Mitosis-Ch 12 objectives_from Canvas_neb

Mnemonic Device: The cat Peed on a MAT.

Explanation: to remember PMAT for cell division Prophase, Metaphase, Anaphase, Telophase

12. Language: cylin-dependent kinase

In order to drive the cell cycle forward, a cyclin must activate or inactivate many target proteins inside of the cell. Cyclins drive the events of the cell cycle by partnering with a family of enzymes called the cyclin-dependent kinases (Cdks) https://www.khanacademy.org/science/ap-biology/cell-communication-and-cell-cycle/regulation-of-cell-cycle/a/cell-cycle-regulators

9. What occurs during cytokinesis? How does cytokinesis differ in animal cells and plant cells?

(khan)In animal cells, cytokinesis is contractile, pinching the cell in two like a coin purse with a drawstring. The "drawstring" is a band of filaments made of a protein called actin, and the pinch crease is known as the cleavage furrow. Plant cells can't be divided like this because they have a cell wall and are too stiff. Instead, a structure called the cell plate forms down the middle of the cell, splitting it into two daughter cells separated by a new wall.

2. What is the difference between chromatin and chromosomes? & Which is visible during each phase of the cell cycle?

(kt) in Phrophase, ◅ Chromatin condenses into chromosomes in telephase, ◅ Chromosomes will decondense and go back to chromatin (?)During interphase, individual chromosomes are not visible, and the chromatin appears diffuse and unorganized.

1 -tell what event(s) occurs in this phase of cell cycle: cytokinesis

(kt) ○ Cytokinesis: division of the cytoplasm ○ Cells take about 24 hours to fully go through mitosis (1 generation time) (khan)cytokinesis - the process of dividing the cell contents to make two new cells - starts in anaphase or telophase. When cytokinesis finishes, we end up with two new cells, each with a complete set of chromosomes identical to those of the mother cell.

5. So, if one diploid cell, with 46 chromosomes, undergoes one complete mitotic division, then the result is ________ cells, each with ______ chromosomes. Are these daughter cells haploid or diploid?

(kt) ○ Goal: ◂ Start: 1 diploid mother cell (2n=46) ◂ End: 2 diploid daughter cells (2n=46 for each)

6.How many chromatids does each chromosome have when it is in: metaphase?

46 Chromosomes and 92 Chromatids (?) during prophase and metaphase of mitosis, a human will have 46 chromosomes, but 92 chromatids (again, remember that there are 92 chromatids because the original 46 chromosomes were duplicated during S phase of interphase

6.How many chromatids does each chromosome have when it is in: prophase?

46 Chromosomes and 92 Chromatids (?) during prophase and metaphase of mitosis, a human will have 46 chromosomes, but 92 chromatids (again, remember that there are 92 chromatids because the original 46 chromosomes were duplicated during S phase of interphase https://datbootcamp.com/biology-strategy/chromosome-and-chromatid-numbers-during-mitosis-and-meiosis/

6.How many chromatids does each chromosome have when it is in:telophase?

92 Chromosomes and 92 Chromatids (?)These numbers remain the same during telophase.It is only after the end of mitosis - when the dividing cells have fully separated and the membranes have reformed - that the normal chromosome number is restored to the cell.

6.How many chromatids does each chromosome have when it is in:anaphase?

92 Chromosomes and 92 Chromatids (?)Now that the sister chromatids have separated, each chromatid is also considered a chromosome. During anaphase, we now have a total of 16 chromosomes and 16 chromatids - in short, each chromatid is now a chromosome. Similarly, in humans, there are 92 chromosomes present and 92 chromatids during anaphase.

1- When does "replication of DNA" occur?

? The S phase of a cell cycle

3. Diagram the following: chromosome with one chromatid

? see pic

12. Language: kinetochore microtubule

Kinetochores Microtubules are large structures made of many different proteins, assembled at the centromeres of chromosomes and part of the cytoskeleton Kinetochores essentially work as tiny machines that interact with cellular structures to move chromosomes during cell division.

3. Diagram the following: chromosome with two chromatids,centromere, kinetochores, genes

see pic

12. Language: equatorial plate of the cell

the central plane of the spindle in a dividing cell, to which chromosomes migrate during the metaphase of mitosis or meiosis.

12. Language: cell cycle

(?) Actively dividing eukaryote cells pass through a series of stages known collectively as the cell cycle: two gap phases (G1 and G2); an S (for synthesis) phase, in which the genetic material is duplicated; and an M phase, in which mitosis partitions the genetic material and the cell divides.

11. How does a prokaryotic cell divide?

(?) Prokaryotes such as bacteria propagate by binary fission. Stages include DNA replication, chromosome segregation, and finally the separation into two daughter cells.

12. Language:interphase

(?) The period between mitotic divisions - that is, G1, S and G2 - is known as interphase

12. Language: cleavage furrow

(?)A cleavage furrow is an indentation that appears in a cell's surface when the cell is preparing to divide. It marks the beginning of the cell's "pinching" its cell membrane and cytoplasm down the middle. Eventually, the cell will pinch itself completely in two, forming two daughter cells. Cleavage furrows are primarily found in animal cells and some algal cells. Plant cells, which have stiff, inflexible cell walls that cannot be easily bent or "pinched," use a cell plate instead.

12. Language: Kinetochore

(?)A kinetochore is a protein structure that forms on a chromatid during cell division and allows it to attach to a spindle fiber on a chromosome. The purpose of the kinetochore is to pull the chromatids apart. Kinetochores also help during cell division by making sure that each new cell has one chromatid from each pair.

12. Language:Centriole

(?)Centrioles are microscopic cylinders (microtubules) that are the building blocks of centrosomes. A single centriole consists of 9 microtubule triplets arranged in the shape of a cylinder with 2 centrioles making up each centrosome. Centrioles are responsible for organizing the spindle fibers in the mitotic spindle apparatus and are thought to participate in the completion of cytokinesis during the process of cell division.

10. What type of signals tell cells if they should divide, or not divide?

(?)Certain substances stimulate or inhibit cell division- .These include:Nutrients, Growth factors, Cell density Cells in G1 grow, and late in G1 phase, will either commit to dividing again, or "drop out" of the cell cycle and go to a nondividing state called G0.

12. Language:chromosome

(?)Chromosome - A large unit used by cells to organize and store their DNA. Prokaryotes generally have only one chromosome, while eukaryotic cells may organize their complex genomes into many chromosomes.

12. Language:DNA

(?)DNA - The "blueprint" or "programming code" for a cell, DNA contains all the information needed to create a cell's proteins, lipids, sugars, and to direct the stages of the cells' lifestyle.

12. Language:G1,

(?)G1 phase. Metabolic changes prepare the cell for division. At a certain point - the restriction point - the cell is committed to division and moves into the S phase.

12. Language: G2

(?)G2 phase. Metabolic changes assemble the cytoplasmic materials necessary for mitosis and cytokinesis.

12. Language:histone

(?)Histones are a family of basic proteins that associate with DNA in the nucleus and help condense it into chromatin. Nuclear DNA does not appear in free linear strands; it is highly condensed and wrapped around histones in order to fit inside of the nucleus and take part in the formation of chromosomes

12. Language: S,

(?)S phase. DNA synthesis replicates the genetic material. Each chromosome now consists of two sister chromatids.

12. Language: spindle

(?)Spindle fibers are microscopic protein structures which help divide genetic material during cell division. The spindle fibers form out of the centrosome, also known as the microtubule-organizing center, or MTOC. Spindle fibers are formed from microtubules with many accessory proteins which help guide the process of genetic division.

12. Language: nuclear Membrane

(?)The nuclear membrane, also called the nuclear envelope, is a double membrane layer that separates the contents of the nucleus from the rest of the cell. The nuclear membrane is a barrier that physically protects the cell's DNA from the chemical reactions that are occurring elsewhere in the cell. It also manages what materials can enter and exit the nucleus.

12. Language: nucleolus

(?)The nucleolus is a round body located inside the nucleus of a eukaryotic cell. It is not surrounded by a membrane but sits in the nucleus. The nucleolus makes ribosomal subunits from proteins and ribosomal RNA, also known as rRNA. Ribosomes make proteins; therefore, the nucleolus plays a vital role in making proteins in the cell. Another component of the nucleus, the nucleolus, disappears during prophase.

12. Language: MPF maturation promoting factors

(?)The signal that sends cells into mitosis was found to be composed of protein, and was named MPF (maturation promoting factor or M-phase promoting factor). MPF provides a good example of how cyclins and Cdks can work together to drive a cell cycle transition.

12. Language:chromatid

(?)When a cell is preparing to divide, it makes a new copy of all of its DNA, so that the cell now possesses two copies of each chromosome. The two copies of the cell's original chromosome are called "sister chromatids." During anaphase of cell division, the two chromatids will be pulled apart, and chromatid will be apportioned to the cytoplasm of each daughter cell. Once they are separated during anaphase, each chromatid is considered to be a chromosome of its own, just like the original chromosome that they are copied from.

12. Language:cytokinesis

(?)a separation of the cell cytoplasm in a cellular division (or cytokinesis) to produce two daughter cells. The final cellular division to form two new cells. In plants a cell plate forms along the line of the metaphase plate; in animals there is a constriction of the cytoplasm. The cell then enters interphase - the interval between mitotic divisions.

1- tell what event(s) occurs in this phase of cell cycle: G1

(kt)growth ( interphase) ○ Growth, increase in size, increase organelles ○ After G1, cells must decide if they are going to divide (pp) cellular contents excluding the chromosomes are duplicated At the G_1 a cell checks whether internal and external conditions are right for division. Here are some of the factors a cell might assess: Size. Is the cell large enough to divide? Nutrients. Does the cell have enough energy reserves or available nutrients to divide? Molecular signals. Is the cell receiving positive cues (such as growth factors) from neighbors? DNA integrity. Is any of the DNA damaged?

1- tell what event(s) occurs in this phase of cell cycle: S

(kt)growth and DNA replication (Interphase) ○ Dna is synthesized and replicated ○ Double ○ Centrioles replicate ○ Histones (proteins) are made (pp) Each of the 46 chromosomes is duplicated by the cell

1- tell what event(s) occurs in this phase of cell cycle: G2

(kt)growth and final preparations for division (Interphase) ○ Much tubulin is made (pp) The cell "double checks" the duplicated chromosomes for error, making any needed repairs.

1 -tell what event(s) occurs in this phase of cell cycle: mitosis

(kt)○ Mitosis: division of the nucleus ◂ Cannot include bacteria because they don't have a nucleus (khan)Mitosis is a type of cell division in which one cell (the mother) divides to produce two new cells (the daughters) that are genetically identical to itself. In the context of the cell cycle, mitosis is the part of the division process in which the DNA of the cell's nucleus is split into two equal sets of chromosomes. Mitosis (or M phase), starts when G2 ends. Once mitosis is complete, the cell is once again in G1.

1- tell what event(s) occurs in this phase of cell cycle: G0

(pp) Cell cycle arrest What happens to cells that "decide" not to divide?If the decision is to not divide, the cell goes into a quiescent, or nondividing state, called G0 (G zero). The decision not to divide is often the result of not receiving the appropriate growth factor that signals that the cell should divide.

1. For the following phases of the cell cycle, tell what event(s) occurs in each: (see below)

1. For the following phases of the cell cycle, tell what event(s) occurs in each: (see below)

12. Language: (see below terms)

12. Language: (see below terms)

13. List the stages of mitosis where the chromosomes look like this. (See Pic)

13. List the stages of mitosis where the chromosomes look like this. (See Pic)

12. Language: cyclin

Cyclins are among the most important core cell cycle regulators. A group of protiens - each cyclin is associated with a particular phase, transition, or set of phases in the cell cycle and helps drive the events of that phase or period

Cytokinesis

Division into two daughter cells is completed

12. Language: cell plate

Plant cells, which have stiff, inflexible cell walls that cannot be easily bent or "pinched," use a cell plate instead to prepare to divide. The cell plate grows a new cell wall from the middle of the cell outward to touch the edges, instead of pinching the cell membrane inward until it meets in the middle.

12. Language: actin microfilaments

Protein fibers in the cytoskeleton Actin filaments have a number of important roles in the cell. For one, they serve as tracks for the movement of a motor protein called myosin, actin is involved in many cellular events requiring motion. For instance, in animal cell division, a ring made of actin and myosin pinches the cell apart to generate two new daughter cells.

12. Language:centromere

The centromere is the point on a chromosome where mitotic spindle fibers attach to pull sister chromatids apart during cell division. Sister chromatids are two identical copies of the same chromosome formed by DNA replication, attached to each other by a structure called the centromere.

Anaphase

The chromatids of each chromosome have separated and are moving toward the poles

Prophase

The chromosomes appear condensed, and the nuclear envelope is not apparent

Telophase

The chromosomes are at the poles, are becoming more diffuse. The nuclear envelope is reforming. The cytoplasm may be dividing.

12. Language: spindle microtubules

The mitotic spindle is a structure composed of microtubules which segregates chromosomes into the daughter cells during mitosis. A microtubule is a rope-like component of the cytoskeleton. The centrosome is an organelle that serves as a microtubule organizing center during cell division.

Interphase

The nucleolus and the nuclear envelope are distinct and the chromosones are in the form of threadlike chromatin

Metaphase

Thick, coiled chromosomes, each with two chromatids, are lined up on the metaphase plate