biology campbell chapter 12: the cell cycle(mitosis)

Sister Chromatids

Copies of the original chromosome that are joined together. They have the same DNA sequence and are attached together at the centromere, glued together by a protein complex called cohesin.

Homologous Chromosomes

Two chromosomes that are passed down, one from each parent. They contain genetic information for alleles of the same gene.

Telophase

Two daughter nuclei and nucleoli will form in the two new cells. Fragments of the nuclear membrane will be combined. Chromosomes become less condensed. Remaining spindle fibers are broken down. This completes mitosis.

Metaphase

Chromosomes are lined up at the metaphase plate, or equator of the cell. The centrosomes are at opposite poles of the cell. Spindle fibers are attached to the chromosomes.

Each duplicated chromosome that is a result of DNA Replication contains _ sister chromatids.

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Centromere

A repetitive sequence in the DNA where the sister chromatids are mostly closest attached. Proteins can bind to the centromere and can be condensed, making the "waist" of the chromosome look small.

Centrosome

A structure in animal cells containing centrioles from which the spindle fibers develop. There are two centrosomes, one on each side of the cell and they hold the spindle fibers in place.

Prophase

Chromatin condenses, turning into visible chromosomes. The nucleolus disappears. The mitotic spindle begins to form, which is made up of centrosomes and microtubules attached. Centrosomes move away from each other, being propelled further apart by the growing microtubules.

Mitotic spindle

Begins to form in the cytoplasm during prophase. It is made up of microtubules and proteins. The microtubules of the cytoskeleton disassemble in order to form the mitotic spindle. The spindle microtubules gain size elongate by adding tubulin proteins and shorten by losing proteins.

Mitosis

Division of genetic material and the nucleus. It is broken down into five stages: prophase, prometaphase, metaphase, anaphase, and telophase(PMAT)

Cytokinesis

Division of the cytoplasm, occurs after mitosis has already divided the nucleus.

Chromatin vs Chromosome

During the cell cycle and through processes like DNA Replication and Transcription, the DNA will be in chromatin form. However, right before M phase(Cell Division), the chromatin will condense into visible chromosomes.

Prometaphase

Nuclear envelope breaks and chromosomes further condense. Microtubules that extend from the centrosome push into the middle. A kinetochore forms at the centromere of each chromatid,, forming two per chromosome and the microtubules can attach to a kinetochore to form a kinetochore microtubule, which can pull back and forth. Polar, non-kinetochore microtubules that are not attached will interact with the microtubules on the opposite side, which lengthens the cell as they continue to search for a kinetochore to attach to.

Mitotic(M) Phase

Phase of the cell cycle that indicates the cell or currently undergoing either mitosis or cytokinesis. It accounts for about 10% of the cell cycle.

Interphase

Phase of the cell cycle that is further divided into three parts: G1, S, and G2. It accounts for about 90% of a cell's life cycle.

S(Synthesis) Phase

Phase where the DNA is replicated before splitting in division. During this phase, the sister chromatids form and attach together. It is in between G1 and G2.

Somatic Cell

The complete set of cells except for the reproductive cells. In humans, they contain 46 chromosomes, two sets of 23, with one parent giving one set.

Cytokinesis

The division of the cytoplasm. Cytokinesis usually starts in late telophase, so it ends shortly after mitosis. A cleavage furrow pinches the cell in two, in animal cells.

Kinetochore

The part where the spindle fiber can attach to the centromere

Anaphase

The shortest stage of mitosis. Anaphase begins when the cohesin proteins that attach the sister chromatids, causing them to separate. The daughter chromosomes move towards opposite ends of the cell as kinetochore microtubules shorten, bringing it away from each other. Nonkinetochore microtubules lengthen and the cell elongates because of that. By the end of anaphase, the two ends of the cell have identical and complete collections of chromosomes.