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GN 301 Module 2: Cell Cycle and Chromosomes

Chromosome Structure

==Chromosome parts:== A chromosome is 15% DNA, 10% RNA and 75% Protein

  • Label the parts of a chromosome and centromere positions (Draw them)

Metacentric, Submetacentric, Acrocentric, Telocentric

  • Metacentric: the centromere is in the middle of the chromosome
  • Submetacentric: the centromere is slightly off-center
  • Acrocentric: the centromere is very off-center
  • Telocentric: the centromere is at the top of the chromosome

\n The Cell Cycle

  • ==G1==

Gap 1. Cells accomplish much of their growth, growing larger and making proteins and organelles needed for DNA synthesis.

  • ==S==

S-phase. The cell synthesizes a copy of the DNA in its nucleus.

  • ==G2==

Gap 2. The cell grows more as it makes more proteins and organelles, reorganizing its contents in

preparation for mitosis.

  • ==M==

M-phase. Nuclear division (mitosis) followed by cytoplasmic division (cytokinesis)

The Cell Cycle

Mitosis

==Prophase, prometaphase, metaphase, anaphase, and telophase==

  • What is ==Cytokinesis?==

The cytoplasmic division of a cell at the end of mitosis or meiosis, bringing about the separation into two daughter cells.

Interphase = G1 + S + G2

When is there one chromatid and when are there 2 chromatids (sister chromatids) on the centromere?

  • During anaphase, there are two chromatids on the centromere. During Telophase, there is just one chromatid on the centromere. \n

Chromosome Preparation

  • Colchicine does… destroy spindle fibers in a cell so the view of chromosomes is unobstructed
  • Hypotonic Salt solution does ….. increase the cell volume
  • Dropping cells from height does …. splinter them apart by force, which reveals chromosomes

==Homologous Chromosomes== have the same: length, centromere, position, banding pattern, and genetic loci.

Karyotype

  • Define: an organized array of a cell’s chromosomes
  • Autosomes: non-sex chromosomes
  • Sex Chromosomes: X or Y chromosomes
  • Describe arrangement in karyotype: homologous chromosomes are matched together

Karyotypes can show whether an individual has a genetic disorder based on the appearance or absence of chromosomes.

FISH technique

  • FISH stands for … Fluorescent in situ Hybridization
  • Purpose: to use fluorescent DNA probes to target specific chromosomal locations within the nucleus, resulting in colored signals that can be detected using a fluorescent microscope