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

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)

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.
  

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