNA helix.

Topoisomerase requires energy and prevents supercoiling.

Topoisomerase I cuts

Topoisomerase II cuts

Enzyme that adds nucleotides to growing DNA strand

DNA polymerase needs an RNA primer before it can start.

RNA primers added by primase during DNA replication get replaced with DNA later in the process

ATP, UTP, GTP and CTP are

dTTP, dATP, dGTP, and dCTP are

Mg is cofactor for DNA polymerase

made discontinuoulsy away from the replication fork

made continuously as replication fork advances

joins Okazaki fragments together

Where are errors more likely due to Okazaki fragments?

DNA polymerase can proofread and repair as well as it adds bases

permanent change in cell's DNA

3 main DNA repair mechanisms

Mutagens that form a lesion by altering DNA bases

Replaces C with U

replaces C with U, A with hypoxantine, and G with xanthine

removes abnormally modified bases by glycosylases and replaces them with right ones. Uses ligase to seal it up.

Lesion formed due to bulky DNA adducts (most often thymines)

Removes entire region of DNA on either side of the lesion and uses DNA polymerase to fill it and ligase to seal it

Used to fix any insertions or deletions

double strand breaks in DNA are lethal to the cell.

Transcription does NOT need a primer

three phases of transcription

Uses Acetyl CoA to add acetate to lysine residue to suppress positive charge of the histone so DNA can dissociate

Removes the acetate from histone to restore positive charge

Before transcription can begin, HATs must remove DNA from histones.

1 gene codes for 1 protein

Transcription factors control what genes get transcribed.

RNA polymerase II

RNA polymerase II binds to promoter region to start RNA synthesis

Stop point for RNA polymerase

Like DNA polymerase, RNA polymerase can proofread

Where are error rates higher?

mRNA is synthesized by RNA polymerase II

RNA polymerase requires 2 cofactors

For mRNA synthesis, DNA must unwind over a short distance forming a transcription bubble

Form BEHIND RNA polymerase

Form AHEAD of RNA polymerase

the Pre-mRNA molecule contains a 5' cap and a poly A tail

the 5' cap is

What is the coding part of DNA?

Part of DNA that does not code for anything

Which one gets spliced out?

Form mature RNA

Translation requires ATP?

synthesized in the nucleus and binds to its complementary mRNA which lead to silencing and ultimately to degredation of the mRNA in the lysosome.

study slides 47-60