Lecture 8B Flashcards
Spindle fibers ?
Spindle fibers (proteins called microtubules): attach to chromosomes & move them around
chromosomes are… in G1? condensed/uncond
UNcondensed . they become condensed in prophase
when do chromosomes get condensed
prophase
Prophase?
nuclear envelope still intact (nuclear membrane present), replicated chromosomes condense
Mitotic spindle just being assembled
Prometaphase: nuclear envelope breaks down.
Mitotic spindle complete & attaching to all the condensed replicated chromosomes
Metaphase?
Replicated condensed chromosomes are aligned at the metaphase plate by the spindle fibers
Anaphase?
Early anaphase: sister chromatids separated by mitotic spindle fibers: sister chromatids each now called an unreplicated chromosome
Later anaphase: unreplicated condensed chromosomes being moved towards the centrioles (at the poles of the cell) by spindle fibers.
telophase?
Early telophase: Chromosomes almost at the poles of the cell
No nuclear membrane yet
Cleavage furrow (belt) present
Late telophase:
Nuclear membrane reforms, unreplicated chromosomes decondense
Once nuclear membrane complete: MITOSIS COMPLETE
Cytokinesis?
not part of mitosis
Ring of protein filaments encircles the cell & contracts, forming a cleavage furrow → splits cell into 2 daughter cells
Mitosis vs cytokinesis?
When mitosis is complete: 2 daughter nuclei
When cytokinesis is complete: 2 daughter cells are formed
how is mitosis in plants
Mitosis in plant cells is similar to animal cells, but no centrioles present
Cytokinesis: is different
Golgi forms a line of vesicles that fuse to become
the plasma membrane of each daughter cell AND
the cell plate: separates the daughter cells
bacteria Reproduce by …?
binary fission, not mitosis
what is binary fission
binary fission, asexual reproduction by a separation of the body into two new bodies. In the process of binary fission, an organism duplicates its genetic material, or deoxyribonucleic acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA.
cell checkpoint?
A checkpoint in the cell cycle is a critical control point where stop and go-ahead signals regulate the cycle.
Benign vs cancerous
Benign tumors tend to grow slowly and do not spread. Malignant tumors can grow rapidly, invade and destroy nearby normal tissues, and spread throughout the body.
If specific genes get mutated & are not repaired→ ?
cancer
