Bio Ex 17.3.14

Asexual reproduction, growth and development, cell replacement

an amoeba, a single-celled eukaryote, is dividing into two cells. each new cell will be an individual organism

The fertilised egg cell of a sea urchin divides. The division of cells enables a multicellular eukaryotes to develop from a single cell.

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.

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

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

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

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