Ch 9 Mitosis and Binary fission Flashcards
cell division
Binary Fission
prokaryotes devide by binary fision, so do chloroplasts and mitochondria.
Eukaryote cell division is termed;
mitosis
what does DNA stand for?
deoxyribonucleic acid
genes are;
the basic units of inheritance. segments of DNA of a chromosome, ranging from a few hundred to many thou sands of nucleotides in length. express a certian trait or traits.
Mitotic cell division
the production of two daughter cells that are genetically identical to the parent cell
four bases of DNA
adenine (A), thymine (T), guanine (G), or cytosine (C)
Stem cells have two important characteristics:
self renewal and potency
what is meant by the term Potency when considering stem cells?
dividing stem cells produce daughter cells that can differentiate into a variety of specialized cell types
what type of cells arise when a stem cell divides?
one daugh- ter cell remains a stem cell (self-renewal, middle left). The other daughter cell may divide a few times, but eventually differentiates into a specialized cell type
sexual reproduction occurs when offspring are produced by the fusion of gametes. what are gametes?
sperm and egg cells.
prokaryotic fission
the division of prokaryotic cells.
what protein holds DNA double helix wound up in the shape of chromosomes?
histone protein, as cell division begins, proteins fold up the chromosome, yielding about another 10-fold condensation
what is a telomere?
(“end part” in Greek) are pro- tective caps at each end of a chromosome. keep chromosomes from fusing with one another.
centromere and its 2 principal functions on a chromosome?
(“central part”) (1) It temporarily holds two daughter DNA double helices together after DNA replication, and (2) it is the attachment site for microtubules that move the chromosomes during cell division.
the period (phase) between cell divisions
interphase
Interphase con- tains three subphases:
G1 (the first growth phase and the first gap in DNA synthesis), S (when DNA synthesis occurs), and G2 (the second growth phase and the second gap in DNA syn- thesis).
most heart muscle and nerve cells, remain in which phase and subphase?
interphase and G1.
Cytokinesis
is the division of the cytoplasm
at what stage are all of the cells chromosomes copied?
S phase of interphase.
identical DNA double helices?
sister chromatids attached to each other at their centromere.
the 4 phases of mitosis? (in order)
prophase, metaphase, anaphase, and telophase
during prophase;
the Chromosomes Condense, the Spindle Forms, the nuclear Envelope Breaks down, and the Chromosomes are Captured by Spindle Microtubules.
spindle
As the duplicated chromosomes condense in prophase, the spindle begins to form. The spindle is composed of micro- tubules, called spindle microtubules
metaphase
(the “middle stage”) Kinetochore microtubules (spindle microtubules) line up the chromosomes at the cell's equator (middle).
Anaphase
Sister chromatids separate and move to opposite poles of the cell; polar microtubules push the poles apart.
Telophase
One set of chromosomes reaches each pole and begins to decondense; nuclear envelopes start to form; nucleoli begin to reappear; spindle microtubules begin to disappear; microfilaments form rings around the equator.
What occurs during the Cytokinesis stage of mitosis (eukarya)
The ring of microfilaments contracts, dividing the cell in two; each daughter cell receives one nucleus and about half of the cytoplasm.
differences of plant cell cytokinesis;
- Carbohydrate-filled vesicles bud off the Golgi apparatus and move to the equator of the cell.
- The vesicles fuse to form a new cell wall (red) and plasma membrane (yellow) between the daughter cells.
forming the cell plate and eventually dividing the cell.
Cell plate
a plant cells golgi apparatus produced vesicles arranged at the equator of the cell that join together forming a structure(cell plate) of which divides the cell during mitosis.
how does a “kinase” function?
an enzyme that adds a phosphate group to another protein, stimulating or inhibiting the activity of the target protein.
Diploid cell
a cell which ends up with 2 sets of chromosomes. produced through mitosis.
Haploid cell
a cell which contains one set of each chromosome. produced during meiosis.
Most multicellular organisms have three categories of cells;
- Stem cells
- Other cells capable of dividing
- Permanently differentiated cells
prokaryotic fission stage 1.
At the start of the growth phase, the single prokaryotic chromosome is usually attached at one point to the plasma membrane of the cell
prokaryotic fission stage 2.
During the growth phase, the circular DNA chromosome replicates, producing two identical chromosomes that become attached to the plasma membrane at nearby, but separate, sites
prokaryotic fission stage 3.
During the growth phase, the circular DNA chromosome replicates, producing two identical chromosomes that become attached to the plasma membrane at nearby, but separate, sites
prokaryotic fission stage 4.
The plasma membrane grows inward between the two chromosome copies
prokaryotic fission stage 5.
Fusion of membrane along the cell equator completes separation (binary fission) of the cells, producing two daughter cells, each containing one of the chromosomes
kinetochore
a protein located on the centromere of a eukarya chromosome allowing kinetochore microtubules (spindle fibres) to attach and manouvre the chromosomes.
the cell cycle has three major checkpoints;
- G1 to S Is the cell’s DNA intact and suitable for replication?
- G2 to Mitosis; Has the DNA been completely and accurately
replicated? - Metaphase to Anaphase, Are all the chromosomes attached to the spindle and aligned properly at the equator of the cell?
The checkpoint proteins determine if a stage requirement has been met and regulate the production of cyclins or the activity of Cdks regulating progression from one phase of the cell cycle to the next.
Cdks
cyclin- dependent kinases.
