Cell Division: DNA Replication PDF

Cell Division 2024-10-29 9:43 AM 5 prime to 3 prime Rna primase = create fragment Rna primase...

Cell Division 2024-10-29 9:43 AM 5 prime to 3 prime Rna primase = create fragment Rna primase Need lil chunk of primer to get started Dna polymerase = take over.- leading strand = tackle on a whole strand + nucleotides. Once hits next fragment = sitch DNA ligase fragments togerther = remove rna primer + replace.w dna = important for creating a sewuence from the fragments The trombone model Ligase = actually attaching diff fragments to one another Important to study: - Leading. + lagging at same time - Therefore looping of one of the strand - in order to make 2 simultanerous 1 will Proofreading acctually liop back - Very few errors = occur - if it does happen in this point in process dna polyemrase = makes edit bc there are very temporalry h-bonds which hold nucelotide in place - easy point where change can be made. = move on - (determines that there is a mistake in hydrogen bondings = how it identifies mistake from bond - therefore cuts out the incorrect base and replace w the correct one bc it contains all of the 4 bases) Pro = circular Eu = linear - Trying to replicate something that is circualr = need anchor point - 2 strands = go in opposite direction around = form on circular ○ Mito+ chlroplast dna replication = same approach used Replication happening multiple origins of replication - Experience replication at same time (diff parts of Proceeds bidirectionally same strand) - Bubble = bidirectional = 1 sequence 5-3 other = 3-5 in both direction - Areas = replicated in diff parts of replication if meet up w one another - Ligase = attaches the ozaki fragments to make continuous sequence= therefore attach bubbles again used to cover the gap in the sugar-phosphate backbone Leadings = create the entire strand all the way until thevery end (leader) But there is an issue: - Lagging strand (kids following the leader) ○ Adding in ozaki fragments ○ Add a new fragment as unzipping ○ There needs to be enough distance for new fragment to form telomeres § During the end = lil control for distance for new fragment to form § Therefore lagging dna strand need enogiuh single-stranded template to begin the next okaski fragment Telo = add § The final primer (rna) = added telomerase onto the § When removed = section that Is not replicated end to extend shorter sequence Important = not every cells happening occurring - Stem cells = replicated infinitely = don’t want to decrease length of sequence everything replication therefore cant go Goal = on forever - very important telomarse funstion lagging - somatic cells = tissue + liver strand ○ Seq = shortening - limit to how many times a cell can Template rNA doesn’t get divide = 50 of those = useless sequence = cell cannot shorter + divide = Hayflick limit shorter w replication Parts that make up steucure = protein rna complex Own primer = rna = template rna = reverse transcriptase activity unlike the dna polymerase = cut + match dna base pairs Here the rna has reverse teranscripate activity from template rna = to convert from rna to dna How does this happen: Lagging strand = 3’ end = prevent shortening Telomere = hang over the edge a bit = by helping the end from degrading = provides stability Overall: Make sequence = replicated double helix = leading strand = entire - lagging = feafments = primer - dna stitches - short at the end - telomeres - attach onto finish sequence haploid diploid S-phase Next: Huge part of dna replication create large strange Histones - red ball - beads on necklace = histones = has 2 loops w dna sequence = wind the bead necklace to create chromatin fibers = dense image - Take chromatin - wind that - create chromosomes - Histones, chromatin - chromatid - chromosomes Sister chromatids - Have duplicate = 2 identical structures ○ Anchored to one another by centromeres Karyokinesis = nuclear division = see them bc highly condensed - G1 - g2 = cant see the characteristic image - w chromosomes + spindles - density at chromosomes at those stages = low - Happen in m phase Prophase Condensing occuring = nicely packaging to be able to move + mitotic spindle = Mitotic spindle fomring - used to move centrosomes chormosomes in the cell - microtuble example Goal: eventially split the cell in the center = create 2 - can use spindle fibers to migrate to diff ends - Chromosomes = become avaibale Prometaphase - Nuclear membrane breaks down = - Tryna split to 2 diff areas = organize bc duplication already Really key that the microtubules attach to the protein kinetochores have the duplicates Protein comlez - mitroctible coming of of it - = microtubule = - Tubules = expand out and shrink back in size to opposite ends of cell essentially find the chromosomes - Centrometer (point in center of x) Metaphase Align at the metaphase plate Strech out = found chromosome Really nice = distincive Anaphase image.= when looking thru microscrope Centrometer = divide - All of this telophase occurs in m phase btw Creates two new nuclei = nicely function in opposite ends of cell Set of information on oppotsite ends of cell = mictouble function onone = degrade M-phase 2nd part: Cytokinesis = acc separate the physical cells Cytokinesis themselves Contractile ring Actin filaments = create membrane - which are eventually split Ring = constrict/contract => pinches cytoplasm = bread = pinch the dough of = middle of batch = 2 separate equal balls = 2 distinctive daughter cells Plant cells a lil diff: cytokinesis. = diff step - Plants HAVE CELL WALL = things = bit diff for 2 things to split How is cell wall created: - Pharagmoplast = important in plant cytokinesis ○ Bunch of microtubules = function: bringing stricital pieces Cell plate for the cell wall - build in the center of the location ○ Plate = forms = cell wall in the middle/center of cell ○ Once wall fuses with the Plant vs animals = cytokinesis 1. Very specific microtubule structure to build the cell wall = plants 2. Cell plate = create to form a barrier to create the unique cell wall structure Visually walk thru it = lost - bwt steps + phases - email here Genetic information - separate things out = m phase