LG 7.1 Chromosome Structure and Karyotyping PDF

LG 7.1 CHROMOSOME STRUCTURE AND KARYOTYPING Biology 2: Fundamentals of Biology 2 First Quarter, SY 2024-2025  THINK THIS OVER: If a rice plant has 2n=24, during anaphase and telophase, how many: 1. chromosomes? 2. chromatids? 3. centromeres?  In a lab experiment, you have been...

LG 7.1 CHROMOSOME STRUCTURE AND KARYOTYPING Biology 2: Fundamentals of Biology 2 First Quarter, SY 2024-2025  THINK THIS OVER: If a rice plant has 2n=24, during anaphase and telophase, how many: 1. chromosomes? 2. chromatids? 3. centromeres?  In a lab experiment, you have been tasked with studying the effects of a new drug on mitosis. You notice that cells treated with this drug appear to get stuck in the metaphase stage and do not progress to anaphase. What would be the consequences? Explain.  LEARNING OUTCOMES Describe the levels of DNA packing in a chromosome; Determine the significance of karyotyping in genetics; Demonstrate how karyotypes are analyzed and used in the detection of chromosomal abnormalities and its associated disorders through paper cut-and-paste simulation.  OUTLINE I. Structure of Eukaryotic Chromosomes II. Karyotyping CHROMOSOMAL LEVELS OF ORGANIZATION DNA → stretch of A-T-C-G Nucleosome → DNA + histones 30 nm chromatin fiber → solenoid 300 nm chromatin fiber Chromatid → 700-nm Chromosome → metaphase chromosome → 1400 nm Image source: Adapted from Concepts of Genetics (10th edition, p.302)  MAIN FUNCTIONS OF CHROMOSOMES 1. Storage of Genetic Information 2. Transmission of Genetic Information 3. Regulation of Gene Expression Image source: Adapted from Cleveland Clinic https://my.clevelandclinic.org/health/body/23064-dna-genes--chromosomes  OUTLINE I. Structure of Eukaryotic Chromosomes II. Karyotyping  THINK THIS OVER: Why are chromosomes not condensed all through the cell cycle?  OUTLINE I. Structure of Eukaryotic Chromosomes II. Karyotyping  KARYOTYPING is the process of sorting and identifying chromosomes to detect changes in its shape, size, and gene positions Image source: https://www.ucsfbenioffchildrens.org/medical-tests/karyotyping  KARYOTYPING Image source: https://labpedia.net/chromosome-studies-blood-chromosome-analysis-cytogenetics-chromosome-karyotyping/ Image source: https://labpedia.net/chromosome-studies-blood-chromosome-analysis-cytogenetics- chromosome-karyotyping/  KARYOTYPING Image source:https://www.ogt.com/ca/resources/fish-resources-support/fish-basics/chromosome-and-gene-basics/  IMPORTANCE OF KARYOTYPING 1. Diagnosis of Genetic Disorders 2. Prenatal Screening 3. Forensic Identification  KARYOTYPING Types of eukaryotic chromosomes: autosomes sex chromosomes X and Y  KARYOTYPE is an ordered display or diagram of the full set of an organism’s chromosomes arranged in homologous pairs (two chromosomes except sex chromosomes with identical features i.e. length and centromere placement) with respect to size, shape, number, and banding pattern. KARYOTYPE  THINK THIS OVER: What happens when there is EXTRA, MISSING, or DEFECTIVE chromosomes? KARYOTYPE  MEDICAL APPLICATION Image source: https://www.toppr.com/ask/content/posts/principles-of-inheritance-and-variation/tough-concepts-made-easy-26554/ What are the STEPS for karyotyping? STEPS in KARYOTYPING Examples of Karyotypes Examples of Karyotypes  THINK THIS OVER: Why should the chromosomes be arrested and observed during the metaphase stage?  CONCEPT CHECK Imagine you are a pathologist examining a pregnant patient’s blood sample in the lab. What can you infer from the generated karyotype shown? Does her baby have any genetic abnormality?  REMINDERS ALWAYS check the Activity/Assessment Tracker, we will update this regularly Sept 18 - AA#2 Wet Laboratory - Identifying Mitotic Cells and Mitotic Index in Onion Root Tips Sept 25 - AA#2 Laboratory Report Sept 28 - FA#3: Meiosis and Gametogenesis Adapted* and Prepared by: Reviewed by: sgd. ANGEL C. PALABRICA JERILE MAE E. CASIMIRO SST- I AUH, Biology September 11, 2024 Date: * Adapted from Biology 2 PPT from Casimiro and Viz (2023)