HMB265H1 Chapter Notes - Chapter 17-18: Antonie Van Leeuwenhoek, Sister Chromatids, Allosome

• School: UTSG
• Department: Human Biology
• Course: HMB265H1
• Professor: Naomi Levy-Strumpf, Stephen Wright

Document Summary

Haploid gametes/cells carrying only a single set of chromosomes. Haploid number (n) the number of chromosomes in a haploid cell. Diploid zygotes/cells carrying two matching sets of chromosomes. Sister chromatids attached to each other by the centromere. Metacentric centromere is more or less in the middle. Acrocentric centromere is very close to one end. Differences in alleles are seen at the molecular level, not the microscopic level. Can now differentiate between maternal and paternal chromosomes (eg. can determine which parent the extra chromosome in down syndrome came from) The number of chromosomes doesn"t correlate with the complexity of the organism. Followed cells from a grasshopper testes and followed them through the meiotic divisions that produce sperm. Observed that prior to meiosis, the cell contained a total of 24 chromosomes (11 matched autosomes and two sex chromosomes - he called them x & y)