How Do Condensins Construct Chromosomes During Interphase

     The zygotene. During this phase begins the pairing of homologous chromosomes. It is also called synapsis and the resulting structure synaptic complex. Directly after initiation of the process does the pairing spread like a zipper across the whole length of the chromosome.

b. S – Strands of dna within a chromosome separate from each other and complimentary strands are made.

Chromosomes are structures inside cells that are made of genes. They carry the genetic information about how the body develops. Normal cells have 23 pairs of chromosomes in each cell. Having an extra chromosome in all or some cells (mosaicism) changes the way these cells develop and function. It interferes with normal growth and development while a baby is in the womb. Trisomy 13 and 18 lead to a number of serious developmental defects. These defects make survival unlikely beyond the first year of life.

Throughout anaphase, the spindle fibers are attached to chromosomes at one end, and to the other chromosomes attached on the other end of the cell. The spindle fibers then pull the centromeres to opposite sides of the cell.

This happens in meiosis 2 which happens after meiosis 1. Metaphase 2 happens after prophase 2. In metaphase 2 spindle fibers form from the centrioles which are found on the opposite ends of the cell and grab the chromosome at the kinetochore region on the centromere. Once the cell grabs the chromosomes they align them at the center of the cell at the equator. Spindle fibers attach to the kinetochore of each of the chromosome and align it in the center. Anaphase 2 happens after metaphase 2. In anaphase 2 the spindle fibers begin to contract in which they move and separate the 2 chromatids within the chromosome. The spindle fibers then pull on the chromosome on both ends and separate the chromatids. In anaphase 2 the chromatids are genetically

18) During which phase of mitosis do the chromosomes line up on a plane equidistant from the two spindle poles? A) anaphase B) metaphase C) telophase D) prophase 19) At the start of mitotic anaphase, A) the chromatid DNA replicates. B) the centromeres of each chromosome come apart. C) nuclear envelopes begin to form around the chromosomes. D) equivalent and complete collections of chromosomes have reached the two poles.

of MT plus ends) and the poleward flux (depolymerisation at MT minus ends); the relative

was found to be packed into chromosomes, of which 23 pairs existed in each cell

Contrast: Chromosomes are a condensed chromatin fibers that are higher up in the order of DNA. Chromatins are composed of nucleosomes and are lower in the order of DNA. Chromosomes are compact, thick and coiled while chromatin is comprised of thin and long fibers that are uncoiled in their structure unlike chromosomes. Chromosomes are paired together while chromatin are unpaired. Chromatin is found everywhere in the cell while chromosomes are usually found when it comes to cell division.

Meiosis I had 6 steps: Interphase, Prophase I, Metaphase I, Anaphase I, Telophase, and Cytokinesis. In Interphase, the cell grows, repairs, performs its usual functions, and replicates DNA. During Prophase I, each replicated chromosome pairs with its corresponding homologous chromosome forming a tetrad. During tetrad formation, sections of chromosomes can be exchanged between chromatids, a process called crossing over. In Metaphase I, paired homologous chromosomes line up across the middle of the cell. During Anaphase I, Spindle fibers pull each homologous pair toward opposite ends of the cell. In Telophase I, a nuclear membrane forms around each cluster of chromosomes. Cytoplasm then occurs resulting in two new daughter cells. The daughter cells contain chromosome sets that are different from each other and the parent

In our mitosis microscope lab, the phase that was most identified was prophase, with a total of 49 times for mine. During prophase, there is a lot that must be accomplished before the actual division of chromosomes including but is not limited to: the breakdown of the nuclear membrane, condensation of chromosomes, and the synthesis of spindles. Prophase can take up as much as 50-60% of the total time required to complete mitosis; it spends around 20 minutes in the cell. In prophase, the chromatin condenses into double rod-shaped structures referred to as chromatin, in which the chromatin becomes visible. There are two identical copies of each chromosome in the cell also known as the sister chromatids. The sister chromatids are attached to

Each telophase I nucleus contains the haploid number of chromosomes, but each chromosome is a duplicated chromosome (it consists of a pair of chromatids). During telophase, the chromosomes are fully separated at opposite poles of the cell and new nucleic begin to form around them. The chromosomes become invisible as they return to their uncondensed formation. In plants, a band of cytoskeletal proteins forms between the nucleic at the future site of new cell wall formation. In animals, a lessening ring forms around the middle of the

Veluchamy et al., (2016), found DNA and histone associations in Eukaryotes plays role in chromatin compaction and in shaping three dimensional topology of the genome. He and his colleagues did an experiment on the role of LHP1 in H3K27me3. PcG which is mentioned as one of the earliest epigenetic regulatory mechanism remodel chromatin such that epigenetic silencing of genes happen. The PcG identified the repression of HOX genes in Drosophila melanogaster. The HOX genes are group of related genes which are in contention of controlling body plan like the embryo. Earlier there are claims on the complex nature of PRc1 and PRC2. Arabidopsis has three PRC2 genes based on the presence of the three animal suppressors of zeste 12 (SU (Z) 12) homologous

2 metres of DNA is packaged and folded by multiple mechanisms and occupy certain positions to form chromosomes in mammalian cells. Levels of folding and their positioning generate contacts between different regions of the genome. Such contacts are the result of distance between DNA sequences, their folding architecture and the proteins that are associated with them, directly or indirectly.

Unlike somatic cell, sperm chromatin is highly organized compact structure. This specific packaging occurs by histone to protamine transition.