Image and Survey; TV; Week
The last argument of biology (which was also the first) was focused on the cell and its physical structure (organelles, cytoplasm, citoschelettro , heart ...). This time I will speak of cell division, showing the manner in which one cell gives rise to other cells. Cell division Cell division
is the process in which a mother cell by a two daughter cells are born : the mother cell does not remain intact, but is divided into two distributions to each of the his daughters, about half of its cytoplasm and its organelles. One can therefore say that cells daughters are equal to their mother
, but this statement does not derive only from the fact that they received the organelles and the cytoplasm, but also from the mother cell () a copy of its hereditary information that, as you will recall, are in the nucleus.
What is cell division? There is no simple question:
In organisms consist of a single cell, cell division increases the number of organizations
In multicellular organisms allows cells to repair damaged components of a tissue
Saturday, January 26, 2008
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. first in-depth post on the cell
) are simple organisms and eukaryotes are much more complex and larger than prokaryotes . division in prokaryotes
In prokaryotes the div. phone, very simple, consists of the following phases: Multiplication of the long circular DNA molecule (ie chromosome) Coupling of identical chromosomes in the cell membrane elongation of the cell membrane with subsequent removal chromosome bending of the cell membrane to the interior Division into two
CF
containing a chromosome inherited from the CM and organelles
Why? First, because
are larger and therefore contain more cytoplasm and organelles. Secondly because eukaryotes have DNA as a molecule containing many more chromosomes than that of the prokaryotic cell. The CM must then duplicate a number of chromosomes (in humans 46). So before you get to cell division, ie the
The first three phases (G 1 , S, G 2), considering them as a group, are called interphase . what happens in them:
G1 - G1 phase during cell growth in size and multiplies its organelles, so that they are sufficient to mitosis, which distributes them in the nuclei of CF
duplicate
) are simple organisms and eukaryotes are much more complex and larger than prokaryotes . division in prokaryotes
In prokaryotes the div. phone, very simple, consists of the following phases: Multiplication of the long circular DNA molecule (ie chromosome) Coupling of identical chromosomes in the cell membrane elongation of the cell membrane with subsequent removal chromosome bending of the cell membrane to the interior Division into two
CF
containing a chromosome inherited from the CM and organelles
- Term of cell division in eukaryotes
- Division
Why? First, because
are larger and therefore contain more cytoplasm and organelles. Secondly because eukaryotes have DNA as a molecule containing many more chromosomes than that of the prokaryotic cell. The CM must then duplicate a number of chromosomes (in humans 46). So before you get to cell division, ie the
- cytokinesis, the CM must take several actions included in the cell cycle
- . The latter is composed of 5 phases: Phase
- G 1 S phase
-
Phase 2 G
The first three phases (G 1 , S, G 2), considering them as a group, are called interphase . what happens in them:
G1 - G1 phase during cell growth in size and multiplies its organelles, so that they are sufficient to mitosis, which distributes them in the nuclei of CF
- S - during S occurs
- duplication of chromosomes (the carriers of info. heritable)
- G2 - G2 occurs during the condensation of chromosomes in ' appearing as the interphase
- filaments that make up in the nucleolus
- The chromatin Following this "readiness" to mitosis and cytokinesis
duplicate
- during G
- 1) move to the "ends" (rather, in regions facing each other) and the nucleus is the formation of
- zone. This is a union of more
microtubules that are particularly close to the poles of melted away in its middle region (middle). Occurs, following the rupture of the nuclear membrane, which breaks down into several parts, and thus the disappearance of the nucleus and the nucleus. The chromosomes are thus in contact with the cytoplasm - Metaphase - at this stage the chromosomes are moved by the microtubules members of the cast in different directions until they are placed in the middle region of the same zone
- that hold together the two chromatids
- identical. The chromatids, so far next to each other, are attracted to the poles (one on one side and the other on the other) Zone telophase - when they reached the opposite ends of the spindle, the chromatids assume their original form (as fibers) and formed two new cell membranes, two nuclei and two nucleoli. completed mitosis, we proceed to cytokinesis. This is a fairly straightforward process that presents two fundamental differences in
- animal cells and in those plants :
- animal cells - the cytokinesis in animal cells , that cell division occurs through a bottleneck cell membrane causing the division in two CF plant cells - in the plant cell cytokinesis is caused by the merger of vesicles that gives life to a plate Here, then, describe the cell division. For this post is all about.
- To access sites (for further discussion) of course I recommend: Wikipedia
Saturday, January 19, 2008
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On 1 January 2008 it was concluded that the survey had as its theme the high school in Italy. Compared to the first
, in this there were fewer responses, even if I conclude that visitors to E (now abbreviated Everything's
- in a blog) is also considered surveys. The poll question, as you can see on the side, is directed mainly at a teenage audience. So here's question and results in order to vote: What do you think of high school (secondary school degree) in Italy? hard - 10 votes with a total of 90% I do not know - 1 vote with a total of 9 (10)%
- Easy - with a total of 0 votes 0%
thank all those who voted and I will end this post by pointing out that this is the first post of the year.
Communication
: Lately there have been problems with the '
upload the logo on
and I was forced to change 
layout. Tuesday, January 1, 2008
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Special Cell division: second survey
- Merry Christmas and Happy New Year!? Did you find something more meaningful to wish happy holidays to relatives, friends, etc ...? I do not, so I decided to proceed as usual. As you can see from the image on the left and the post title, Everything in a blog wishes in advance to all its visitors a Merry Christmas and a Happy 2008. I do not know what else to say except that this blog is about to take a year and are pleased with the number of visitors I get each day (before to criticize my last statement keep in mind that a blog is very small). Thanks to Radio Blog Club have the opportunity to enter Jingle Bells in this post, so if you do not feel like a long clicked play. So, even at the risk of being repetitive: Good
- Christmas and Happy
New Year to all!
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