Qualification > Sciences
bio AS ..doubt !!:(
Assi1993:
heyy, i cant understand the difference between chromatic and nucleolus??
can some1 explain plzz..would b very thankful !!
MaNi_DaDuDe:
--- Quote from: Assi1993 on January 23, 2010, 09:35:19 am ---heyy, i cant understand the difference between chromatic and nucleolus??
can some1 explain plzz..would b very thankful !!
--- End quote ---
What? You mean Chromatin ? orrr ???
If that's the case, I can easily tell you the difference by showing you a picture or two. Let me know.
Chromatin
(a) Chromatin is a complex of DNA and protein
(b) Chromatin is not visible, as individual chromosomal entities, through a light microscope
(c) Prior to cell division (M phase) a eukaryotic cell's genome consists of chromatin
Nucleus
(a) In eukaryotic cells the cell DNA is separated from the cytoplasm
(b) Most of this DNA is contained within the cell's nucleus
(c) The DNA within the nucleus is found as DNA-protein structures called chromatin
(d) During cell division, nuclear DNA is organized into chromosomes
(e) The structure that serves to divide the interior of the nucleus from the cytoplasm is the nuclear membrane
(f) Prokaryotic cells, by definition, lack nuclei (which is the plural of nucleus)
--- Quote from: Assi1993 on January 23, 2010, 09:35:19 am ---heyy, i cant understand the difference between chromatic and nucleolus??
can some1 explain plzz..would b very thankful !!
--- End quote ---
What? You mean Chromatin ? orrr ???
If that's the case, I can easily tell you the difference by showing you a picture or two. Let me know.
Chromatin
(a) Chromatin is a complex of DNA and protein
(b) Chromatin is not visible, as individual chromosomal entities, through a light microscope
(c) Prior to cell division (M phase) a eukaryotic cell's genome consists of chromatin
Nucleus
(a) In eukaryotic cells the cell DNA is separated from the cytoplasm
(b) Most of this DNA is contained within the cell's nucleus
(c) The DNA within the nucleus is found as DNA-protein structures called chromatin
(d) During cell division, nuclear DNA is organized into chromosomes
(e) The structure that serves to divide the interior of the nucleus from the cytoplasm is the nuclear membrane
(f) Prokaryotic cells, by definition, lack nuclei (which is the plural of nucleus)
--Maybe Irrelevant--
If you are studying nuclear division. . have a look at :
Interphase is stage I of the diagram
* Prophase, Stage II,III- The chromatin condenses into a highly ordered structure called chromosomes and the nuclear membrane begins to breakup. The nucleus also breaks up and forms part of several chromosomes. Centrioles move to opposite poles of nucleus.
* Metaphase, Stage IV - Condensed chromosomes, carrying genetic information, align in the middle of the cell before being separated into each of the two daughter cells.
* Anaphase - Stage V, VI Chromatids (identical copies of chromosomes) separate as they are pulled towards opposite poles within the cell. They are pulled because the microtubule fibres begin to shorten, pulling them along.
* Telophase - Nucleus, nucleolus reforms and chromosomes unravel into longer chromatin structures for reentry into interphase. Cytokinesis also occurs - the division of cytoplasm and cell into two by constriction from edges of cell.
This section is called the PMAT section as it is an easy way to remember the stages of mitosis (Prophase-Metaphase-Anaphase-Telophase).
Hope I helped.
-MaNi
P.S. Asmaa? lol
MaNi_DaDuDe:
Googled something for ya:
In eukaryotic cells, the structure and contents of the nucleus are of fundamental importance to an understanding of cell reproduction. The nucleus contains the hereditary material of the cell assembled into chromosomes. In addition, the nucleus usually contains one or more prominent nucleoli (dense bodies that are the site of ribosome synthesis).
The nucleus is surrounded by a nuclear envelope consisting of a double membrane that is continuous with the endoplasmic reticulum. Transport of molecules between the nucleus and cytoplasm is accomplished through a series of nuclear pores lined with proteins that facilitate the passage of molecules out of and into the nucleus. The proteins provide a certain measure of selectivity in the passage of molecules across the nuclear membrane.
The nuclear material consists of deoxyribonucleic acid (DNA) organized into long strands. The strands of DNA are composed of nucleotides bonded to one another by covalent bonds. DNA molecules are extremely long relative to the cell; indeed, the length of a chromosome may be hundreds of times the diameter of its cell. However, in the chromosome, the DNA is condensed and packaged with protein into manageable bodies. The mass of DNA material and its associated protein is chromatin.
To form chromatin, the DNA molecule is wound around globules of a protein called histone. The units formed in this way are nucleosomes. Millions of nucleosomes are connected by short stretches of histone protein much like beads on a string. The configuration of the nucleosomes in a coil causes additional coiling of the DNA and the eventual formation of the chromosome.
Assi1993:
lol ya sorry *Chromatin*!!
well maanii!!! thank you so much for ur consideration :D but i got the answer..as simple,,
Chromatin is DNA in its active form. It consists of DNA looped around histone proteins. The nucleolus is a knot of chromatin and manufactures ribosomes....
:)
MaNi_DaDuDe:
--- Quote from: Assi1993 on January 23, 2010, 02:55:30 pm ---lol ya sorry *Chromatin*!!
well maanii!!! thank you so much for ur consideration :D but i got the answer..as simple,,
Chromatin is DNA in its active form. It consists of DNA looped around histone proteins. The nucleolus is a knot of chromatin and manufactures ribosomes....
:)
--- End quote ---
yeah no problemo.
Take care now
Navigation
[0] Message Index
[#] Next page
Go to full version