Bio Ex 17.3.14
Bio
Bio
Fichier Détails
| Cartes-fiches | 13 |
|---|---|
| Langue | English |
| Catégorie | Biologie |
| Niveau | Collège |
| Crée / Actualisé | 16.03.2014 / 16.03.2014 |
| Lien de web |
https://card2brain.ch/box/bio_ex_17_3_14
|
| Intégrer |
<iframe src="https://card2brain.ch/box/bio_ex_17_3_14/embed" width="780" height="150" scrolling="no" frameborder="0"></iframe>
|
Functions of Cell division
Asexual reproduction, growth and development, cell replacement
Asexual reproduction
an amoeba, a single-celled eukaryote, is dividing into two cells. each new cell will be an individual organism
Growth and development
The fertilised egg cell of a sea urchin divides. The division of cells enables a multicellular eukaryotes to develop from a single cell.
cell replacement
these dividing bone marrow cells will give rise to new blood cells. cell division functions in RENEWAL AND REPAIR, replacing cells that die from normal wear and tear accidents.
The cell cycle
M-phase: (mitotic phase) cell division takes place, chromatin condenses into chromosomes
Interphase: 90% of cell cycle, uncoiled DNA called chromatin
G1-Phase: (G for Gap): growth and metabolic functions
S-Phase: (s for synthesis) DNA replication,G2-Phase: growth and preparation for mitosis
Mitosis in an animal cell
interphase: cell, nucleus, wirrwarr drin, (chromatin: dublicated DNA)
prophase; cell, nucleus, chromosomes drin (condense 2 grossi/chlini krütz), centrosome (grüne hütchen)
prometaphase: cell, fragments of nuclear envelope (nucleus), poles with centrosomes, kinetochore microtubules (spindle) grüne verbindung zw polen plus zu 4 chromosomes
metaphase: cell, kei nucleus, poles with centrosome, vo beidne pol verbindig zu chromosomes, mepaphase plate (imaginary)
anaphase: cells, pole with c. chromosomes sind usenandgrusse, sister chromatids
telophase: cell zei mal mit nuclear envelope is formaing, cleavage furrow, chlini strichli drine chromosomes (become less condensed, cetrosomes ah de pole (ned ahgschribe) ==> two genetecally identical daughter cells
cytokenesis: zw telophase und neue interphase
prophase
the chromatin fibres become more thighly coiled, condensing into discrete chromosomes, while the nucleus starts to fragment, even though not ih the LM microscope visible, the mititic spindle begins to form
prometaphase
the chromosomes have become even more condensed and are thick enough to be seen individually in a light microscope. each chromosome exists as two identical sister chromatids joined together at the centromere. the nucleus disappears. the microtubules attach to the kinetochors
metaphase
the mitotic spindle is now fully formed. the chromosomes convene (line up) at the metaphase plate, a plane that is equidistant between the spindles two poles
anaphase
the chromatids of each chromosome seperate. the two sister chromstifs begin moving toward opposite ends of the cell as their kinetochore mcrotubules shorten
telophase
the chromosomes become less condensed. two daughter nuclei has been formed in the cell. the division of the cytoplasm is well under way and vesicles forming the cell plate ar visible
eukaryotic chromosomes
chromosome, two sister chromatids (both have genetically identical DNA (gens), ih de mitti centromer, wie blueme mit 4 blätter
take home message
in the process of mitosis two sister chromatids of a chromosome are seperated and distributed to two genetically identical daughter cells
