BIOL 240 1st Edition Lecture 1 Outline of Last Lecture I. Introduction to syllabusOutline of Current Lecture I. Chromosomes1. Designationsa. Types of designations2. Diploid cellsa. HomologsII. Cell Cycle1. Mitosisa. Phases of mitosisb. Cohesionc. Cytokinesis2. Overview of Meiosisa. Phases of meiosisCurrent LectureI. Chromosomes1. Designations:b. Metacentric- when the centromere location is in the middle of the paired sister chromatidsc. Submetacentric- when the centromere location is between the middle and the end of the paired sister chromatidsd. Acrocentric- when the centromere location is close to the end of the paired sister chromatidse. Telocentric- when the centromere location is at the end of the paired sister chromatids2. Diploid cellsb. Chromosomes are present in pairs of homologs, meaning that they are physically identical, but not genetically identical.c. One homolog from each parentd. Distinguishing feature of males and females are large gametes (egg) and smallgametes (sperm)II. Cell CycleThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. Mitosisa. Interphase- chromosomes are distributed all throughout the nucleus; they are uncoiled and chromatin is formedb. Prophase- condensation of chromosomes; centrioles divide and begin to move apart; spindle begins to formc. Prometaphase- chromosomes are completely condensed and are evident double structures; centrioles reach opposite ends; spindle fibers formedd. Metaphase- centromeres align of the metaphase plate in the center of the cell; spindle microtubials are tugging on the chromosomese. Anaphase- centromere split and daughter chromosomes are segregated to opposite polesf. Telophase- nuclear envelop reformed and cytokinesis cleaves the cell into twog. Cohesion- during DNA replication, a ring shaped protein complec called cohesin is formed around the duplicated strands to hold the chromatids together through much of the cell cycle; once anaphase is reached, the enzyme separase cleaves the cohesin ringsh. Cytokinesis- division of the cytoplasm between daughter cells; driven by cleavage furrow formed in telophase2. Overview of Meiosisa. Prophase 1 (synapsis)b. Metaphase (two tetrads)c. Reductional division (four dyads)d. Equational division (eight monads; four gamete
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