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

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\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)

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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.

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Interphase = G1 + S + G2

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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

  

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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

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==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

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