27. Chromatin, Chromosome

Question 1

Chromatin
What is chromatin a combination of? What is a heterochromatin? Where is a marginal chromatin located? Where are chromocenters? How does chromatin stain?

What is euchromatin? How does it stain? How much of a chromatins content is it? Is it condensed or de-condensed?

Sex chromatin
What is a sex chromatin also called? Where does it only exist? What is it? What is it adhering to?

Chromatin composition
What is it a combination of? How is it’s shape?

Proteins of chromatin
How much is non histones and where are they seen? How many are histones and where are they only found? What can be found in the nucleosome core? What is h1 see as?

Nuclesome
What is a nuclesome? What is it composed of? How many loops of DNA does it have? What do the loops of DNA form?

Answer 1

Chromatin is a combination of DNA and associated proteins. A heterochromatin is condensed and it’s about 90% of a chromatin. A marginal chromatin is located close to the nuclear membrane. Chromocenters are dispersed throughout the nuclear matrix in the form of nucleoplasmic granules. It stains darkly

A euchromatin is the active part of the chromatin in transcription and replication. It stains lightly. It is about 10% of a chromatins content. It’s a in a de-condensed form.

A sex chromatin also known as a Barr body. It only exists in females. It is a tightly packed X chromosome. It’s adhering to the nuclear envelope.

The chromatin is a combination of DNA and associated protein. It’s shape is in the form of DNA strands.

About 20% of the chromatins protein are non-histones. They are mostly seen in the nuclear matrix. 80% of the chromatins protein content are histones which are only in the nucleus. In the nuclesome we can find H2A, H2B, H3 and H4. H1 is seen as a linker DNA between nucleosomes.

A nuclesome is a basic structural unit of chromatin. It is composed of core histone octamers. It has two loops of DNA which together forms a globular structure called a nuclesome.

Question 2

Chromosomes
What is a chromosome? What is it responsible for? What is the total number in humans? How many of the are autosomes? How many pairs are sex chromosomes(gonosme)? What is the size of a chromosome? What is the Total length of DNA in our body?

Structure
How are the arms of the chromosome? What is the part where they meet called?

Chromosomal anomalies
What is it called when the number of chromosomes are abnormal? What are some diseases caused by abnormal number of chromosomes? Give an example of an structural chromosomal abnormality? Duplications? What is it called when two cells in one individual has different genetic information?

Answer 2

A chromosome is a long DNA molecule that contains may genes and associated proteins. It is responsible for storage of genetic information. The total number of chromosomes in humans are the diploid number which means it’s 46 chromosomes. In sex cells there’s the haploid number which is 23 chromosomes. 22 of the chromosome pairs are autosomes. 1 pair is a sex chromosome which also is called a gonome. The size of chromosomes varies each chromosome has a varying size. The total length of DNA with genetic information in our body can be up to 2 meters.

It has two arms one is short and one is long. The part where they meet is called the centromere.

Chromosomal anomalies
It is called aneuploidy. I can get turners syndrome, Down’s syndrome or Edwards syndrome. An example of structural abnormality from chromosomes can be duplication where chromosomal material is gained. It is called Mosaicism.