General Biology 1: M Checkpoint Overview

The M checkpoint ensures that all chromosomes are attached to the mitotic spindle by a kinetochore.

P53 either repairs the damaged cell or initiates apoptosis to eliminate it.

During the G1 phase, the cell is in a resting state and neither dividing nor non-dividing.

<p>Kinase activates these signals, and cyclins are the activating molecules.</p> Signup and view all the answers

<p>The cell aborts division if all DNA strands have not been completely duplicated.</p> Signup and view all the answers

<p>The primary purpose of mitosis is to divide one parent cell to produce two genetically identical daughter cells.</p> Signup and view all the answers

<p>The main phases of mitosis are Prophase, Metaphase, Anaphase, and Telophase.</p> Signup and view all the answers

<p>During prometaphase, the nuclear envelope breaks down, allowing the mitotic spindle to capture and organize chromosomes.</p> Signup and view all the answers

<p>Microtubules bind to chromosomes at the kinetochore, which is a protein patch on the centromere.</p> Signup and view all the answers

<p>During early prophase, the chromosomes condense, making them easier to separate later in the process.</p> Signup and view all the answers

<p>The kinetochore binds microtubules to chromosomes at the centromere, allowing for proper segregation during cell division.</p> Signup and view all the answers

<p>Kinetochore microtubules attach to the kinetochores of chromosomes, ensuring they are aligned at the metaphase plate.</p> Signup and view all the answers

<p>The spindle checkpoint checks if all chromosomes are correctly attached to microtubules and aligned at the metaphase plate.</p> Signup and view all the answers

<p>Sister chromatids are separated and pulled towards opposite ends of the cell.</p> Signup and view all the answers

<p>Microtubules not attached to chromosomes elongate to push apart the spindle poles, resulting in cell elongation.</p> Signup and view all the answers

<p>Motor proteins walk along microtubule tracks, carrying chromosomes and aiding in their movement during mitosis.</p> Signup and view all the answers

<p>Centrosomes are positioned at opposite ends of the cell during metaphase.</p> Signup and view all the answers

<p>The metaphase plate is the imaginary plane where all chromosomes line up during metaphase.</p> Signup and view all the answers

<p>About 80%.</p> Signup and view all the answers

<p>The cell grows in size, produces RNA, and synthesizes proteins.</p> Signup and view all the answers

<p>The cell exits the cell cycle and enters a non-dividing state called GO.</p> Signup and view all the answers

<p>To check readiness for mitosis and correct any deficiencies.</p> Signup and view all the answers

<p>In the S phase.</p> Signup and view all the answers

<p>They regulate 'stop' and 'go-ahead' signals in the cell cycle.</p> Signup and view all the answers

<p>The Restriction Point.</p> Signup and view all the answers

<p>To check readiness for mitosis and to correct any deficiencies.</p> Signup and view all the answers

<p>A cell plate forms between daughter cells during plant cell cytokinesis.</p> Signup and view all the answers

<p>Mitosis produces diploid daughter cells, while meiosis produces haploid gametes.</p> Signup and view all the answers

<p>Cytokinesis in human liver cells takes about 2 hours.</p> Signup and view all the answers

<p>The cleavage furrow is the indentation that forms on the cell surface to help separate the two daughter cells.</p> Signup and view all the answers

<p>The two processes are spermatogenesis for male gametes and oogenesis for female gametes.</p> Signup and view all the answers

<p>During telophase, two new nuclei form, chromosomes decondense, and the cell begins to re-establish its structures as cytokinesis occurs.</p> Signup and view all the answers

<p>In animal cells, cytokinesis involves a cleavage furrow and a contractile ring, while in plant cells, it results in the formation of a cell plate.</p> Signup and view all the answers

<p>During telophase, the mitotic spindle is broken down into its building blocks as the cell prepares to complete division.</p> Signup and view all the answers

<p>The G1 checkpoint ensures the cell is large enough and has sufficient nutrients to divide.</p> Signup and view all the answers

<p>DNA synthesis and replication take place during the S phase.</p> Signup and view all the answers

<p>During telophase, nuclear membranes and nucleoli reappear as the cell prepares for the final stages of division.</p> Signup and view all the answers

<p>Cytokinesis may begin in either anaphase or telophase, depending on the cell.</p> Signup and view all the answers

<p>The G2 checkpoint checks if everything is ready for mitosis and corrects any deficiencies.</p> Signup and view all the answers

<p>In animal cells, cytokinesis is contractile and involves a band of actin filaments pinching the cell into two via a cleavage furrow.</p> Signup and view all the answers

<p>The G0 phase is a resting phase where the cell is neither dividing nor preparing to divide.</p> Signup and view all the answers

<p>Chromosomes begin to decondense and revert to their stringy form during telophase.</p> Signup and view all the answers

<p>The M checkpoint ensures that all chromosomes are attached to the mitotic spindle.</p> Signup and view all the answers

<p>The cell exits the cell cycle and enters a non-dividing state known as G0.</p> Signup and view all the answers

<p>Completing cytokinesis results in two new cells, each with a complete set of chromosomes identical to those of the parent cell.</p> Signup and view all the answers

<p>During the G2 phase, the cell reproduces its organelles and synthesizes proteins.</p> Signup and view all the answers

<p>If DNA damage is present, the cell will not proceed with division.</p> Signup and view all the answers

<p>Apoptosis is triggered by P53, which can either repair the cell or induce programmed cell death.</p> Signup and view all the answers

<p>It ensures that proteins, organelles, and other structures are in sufficient quantities for proper function.</p> Signup and view all the answers

<p>Crossing over introduces genetic variability by exchanging genetic material between homologous chromosomes.</p> Signup and view all the answers

<p>The random orientation allows for different assortments of chromosomes, leading to genetic diversity in gametes.</p> Signup and view all the answers

<p>Sister chromatids are separated and pulled to opposite ends of the cell.</p> Signup and view all the answers

<p>Meiosis II results in four haploid gametes, each with one chromatid per chromosome.</p> Signup and view all the answers

<p>The newly forming cells are haploid, but the sister chromatids remain together.</p> Signup and view all the answers

<p>Each tetrad is attached to microtubules from both poles, with one homologous chromosome facing each pole.</p> Signup and view all the answers

<p>Independent assortment is the random orientation of homologous pairs at the equator during Metaphase I.</p> Signup and view all the answers

<p>The sister chromatids remain attached to one another while the linked homologous chromosomes are pulled apart.</p> Signup and view all the answers

<p>Two haploid daughter cells are formed.</p> Signup and view all the answers

<p>Meiosis II occurs without copying DNA and is shorter and simpler than Meiosis I.</p> Signup and view all the answers

<p>Chromosomes condense and the nuclear envelope breaks down, if needed.</p> Signup and view all the answers

<p>The sister chromatids separate and are pulled towards opposite poles of the cell.</p> Signup and view all the answers

<p>Cytokinesis results in four haploid cells, each with one chromatid per chromosome.</p> Signup and view all the answers

<p>Crossing over and random orientation of homologue pairs.</p> Signup and view all the answers

<p>Nuclear membranes reform around each set of chromosomes, and chromosomes decondense.</p> Signup and view all the answers

<p>Meiosis reduces the chromosome number to haploid, while mitosis maintains the diploid number.</p> Signup and view all the answers

<p>Homologous chromosomes carry the same genes from each parent and are crucial for genetic variation during meiosis.</p> Signup and view all the answers

<p>Homologous chromosomes align and pair up, forming a synaptonemal complex that facilitates crossing over.</p> Signup and view all the answers

<p>Independent assortment refers to the random orientation of homologous chromosomes at the metaphase plate, leading to genetic variation.</p> Signup and view all the answers

<p>In Anaphase 1, homologous chromosomes are pulled apart while sister chromatids remain attached.</p> Signup and view all the answers

<p>Chiasmata are structures that form at points of crossover and keep homologous chromosomes connected.</p> Signup and view all the answers

<p>The first meiotic division produces two haploid cells from one diploid cell.</p> Signup and view all the answers

<p>Spermatogenesis is the process of male gamete formation that occurs through meiosis, producing haploid sperm cells.</p> Signup and view all the answers