Question

what is the difference between chromosomes and chromatin??? 3 points.....9th class

Answer 1

Chromatin Chromosome
Definition
In the nucleus, the DNA double helix is packaged by special proteins (histones) to form a complex called chromatin. The chromatin undergoes further condensation to form the chromosome. A compact structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
Structure
Composed of nucleosomes-a complex of DNA and proteins (called histones). Represent DNA folded on nucleoproteins by a magnitude of 50. The chromatin fiber is app. 10 nm in diameter. Chromosomes are condensed Chromatin Fibers. They are a higher order of DNA organization, where DNA is condensed at least by 10,000 times onto itself.
Appearance
Chromatin Fibers are Long and thin. They are uncoiled structures found inside the nucleus. Chromosomes are compact, thick and ribbon-like. These are coiled structures seen prominently during cell division.
Pairs
Chromatin is unpaired. Chromosome is paired.
Metabolic activity
Permissive to DNA replication, RNA synthesis (transcription) and recombination events. Refractory to these processes.
Presence
Found throughout the cell cycle. Distinctly visible during cell division (metaphase, anaphase) as highly condensed structures upto several thousand nm.
Conformation
May have open (euchromatin) or compact (heterochromatin) conformations, which is dynamically regulated during the cell-cycle stages. Predominantly heterochromatic state with a predetermined position in the nucleus and a specific shape such as metacentric, submetacentric, acrocentric, telocentric.
Visualization
Electron microscope (beads on string appearance) Light microscope (classic four-arm structure when duplicated)

Answer 2

The genetic material in our cells is present in the form of DNA. This DNA is coiled around proteins and is present in the nucleus in the form of loose threads called the chromatin material. When the cell divides, the chromatin material gets condensed into distinct X-shaped structures called chromosomes.


Or
Chromatin is essentially the substance of chromosomes. It is made up of DNA attached to a protein structure, together with chromosomal RNA. Chromatin exists in two states, euchromatin and heterochromatin, with different staining and functional properties.

The chromatin condenses to form Chromosomes during cell division. The chromatin in the nucleus forms a 'beads-on-string' structure or Nucleosome. The 'beads' are octamer histone proteins and the 'string' is the double-stranded DNA.

hope this helps....